Short answer: For PTFE sheet surface and flatness, ask your supplier four questions: what surface finish do you deliver as standard (as-molded, as-skived, or machined), what flatness guarantee applies to my sheet size (not a generic one), how is thickness measured and certified (points per sheet, tolerance band, temperature), and what packaging prevents transit distortion. Flatness is the property buyers assume and most often discover missing.
PTFE sheet leaves the factory flat and can arrive otherwise — the material’s creep and thermal behavior make surface condition and flatness a conversation, not an assumption.
Question 1: Surface Finish, Stated as Standard
| Finish state | Typical use |
|---|---|
| As-molded plate faces | General machining stock; smooth mold-face, cut edges |
| As-skived | Smooth, slightly directional — gaskets, lining, thin work |
| Machined/ground faces | Sealing surfaces, dimensional-critical applications (added cost) |
State which you need; a sealing application on as-molded faces is a mismatch discovered at leak-test time.
Question 2: Flatness for Your Size
Flatness guarantees are size-dependent: a 300 mm square and a 1500 mm sheet do not share a spec. Ask for the flatness value for your dimensions, how it’s measured (free on a flat table, at what temperature), and whether large plates are stress-relieved or supported in transit.
Question 3: Thickness Certification Method
- How many measurement points per sheet (a 5-point map is the professional standard)?
- Tolerance band: ±5%, ±0.1 mm, or better — and nominal vs minimum.
- Measurement temperature stated: PTFE moves with temperature; a tolerance without a temperature is an opinion.
Question 4: Transit Protection
Flat, fully supported packaging; no edge stacking; wrap retained until use. A flatness guarantee that survives the warehouse but not the freight forwarder is worth nothing — ask how sheets ship.
Chunhuan supplies skived and molded PTFE sheet with per-sheet thickness maps at stated temperature, size-specific flatness commitments, and flat supported packaging — certified per lot since 1985.
Frequently Asked Questions
What surface finish does PTFE sheet have as delivered?
Molded plate has smooth mold-face surfaces with cut edges; skived sheet is smooth with slight directionality. Machined or ground faces are available for sealing duties at added cost.
How should flatness be specified for large PTFE sheets?
Size-specific flatness values, with the measurement method and temperature stated — a generic flatness claim doesn’t transfer from a 300 mm square to a 1500 mm sheet.
What thickness measurement should PTFE sheet certificates include?
A multi-point map per sheet (5 points standard), a stated tolerance band (nominal or minimum), and the measurement temperature.
How is PTFE sheet protected from transit distortion?
Flat, fully supported packaging without edge stacking, wrap retained until use — ask how large plates are shipped before accepting a flatness guarantee.
English
Russian
French
Spanish