Seal and back-up rings
Outside and inside diameters, section thickness and any split detail define the ring. Include the mating groove drawing when it controls the fit.
PTFE CNC
Machining
Custom PTFE rings, bushings and insulating parts
Valve seats
Mark the seat profile, contact band and edge detail. Include the mating component and the conditions used for functional testing.
Flanged bushings
Send the bore, wall and flange dimensions together. State whether the bore is checked loose or after the bushing is fitted into its housing.
Insulating spacers
Define the mounting geometry and the required electrical properties. Name the grade and any permitted filler, rather than identifying the material by color.
Insulator and mounting blocks
Mounting holes, stepped faces and clearances can be reviewed on one drawing. Identify any electrical contact, support or no-marking areas.
Interface plates and guide strips
Specify thickness, flatness and the support used during measurement. Show how the finished part is fastened or supported in the assembly.
Virgin and filled PTFE grades
PTFE is often considered for sliding, chemical-contact and electrical-insulation applications. It combines low friction and broad chemical resistance with relatively low stiffness. Fillers change the material, so the grade matters as much as the polymer name.[1]
Send the manufacturer and grade already on your drawing. When the choice is still open, describe the mating part, working conditions and properties that need checking. Any proposed alternative should be agreed before stock is purchased.
- Material name
- Polytetrafluoroethylene (PTFE)
- Stock to review
- Rod, tube or plate suited to the part
- Grade definition
- Manufacturer, product code and filler details
- Delivery records
- Material identity and lot documentation as agreed
Virgin / unfilled PTFE
Use the full material designation on the order, including any restriction on reprocessed content. For an insulating spacer or wetted part, record the required electrical or chemical data separately.
Filled PTFE
Glass, carbon, bronze and other fillers are available in PTFE compounds. Ask for the exact filler type, proportion and grade data before comparing candidates; one filled grade cannot stand in for every other.[1]
A grade already on your drawing
A trade name or internal material code needs a matching specification. Attach the approved datasheet or material requirement so the quote can identify the same stock, rather than silently substitute a similar name.
PTFE turning and milling
CNC-turned PTFE parts
Rings, sleeves, seats and spacers start with the diameters, lengths and profiles on your drawing. Identify the sealing edge or fitting bore before choosing where the part can be held and where a second operation may be needed.
Explore CNC turningCNC-milled PTFE parts
Blocks and plates bring together mounting holes, pockets, flat faces and locating features. Show the supported faces and access to the deeper details. A broad, thin plate needs a different holding review from a compact block.
Explore CNC millingThe holding method is part of the dimensional review. PTFE’s low strength and thermal expansion make close dimensions more demanding than a machine tolerance label suggests.[2] Discuss how the part is supported during cutting, released and checked before accepting a tight feature.
PTFE dimensions and measurement conditions
Check the part without assembly loads
A loose bushing and a bushing pressed into a housing are different checks. For the loose part, state the measurement temperature, support, any conditioning period and the required dimensions. Agree a measuring method that does not squeeze the feature into a different shape.
Check the fit in the mating component
Provide the housing bore, shaft dimensions, mating materials and assembly method. Identify which clearance or contact surface must be checked after installation. Keep that assembly test separate from the loose-part size limits.
Define the functional test separately
For a loaded seal or sliding part, include temperature, pressure or load, contact medium, motion and duration. PTFE can deform over time under sustained stress; this time-dependent behavior is called creep.[3] A dimensional report alone does not establish performance in that environment.
PTFE tolerances and inspection requirements
| Feature | Drawing information | Inspection agreement |
|---|---|---|
| Bores and outside diameters | Dimension limits, controlled length and the mating geometry. | Measurement temperature, support and whether the requirement applies before or after installation. |
| Thin rings and sleeves | Wall or section thickness, split details and any shape-control requirement. | How the part is supported without forcing it to match the inspection fixture. |
| Seat and sealing faces | Contact profile, edge detail, specified finish and surface defects to reject. | Which checks are dimensional and which need a separate leak, pressure or assembly test. |
| Holes and mounting faces | Hole sizes, pattern, datums and the surfaces that locate the component. | Fixture contact points and any permitted marking on nonfunctional faces. |
| Material identity | Grade, filler designation, stock condition and document requirements. | The material record and how it is associated with the delivered lot. |
Send the feature-specific limits and any general tolerances stated on the drawing. Where a requirement is unclear, resolve it during review rather than applying a new tolerance without agreement.
Protect sealing edges and control the final surface
Deburring without changing the profile
Identify lips, seat edges and contact bands that must retain their shape. Put any chamfer or edge-break requirement on the drawing so it is not treated as a general cleanup instruction.
Cleaning and packaging
Specify acceptable residues, handling restrictions and how contact faces should be protected. For easily marked components, agree separators, bagging or individual protection before the batch is packed.
