PEEK questions and answers
230 questions, collected from every page on this site. Technical answers link back to the guide they came from, where the reasoning and the numbers sit.
Buying and matching
Is this service free for buyers?
Yes. You pay nothing to send an RFQ or to receive quotes. Shops pay us for matched requests. Price, lead time and terms are agreed between you and the shop.
Who sees my drawing?
Shops first see a short preview: part type, PEEK grade, size, quantity, tolerance and deadline. It does not include your name, company or files. Your contact details and files go only to the shops we match, up to 3. If you ask for an NDA, we hold the files until it is signed.
Do you machine PEEK parts yourselves?
No. We are a matching service, not a machine shop. The shops that quote you run the machines, buy the stock and ship the parts. You place the order with them.
Which PEEK grade should I put on the drawing?
Unfilled PEEK for toughness, steam and repeated autoclave cycles. Glass filled for stiffness and creep resistance under load at temperature. Carbon filled for the best dimensional stability and heat transfer. Bearing grade for dry sliding. If you are not sure, send the operating temperature, load and media and let the shops suggest a grade.
Does PEEK stock need annealing before machining?
Extruded and moulded PEEK holds internal stress, and heavy material removal releases it. Shops normally use stress relieved stock, then anneal again between roughing and finishing on thin walls, deep pockets and tight bores. Say on the RFQ if your part is thin or has a bore you cannot lose, so the quote includes the oven time instead of discovering it later.
Can I get material traceability and biocompatibility documents?
Ask for it in the RFQ. Shops can pass through the resin maker lot certificate, and for medical work stock is available with documented testing to ISO 10993 or USP Class VI, or to ASTM F2026 for implant grade material. The documents come from the material maker, not from us.
What tolerances are realistic on PEEK?
General features land around ±0.05 mm. Small annealed features on carbon filled stock can hold ±0.025 mm or a little better. PEEK expands roughly four times more than steel per degree, so a part inspected at 20 °C and used at 150 °C moves. State the temperature that the tolerance has to hold at.
Where are the shops located?
That depends on the part and on the region you pick on the RFQ form. You can ask for shops in North America, Europe, Japan, Korea or the rest of Asia, or leave it open and let us match on fit alone.
For machine shops
Is one RFQ sold to many shops?
No. Each RFQ goes to 3 shops at most, and only to shops that cut the grade and part size in the request.
How much does a lead cost?
The price is on every preview, before you decide. It depends on the grade, part complexity and order size. You only pay for the leads you choose.
What if a lead is not what the preview described?
Tell us and we review it. If the buyer contact does not work or the part differs clearly from the preview, we credit the lead.
We run plastics only, no metal. Is that a problem?
No. Plastics only shops are the reason this site exists. Tell us which grades you cut, whether you keep separate tooling for filled grades and whether you have an annealing oven, and we match on that.
Do you send medical work to any shop?
No. Requests that need ISO 13485, documented cleaning or cleanroom packing go only to shops that list those. If you do not have them, you still get the industrial and semiconductor requests.
For vendors
Can I pay to be listed or ranked?
No. Placement is not sold and there is no paid ranking. A vendor is named in a guide only where the technical context calls for it.
What do you want from a vendor?
Specifics: what you hold in stock and where, real lead times from that stock, whether you support the shop floor and in which language, and what you cannot supply. That is what makes a mention useful to the shop reading it rather than an advert.
Will you send me the shop list?
No. We do not sell or share contact lists. Where an introduction genuinely helps a shop we ask the shop first.
How often are guides updated?
When something changes that affects the advice, for example a lead time, a grade being discontinued or a document a customer now demands.
Grades
From the grades guides.
Is natural PEEK visible on X-ray?
Barely. Natural PEEK is radiolucent, so it shows as a faint shadow close to soft tissue. That is useful for seeing bone growth around an implant but makes the device itself hard to locate, which is why radiopaque grades and metal markers exist.
X-Ray Opaque PEEK: What Barium Sulfate Changes in a Medical Part
How much barium sulfate is in radiopaque PEEK?
It varies by supplier and grade, from a few percent to roughly a fifth by weight. More filler means more visibility and a larger drop in toughness, so the level is chosen to give enough contrast without giving up the properties the part needs.
X-Ray Opaque PEEK: What Barium Sulfate Changes in a Medical Part
Is radiopaque PEEK implant grade?
Only if the supplier sells that specific grade with implant documentation. Implant grade claims attach to a named grade and its testing, not to PEEK in general, so check the certificate for the exact filled grade.
X-Ray Opaque PEEK: What Barium Sulfate Changes in a Medical Part
At what temperature should I move from PEEK to polyimide?
When continuous service goes above roughly 250 °C, or when the part must keep stiffness and wear performance close to or above 260 °C. Below that, PEEK is usually the better value. Between 250 and 260 °C, check creep and wear data under your load before deciding.
Is Vespel just a stronger PEEK?
No. Vespel is a polyimide, a different polymer family. It keeps its properties at far higher temperatures but is more brittle, absorbs more moisture, resists steam and strong bases less well and costs several times more.
Can polyimide parts be machined like PEEK?
Yes, but with more care. Polyimide is hard, brittle at edges and abrasive on tools, and stock shapes are limited and expensive. Many polyimide parts are direct formed to near shape, then finished by machining, so the machining stock is only part of the story.
Does Ultem handle higher temperature than PEEK?
On paper Ultem has the higher glass transition, near 217 °C against about 143 °C for PEEK. But PEEK is semicrystalline and keeps most of its stiffness to well above its glass transition, while amorphous Ultem softens rapidly near its own. For load bearing parts at high temperature PEEK usually has the edge.
PEEK or Ultem: Choosing a Material for a Hot Electrical Insulator
Which has the better electrical insulation, PEEK or Ultem?
They are close. Both have volume resistivity above 10 to the 16 ohm centimetres and dielectric constants near 3.2. Dielectric strength is similar in the typical range, so the choice is usually decided by temperature, chemical exposure, toughness and cost rather than electrical numbers.
PEEK or Ultem: Choosing a Material for a Hot Electrical Insulator
Is Ultem cheaper than PEEK for machined parts?
Generally yes. Ultem stock costs noticeably less and it machines with less internal stress, so cycle times and scrap are often lower. The saving matters most on larger insulators.
PEEK or Ultem: Choosing a Material for a Hot Electrical Insulator
Is PPS cheaper than PEEK?
Yes, usually by a clear margin. Machining stock of PPS typically costs a fraction of PEEK, and it machines well, so a PPS part is often noticeably cheaper. The price gap is the main reason to consider PPS when the service conditions allow.
PEEK or PPS: Which Plastic Fits a Pump, Valve or Electrical Part
Which is tougher, PEEK or PPS?
PEEK. Unfilled PEEK stretches before it breaks and absorbs impact, while PPS, especially glass filled, is stiff but brittle. A part with snap features, thin walls or shock loads usually favours PEEK.
PEEK or PPS: Which Plastic Fits a Pump, Valve or Electrical Part
Can PPS replace PEEK in hot water or steam?
Sometimes at lower temperatures, but check carefully. PEEK keeps its properties in hot water and steam far better, and long exposure to steam is where PPS most often falls short. Test or ask for supplier data on your exact conditions.
PEEK or PPS: Which Plastic Fits a Pump, Valve or Electrical Part
Is PEKK better than PEEK?
