Polyimide Tape Roll Acceptance: 10 Checks That Hold Lot to Lot

Technical guidesPublished 07 November 2026Updated 07 November 2026

Ten checks decide whether a polyimide tape roll matches the datasheet you quoted from, and each one maps to a document, a record or a test condition a converter should produce for the lot in front of you. We convert PI films across a 1,000-plus SKU range in Shenzhen, and the disputes that end a supply conversation are rarely about adhesion. They are about which number, measured how, on which surface, in which lot.

1. Does the grade identity travel with the lot?

Ask for the grade name and the source lot number on every carton, not only on the first delivery. PI is a family, and two films sold under one family name can differ in thickness, adhesive chemistry and liner. On our side the roll label carries the incoming batch and the work order, so a question about a bad reel resolves to a record rather than to a guess.

2. Which property carries the heat claim?

Ask what the temperature figure was measured on: the film alone, the coated construction, or a part that was baked and then peeled. A film that survives an oven tells you nothing about the adhesive underneath it. Our functional tape page publishes −40 °C to +260 °C for PI grades; the number that binds your process is on the TDS for the grade you order, with its method attached.

3. Is the rating short-exposure or continuous?

Ask for both declarations on the polyimide tape TDS and check which one your process loads. A thirty-second peak and an eight-hour bake are different tests, and a construction can pass one and fail the other. Where a process has several thermal passes, add them up before comparing the total against a single-point figure, and put the pass count in the enquiry.

4. Was residue judged on your substrate and your chemistry?

Ask for the peel condition: surface, temperature, dwell, angle, speed, and whether flux or paste was present. Residue is an interface result, so a clean coupon on bare glass says little about solder resist that has been through reflow with your flux. If the area is later coated, bonded or wire-bonded, add a siloxane-transfer question.

5. Is release force quoted with its method?

Ask for the release value together with peel angle, speed, temperature and the age of the sample at test, and for the same figures on a used liner. Release drifts with liner film, coat thickness, storage temperature and time, and a part that was feedable in March is not automatically feedable in October. Values quoted without a method are not comparable across two converters; a TDS and a joint test protocol are.

6. Does the thickness figure say what it covers?

Ask whether the quoted thickness is total build, carrier only, or adhesive plus carrier. Our published band for functional tapes is 0.03–0.3 mm depending on carrier and adhesive, a wide enough range that one number decides whether a part fits a stack height. Confirm the measurement point on the TDS and the tolerance you both accept, stated against your drawing before tooling is cut.

7. What is the edge and slit record?

Ask what the converter inspects on a slit edge and what happens to a roll with a nick. In a thin film an edge defect propagates under unwind tension and reads on the line as a broken web, not as a cosmetic issue. Our slit process checks width, edge quality and roll build at first article and records the batch on the label, as the slitting page describes.

8. Are core, wrap direction and length specified?

Ask the supplier to confirm the winding direction, the core size, the face-out or face-in condition and the metres per roll on the packing list, and to keep them fixed across the contract. A correct grade with a reversed wrap goes to the scrap bin at the station, and this is the least expensive defect to prevent on paper.

9. What is the storage and aging declaration?

Ask for the storage condition and shelf declaration for the grade, the manufacture date on the lot, and how the converter rotates stock. We keep batch and work-order records including slitting date and inspection results, and a buyer running a first-in-first-out policy should be able to see those dates on the label.

10. Who notifies you when something changes?

Ask for a written change-notification term covering source film, adhesive coat, liner and cutting route, and for any substitution to be approved before it runs rather than explained after it ships. Where the material is branded, ask for the authorization scope for your market, product family and channel, confirmed per enquiry. Ask too what stays fixed between a prototype lot and a series lot, because a route change and a material change produce the same symptom on the line. See how we describe our records on the quality page.

The document set to ask for, per grade

Technical data sheet for the ordered grade, with test methods. Safety data sheet. RoHS and REACH statements scoped to that construction. For cut parts, a first-article dimensional and visual report against your drawing. Plus the batch record that links a reel to its incoming material, its slitting date and its inspection. Documents issued against the ordered grade are worth more than generic sheets, and the folder is what an auditor asks to see.

To have a grade assessed against your profile and your flux, send the reel you use now and the thermocouple trace; we will say which of these checks we answer from records and which needs a trial on your board.

Commercial and process terms on this page are the questions a converter has to answer, not a standing offer. Order quantities, lead times, tooling charges, sample terms, freight and payment structures are confirmed at quotation against your drawing, your material and your destination, and only figures already published elsewhere on this site are stated as commitments.