Contextual Electronics Blog

Drill Tables and Fab Notes on a PCB Fab Drawing

Chris Gammell — Wed, 24 Mar 2021 12:45:21 GMT

Summary

In the video below, we're adding more information to our fabrication drawing for our PCB, including a drill table and fab notes. This allows us to get a board quoted or manufactured by a wider range of PCB houses than the online options. The online fab services capture all of this information in an online form dialog, like the one shown at the bottom of this post. Instead, we will add the required information to our fab drawing. With a fab drawing, we have a record of what we want the PCB to look like and what the critical specifications are.

Watch the associated video

This post is associated with a video on YouTube. Watch it below or over on YouTube.com.

Adding a drill table to your fab drawing

We use KiCad for all Contextual Electronics projects. If you use a different layout tool, you will need to figure out how to generate and add a drill table. The idea is the same for all designs though: we want to indicate how many different size drills are used on the PCB shown, and how many drill operations are required. This will impact the cost of the PCB because more drills means more time spent on the machines that do the drilling. See this time-tagged link to Scotty's video tour of JLC (Strange Parts) to see how drilling is done. KiCad has a tool buried in the "generate drill file" dialog. Normally this dialog is used to generate a .drl file, which gives all details about the location of drills and is used to actually program the machine that does the drilling. There is also a "generate map" button in the lower right, which will generate a vector based image showing where all of the various drill types are located on a particular PCB. After we generated this

Adding fab notes to your fab drawing

Fab notes are there to tell your manufacturer the detailed build information for creating your PCB. In an era before online tools (screenshot example below), this was the only way to get information across in a standardized manner. Many PCB fabs without an online interface requires fab drawings to ensure they are making a PCB that the engineer and company requesting the board actually wants. This includes details like the soldermask color, the silkscreen color, the overall board thickness, inspection requirements (IPC), or any other requests you have. We recently were pointed at this article from Supplyframe Hardware about some standardized notes you can add to your drawing. This is not an exhaustive list, but it includes a good "starting point" for people that are new to building out their fab drawings for working with traditional PCB fabs. It's also possible to include the fab drawing with your designs going to online PCB houses, to ensure they are hitting your requirements. Be sure to call out the fab drawing (and remember to upload it) when you are submitting your design.

Previous video about fab drawings

In the previous video about fab drawings (below), we discussed the stackup and how to create your own. We also linked to our library of templates for adding to your drawings.

Learn more about the ABC board

The ABC board shown in this video is part of a many part series (100+ videos) showing the entire design, board bringup, and firmware design of a cellular and bluetooth device. New members can try a week of Contextual Electronics for free.

Example PCB Fab Drawing

[caption id="attachment_11981" align="alignnone" width="1024"] Example PCB Fab Drawing (The Contextual Electronics ABC board)[/caption] Click the image above for a PDF version of the fab drawing

Example online selection tool

This is a screenshot of a popular online PCB provider (JLC). Interfaces such as these allow for a standardized quoting process and fast-forwards board ordering, compared to how PCB orders traditionally are done. However, with these interfaces you have less overall control. You are basically ordering from a standard offering.

Add mounting holes to a layout, but not the BOM (KiCad 5.1)

Chris Gammell — Wed, 17 Mar 2021 09:55:17 GMT

This video was inspired by a question on Twitter a couple days ago: How do you add a mounting hole to a design, but not have to worry about it when you get to production?

Add custom fields (Like "Population") to indicate it's a Do Not Populate (DNP) component
Mark all manufacturing fields as N/A
Use the KiBOM plugin to generate your BOM, which uses Regular Expressions (Regex) to exclude mounting holes, test points, solder bridges and other non-component components from the BOM

This is only a problem when you add your mounting hole to the schematic, so that it has a symbol that can be paired with the footprint. If using the footprint in a standalone manner on the layout, be sure to "lock" your footprint.

Joulescope Unboxing and Teardown

Chris Gammell — Wed, 10 Mar 2021 08:57:50 GMT

In a first for this channel, Chris does an unboxing video (and brief teardown) of the Joulescope. Matt Liberty, creator of the Joulescope, sent a replacement unit to Chris after a unit issue. This unit will be used to measure current on the ABC Board in upcoming videos. Chris hopes to measure how long the ABC board will be able to survive in the field without charging via a solar panel. The Joulescope is a high dynamic range measurement device, which is good at quickly switching between measuring the low current of a sleep state on microcontroller and then measuring the much higher current draw of a transmit cycle on something like a wifi or cellular modem.

Importing Eagle files into KiCad 5.1

Chris Gammell — Wed, 27 Jan 2021 09:53:44 GMT

In this video, Chris imports the adafruit Feather M4 Express board Eagle files (which is OSHW) into KiCad 5.1. Here are some of the pitfalls of importing into KiCad.