Not in general. PEKK has a higher glass transition and can be stiffer and harder, but PEEK has far wider stock availability, a long qualification history and more suppliers. The better material is the one with the property you need in the form you can buy.
PEEK, PEKK, PEK: Choosing Between PAEK Polymers for Machining
Can PEKK be machined like PEEK?
Yes, PEKK machines in a similar way and the same rules apply: sharp tools, heat control and stress relief. Check the stock supplier's crystallinity and annealing guidance, because amorphous and semicrystalline PEKK behave differently under heat.
PEEK, PEKK, PEK: Choosing Between PAEK Polymers for Machining
Do I need to name the PAEK type on a drawing?
Yes. PAEK is a family, and PEEK, PEKK and PEK have different melting points, glass transitions and certifications. Name the polymer, the grade or trade name and the supplier or specification, so a shop does not substitute.
PEEK, PEKK, PEK: Choosing Between PAEK Polymers for Machining
What surface resistance should an ESD PEEK part have?
Static dissipative parts usually sit between 10 to the 6 and 10 to the 9 ohms per square, which discharges a charge in a controlled way. The range your tool needs is set by the equipment maker or the fab, so ask for the number before choosing a grade.
Does machining change the resistance of ESD PEEK?
It can. The surface skin of stock sometimes reads differently from the bulk, and a cut surface may read higher or lower than a moulded or extruded skin. Measure the finished part, not the stock, and say where on the part the measurement applies.
Is carbon fibre filled PEEK the same as ESD PEEK?
Not necessarily. Standard carbon filled PEEK is often conductive in places and its resistance varies widely. ESD grades use a controlled filler, such as carbon powder or nanotubes, to hold resistance inside a narrow dissipative window and to shed fewer particles.
Is black PEEK weaker than natural PEEK?
Not in a way that matters for most parts. The mechanical properties of black and natural PEEK from the same resin family are very close, because the pigment loading is small. Differences are mainly in electrical behaviour, appearance and what each colour hides or shows.
Can black PEEK be used for implants?
Implant grade claims belong to a specific named grade and its documentation, and the implant grades supplied to ASTM F2026 are natural or specific approved colours. A black pigmented PEEK is not implant grade unless the supplier says so for that exact grade.
Why do some buyers insist on natural PEEK?
Natural PEEK lets you see contamination, voids and burn marks, and it avoids any question about what the pigment or carrier added. Medical, food and semiconductor buyers often specify natural for those reasons.
Is implant grade PEEK mechanically different from unfilled PEEK?
No. It behaves like unfilled PEEK on the machine and in service. What is different is the documentation: lot traceability, controlled resin handling and testing to a standard such as ASTM F2026, which unfilled industrial grade does not carry.
Does USP Class VI mean a part is approved for implant use?
No. USP Class VI is a biological reactivity classification for the plastic, not a device approval. A finished implant needs its own regulatory clearance, which depends on the device, not on the material class alone.
Can a machine shop certify a part as implant grade?
A shop can supply a certificate of conformance stating the stock lot and grade used, and can maintain traceability through the job. It cannot certify biocompatibility itself, because that testing belongs to the resin, not to the machining.
What is bearing grade PEEK made of?
PEEK blended with carbon fibre, PTFE and graphite, in roughly 10% each in the common formulation. Carbon carries load, PTFE lowers friction and graphite helps the transfer film form.
Can PEEK bushings run without lubrication?
Bearing grades are designed for it, with a dry coefficient of friction around 0.1 to 0.2. Unfilled PEEK at 0.3 to 0.4 and glass filled PEEK are both poor choices for dry sliding.
Is PEEK better than bronze for bushings?
In hot, dry, chemically aggressive or electrically isolated service, usually yes, and it will not score a shaft the way a hard bronze can. Under high static load at room temperature bronze still wins.
Is PEEK CF30 stronger than GF30?
GF30 is usually higher in tensile strength, around 150 to 170 MPa against 130 to 140 MPa. CF30 is stiffer, with a modulus near 13 GPa against roughly 10 GPa, and far more dimensionally stable.
Is carbon filled PEEK electrically conductive?
Enough to dissipate static charge, which is why it is used in wafer and display handling. If your part has to insulate, carbon filled PEEK is the wrong choice and GF30 or unfilled is right.
Which filled PEEK grade machines better?
Carbon filled, slightly. It conducts heat away from the cut and holds tighter tolerances. Both wear cutting edges quickly, and glass is the more abrasive of the two.
What dissolves PEEK?
Concentrated sulfuric acid attacks and eventually dissolves it. Strong oxidising acids such as concentrated nitric acid also attack it. Almost nothing else in normal industrial use does at room temperature.
Can PEEK be used in steam and autoclaves?
Yes, and it is one of the few plastics that takes hundreds of steam cycles without losing strength. PEI and polysulfone hydrolyse in steam, which is why autoclave hardware ends up in PEEK.
Does PEEK resist hydrocarbons and sour gas?
It resists hydrocarbons, drilling fluids and hydrogen sulfide well, which is why it appears in downhole seals and insulators. Rapid pressure changes and dissolved gas, not chemical attack, are the usual limits.
What is the difference between PEEK GF30 and CF30?
GF30 is 30% glass fibre and adds stiffness and creep resistance at a lower material cost. CF30 is 30% carbon fibre and adds more stiffness, about half the thermal expansion and three to four times the thermal conductivity, plus enough conductivity to dissipate static.
Which PEEK grade is best for autoclave parts?
Unfilled PEEK. It is the toughest of the family and handles repeated steam cycles well. Filled grades are stiffer but more brittle, and the fibre ends at a machined surface give steam a path in.
Is implant grade PEEK a different material?
Mechanically it behaves like unfilled PEEK. What you pay for is documented biocompatibility testing, lot traceability and controlled handling under a standard such as ASTM F2026.
What temperature can PEEK withstand?
Continuous service around 250 °C, with short excursions to about 260 °C. The glass transition at 143 °C is the more useful number, because stiffness and creep resistance fall off above it.
How strong is PEEK compared with aluminium?
Unfilled PEEK reaches 90 to 100 MPa tensile against roughly 300 MPa for 6061-T6, but at 1.30 g/cm³ against 2.70. Specific strength is closer than the raw numbers suggest, and stiffness is not.
Does PEEK absorb water?
Very little. Around 0.1% in 24 hours and about 0.5% at saturation, so parts hold their size in humid air and in water, unlike nylon.
Machining
From the machining guides.
How many assembly cycles can a thread cut directly in PEEK take?
A fine, correctly cut thread in PEEK survives a few assemblies with a plastic or soft mating part, but a steel screw tightened and removed many times wears it. For a joint opened more than about 5 to 10 times, specify a metal insert.
Which Thread Method Works for a PEEK Part: Tap, Mill or Insert
Is thread milling better than tapping for PEEK?
For anything above a small tap size, yes. A thread mill cuts a thread with light radial force and small chips, and one tool covers a range of sizes. Tapping is faster and fine for small blind holes if the tap is sharp, two flute and well lubricated.
Which Thread Method Works for a PEEK Part: Tap, Mill or Insert
Should a PEEK thread be fine or coarse pitch?
Coarse pitch carries more load in plastic because the thread flank is taller and spreads the force over more material. Fine pitch suits thin walls and sealing threads where length is limited. Match pitch to the load and wall thickness, not to the metal standard by habit.
Which Thread Method Works for a PEEK Part: Tap, Mill or Insert
What is the smallest PEEK part a Swiss lathe can turn?
