Polyimide Tape FAQ: Reflow Heat, Gold Fingers and Residue

FAQ libraryPublished 07 November 2026Updated 07 November 2026

Twelve questions on polyimide tape for masking and insulation sites, each answered with the condition behind the claim: a temperature figure without dwell time and substrate is not an engineering statement.

What temperature can polyimide tape actually withstand?

The governing figure is the exposure temperature and time declared on the TDS for the ordered grade, because peak, dwell and continuous service are three separate declarations and a construction can pass one and fail another. Our functional tape page publishes −40 °C to +260 °C as a family envelope, not a rating for your part.

Is a 130 degree bake the same demand as a 200 degree bake?

No: 130 degrees for an hour is a soak that loads the adhesive continuously, while 200 degrees for thirty seconds is a brief peak, and a grade chosen for one can fail the other. Name the duration next to the temperature when you request a grade.

Does PI film leave residue after reflow?

Sometimes, and the cause is usually the interface rather than the film: a softened coat can flow to the mask edge during dwell and anchor on cooling, or the coat splits and part of it stays behind. Run your own flux and paste on a board, peel at a steady angle, then judge the grade.

Can PI film be die-cut into small masking parts?

Yes, PI film constructions are slit, flat-bed or rotary die-cut and laser-cut depending on outline, thickness and pickup method, with the liner format set against a feeder or a hand station. Tolerance is stated against your drawing before tooling is cut, so a prototype run checks geometry and peel behaviour together, as the die-cutting page sets out.

Is laser cutting suitable for PI film parts?

Laser cutting is often the right prototype route because it needs no hard tooling and handles complex outlines quickly, but the cut edge comes away darker and that is worth planning for. On a permanent insulator rather than removable masking, edge condition and withstand behaviour become qualification items.

What is different about gold-finger masking tape?

A gold-finger mask sits on a clean, low-profile conductor array, survives the process and lifts without dragging solder resist or leaving anything behind, so release level, coat edge and slit quality outweigh the peak rating. The same film on a different liner or coat behaves very differently on that surface.

Can the same PI film serve as permanent insulation, not only masking?

Yes, and the specification reverses: a masking tape is judged on how cleanly it releases, a permanent insulator on how well it keeps adhering, on withstand voltage and on its cut edge. Tell us the job before we quote: the answers are not interchangeable.

Can you supply the branded PI grade we already use?

We supply and convert tesa, 3M and Sekisui materials, with the authorization scope confirmed per enquiry, brand, market and product family, and the converted part is quoted from your drawing like any other construction. Coat weight, liner and release differ between grades of the same colour and thickness, so the report on your substrate decides, not the cross-reference, per our cross-reference page.

Why does PI film tear when a narrow roll unwinds?

Thin film turns an edge defect into a web break, so the usual causes are a slit nick, a crushed roll shoulder or a rough core edge, each propagating the moment unwind tension is applied. Ask for the edge inspection record, state core, wrap direction and face, and check station tension before blaming the film.

How narrow can you slit PI rolls?

Widths below 10 mm are feasible on most materials, but the real limit is film thickness, adhesive coat and the edge quality your process needs, confirmed at specification review before tooling. Send the current roll and the failure you see before anyone promises a width.

How do I compare a new PI lot with the last one?

Compare four figures with their methods attached: the heat declaration for the ordered grade, the release force with peel angle and speed, the thickness with its measurement point, and the slit edge record. A grade name alone is not a specification; a liner or source-film change stays invisible until it reaches your line.

How much polyimide tape material can I get for evaluation?

Roll stock samples ship as a single roll, enough for a bench trial and a short line trial, and for cut parts we supply prototype quantities first with fit and function checked, then agree production quantities per part. Tell us the profile, substrate and station format so the sample is representative.

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.