Bonding or treated surfaces
PTFE is difficult to bond because of its low surface energy.[1] If bonding is part of the assembly, identify the exact treatment, treated area and acceptance test. Do not leave the bonding process to a generic “surface finish” note.
PTFE seals, insulators and sliding parts
Seals and valve interfaces
Provide the fluid or gas, concentration, temperature, pressure, motion and mating surface. The quote should separate machining to the drawing from any required functional testing.
Electrical isolation
Specify the property and test that matter in the assembled device. Confirm the chosen grade’s data, especially when fillers or other modifications are involved.
Bushings and sliding contacts
Include the shaft or guide material, load, motion, lubrication and service conditions. When another polymer is being considered, compare it against the same requirements.
Compare engineering plasticsFrom the first PTFE sample to repeat batches
Send the drawing
Include the revision, grade, quantity and the surfaces or fits that need particular attention.
Agree the sample checks
Separate material records, dimensions and assembly tests. Confirm who performs each check.
Release the batch
Record the accepted revision, stock designation, inspection plan and delivery quantity.
Protect the finished parts
Match lot identification and packaging to the order, keeping exposed contact surfaces protected.
What affects the PTFE machining quote?
Request prices for sample and repeat quantities separately. Keep the stock grade and size, material removal, delicate features, secondary setups, inspection and packaging scope consistent when comparing quotations.
Prepare a clear RFQKnow who is making the part
Discuss the specified PTFE grade and machining requirements with Kevin. Confirm the production source, inspection and communication responsibilities before ordering.
How VETCNC works with customersPTFE CNC machining questions
Can PTFE be CNC machined?
Yes. PTFE stock can be turned or milled into custom mechanical parts.[2] Send the drawing and grade to review stock availability, workholding, dimensions and the inspection method for your geometry.
What is the difference between virgin and filled PTFE?
Virgin PTFE is unfilled. Filled compounds include added materials such as glass, carbon or bronze, which change the properties.[1] Use the full grade and filler designation. Choose against the actual mechanical, electrical and chemical requirements, not just the label “filled.”
What tolerances can you hold on a PTFE part?
A useful answer needs the drawing, grade, feature size and inspection state. Highlight the critical fits and any applicable general tolerances. We can then discuss which requirements need a sample check or a revised inspection agreement instead of quoting one tolerance for every PTFE component.
Should my PTFE bushing be measured before or after assembly?
Both may be relevant. State the loose-part dimensions separately from the installed fit. Include the mating housing and shaft requirements when the acceptance check is performed after installation.
Can you make PTFE seal rings or valve seats from my drawing?
These are suitable part types to submit for a machining review. Include the exact contact geometry, material and edge requirements. Pressure, leak and service-life tests are separate items to agree; they are not established by the machined dimensions alone.
Is PTFE the same as Teflon?
PTFE is the polymer name. Teflon™ is a Chemours brand used for a range of fluoropolymers, including PTFE.[4] If your specification names a branded resin, provide the product designation so that a substitution is not assumed.
What finish should I specify on a PTFE sealing face?
State the required surface texture, contact area, edge condition and any prohibited marks. A note such as “smooth” is open to interpretation. Identify separately any cleaning, bonding treatment or functional test required after machining.
Can I request material certificates and inspection reports?
Yes—list the exact documents required with your inquiry. The quote needs to confirm what is available for the chosen grade and lot, how parts are identified, and which dimensional or other results will be recorded.
Can I order samples before a production batch?
Include both sample and production quantities in the request, along with what the sample must demonstrate. Record approval against the specific drawing revision, grade and checks before releasing the batch.
What do you need to quote PTFE CNC machining?
Send a dimensioned drawing and a matching 3D model when available, the material specification, sample or batch quantities, inspection conditions and desired delivery date. Flag any unresolved grade or fit question. Price and timing can then be reviewed against the complete scope.
Your PTFE part and inspection brief
Send the dimensions that matter to your assembly
A ring might need a close diameter, a particular seat profile, or an installed clearance. Tell us which one controls the job and include the mating-part information when you have it.
Use this optional brief to collect those details, or open the quote form directly to attach your drawing.
Selected example
Discuss your PTFE part
Share your drawing, material and quantity. Tell us what you need and we will reply by email.
Related materials and design guides
Material and technical references
- Ensinger — PTFE material: properties, stock forms and fillers
- Ensinger — PTFE machining: dimensional and process considerations
- Mitsubishi Chemical Group — Thermal expansion and creep terminology; comparison includes PTFE
- Chemours — Teflon™ fluoropolymer resins and brand information
Manufacturer references for PTFE grades and properties. Application suitability and supply scope require confirmation for each project.
PLAN YOUR NEXT PART
Resources for material selection
Prepare the material and processing requirements for your part.
CNC Materials & Surface Finishes: A Practical Selection Guide
Compare CNC metals, engineering plastics and surface finishes through worked selection cases, dimensional calculations and a reusable decision worksheet.