Diameters under 3 mm are routine on a Swiss machine in unfilled PEEK, and some shops go below 1 mm. The limit is usually not the machine. It is how straight the bar is, how well the burr is controlled and whether the part survives handling and cleaning afterwards.
Specifying Swiss-Type Turned PEEK Parts Without Burrs or Runout
Why does PEEK bar stock need to be ground for a Swiss lathe?
The guide bushing supports the bar a fraction of a millimetre from the cut. Extruded rod is not precisely round or straight, so it either binds in the bushing or rattles in it. Ground or centreless ground rod, sized to the bushing, gives the support the process depends on.
Specifying Swiss-Type Turned PEEK Parts Without Burrs or Runout
Can Swiss turning hold concentricity between features on a PEEK part?
Yes, when the features are cut in one setup or handed to the sub-spindle without re-clamping. Concentricity is lost when a part is removed and re-chucked, so ask which features are made in the same hold and which need a second operation.
Specifying Swiss-Type Turned PEEK Parts Without Burrs or Runout
How long should a PEEK part rest before final inspection?
At least until it reaches the inspection room temperature, often a few hours for a thick part. Parts coming straight off a machine or out of an annealing oven are warm and larger than they will be. Shops that hold tight tolerances measure after a defined rest, in a room held near 20 °C.
Does moisture change PEEK dimensions?
Slightly. Unfilled PEEK absorbs only about 0.5 percent water at saturation, which grows a part by a few hundredths of a percent. For ordinary tolerances this is small, but on very tight fits or large parts it adds to the thermal effect.
Can a caliper measure a thin PEEK wall accurately?
Only with care. Jaw force compresses soft plastic and gives a smaller reading than the true wall. Use a gauge with a ratchet or a light contact force, a larger anvil or a non-contact optical method for thin walls.
What depth to diameter ratio is realistic for a drilled hole in PEEK?
Up to about 5 times the diameter is routine with pecking and coolant. Between 5 and 10 times needs a plastics drill, tight chip control and often a pilot. Beyond 10 times, shops usually gun drill or split the hole from both ends, and the tolerance has to open up.
Why does a drilled hole in PEEK end up smaller than the drill?
Heat and stress. The wall around the hole warms, expands and is cut at the expanded size, then the material cools and the hole closes slightly. Releasing stress by annealing after roughing can also move the bore. Shops drill undersize, then ream or bore after the part has settled.
Do filled PEEK grades drill differently from unfilled?
Yes. Glass and carbon fibre fill wear drill edges quickly and push the shop towards diamond coated tools. Filled grades also chip at the exit of a hole more than unfilled, so the exit edge needs support or a backing plate.
Can PEEK be deburred with thermal deburring?
Generally no. Thermal deburring burns burrs off metal with a gas explosion. PEEK absorbs that heat and distorts, so shops use hand tools, brushes, fine abrasive media or cryogenic methods for plastics instead.
What cleaning process do machined PEEK parts need?
At least removal of coolant, chips and handling residue. Typically that is a warm detergent wash, a rinse in deionised water and drying. Medical and semiconductor parts add ultrasonic cleaning, cleanroom assembly and bagging, and a documented process.
How do I specify an edge condition for a PEEK part?
Give a chamfer or radius size on every edge that matters, for example 0.2 mm by 45 degrees, and say which edges may be left as machined. A note that only says break all sharp edges leaves the finish to the operator's judgement.
Can PEEK be glued with ordinary super glue?
It can stick for light handling, but the joint is weak and does not survive heat, moisture or chemicals. PEEK has a low surface energy and resists solvents, so a lasting bond needs surface preparation and an adhesive chosen for the service conditions, usually a two part epoxy.
Is PEEK weldable?
Yes. PEEK is a thermoplastic and can be joined by ultrasonic, laser, hot plate or friction welding. Its high melting point near 343 °C means more energy than most plastics need, and the joint design and grade, especially filler and colour, decide whether the weld is strong.
Do bonded PEEK joints survive steam sterilisation?
Some do, but not all. The adhesive has to be rated for the sterilisation method and the number of cycles, and the joint should be tested on real parts. The PEEK itself tolerates steam far better than most adhesives.
Why does a PEEK part crack days after machining, not during it?
Residual stress released by machining does not always show up as a visible failure immediately. In a thin or highly loaded feature, that stress can propagate a crack over hours or days as the part sits, especially if it also picks up moisture or a temperature swing.
Is warping a sign of a bad shop or a bad drawing?
Usually neither on its own. It is more often a spec gap: the drawing did not call out stress relief and the part geometry, thin walls held to a tight tolerance, needed it. The fix is a process instruction, not a different shop.
Can a warped PEEK part be corrected after the fact?
Sometimes, with a re-anneal and a light finish pass, if the part has stock left to remove. A part already at final dimension when it warps usually has to be remade, which is the reason to catch the risk on the drawing rather than after inspection.
What is the single biggest specification mistake on a PEEK drawing?
Copying a metal tolerance onto every feature. PEEK moves more than metal with temperature and with residual stress, so a blanket ±0.02 mm callout usually prices the whole part at the cost of its tightest feature for no functional reason.
Can one drawing specify grade, tolerance and stress relief all at once?
Yes, and it should. Grade decides how much the part will move, tolerance decides which features actually need that control, and a stress relief note tells the shop when to anneal. Leaving any one of the three off shifts the decision, and the cost, onto whoever quotes it.
Who decides whether a part needs annealing, the buyer or the shop?
The buyer decides by specifying wall thickness, tolerance and service temperature. The shop decides how to meet that. A drawing that specifies the outcome without dictating the process gives a competent shop room to do it well.
Do all machined PEEK parts need annealing?
No. Chunky parts with open tolerances are usually fine from stress relieved stock. Thin walls, deep pockets, long slender parts and tight bores are the ones that move, and those get an anneal between roughing and finishing.
What does a PEEK annealing cycle look like?
A slow ramp up, a soak above the glass transition of 143 °C but well below the 343 °C melting point, then a slow controlled cool. The exact schedule depends on wall thickness and comes from the stock supplier.
Can annealing fix a part that already warped?
Sometimes it stabilises a part enough to finish machine it back into tolerance, which is why the cycle belongs between roughing and finishing. A finished part that has moved out of tolerance is usually scrap.
Is PEEK hard to machine?
PEEK cuts easily compared with metal, but it is unforgiving about heat and internal stress. Sharp polished tooling, good chip evacuation and a stress relief step on thin parts matter more than horsepower.
What tolerance can a shop hold on PEEK?
General features land around ±0.05 mm. Small annealed features on carbon filled stock can reach ±0.025 mm or a little better. Anything tighter needs a temperature controlled shop and an agreed inspection temperature.
Does machined PEEK need annealing?
Stock is normally supplied stress relieved. Parts with thin walls, deep pockets or tight bores usually get a second anneal between roughing and finishing, because heavy material removal releases the stress that is left.
What is the tightest tolerance for machined PEEK?
Small features in annealed carbon filled stock reach ±0.025 mm, and a little better on a short feature in a temperature controlled shop. Unfilled PEEK on a long feature is realistically ±0.05 mm.
Why does my PEEK part measure differently than the drawing?
Two reasons. Internal stress released by machining moves the part over the next hours, and PEEK expands about four times more than steel per degree, so the measuring temperature matters.
What surface finish can shops hold on PEEK?
