PCB Placement Stencils

> line up well enough for reflow.

> If you used FR4 instead of acrylic or whatever, you might be able to leave the aligner stencil in place for reflow. That might let you do some of the smaller parts.

When the solder wets it will 'suck' the part into place, the alignment of the part isn't particularly critical. If you are dealing with extremely small parts like 0402 or under caps, you can run into issues where the wetting of one side just before the other causing the cap to pop up on end, but that isn't an alignment issue and the stencil won't help. In a proper production line these parts would have what is basically glue holding the middle in place enough to avoid this.

EDIT: If you're finding the parts aren't sucking into place, chance are you need to use more flux or check the solder formulation you're using against the PCB finish.

Having watched the video, I can place components significantly faster with tweezers and an Optivisor. If you really must populate a batch of SMD boards by hand, the best option is a Hakko 392 and a sensibly laid-out board for your cut tape.

The Liteplacer doesn't seem like great value for money IMO - for a bit more money, you could have a small used industrial machine with a decent set of feeders.

Same here, DirtyPCBs is great! I particularly like that you can update orders right up until they have started in production.

The SLA printing service is a real game changer too.

Agrreeeeeed. I just did a run of 300 boards through DirtyPCBs and their quality was actually surprising. I feel like OSH Park is a bit higher, but being able to choose the soldermask and the amount of options available is crucial in some of my projects.

If you're in the market for cheap PCBs, PCB Shopper is a fantastic tool - you can fill out one form and get quotes from 24 companies.

https://pcbshopper.com/

Prices for 4-layer boards and boards larger than 100x100mm have fallen significantly over the last year (driven mostly by JLCPCB), which has hugely expanded the possibilities for hobbyist electronics.

Additionally, the accuracy of the PCB fab when drilling holes is going to be better than when routing the edges of the board. Just need to ensure you pick a hole diameter that matches the fabs drill sizes. (and oversize the hole a little or the fit is going to be very tight)

Chinese PCBA services are relatively affordable for short runs. Unless you place a very low value on your time (a reasonable choice if you're doing it for fun) or need a one-off prototype in a hurry, you should probably just use a service like Seeed Fusion.

It seems like this could work for small components especially if one were using solder paste. Would something like this work better machined in aluminum (instead of acrylic) if the holes were bigger on the bottom instead of on the top to allow for the devices to not get stuck to the acrylic?

(author here) Fixed, thanks!

The routed edges of a PCB are generally +/-0.1mm. Most laser cutters will match or exceed that tolerance, even on acrylic. In the worst case this jig will be 0.2mm out, but it's a lot easier to nudge a package from almost aligned to perfectly aligned than to place it purely by eye.

For reflow soldering they really don't have to be that precise. Capillary action pulls the part into place and aligns it as long as it's somewhat close when the solder wets, it's really neat. Even QFN packages the author mentions don't really need to be that precise, for those it's more important to get the right amount of solder paste dispensed so that you don't have bridging of pads.

for small stuff the real limit may be "how round are the corners"

My gut feeling is 0603 might still work but probably not reliable, 0402 tends to get stuck to everything by static attraction so very doubtful in acrylic.

One possibility is that you can do the C's and R's by hand with regular wire solder.