Flags get converted into (tiny!) labels that might not be clear.
The frame in schematics is gone. Not a big deal, but will look different than other KiCad projects.
Some silkscreen layers will not map as expected.
All footprints are imported from Eagle, since KiCad doesn't know how to map existing footprints. This means that none of the 3D models are included.

Should you switch to KiCad 5.0?

Chris Gammell — Fri, 02 Mar 2018 06:13:30 GMT

TL;DR: The KiCad 5.0 package is not yet at a stable status, as of March 1st, 2018. Wait until the official 5.0 stable is announced to switch.

Should you consider moving to version 5.0, since the new release candidates (rc1) are now being tested? I don't think so, yet. Watch below to learn more.

Links from the video

Using the Digikey Open Parts Library components

Chris Gammell — Wed, 28 Feb 2018 04:04:58 GMT

TL;DR: Digikey created a library for open parts library components and we made a video (below) showcasing how to pull that into your design One of the exciting thing in open source projects is the beginnings of broader adoption. Not only is it rewarding for the project members who have put in hard work on a software project they believe in; for the users of the project, it means there will be broadening support from the community. We hadn't announced it on here, but Digikey started supporting the KiCad project. This was both a monetary donation (announced at FOSDEM) and also in terms of internal support. What that means for users is there are now component libraries pre-built for components listed on the Open (Common) Parts Library. The "atomic" part refers to the fact that the schematic symbol and footprint are tied together. If you select the symbol for your schematic, no updating is required when you import components from your netlist into your layout. There are reasons for and against doing it this way, both of which I discuss in this video. Watch to see how you can add the library to your next project:

Also, as mentioned in the video, we started selling KiCad apparel and all proceed will benefit the software development process. Read more about the donation here, if interested.

Should you buy high end test equipment?

Chris Gammell — Sat, 26 Aug 2017 22:07:05 GMT

New members of Contextual Electronics and people learning electronics often ask me if they should be buying expensive test gear. I don't think so. Instead, I think you should focus on getting started with lower end equipment and using it to its limits before deciding to upgrade to high resolution or speed models. The important thing is to focus on the methods of measurement and troubleshooting, not getting bogged down with the specs of the gear you're using. Two of the devices we use for the course that were discussed in the video above:

Those links go to the "skills" modules, showing overviews of how to use the devices. We also use them regularly in course content. The 2017 Analog Discovery 2 bundle announcement is kept for historical reference; the discount described there is no longer available. See current course pricing for membership options. If you have questions about the equipment discussed above, please ask in the forum below.

(KiCad) Information Wants To Be Free

Chris Gammell — Mon, 28 Jul 2014 04:39:02 GMT

TL; DR: I am releasing all of the KiCad videos that were part of Contextual Electronics to the public and have started a new site/forum to support them. See below for announcement video. I officially finished the first two sessions (1A & 1B) of Contextual Electronics in early June. It was a great experience, especially for a first time course, especially one where there was money involved and I was the IT guy on the project. It wasn't a super smooth build, but that kind of added to the project; we were all "in it together". At the very least, I can very confidently say I don't regret quitting my job to teach electronics; it has been rewarding and an eye opening experience. The first part of the course (session 1A) was all about how to design a PCB for a particular application. We use an open source PCB CAD program called KiCad. The open source was important to me because it not only meant that members would be able to download and use the software free of charge, it also meant the final product--which is licensed as open source hardware--could also be replicated and improved upon without needing to buy a license for the software that designed the product. I had been a fan of KiCad long before starting the course and the software has been in development long before that (since 1992!). But it has never really taken off either in the professional nor the hobbyist community, the latter being the more perplexing data point; the predominate piece of CAD software with electronics hobbyists is CadSoft EAGLE. I think it's a good piece of software and have used it a bunch for previous designs, but also think KiCad has surpassed EAGLE in many ways. Not only am I a fan of KiCad, I also see how fast it is moving. It is a dynamic software environment, with developers who are regularly working to make it better. In fact, CERN recently added resources to assist in the project and have been rolling out some exciting new features. They are helping to inject some advanced techniques into the package, which should help move it towards being a world-class piece of CAD software. So between enjoying my own use of KiCad, educating others how to use it and still not seeing it take off, I decided that I am going to release all of the videos that were part of Contextual Electronics about KiCad onto YouTube. I hope that these will encourage people browsing YouTube for help with KiCad to take a deeper look and start using it for all of their projects. I will also add move videos as newer features become standardized and new stable builds are released. The other thing I noticed that was missing was a place to discuss KiCad. There is a Yahoo group but I am not a big fan of Yahoo groups nor how they are run. So I decided to start up a new site with information on how to do the builds and a forum where people can discuss KiCad and the videos I posted. It is meant to be a resource for people getting started who want to build their own PCBs with KiCad.

So that's all for the big announcements today. I will be over at the new KiCad.info forums, answering questions and supporting the site. I hope you will join me over there!