Ra 0.8 µm comes off a normal finishing pass. Ra 0.4 µm is achievable with a sharp polished tool and light passes. Filled grades show fibre at the surface, so a mirror finish is not realistic.
What cutting speed works for PEEK?
Turning unfilled PEEK usually starts between 200 and 500 m/min with polished carbide and a positive rake. Filled grades run at the lower end because tool wear, not the material, sets the limit.
Do you need coolant to machine PEEK?
Something to carry heat away, yes. Air blast works for light cuts and open features. Water soluble coolant is normal for deep pockets, drilling and long finishing passes, because PEEK cannot shed heat itself.
Can PEEK be tapped and threaded?
Yes. Cut threads rather than form them, use a two flute tap with a polished flute, and keep chip room clear. For a joint that gets assembled repeatedly, a threaded metal insert lasts far longer.
Cost
From the cost guides.
At what volume does injection molding PEEK become cheaper than machining?
It depends on the part, but for a small, simple part the break-even is often in the low thousands of pieces, because a mold costs tens of thousands of dollars while a machined part costs a fixed amount each. Large or complex parts push the break-even higher, since mold cost rises with size.
Can a molded PEEK part hold the same tolerance as a machined one?
Not on every feature. Molded PEEK typically holds around ±0.1 to ±0.2 percent of a dimension, while machining can hold ±0.01 to ±0.05 mm on small features. Many molded parts are finished by machining the critical surfaces.
Does a molded PEEK part have the same properties as a machined one?
Not exactly. Molded parts have a skin and flow orientation, especially in fibre filled grades, and their crystallinity depends on mold temperature. Machined parts come from extruded or compression molded stock, which has its own stress history. Test the part you intend to use.
Why is PEEK so expensive?
The resin itself is expensive to make and sells for many times the price of acetal or nylon per kilo. On a machined part the stock is often the largest single line in the quote, so the block size matters more than the cycle time.
How can I reduce the cost of a PEEK part?
Start from stock closer to the finished size, open the tolerances that do not need to be tight, remove features that force a second setup, and order in batches rather than one at a time.
Is moulding cheaper than machining PEEK?
Only at volume. Tooling for an injection moulded PEEK part is a serious investment, so machining usually wins up to a few hundred pieces a year. Past that, ask for both numbers.
Is it cheaper to machine PEEK from rod or plate?
Rod, for anything round, because you throw away far less expensive material. Plate makes sense for flat parts, large footprints and parts machined from both faces.
What is the difference between extruded and compression moulded PEEK?
Extruded stock is cheaper and available in smaller sizes. Compression moulded stock carries less internal stress and is how large plates and thick sections are made, so it holds tolerance better on big parts.
Can I supply my own PEEK stock to a machine shop?
Yes, and many buyers do when they hold approved material. Say so in the RFQ with the form, size and certificate, because it changes the quote structure completely.
Sourcing
From the sourcing guides.
Why use PEEK instead of metal for pump wear rings?
A PEEK ring can rub the rotor without galling or seizing, so the pump can run a tighter clearance than metal on metal allows. That reduces internal leakage and lifts efficiency, and it tolerates dry running at start up and upset conditions far better than a metal ring.
Clearance, Grade and Fit for PEEK Pump Wear Rings and Bushings
Which PEEK grade suits wear rings and bushings?
Carbon fibre filled PEEK (CF30) and bearing grade blends with carbon, graphite and PTFE are the usual choices. They combine stiffness, low friction and wear resistance. Unfilled PEEK is too soft and wears faster, and glass filled PEEK can abrade the mating metal surface.
Clearance, Grade and Fit for PEEK Pump Wear Rings and Bushings
How does temperature change the running clearance of a PEEK wear ring?
PEEK grows faster with heat than the steel around and inside it. A ring pressed into a casing tightens its grip as it warms but its bore also changes size, so the running gap at temperature can differ from the cold gap. Size the fit at the pumped fluid temperature.
Clearance, Grade and Fit for PEEK Pump Wear Rings and Bushings
Can prototype spinal cages be machined from the same PEEK as production implants?
Yes, and for mechanical testing they often should be. Machining from implant grade stock, with the same lot documentation the production route will use, makes test results comparable. The prototype is a test article, not an implant, and it carries no approval.
What file format does a shop need for a spinal cage?
A 3D model in STEP format for the geometry plus a 2D drawing for tolerances, surface finish and notes. The model alone does not say which features are critical, and the drawing alone does not carry the organic surfaces of a cage.
Why do prototype cages use machining instead of moulding?
Machining needs no tool, so a design can change between batches at the cost of a program edit. Moulding needs a mould that costs far more and takes weeks. Prototype and early test volumes are almost always machined, then moulded or machined for production depending on volume.
Why make gripper fingers from PEEK instead of aluminium?
Weight, insulation and part protection. A PEEK finger weighs about half as much as an aluminium one of the same shape, so the robot moves faster with less load. It also insulates, resists chemicals and is softer than the part it grips. Aluminium is stiffer, so a thin finger may need CF30.
Which PEEK grade is best for gripper fingers?
CF30 is the usual choice when stiffness matters because it roughly triples the modulus of unfilled PEEK. Natural PEEK suits short fingers, insulating needs and clean applications. ESD grades protect static sensitive parts, and bearing grades suit contact pads that slide.
How accurate does a gripper finger need to be?
Mounting faces and the finger alignment usually carry the tight tolerances, around ±0.02 to ±0.05 mm. Flatness of the gripping surface and parallelism between the two fingers matter more than the outside dimensions, and PEEK needs measuring at a stated temperature.
Can a PEEK gear replace a steel gear?
Only at lower loads. PEEK gears run quietly, resist chemicals and can run with little or no lubrication, but their tooth root stress limit is a fraction of steel. They suit light to moderate torque, high temperature or chemical environments, and cases where noise or lubrication is a problem.
What is a PV limit for a PEEK thrust washer?
PV is contact pressure times sliding speed. It sets how much frictional heat a washer can shed before it softens or wears quickly. Bearing grade PEEK has a much higher limit than unfilled PEEK, and the supplier datasheet gives figures for each grade.
How accurate can a machined PEEK gear be?
A machined plastic gear can reach roughly DIN 7 to 9 quality on a good setup, which is adequate for most light duty drives. Accuracy depends on stock stress, tool sharpness and whether the gear is hobbed, milled or wire cut, and thermal growth changes the mesh at temperature.
Why do battery equipment makers use PEEK instead of cheaper plastics?
Cell lines combine solvents, dry rooms, heat during formation and strict cleanliness. PEEK resists the solvents, holds shape at formation temperatures, is a strong insulator and can be machined clean. Cheaper plastics soften, absorb moisture or shed material in those conditions.
Should battery line parts be natural or carbon filled PEEK?
It depends on whether the part must insulate or dissipate. Fixtures near live cell tabs usually need natural PEEK as an insulator. Handling parts that touch electrodes and separators in a dry room often need an ESD grade, because static builds easily at low humidity.
Does PEEK resist battery electrolyte?
PEEK resists the common carbonate solvents used in lithium ion electrolyte. Electrolyte salts can form acidic by-products when moisture is present, so check the exact exposure and the supplier's chemical data for the grade before committing.
Why use PEEK for a connector insulator instead of nylon or PBT?
PEEK keeps its shape and insulation at far higher temperatures, resists oils, fuels and hot water and does not absorb enough moisture to change its size or electrical behaviour. It costs more, so it is used where the environment would degrade cheaper plastics.
