PCB Friday: Design 3D-Printed Jigs to Enhance Your Printed Circuit Board Assembly Game

I love making PCBs. I also do a lot of 3D printing, and (any potential allergies aside) when properly implemented, these techniques can work together like peanut butter and jelly. Or close at least. Feel free to insert your own simile here.

3D printers allow you to turn out enclosures for your board, inexpensively and near-instantly make a physical representation of its size, and construct jigs to place components or perform other operations. In this article, we'll focus on 3D-printed jigs, discussing their general use and how to get your KiCad design into Fusion 360 for jig creation.

3DP PCB jigs: what and why?

Jigs: loosely defined as (often custom) things designed to help you make other things. If you need to do something over and over and/or with more precision than you can attain by hand, making a jig can be a good time investment. If you can find a ready-made jig to buy or 3D print, even better.

For example, I designed the Arduino solder jig seen below when I had to put a lot of Pro Micros together as part of my JCPM2 project. It properly lines up headers with the dev board so that they can be soldered on easily and accurately.

This saved jig me quite a bit of time and frustration during assembly. In addition to the Pro Micro for which it was originally designed, the print also works with other boards like the Arduino Nano and Arduino Pro Mini.

During this project, I also designed a jig for soldering key switches to the main JCPM2 board, using a model generated in KiCad to get the dimensions just right. The video below outlines my fulfillment setup, with the jig explained at around the 6:25 mark.

This and other accessories for the project are found in the project's GitHub repository. Given their specialized nature, I haven't yet put everything on Printables like the Arduino solder jig.

How to make your own 3DP jigs [KiCad + Fusion 360]

Broadly speaking, there are three ways to obtain jigs. If it's for something common, you may be able to simply buy one that works for your purposes. If it's something that a few people might need (e.g., an Arduino solder jig👇), search your favorite 3DP repository to see if there's something already designed that you can print. No reason to reinvent the wheel.

If it's truly a unique device — e.g. a custom PCB that needs key switches — then you'll likely have to design a jig yourself, or pay someone to do so. Designing a jig will require 3D-modeling skills, from rather basic to quite substantial, depending on the project.

For example, the Pro Micro solder jig has rather basic modeling requirements. Everything is at right angles, and the geometry is limited. The key switch jig below is significantly more involved because of its relatively complicated geometry.

However, even with custom jigs, you don't have to start from scratch. To design the more complicated key switch jig, I exported the JCPM2 model from KiCad and imported it into Fusion 360. With the model in fusion, I could use its features to base the jig off of, rather than plugging every dimension in by hand.

I outline how to export models from KiCad and import them into Fusion 360 for further usage below. Jig features will be highly dependent on project needs, so what you do with the model is up to you. Broadly, these import/export steps will be applicable to other ECAD/MCAD systems, but the details will be different.

Model export from KiCad [How-to]

To export your model from KiCad, navigate to File > Export > STEP... which will bring up the Export 3D Model dialog. If you want to pop your model into Fusion 360, STEP is likely what you want. The STL format is also available, which you can throw directly into a slicer for 3D printing. While Fusion 360 will open STLs, STEP is a much better CAD representation.

Model Import to Fusion 360 [How-to]

With your model exported, in Fusion 360, navigate to File > Open to bring up the Open dialog. Select Open from my computer and choose your STEP model. Click on Open, and voila your PCB model will appear in a new design.

From here, you can perform operations like creating a sketch on the bottom of your PCB, then drawing offset lines around the perimeter as a jig's basic form. Or you can create jig features according to model features as expedient for your operation.

Alternatively, you can shortcut this import export business altogether and design your board in Fusion 360 via its built-in ECAD tools. I personally haven't experimented with this much, as I'm comfortable with KiCad. However, this functionality does seem like it could be very helpful, especially as the board and mechanical designs get updated.

Jigs: work better and smarter!

I hope this article gets you thinking about how making a 3D-printed jig can enhance your PCB production capabilities. How your jig is designed may work for just your "thing," or it could have uses well beyond one particular job, a la my Pro Micro soldering block.

Search around before designing your own jig, and if you do go to the trouble of making your own 3D-printed device, don't be afraid to share. Finally, if MCAD isn't your thing, you might be better off hiring someone for jigging duties. I — as someone with significant experience in manufacturing automation — am always happy to talk, though there are certainly others who are competent jig makers, 3D-printed or not! — JC

Thanks for reading!

Thanks for reading my biweekly PCB Friday column! I'm looking forward to sharing more PCB-related knowledge and insights here, and I hope you'll follow along for the journey. You can see more of my hacking/DIY exploits on the Jeremy Cook DIY YouTube page, read my semi-technical musings at TechAdjacent.io, or email me: hi@jeremyscook.com!

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