Good source for framed stencils? JLC's aren't holding up.  - Page 1
Forum section: electronics / general

author: Rat_Patrol
author_rank: Frequent Contributor
timestamp: March 23, 2022, 07:13:15 pm
content: I usually get them from JLC PCB, but after about 6-8 sessions and washes, they start falling apart. The Epoxy starts to just crack and break, and the stencils lose all tension. We use them in a manual stencil machine.Looking for recommendations for better framed stencils.

author: mon2
author_rank: Frequent Contributor
timestamp: March 23, 2022, 07:21:54 pm
content: Try the following - Stone has supplied us for years for our SMT stencils. For our Ekra X4 we were sourcing 29" x 29" framed stencils and were paying ~$50 USD each (F.O.B. Shenzhen - believe this is where their factory is located).QuoteWe can relay details of another shop that is more $ but also even higher quality and recall them being ~$150 USD ea out of Shenzhen. That firm supplies Intel and others for complex PCBs.These days we are fine to use JLCPCB for our stencils and our equipment - used some of the stencils @ 400+ PCBA runs without issues.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 23, 2022, 07:23:31 pm
content: Have used ALLPCB before, framed stencil was something like $100 I think?Tim

author: Mangozac
author_rank: Frequent Contributor
timestamp: March 23, 2022, 09:50:29 pm
content: Quote from: Rat_Patrol on March 23, 2022, 07:13:15 pmHow many panels have you pasted? One of our JLC stencils has done several thousand operations and the only issue is that it's starting to get a bit marked from the squeegee blades. This is on an automatic printer though, so I guess the manual process is putting a lot of stress on yours?

author: SMTech
author_rank: Frequent Contributor
timestamp: March 24, 2022, 08:35:03 am
content: I would guess the OP is running them though a proper wash process not just a wipe down. I have quite a few of this type of stencil form various sources when the client or end use means they cannot or will not pay for a proper stencil. However the difference is night and day between these and the "real thing", I really don't like them very much.You local stencil supplier will manufacture stencils to standard sizes is properly rigid frames, they will properly finish and polish the stencil as standard and optionally offer things like nano coatings. They will offer advice and feedback on your stencil design and may even utilise the top copper layers to double check what you are doing suggest options like multi-step etc. They are also, broadly speaking pretty competitive with each other so pricing is fairly consistent and you typically get a stencil in 2 days. I would recommend tracking down some more local to youIf you are using a lot of stencils I can recommend a self tensioning system, this means you get a standardized foil that fits into a frame you own/rent/borrow that uses a pneumatic or mechanical system to tension it correctly and the stencil itself takes up ~6mm in a cardboard sleeve/hanger rather than 25-30mm. The most common of these systems is DEK VectorGuard but there are several others you might encounter, these can also be somewhat cheaper than fully framed stencils, our current pricing for VG is ~120 GBP plus delivery, still a lot more than JLC/PCBway but not outlandishly so when you consider you get a better service and a better product.

author: 48X24X48X
author_rank: Frequent Contributor
timestamp: March 24, 2022, 09:22:30 am
content: I think I know why this is happening with a manual stencil. With a manual printer, area other than the ones occupied by the PCB doesn't have any standoff to support the force pressed by the user. Maybe if you could add some support to those area closer to the frame perimeter where there's no PCB, I think that would reduce the stress on the stencil.

author: SMTech
author_rank: Frequent Contributor
timestamp: March 24, 2022, 09:36:52 am
content: Quote from: 48X24X48X on March 24, 2022, 09:22:30 amI highly doubt it, who's wielding the squeegee, Popeye, Brian Shaw? Plus you make some big assumptions as to what their manual printer looks like. An awful lot of them have much of the stencil clamping and PCB support systems you'd find in an automatic one. We were testing a (handheld) stencil cleaning system and the rep noticed our collection of these rubbish stencils and mentioned that he'd been seeing them increasingly recently, clients who have the big washer cleaning systems find they fail rapidly (and its not really surprising).

author: 48X24X48X
author_rank: Frequent Contributor
timestamp: March 24, 2022, 02:08:26 pm
content: [ Specified attachment is not available ]Quote from: SMTech on March 24, 2022, 09:36:52 amI'm not too sure what model the TS is using but when manual stencil printer is mentioned, the attached model spring into my mind. I think the ones with the a lot of positioning holes look more convenient than a flat (cheaper) one but as I mentioned previously the area without PCB doesn't get that much of support? I used mainly JLCPCB framed stencil but on a table surrounded by similar height PCB, probably that's why I'm not seeing the issues. Previously I was using KingFull stencil (they specialize in stencil making only), and they were great too and of similar quality like JLCPCB.

author: Rat_Patrol
author_rank: Frequent Contributor
timestamp: March 24, 2022, 05:08:05 pm
content: Quote from: 48X24X48X on March 24, 2022, 02:08:26 pmYes, that is the type of machine we use. I actually did put spacer to the sides of the PCB, and I sized the squeegee to just a bit over the PCB size. The deterioration comes from the washing, we use a full immersion washing process to get the stencils really clean, though they are only submerged for about 3 minutes. The tape that JLC uses starts coming off, the epoxy (I believe it is some form of epoxy) starts cracking, they just don't hold up.

author: Rat_Patrol
author_rank: Frequent Contributor
timestamp: March 24, 2022, 05:08:51 pm
content: Quote from: Mangozac on March 23, 2022, 09:50:29 pmI'm getting about 100-150 panels before they start falling apart.

author: Mangozac
author_rank: Frequent Contributor
timestamp: March 24, 2022, 10:38:17 pm
content: Quote from: Rat_Patrol on March 24, 2022, 05:08:51 pmWow that's shockingly low!Interesting to learn about the washing thing - while I was aware of washing them I was under the impression it wasn't so common and relegated to very high spec shops.

author: jmelson
author_rank: Super Contributor
timestamp: March 27, 2022, 02:31:35 am
content: I have gotten framed stencils from PCBway. They have worked quite well for a few dozen boards, but I do relatively small batches. I see no signs of the epoxy coming apart so far.Jon