Machining PEEK Connector Bodies and Insulators That Survive the Field
Should a connector body be unfilled or glass filled PEEK?
Glass filled PEEK is stiffer and expands less, which helps pin retention and fit to a metal shell. Unfilled PEEK is tougher and suits parts with thin snap features. Many connector bodies use GF30, with fillet radii and thick enough walls to avoid cracking.
Machining PEEK Connector Bodies and Insulators That Survive the Field
How tight must pin holes be in a PEEK insulator?
Tight enough to hold the contact without cracking the web between holes, usually in the range of ±0.03 to ±0.05 mm for a pin hole, depending on contact design. The contact maker's drawing sets the figure, and the bore finish and edge break matter as much as the size.
Machining PEEK Connector Bodies and Insulators That Survive the Field
Does AS9100 mean a shop's PEEK parts are guaranteed correct?
No. AS9100 certifies that the shop runs a documented, audited quality management system. It does not test or certify any specific part, and it says nothing about that shop's specific experience machining PEEK or any other plastic.
If a shop is not AS9100 certified, can they still make good aerospace PEEK parts?
Often yes, particularly for non-flight hardware such as ground support equipment, fixtures and tooling. What matters more day to day is material traceability, first article inspection and a documented process, which a non-certified shop can still provide in writing.
What should I ask for instead of just requiring the certificate?
Ask for material traceability to the resin producer, a first article inspection report against your drawing, and process controls specific to the feature that matters, such as stress relief or bore roundness. The certificate is a starting filter, not the answer to any of those questions on its own.
Does NORSOK M-710 apply directly to PEEK parts?
It was written for elastomeric sealing materials, so its methods are widely borrowed for thermoplastics but it does not cover PEEK by default. Ask specifically which standard a stated qualification was tested against before assuming NORSOK M-710 applies.
Is API 6A material qualification the same as ISO 23936-1?
No, they cover different scopes. API 6A sets requirements for wellhead and christmas tree equipment generally, while ISO 23936-1 is specific to non-metallic materials including thermoplastics like PEEK. A part can reference either, both, or neither depending on what it is and where it sits.
If a supplier says a grade is NORSOK qualified, what should I ask for?
Ask for the qualification test report itself, the specific test conditions used, the material grade and lot it covers and confirmation the report is for that resin producer's grade rather than a generic reference to PEEK as a family.
Why would a PEEK bracket fail after it already passed inspection?
Most of these failures are not visible at inspection. Residual stress relaxes over hours or days, a fastener loosens after repeated thermal cycles, or a fatigue crack needs a number of vibration cycles to show up. The part measured correctly and still failed later.
Why PEEK Brackets Crack, Warp or Loosen After They Pass Inspection
Is a cracked PEEK bracket always a material defect?
Rarely. It is more often a geometry or process gap, a sharp internal corner, a skipped anneal, or a boss without a metal insert under real clamp load. The fix is usually a drawing change or a process step, not a different batch of resin.
Why PEEK Brackets Crack, Warp or Loosen After They Pass Inspection
Does annealing prevent all of these failure modes?
No. Annealing addresses residual stress and the warping it causes. It does not fix a sharp stress-concentrating corner, an under-designed boss, or a thin section in a high-vibration zone. Each failure mode needs its own fix.
Why PEEK Brackets Crack, Warp or Loosen After They Pass Inspection
Can PEEK replace a metal part carrying primary structural load?
No. PEEK belongs in secondary structure, systems and interiors. Primary load paths, the members that carry flight and ground loads through the airframe, stay metal or composite because that is what the structural substantiation is built around.
Which PEEK grade is used most often on aircraft parts?
Carbon filled (CF30) for brackets and mounts that need stiffness and low thermal expansion, unfilled where electrical insulation matters. Glass filled shows up where stiffness is wanted without the conductivity that carbon fibre brings.
Does a machined PEEK part need its own certification to fly?
The resin does not carry an aviation certificate on its own. What matters is that the part traces to a qualified material and process under the aircraft program's own approval, which is a documentation question more than a material one.
Does every PEEK aerospace part need FST testing?
No. Flame, smoke and toxicity testing is a cabin-interior requirement tied to occupant safety in an enclosed space. A bracket or bushing outside the cabin, in an unpressurized bay or on ground support equipment, does not carry that requirement unless a specific program spec calls for it.
What is the single most useful line to add to a PEEK aerospace drawing?
The temperature at which a critical tolerance applies. PEEK expands roughly four times more than steel per degree, so a tight fit specified without a temperature is not fully specified, whatever else the drawing says.
Do I need to specify AS9100 on every PEEK aerospace RFQ?
Only where your program's quality flow-down requires it, typically flight hardware under a manufacturer's own quality system. For non-flight parts, traceability and inspection requirements written out explicitly often matter more than the certificate itself.
Can PEEK handle both caustic cleaning and steam sterilization?
Yes, and that combination is where it separates from most engineering plastics. It resists hot caustic and acid cleaning chemicals and holds up through repeated steam cycles, where plastics that survive one of the two often fail the other.
What PEEK grade should a CIP valve seat use?
Unfilled PEEK for toughness and steam resistance is the usual default. A bearing grade blend is worth considering where the seat also slides against another surface and low friction matters more than peak strength.
Does PEEK need special handling after many CIP or SIP cycles?
Not special handling, but repeated thermal cycling can reveal residual machining stress over time. Parts machined from properly annealed stock hold their dimensions better across hundreds of cycles than parts cut without that step.
Is PEEK used for dental implants?
PEEK is used clinically in some dental implant abutments and frameworks, but that is an implant grade, clinically regulated application outside the scope of this article. This article covers non-implant instrument and equipment components such as handles, trays and fixture parts.
Why does PEEK hold up well in dental equipment?
It survives the same steam autoclave cycles dental instruments go through repeatedly, and it resists the disinfectants and cleaning chemicals used between patients without the surface degradation some plastics show over time.
What grade of PEEK is typical for dental instrument handles and trays?
Unfilled PEEK is the usual default for the same reason it is used in surgical handles: toughness under repeated handling and sterilization matters more than stiffness for these parts.
Is PEEK immune to explosive decompression?
No. It is more resistant than most elastomers because it absorbs less gas, but it is not immune. Thick sections, sharp internal corners and fast decompression rates can still blister or crack a PEEK part, particularly in CO2 rich or sour service.
What standard covers explosive decompression testing?
NORSOK M-710 is the reference most people mean when they say RGD testing, but it was written for elastomeric sealing materials. ISO 23936-1 covers thermoplastics for oilfield media, but its 2022 edition excludes blistering by rapid gas decompression, so that test needs its own basis.
Does a thicker PEEK part resist decompression better?
Not automatically, and often the opposite. A thick section holds more dissolved gas and gives it a longer path to escape, which can make a thick, solid part worse off than a thinner one of the same grade at the same pressure and rate.
Is all PEEK automatically food contact compliant?
No. Compliance is tied to a specific resin grade tested and listed under the relevant regulation, not to PEEK as a material class. A grade that has never been through that testing is not compliant even though it is chemically similar to one that has.
Does adding glass or carbon fiber change food contact status?
Yes. A filled or compounded grade is a different formulation from the base resin and needs its own compliance listing or supporting data. Do not assume a filler carries over the base resin's status.
What document proves a PEEK grade is food contact compliant?
