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Topic: A stencil8 PCB tooling block for doing solder paste stencils (Read 25607 times) previous topic - next topic

A stencil8 PCB tooling block for doing solder paste stencils

So, I've been converted to the stencil8 way of doing things, but I need a decent tooling block to do it on. Getting these commercially CNCed in small quantities is very expensive, but a bulk order - 10 or more - is a lot more affordable. So I've put together a fundraiser on Tindie to get some made. Please do join in if you'd find it useful to own one of these.

For those who don't know, these are robust precision machined Aluminium tooling blocks. They've got a grid of precisely aligned holes, and come with matching steel dowels. You design your PCB (possibly panelized) and stencil with matching holes, and all you have to do to apply solderpaste is put the PCB, then the stencil, on the pins, and wipe paste over them. No more alignment hassles!

I'm not really making any profit on these - I just want to get enough orders together to make it cost effective.

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #1 –
I've been thinking about having one of those made as well.  When looking into the costs I realized that a 3 kilo block of aluminium might be a bit of an overkill.  A sheet of 8-10 mm acrylic (or even better polycarbonate/Lexan since it's more resistant to chipping) with holes either drilled all the way or just part through would most likely be enough for most non-professional applications. And would also be far cheaper than an aluminium slab.

Too bad that laser cutting probably won't make holes with enough precision - otherwise $13 for 5 custom lasercut 20x20 cm sheets from Seeedstudio would be a nice option.


FYI -  200x150mm is not A4 as the fundraiser says, it's actually only a half A4 I.E. A5.

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #2 –
[quote author="matseng"]I've been thinking about having one of those made as well.  When looking into the costs I realized that a 3 kilo block of aluminium might be a bit of an overkill.  A sheet of 8-10 mm acrylic (or even better polycarbonate/Lexan since it's more resistant to chipping) with holes either drilled all the way or just part through would most likely be enough for most non-professional applications. And would also be far cheaper than an aluminium slab.[/quote]

Actually, the Aluminium is only a small portion of the final price - machining is a significant cost. But postage is a significant WRT the weight.

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Too bad that laser cutting probably won't make holes with enough precision - otherwise $13 for 5 custom lasercut 20x20 cm sheets from Seeedstudio would be a nice option.

I've put out a quote request for a 10mm acrylic option, just to see if it works. I'm not sure about the hole size precision either, but it's worth a try.


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FYI -  200x150mm is not A4 as the fundraiser says, it's actually only a half A4 I.E. A5.

Oh crap, how did I get that wrong? I'll fix it immediately - and maybe take it down if that's too small to be useful.

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #3 –
[quote author="nickjohnson"]I've put out a quote request for a 10mm acrylic option, just to see if it works. I'm not sure about the hole size precision either, but it's worth a try.[/quote]
Drilled or laser cut?  Even with a powerful enough laser the divergence of the beam would make the hole much wider at the bottom than the top.

If I would do it with a laser I probably cut 4 pcs of 2.5mm boards and sandwich them with a uncut board in the bottom, put in the dowels and glue/bond them together.

Just for the fun of it I'll order one of the 10x10 laser service the on Monday when I send for my weekly PAW project. And put a bunch of holes in increasing sizes from 2.3 to 2.6 mm in 0.025 mm steps and see what size that will be the best fit.  Of course I need to find a 2.5mm steel dowel as well :-)

Well, A5 seems a bit wimpy , but you could actually fit a eurosized board 100x160 mm on it with margins for the holes, so it might be enough.

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #4 –
[quote author="matseng"][quote author="nickjohnson"]I've put out a quote request for a 10mm acrylic option, just to see if it works. I'm not sure about the hole size precision either, but it's worth a try.[/quote]
Drilled or laser cut?  Even with a powerful enough laser the divergence of the beam would make the hole much wider at the bottom than the top.[/quote]

I asked for a pricing with a laser; the place I asked for a quote from has a very good machine. I'm not sure how bad the divergence will be.

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If I would do it with a laser I probably cut 4 pcs of 2.5mm boards and sandwich them with a uncut board in the bottom, put in the dowels and glue/bond them together.

That's also a viable option.

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Just for the fun of it I'll order one of the 10x10 laser service the on Monday when I send for my weekly PAW project. And put a bunch of holes in increasing sizes from 2.3 to 2.6 mm in 0.025 mm steps and see what size that will be the best fit.  Of course I need to find a 2.5mm steel dowel as well :-)

Good idea!

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Well, A5 seems a bit wimpy , but you could actually fit a eurosized board 100x160 mm on it with margins for the holes, so it might be enough.

I think I'll find a way to do it at A4 (a 10mm thick piece of Aluminium in that size would be under 2KG) or not at all.

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #5 –
Just ordered "2.5 mm X 20 mm STAINLESS STEEL DOWEL PIN X 10 (SPN 110-069-10) 180827351774 - Price: GBP 2.99" from eBay. They will probably turn up before I get the acrylics from Seeed. ^_^

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #6 –
There's a lasercutter at my local hackerspace, and I'm going there this evening. I'll give it a try with different sizes of hole. I've ordered some dowel pins myself, but it'll take a couple of days for them to arrive.

-Nick

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #7 –
nice idea nick.  I hope you find enough takers on this.  Maybe send it to a few different blogs as well (I know hack a day ran an article featuring this tooling method a while back).

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #8 –
[quote author="nickjohnson"]There's a lasercutter at my local hackerspace, and I'm going there this evening. I'll give it a try with different sizes of hole. I've ordered some dowel pins myself, but it'll take a couple of days for them to arrive.

-Nick[/quote]

I use old micro drill bits (1/8" dia shank in my neck of the woods) - they work well (just don't put your hand down on top of them accidentally).  dowels would certainly be preferable, but you might be able to scrounge up some bits locally to try this out - can you tell I'm inpatient...:)

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #9 –
Okay, so I cut a sample out of 3mm acrylic on the lasercutter at the hackspace, with a variety of hole sizes from 2.5mm down to 2.2mm in 0.05mm increments. I don't have my 2.5mm pins yet, but I do have some 2.54mm ones. They fit a little loosely into the 2.35mm hole, and very snugly - a fraction too snugly - into the 2.3mm hole.

Even just one sheet of acrylic holds them fairly well, so I'm optimistic three sheets, with the bottom one blank, would suffice for a good jig. This would require figuring out a way to bond them together without the glue gumming up the holes. There's rather good 'water thin' acrylic solvent around which might do the job.

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #10 –
what if you sandwiched 10 PCBs from a cheap seeed order and just had them milled with holes?

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #11 –
[quote author="dolabra"]what if you sandwiched 10 PCBs from a cheap seeed order and just had them milled with holes?[/quote]

I suspect 10 A4 PCBs would come to a lot more than a couple of sheets of acrylic, unfortunately.

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #12 –
I've fixed up the Tindie fundraiser: $85 will now get you an A4 block, 200 x 300 x 10mm, with 6mm deep holes.

Re: A stencil8 PCB tooling block for doing solder paste sten

Reply #14 –
congrats, nick!