Larger size

[mandreko]

I currently have several PCBs where my stencil is 190x190mm. I'm going to build this up, and see how well it works with a stencil that is larger than the base (the PCB is smaller though).

I'd be curious if there was any interest or issues creating a 200x200mm or so version of this? If I can get some free time, I may modify the CAD to do this myself, but didn't know if you had any experience with it already. I'd be curious if the current motor and impeller could handle the size difference or not.

[scheffield]

Hey Matt, I was initially considering to make the model parameterised so that larger and smaller version could be created but it wasn't straight forward. Maybe I give it a try once I find some time.

Regarding a version that is much larger than the current one: the lid will most likely sag and some extra support would be needed.

[mandreko]

The lid sag is a super valid concern. I hadn't thought of it either. Thanks for thinking of it.

[clazarowitz]

Making a 200mmx200mm version was pretty straightforward, but it did involve some changes. Sag was absolutely an issue. I suspect PLA might have been better, or carbon filled PLA, but the print times were horrible, so I laser cut acrylic instead. Its quite stiff. I made the lid from "3/16" acrylic (5mm). I made the lip for the lid from the same stuff. Other than cutting out the holes and the outline, I made a light engraved line to show me where to glue the lip. For the lifter, I used 6mm acrylic. I cut all the holes including an 11.5mm hole for the lifter points. Then I glued 6mm acrylic to 2mm acrylic and cut plugs to make the alignment pins. I cut a 3.2mm hole straight through each one, and engraved a hole to enclose the socket head cap screw. This was more than stiff enough to prevent sag. Additionally, I wanted the motor quick, so I used a slightly smaller one 1800KV and ran it off a 6S pack (well, a 24V DC power supply). I needed to go a little past half throttle to get enough hold down force for the stencil, but I suspect that is because I accidentally ordered by stencils wav oversized. I cut them with aircraft shears, and still oversized, but I think it caused a slight warping. I also think re-adding the outer layer of holes would help a bunch for such oversized boards. The main problem I have is it really needs some longer springs. These just barely compress and the solder paste held the stencil down to the board. I had to manually lift the lifter, and even then, getting the stencil off without smearing (much) was a trick! a

I'm more than willing to share files, but I prefer inventor to fusion, so when I remodeled everything I used inventor. Fusion can import ipt files, but I don't think its any better than step files. I could...probably...redo it in fusion. I just find the multiple parts in one file frustrating and having to close the inspect tool every time I want to start a new measurement infuriating, so I gave up and went back to inventor (not free). I should have saved my settings for the alignment pins, but I was adjusting in lightburn. I'm probably going to redo it again with the last line of holes on the lifter, so maybe I'll write down the actual settings this time. I am using a 2.5" err....what is that, 63.5mm lens on the laser. There will be variances in kerf width even between lenses, but the same class of lens should be pretty close :) I also would have to export my dxf's since I modified the sketches for kerf width.

So what I made is recognizable as a stencil fix portable, its very different. I'll open another issue for this, but my one suggestion would be to make the motor mount a separately printed item that is bolted to the main frame to account for different bolt hole patterns and motor diameters. I used a 2306.5 motor so I had to move the whole mount up a bit and make the enclosing circle a bit smaller, it used a 16mm pattern rather than a 19mm pattern. The motor has plenty of power even for a 200mm version!