A declaration or statement of compliance from the resin producer or compounder, naming the specific grade and the regulation it meets. A generic "food grade" label on a stock tag is not that document.
What is the single most common thing missing from a food or pharma PEEK drawing?
A clearly stated grade with its compliance status. "PEEK" alone tells a shop nothing about whether the specific formulation is food contact compliant or carries USP Class VI data, and that gap is usually caught late rather than at quoting.
Does the surface finish need to be called out separately from tolerance?
Yes. Tolerance controls dimensions, finish controls the surface texture that residue and organisms can collect in. A drawing can hold a tight tolerance and still specify a finish too rough for the cleaning validation the part needs to pass.
What paperwork should ship with the parts, not just the quote?
A certificate of conformance naming the resin grade and lot, plus whatever food contact declaration or USP Class VI data the part requires. Ask for these to travel with the shipment, not to be emailed separately after the fact.
Is PEEK better than stainless steel for HPLC fittings?
Not universally. PEEK is the better choice when the fluid path has to stay chemically inert and free of metal ions, such as trace metal or ion chromatography work. Stainless still wins on raw pressure ceiling, which is why UHPLC systems running above roughly 15,000 psi mostly stay on steel.
What pressure can a machined PEEK HPLC fitting handle?
Typical machined PEEK fittings and tubing are rated in the 6,000 to 10,000 psi range at room temperature, depending on wall thickness and bore. That drops as temperature rises, so a fitting rated for a cold lab bench is not automatically rated for a heated column compartment.
Does PEEK tubing swell or degrade in HPLC solvents?
Most mobile phases used in reversed phase and ion chromatography do not affect it. Concentrated chlorinated solvents and high percentages of THF are the exceptions worth checking against a resistance table before you commit a method to PEEK tubing.
Why does chemical inertness matter more in lab equipment than industrial parts?
An industrial fitting that reacts slightly with its contents is a maintenance problem. An analytical instrument component that reacts slightly with the sample changes the measurement itself, and often in a way that looks like a method problem rather than a hardware problem.
Why Chemical Inertness Is Not Optional on Analytical Hardware
What chemicals actually attack PEEK in a lab setting?
Concentrated sulfuric acid and strong oxidizing acids such as concentrated nitric acid are the real exceptions. Almost everything else common in analytical chemistry, including most acids, bases and solvents at working concentration, does not touch it.
Why Chemical Inertness Is Not Optional on Analytical Hardware
Can a part be chemically inert and still cause bad results?
Yes, if it adsorbs analyte at low concentration even without reacting. Adsorption is a surface effect tied to the specific compound and surface finish, and it is a separate question from chemical attack, worth checking for trace-level methods.
Why Chemical Inertness Is Not Optional on Analytical Hardware
What thread standard should I specify on a lab fitting drawing?
Name the exact standard your instrument port uses, such as a flat-bottom or flangeless fitting standard common to a specific instrument family, rather than assuming a shop will infer it from a general thread callout. Lab fitting threads are not interchangeable across standards even when they look similar in a drawing.
Do I need to specify surface finish inside a fluid path?
Yes, whenever adsorption or cleanability matters. A rougher bore holds more residue and adsorbs more analyte at trace concentration than a finer finish does, and a shop needs the finish called out to know which finishing pass and tooling to use.
Does every PEEK lab part need a cleaning or passivation requirement?
No. A part with no trace-level or cross-contamination concern often needs nothing beyond normal machining. State it explicitly when the application does require it, since a shop cannot guess a cleanliness standard from silence on a drawing.
How can I tell if PEEK is virgin or regrind without lab equipment?
You mostly cannot, by eye. Colour and feel do not reliably separate a properly reprocessed regrind from virgin resin. Ask for the certificate of conformance and lot number instead of trying to judge stock visually.
Does a certificate of conformance guarantee genuine material?
It shows what the seller is claiming, not proof on its own. It becomes useful evidence when the lot number traces back to a named resin maker, which is what you check before you rely on the document.
Is DSC testing worth the cost for a small order?
For a one-off low-risk part, usually not. For implant grade stock, a filled grade you have not bought before, or any lot without a traceable certificate, a single DSC run costs a few hundred dollars and settles the question before the part is cut.
Is PEEK an FDA approved material?
FDA does not approve or clear a raw material on its own. It clears or approves a finished device under a specific submission, and a PEEK resin grade is one input the device maker documents as part of that submission, not something that carries its own FDA approval.
What FDA Clearance Does and Does Not Cover for a Machined PEEK Component
What documentation should I ask a PEEK stock supplier for on a non-implant medical device component?
Ask for USP Class VI or ISO 10993 biocompatibility data for the specific resin grade, not just the word 'medical grade,' plus a certificate of conformance with lot traceability. If the supplier or grade ever changes, ask how that change gets communicated.
What FDA Clearance Does and Does Not Cover for a Machined PEEK Component
Does a certificate of conformance mean the part is cleared for use in my device?
No. It documents that the part matches the specified material lot and grade. Device clearance is a separate regulatory step that belongs to the device manufacturer's own submission, and it depends on the whole device, not on one component's material certificate.
What FDA Clearance Does and Does Not Cover for a Machined PEEK Component
Why use machined PEEK instead of glass for a microfluidic chip housing?
Glass is chemically inert and optically clear but brittle, slow to machine and expensive to modify once cut. Machined PEEK holds pressure, resists the same chemistry in most cases, tolerates thermal cycling without cracking, and is far cheaper to iterate on during development.
How small a channel or port can a shop hold in PEEK?
Small ports and shallow channels in the range of a few hundred microns are realistic for a shop with the right small-diameter tooling, but the achievable size depends heavily on aspect ratio and wall thickness around the feature. Confirm the specific geometry with the shop before committing a design to it.
Does PEEK's chemical resistance matter for microfluidics specifically?
More than it does at larger scale, because a microfluidic channel has far more surface area relative to its volume. A material that reacts slightly with the fluid affects a small channel's chemistry faster and more visibly than it would a larger vessel.
Does a pharma process part need to be implant grade PEEK?
Usually not. Implant grade stock is documented for long-term body contact, which is a different requirement from a part that only contacts product briefly during manufacturing. Most pharma process parts specify unfilled PEEK with USP Class VI data rather than full implant grade documentation.
Why use PEEK instead of stainless steel for these parts?
PEEK does not corrode, does not introduce metal ions into the product stream and can be machined to close tolerance without the weight or cost of the equivalent stainless part. Stainless still wins where the part needs to resist impact or where cost rules out an engineering plastic.
What documentation should a pharma equipment buyer request?
A certificate of conformance naming the resin grade and lot, plus USP Class VI or extractables data if the part contacts product, especially if it was not originally designed with that in mind.
Should a PEEK backup ring be unfilled or CF30?
Start with the clearance gap the ring has to bridge. A tight, well controlled gap under moderate pressure favours unfilled PEEK for its toughness. A wider gap, higher pressure or a hot dynamic seal favours CF30 for its stiffness and lower creep.
Why does a backup ring fail before the seal it protects?
Because it is doing the harder job. The elastomer only has to seal. The backup ring has to resist extrusion into the clearance gap at full pressure while staying dimensionally stable, and a ring that creeps or cracks lets the seal behind it extrude next.
Does a backup ring need the same tolerance as the seal gland it sits in?
