Dupont Dynamask dry film solder mask minor DIY troubles - Page 1
Forum section: electronics / general

author: jakeisprobably
author_rank: Regular Contributor
timestamp: March 22, 2019, 10:44:51 pm
content: Hopefully someone here has a bit of experience with Dynamask dry film solder masks. I attached images below containing my last 2 attempts at using this stuff. My basic process is as follows,1) manually tin etched board using my typical solder (MG Chem)+ lots of Amtech 559 flux2) clean with alcohol3) clean with alcohol + scuff pad4) clean with powder based dishwashing detergent until water cleanly "sheets" off the surface5) dry with clean paper towels6) run through Amazon Basics laminator on higher heat setting (I always use a clean sheet of paper folded in half with the board in the middle for all steps)7) V1 -A) place clean board in a container with clean distilled waterB) cut Dynamask to sizeC) remove 1 side coverD) apply exposed side to submerged boardE) use credit card to squeegee out most waterF) remove board from waterG) squeegee out any remaining water (thoroughly)V2-A) remove 1 side coverB) apply exposed side to dry boardC) use credit card to squeegee out any remaining air (thoroughly)run board inside folded paper through laminater twice9) apply bicycle chain oil to protected side of dynamask10) apply transparency toner side down11) squeegee out all oil/air leaving the transparency/image tight against the film12) expose in direct sunlight for 5 seconds (tested and established as my best fine line resolution)13) remove outer protective film and develop in 1 liter of microwave warmed distilled water (@~32C) with 4 grams of dissolved sodium carbonate (not bicarbonate)14) develop until masked bits are clean15) rinse in tap water16) pat dry with paper towel17) leave board in direct sun for 5 to 10 minutes to fully cure the dynamaskThe problem with the spots/deformations seen in the pictures are visible after step 12. I can not see them after laminating the film to the board. However I am in a dark room and can't see very well at this stage. I thought I was trapping water under the mask with V1, but I have a similar issue with V2 and a dry application. Any suggestions?

author: Fred27
author_rank: Unknown
timestamp: March 23, 2019, 08:43:56 am
content: I never managed to get it much better than that. My prices was far less rigorous though.

author: jakeisprobably
author_rank: Regular Contributor
timestamp: March 23, 2019, 02:37:33 pm
content: Thanks for the reply.I think the datasheet mentions a roller based application. I'm thinking about adding an extra switch to my laminator's heating element. Perhaps I could use the cold rollers as an extra step.The areas with the problems appear to be locations where air could get trapped more easily. I wonder if I should be altering the directionality of the board through the laminator more. I put them through at a 45 degree angle first then rotate the board 90 degrees for the second pass (or there abouts). The only other thing I can think of is intentionally perforating the film. Maybe going back too water submersed application combined with a cold rolled application...but adding water to an unprotected AC mains appliance is a recipe for stupid outcomes. The water based application works great for photoresist. The solder mask film is a whole different animal though.Ultimately I need to fix this issue before trying much more useful applications involving TSSOP's/QFN's/TQFP's.

author: jmelson
author_rank: Super Contributor
timestamp: March 23, 2019, 10:09:24 pm
content: Is your issue is with "wrinkling" of the film surrounding the copper traces, in the non-copper area of the board? That's the only thing I can see in your pictures. Well, if the laminator has pretty hard rollers, then these areas will get less compression than the copper areas.I have a Kepro laminator that I use for PCB etch resist, and the rollers are fairly soft. (Also, there is no etched/non-etched areas at the stage where I use the laminator.)Jon

author: jakeisprobably
author_rank: Regular Contributor
timestamp: March 24, 2019, 07:02:32 am
content: Yeah, sorry, the problem is the blotchy "wrinkled" areas. I think these are around the 5th/6th attempts I've made with this solder mask material. I've had a few other issues I've worked through, but on a test board I had a similar issue only far worse. With that one the wrinkles/blotches cracked open and showed signs that the issue is related to adhesion. I don't believe it's a chemical issue like contamination. That was why I mentioned such a thorough cleaning regiment. I don't have a tangible comparison for the "roller softness." I know I didn't get useable results with a travel iron (useful bc no steam holes). I wonder if there is a better option than printer paper for the folded protection layer used to pass the board through the laminator. Perhaps some fabric would work to improve conformity. Good suggestion, I'll have to try that next round.

author: SenseofScale
author_rank: Contributor
timestamp: April 20, 2019, 01:53:29 am
content: I just received an "Amazon Basics" laminator and it's junk.Take it apart and look for yourself. If your unit was assembled like mine was, that switch you're rocking to the 5 mil setpoint is actually jumpered to the 3 mil terminal on the other side of the switch, so it doesn't matter which setting you use. It's not a matter of miswiring either. The rest of the components in the unit couldn't be configured to have two heat settings.I don't have a point of comparison for roller softness but they seem like they'd be soft enough to comply, if the shafts they were molded over weren't so weak that they bowed apart when a circuit board went through. This probably explains the bubbling/wrinkling you're seeing. I'll post pics and a schematic tomorrow if anyone is interested.Edited to add: It maybe could be modified to have two heat settings. I suspect that the components could be rearranged so that it has a lower temperature setting.I posted some pics and a schematic here, probably in the wrong category :https://www.eevblog.com/forum/dodgy-technology/junk-scamazon-laminator/msg2356005/#msg2356005