Carve a PCB at Home? Meet Prometheus
One company has decided to make creating PCBs a whole lot easier with the help of an at-home PCB fabricator named Prometheus.
Every EE knows the special agony of ordering a custom PCB for prototyping--the process can take weeks, and a single mistake can mean an annoying delay in production. Roccio Tuccio struggled with the same issue, so he decided to fix it by building a machine to carve PCBs for him: meet Prometheus. We talked to the inventor of the machine to find out more.
How did you get the idea to make an at-home PCB machine?
When I was at the University of Maryland, the physics department offered a machine shop class. I got to learn how to use large metalworking milling machines and lathes. These were all manually operated, but I soon learned about computerized machine tools (CNC machines) and was hooked. I started Zippy Robotics to bring the power of all kinds of CNC tools to everyone so they can make anything. That's obviously a huge task, so I had to focus on one particular area first. I decided to start by making a tool to make circuit boards, and Prometheus was born.
What do you think the biggest challenge for designers (in terms of getting accurate prototypes) currently is?
I think the biggest challenge is the lead time. There are plenty of PCB fab houses to choose from that will do great work, and that's great if you're ordering 100 or 1,000 boards of a finished design. The trouble is that if I'm waiting a few weeks to get a board in the mail just so I can test it, and then I have to make an update or a correction and repeat this cycle again, I'm waiting weeks or months to do something that should only take a couple of days.
How is Prometheus better than what’s currently on the market?
My favorite question! Prometheus is the best performance-to-price ratio out there. No other machine can achieve 7 mil (.178 mm) trace width and trace space, unless you're willing to spend $8,000+. The reason we can do this is because we've invented a low-cost spindle that is 30 to 50 times more precise than a typical hobby spindle. When I say it's more precise, I'm referring to the spindle's runout, which is basically a measure of how much the bit wobbles as it rotates. The smaller the runout, the smaller the diameter of the bits you can run without breaking them. Prometheus can run some tiny bits - square end mills with a diameter of .007 inches! We're actually working on going even smaller. Our spindle allows Prometheus to compete with the professional PCB milling machines but at a much lower price - roughly 75% less (our early-bird Kickstarter price is $1,899). In addition, we also wrote our own circuit design software for beginners, called Circuit Factory. The software is in alpha right now and it will be available for free on our site. We're not forcing anyone to use it, but I think Circuit Factory will add a lot of value for the user that is just getting started in PCB design. For everyone else, you can use whatever software you prefer and import the Gerber files.
You’ve partnered with Upverter for your software. What’s been the biggest benefit?
We're really excited about the partnership. While we wrote our own design software (Circuit Factory), it's meant to be a super-simple option for beginners, and therefore it's also stripped-down compared to a professional, feature-rich tool that an engineer would want to use. Recognizing this, we reached out to Upverter to see if they could be our recommended solution for the pros. Right now, anyone can sign up for Upverter's free plan, but you're limited to having 2 private projects (in addition to unlimited public ones). With our partnership, they are going to give Prometheus users extra private projects for FREE (we're talking about having between 5 - 10). The reason we're going with Upverter is because they make awesome software that I can recommend because I personally enjoy using it. If anyone is looking for a better EDA tool, I'd suggest going through their in-depth tutorial and giving them a try at Upverter.com.
You’re using US manufacturers (hooray!) and suppliers; any advice to designers who want to source reputable manufacturers?
It's tough! I started with Google. It's one of those things that just takes a lot of time, phone calls, and trying them out. All of our custom parts (sheet metal and machined parts) are coming from Rapid Manufacturing from New Hampshire. I can recommend them to designers if they're looking for sheet metal fabrication or machined parts. The major benefits of working with them is that I can get instant quotes directly from CAD data for most parts, and for those few that require a person to look it over, I typically hear back within 24 hours. When you place an order, they get the part to you FAST. Some other shops I've worked with have taken 2 weeks just to quote me - insane!
The price of a Prometheus is a little steep for most EEs: does the cost savings come back after time?
I agree it may be a bit pricey for an individual (and I'm always looking at ways to reduce costs and maintain quality) but for businesses, makerspaces, universities, entrepreneurs, or anyone that puts a premium on their time and is always designing boards, it pays for itself quickly. It's really about the value of time. Unless you're lucky enough to live down the street from a PCB manufacturer, the quickest you can expect to get a board delivered is in 2 days (and you'll pay a lot more for this quick turn-around). In that same time, you could work at a leisurely pace with Prometheus and make 4 new versions and be done with your project before you even receive the first manufactured board in the mail. If you compare the price of Prometheus to a professional machine like this LPKF, Prometheus is a bargain, and we even have a faster spindle.
Why should we invest in and buy Prometheus?
I would hope that people back Prometheus because they see how it can be a valuable tool when they are prototyping. Beyond that, they'd be supporting our mission of democratizing the tools of manufacturing and empowering individuals to make anything. Prometheus is just the beginning. If we can provide a tool to help people make something - whether it's PCBs, plastic parts, metal parts, any physical thing - then we're going to make that tool. We're also going to pair it with great software and support. If anyone is interested in backing Prometheus, they can visit us at our Kickstarter page.
Does Prometheus cut through the solder mask to make pad openings, or is the solder mask applied later by conventional means?
If I have a board with some through-holes, will Prometheus drill the holes? Thanks!
Can it build RF application PCB’s with 4 layers that need 50 OHM impedance controls?