Close to it. The ring's outside and inside diameters set how well it centres in the gland and closes the gap, so they carry the tight tolerance. Ring thickness usually has more room, unless the gland groove itself is shallow.
What does cleanroom packed actually mean for a small machined part?
In practice it means the part was wiped down or cleaned after final machining, handled with gloves rather than bare hands and double bagged, with the inner bag opened only inside a clean environment. The exact steps should be agreed with the shop rather than assumed from the phrase alone.
Do SEMI standards certify a specific plastic part as cleanroom grade?
No. SEMI standards mostly define facility, equipment and process classifications, and a shop should describe what it actually did (cleaning method, bagging, particle count of the room) rather than claim a SEMI certification the part itself does not carry.
What particle count class should I ask a shop to pack to?
That depends on where the part goes in the tool, and it is a question for your process engineer, not a default a shop can pick. Ask for the room class the packing was done in and the visible cleanliness steps taken, and match that against what the tool actually requires.
What is TML and what counts as a low number for PEEK?
TML is total mass loss under vacuum bake, measured as a percentage of starting weight. A widely used screening threshold from aerospace vacuum work is under 1.0 percent TML and under 0.10 percent CVCM, and unfilled PEEK typically screens well under those numbers. That does not mean every PEEK part does.
Does a generic PEEK outgassing figure apply to the part I am buying?
Not automatically. The published figure usually comes from a molded plaque of one grade, tested once, by the resin maker. Your machined part may be a different grade, a different surface area to volume ratio and a different lot, all of which can move the number.
Do carbon filled and glass filled PEEK outgas more than unfilled resin?
Often somewhat more, and not always in the same way. Fiber ends exposed by machining and moisture held at the fiber to matrix interface both add outgassing paths that a plaque test of the base resin does not capture. Ask for data on the filled grade itself, not the unfilled figure.
Is autoclave the best sterilization method for PEEK parts?
For repeated use PEEK components it usually is. Unfilled PEEK resists the steam and heat of autoclave far better than PEI or polysulfone, which is why reusable PEEK hardware is built around that cycle rather than around EtO or gamma.
Autoclave, EtO, Gamma and VHP: What Each One Does to a PEEK Part
Does gamma sterilization degrade PEEK?
Less than it degrades many other polymers, but dose limits are still grade specific and should be checked against the resin supplier's data rather than assumed safe by default, especially for filled or bearing grades.
Autoclave, EtO, Gamma and VHP: What Each One Does to a PEEK Part
What happens if EtO residuals are not aerated properly on a PEEK part?
Ethylene oxide can remain absorbed in the material and off gas later, which is a documentation and validation issue rather than a PEEK weakness specifically. Aeration time has to be validated per part geometry and wall thickness, not assumed from a generic cycle.
Autoclave, EtO, Gamma and VHP: What Each One Does to a PEEK Part
Why use PEEK instead of stainless steel for a reusable instrument handle?
PEEK is roughly one fifth the density of stainless steel, it is radiolucent so it does not appear on an X ray or under fluoroscopy, and unfilled PEEK survives hundreds of autoclave cycles without the finish or fit degrading the way some polymers do.
What PEEK grade is used for surgical instrument handles?
Unfilled PEEK is the default because toughness matters more than stiffness on a handle that gets dropped, gripped hard and run through the autoclave repeatedly. A filled grade is considered only where a specific rigidity or wear requirement calls for it.
Can a PEEK handle be sterilized the same way as its metal equivalent?
Usually yes for steam autoclave, which is PEEK's strongest sterilization method. Confirm the exact cycle and count against the resin supplier's data before assuming a metal instrument's validated cycle carries over unchanged.
Why is PEEK used in test sockets instead of a cheaper plastic?
Test hardware cycles through heat every time a device under test runs, over and over, for years. Cheaper plastics creep or soften under that repeated thermal load, while PEEK holds its dimensions and electrical insulation through the cycling.
How tight are tolerances on test socket components?
Pin field alignment and pocket dimensions commonly run to a few hundredths of a millimeter, tighter than most general PEEK machining work, because a misaligned pocket or pin hole causes a false test failure rather than a real one.
Does test socket PEEK need to be filled or unfilled?
Unfilled or glass filled PEEK is typical where electrical insulation matters most. Carbon filled grades are avoided in most test socket bodies specifically because carbon fiber can affect the electrical isolation the part exists to provide.
Should a PEEK valve seat be bearing grade or CF30?
Bearing grade when the seat runs dry or poorly lubricated against a moving ball or plug, since it needs low friction more than raw stiffness. CF30 when lubrication is adequate and the priority is dimensional stability and creep resistance under seating load.
How long do PEEK valve seats typically last?
There is no single figure, since life depends heavily on the mating surface, lubrication, particulate content in the fluid and seating load. A seat qualified against clean, lubricated service can fail far sooner in an abrasive or dry running application.
When should a valve seat be metal or ceramic instead of PEEK?
When the fluid carries enough sand or solids to erode a polymer seat quickly, when temperature or pressure exceeds PEEK's practical range, or when the seating load alone would creep any polymer out of tolerance over the valve's service life.
Can PEEK replace ceramic insulators downhole?
Within PEEK's service window, often yes, and it machines far more easily and cheaply than ceramic. Above roughly 250 °C continuous, or where a hermetic ceramic to metal seal is required, ceramic stays the right choice.
Does PEEK have enough dielectric strength for downhole connectors?
Unfilled PEEK typically runs 19 to 23 kV/mm, which is adequate for most downhole connector and insulator duty within its temperature and pressure window. Filled grades reduce or remove that insulating property, so grade choice matters as much as the material family.
Why does galvanic corrosion favour PEEK over a metal insulator?
A metal insulator or spacer in contact with dissimilar metals in a conductive brine environment can set up a galvanic cell that corrodes one of the metals. PEEK does not conduct and does not participate in that cell, which removes the failure mode rather than managing it.
Is PTFE or PEEK better for a food-grade seal?
For a low-load static seal or gasket, PTFE's chemical range and non-stick surface are usually the better fit at a lower cost. For a seal that also has to hold a precise geometry under sustained pressure, PEEK holds its shape better over time.
PEEK or PTFE: Picking the Right Plastic for a Food or Pharma Part
Why does PTFE lose tolerance over time and PEEK does not?
PTFE cold-flows, meaning it slowly deforms under sustained load even at room temperature, which is a mechanical property of the polymer rather than a sign of failure. PEEK is far stiffer and does not cold-flow under normal service loads.
PEEK or PTFE: Picking the Right Plastic for a Food or Pharma Part
Can PEEK replace PTFE anywhere in food processing equipment?
Not everywhere. Where the part needs the lowest possible friction with no load to carry, such as a non-stick liner, PTFE still wins on cost and performance. PEEK is the better choice once the part is structural or has to hold a seal geometry under pressure.
PEEK or PTFE: Picking the Right Plastic for a Food or Pharma Part
Why do PTFE ferrules need retightening over time?
PTFE cold-flows under sustained compression, meaning it slowly deforms rather than holding its exact shape. A ferrule that sealed perfectly on installation loosens as the material creeps, especially with vibration or repeated disconnect and reconnect cycles.
Are PEEK ferrules worth the extra cost over PTFE?
For a connection made once and left alone at low pressure, usually not. For a fitting disconnected and reconnected often, run under vibration, or run near the top of its pressure rating, PEEK's resistance to creep pays for itself in fewer leaks and less retightening.
Can PEEK and PTFE ferrules be mixed on the same system?
