Do you have flexible, positive-coated photo base material (Flexpcb) which can also be soldered?
It is possible in principle, to coat Kapton (or other films) with our photoresist. But, because the photoresist is NOT flexible, handling (exposure, development, etching) is easily generating cracks.
Unfortunately, this is almost normal, even if our competitors conceal this fact to create fast business.
If you really want to have flex material coated, then you should think about NEGATIVE PHOTO COATING. Negative dry resist is flexible and not kink-sensitive.
One more question: Can you also work with so called RIGID-FLEXIBLE or semiflexible pcbs?
What is the bending radius you need?
Background: We have also FR4 with a thickness of 0.125 mm carrier and 35μm copper layer (single or double sided) in stock. We sell this for the same price as 0.5 mm FR4 in size 510x1150mm. Cutting service is possible.
With these thin FR4 FR4 you have normal (solder) properties at an extremely small bending radius (see photo). Perhaps that would help you already?
By the way, I love the "Isolation Milling vs. Etching" statement on your web site, I couldn't agree more. Last year we bought a chemical processing line for PCB prototyping while other universities spend about the same amount of money on routers from your competitor near Hannover. Since then we made hundreds of industry-quality PCBs while they keep their ProtoMats on display, as rare artifacts. Once the process is established the costs of etching PCBs is a tiny fraction of the costs of isolation milling. The only problem was that we had to drill the holes manually, which hopefully will be solved now...
Marius RANGU, PhD
"Politehnica" University of Timisoara, RO Electronics and Telecommunications Faculty 2