Advice on stainless stencils – What do I need to know

[Mr.B]

As a hobbyist I have designed and built many SMT circuits.
I usually have 10 boards made by Seeed Studio, but only build a few, maybe 5 at most.
Apart from the first few where I hand applied the paste, I have used OSH Stencils to make my mylar/kapton stencils.
I have had a very high success rate and am very pleased with the mylar stencils.
I use two ‘L’ shaped pieces of 1.6mm acrylic to lock the PCB in place and support the stencil.
These were supplied by OSH Stencils and work very well.

My latest project is much higher volume, for me at least, and I am building 50 fairly simple boards for a community project.
The boards measure 160mm X 58mm and have about 25 components.
(The boards are that big because they need to provide mechanical support for a similar sized LCD display.)

With this run of PCBs I have ordered a stainless stencil – electropolished, not framed.
Why did I do this?
1. The price of stainless stencils out of China is now down to a level that is not much more expensive than OSH Stencils.
2. I have read that the mylar ones are reasonably good for up to about 20 uses, after that they start to deteriorate.

My question is:
Is there any special considerations I should be aware of when using stainless stencils over the mylar ones?

Many thanks in advance.

[Mr.B]

Thanks @blueskull,
The stencil is already on its way.
It is the non framed version.

I am assuming that there is no special considerations when using it - just treat it the same as I have with the mylar ones?

[OSHStencils]

Thanks @blueskull,
The stencil is already on its way.
It is the non framed version.

I am assuming that there is no special considerations when using it - just treat it the same as I have with the mylar ones?

Yes. Do be careful that OSHStencil's SS stencils are not SUPER smooth, so it may catch some fibers when you try to wipe it with paper towel. Always wipe with WET paper towel, and it won't stick.
Also, due to the rigidity, if you do 0402 and smaller, be sure to keep your hands absolutely stable. Otherwise you may ruin the entire PCB's paste. I always have to print 2x or 3x to get a perfect print. So prepare to use a lot of paste and flux cleaner (I use MG 431B).

Hey Blueskull, I'd like to know when you had this issue.  Is this on a recent order?  We had this issue when we first released Stainless, but this has been fixed for a very long time.  Our stencils are cut utilizing the best equipment on the market and the final product has continually been proven to be superior to electropolished products.  The only step above would be a nano coated stencil but for most customers that's an extreme overkill and is really designed more for high volume manufacturing.

If you did have an issue with the fibers catching, I definitely want to know because we test everything that goes out the door and if there is a break down there I want to ensure we get it rectified.

Also for some clarity, OSH Park and OSH Stencils are not the same company, and OSH Park supplies boards, we supply stencils.  We work closely together, but not the same group of folks

[OSHStencils]

Hey Blueskull, I'd like to know when you had this issue.  Is this on a recent order?  We had this issue when we first released Stainless, but this has been fixed for a very long time.

Alright. Thanks for the clarification. I was mentioning some very early SS stencils, tracing back to this one year old thread: https://www.eevblog.com/forum/projects/building-a-quick-and-cheap-solder-paste-printing-jig/

As for my recent OSHStencils orders are mylar, I have no idea how the recent SS stencils are, but I will order one SS stencil very soon.

Awesome, yah we hadn't solved the issue (or rather, weren't even aware of it) back then.  It was fixed after that date, so your new ones shouldn't have that issue and should be best of breed in the market now

Thanks for clarifying the timeline, that's helpful.  Thanks for your continued support of our business as well!