Yes, and it is common practice. Low-duty connections that rarely get disturbed often keep PTFE for cost, while ports that see frequent column changes or higher pressure get PEEK.
Is PVDF cheaper than PEEK?
Yes, usually by a wide margin, both in raw material cost and machining time. For a fluid path part where PVDF's chemical resistance already covers the application, that cost difference is a legitimate reason to specify it over PEEK.
Can PEEK replace PVDF in every fluid handling application?
Chemically, PEEK covers most of what PVDF resists and adds strength and temperature range PVDF does not have. It is rarely the cheaper choice, though, so PVDF stays the default wherever its chemical resistance and temperature range are already sufficient.
Does PVDF handle strong acids as well as PEEK?
PVDF has excellent resistance to many strong acids and halogens, in some cases better than PEEK. Neither material tolerates concentrated sulfuric or strongly oxidizing acids well, and that combination calls for PTFE, PFA or a metal or lined alternative instead.
Is PEEK stronger than stainless steel?
No. Stainless steel is far stiffer and holds a much sharper, longer lasting edge, which is why cutting instruments stay metal. PEEK's advantages are weight, radiolucency and insulation, not raw strength or stiffness.
Choosing Between PEEK and Stainless Steel for a Medical Instrument Part
Can PEEK replace stainless steel in every part of a surgical instrument?
No. A mixed assembly is normal: stainless steel where cutting, rigidity or extreme load is required, PEEK where weight, imaging compatibility or electrical insulation matters more than stiffness.
Choosing Between PEEK and Stainless Steel for a Medical Instrument Part
Does PEEK corrode the way stainless steel can?
PEEK does not corrode in the chemical sense stainless steel does, and it will not pit or develop the surface staining that repeated sterilization and chemical exposure can cause on some stainless grades over time.
Choosing Between PEEK and Stainless Steel for a Medical Instrument Part
Is Torlon always stronger than PEEK?
At a given temperature, most Torlon (PAI) grades beat unfilled and filled PEEK on tensile strength and stiffness, especially as temperature climbs. The gap narrows against PEEK's own filled grades, but it does not close.
Why does Torlon cost more than PEEK for the same part?
Two reasons stack together: the resin itself costs more, and most Torlon parts need a post-machining thermal cure that can run for days depending on section thickness. That cure adds oven time and lead time on top of the material price.
Can a shop just swap Torlon in for PEEK on an existing drawing?
Not without checking the design intent. Torlon needs its post-cure schedule built into the process, is more moisture sensitive, and costs enough more that swapping it in without a reason usually means someone specified it out of habit rather than need.
What PEEK grade is normal for a wafer carrier or comb?
CF30 is the default for most wafer handling hardware, chosen for static dissipation near the wafer and for dimensional stability under repeated temperature cycling. Unfilled PEEK is used where electrical insulation matters more than charge dissipation.
Why does deburring matter more on a wafer carrier than on a typical machined part?
Any metallic residue left by a steel tool or a dirty fixture can transfer to a wafer on contact. Shops that work in this niche use dedicated non-metallic deburring tools and clean fixtures, and it is worth asking for that in writing.
Does a wafer carrier need to be annealed?
Usually yes, for anything with thin fingers or slots. Residual stress from machining relaxes over time and moves narrow features out of tolerance, and annealing before final sizing catches most of that movement before it reaches the customer.
Is ISO 9001 enough for PEEK work?
For industrial, semiconductor adjacent and general precision work, usually yes. It is a floor rather than a differentiator, because it says nothing about plastics or about the specific handling PEEK needs.
Does ISO 13485 pay for itself in a small shop?
It depends entirely on whether you want medical device components or are content with instruments, trials and fixtures. The certificate opens a category of work that is otherwise closed, and it carries real ongoing cost in documentation and audits.
Can we do semiconductor work without any certification?
Often yes. Fabs care more about virgin resin, traceability, contamination control, cleaning and packing than about a certificate. Demonstrated process discipline wins that work more reliably than a logo does.
How much scrap allowance should a PEEK quote carry?
It depends on wall thickness and tolerance rather than on a flat percentage. The honest approach is to price the stock you actually need including a setup piece, and to say so on the quote, rather than absorbing it and hoping the first article passes.
Should tool wear be a line item?
On filled grades it should at least be in your own costing, whether or not the buyer sees it broken out. Glass and carbon fibre change consumable cost enough that pricing a CF30 job at unfilled rates turns a good order into a loss.
Do buyers accept a separate material line?
Serious ones prefer it. Splitting material and machining shows where the price comes from and makes it obvious when a different stock form would save them money, which is the kind of answer that wins the next job.
Why do buyers ask which grades we decline?
Because a shop that declines something is telling you its acceptance means something. A shop that says yes to every grade, tolerance and deadline reads as a shop that has not thought about the work, and experienced buyers treat it that way.
Do we need ISO 13485 to get medical PEEK work?
For finished device components under a manufacturer quality system, usually yes. For instruments, trials, fixtures and tooling, often not. Say clearly what you hold and what you do not, because the requests get filtered on it either way.
Is it worth answering a buyer questionnaire in detail?
Yes, and quickly. The shops that win niche work are rarely the cheapest, they are the ones whose answers arrive the same day and read like the work is familiar.
What temperature and pressure can PEEK take downhole?
Continuous service around 250 °C is the material limit, and PEEK parts run at high pressure routinely. The limit in practice is the combination of temperature, load and pressure cycling on that geometry, which is why parts get qualified rather than assumed.
Is PEEK resistant to sour gas?
It resists hydrogen sulfide, hydrocarbons and drilling fluids well, which is why it is used where elastomers fail. ISO 23936-1 covers how thermoplastics are assessed for oilfield media.
Why does PEEK fail after a pressure drop?
Gas dissolves into the polymer under pressure. If pressure drops quickly, that gas expands inside the part and can blister or split it. This is rapid gas decompression, and it is a design and qualification issue, not chemical attack.
Is PEEK biocompatible?
Stock can be supplied with documented testing to ISO 10993 or USP Class VI, and implant grade material is sold to ASTM F2026. Biocompatibility belongs to the material and the finished device, never to the machining.
Machined PEEK in Medical Devices, from Handle to Implant Stock
Can PEEK be autoclaved?
Yes, and that is its main advantage over PEI and polysulfone. Unfilled PEEK takes hundreds of steam cycles at 134 °C without meaningful loss of strength.
Machined PEEK in Medical Devices, from Handle to Implant Stock
Why is PEEK used instead of metal in medical devices?
It is radiolucent so it does not obscure imaging, its stiffness is closer to bone than titanium is, it insulates thermally and electrically and it saves weight in a handheld instrument.
Machined PEEK in Medical Devices, from Handle to Implant Stock
Why is carbon filled PEEK used for wafer handling?
Three reasons in one material: it is static dissipative so charge does not build up near the wafer, it expands about a third as much as unfilled PEEK so parts stay located, and it conducts heat out of the part.
Does PEEK outgas in vacuum?
Less than most plastics, and it is used in vacuum tools, but it is not metal. For high vacuum and hot zones, ask for outgassing data for the specific grade and lot rather than assuming the generic figure.
What should a semiconductor PEEK drawing ask for?
Grade, virgin resin, lot traceability, no metallic contamination in handling, deburring and cleaning method, then double bagged or cleanroom packing. All of it at RFQ time, not after the parts are cut.
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