Community Spotlight: Randy Cox (CEO of Virtjoule Inc.)

This month, we talked with Randy Cox, who is the CEO of Virtjoule Inc. He has been a wonderful supporter of Opulo and an avid user of the LumenPnP. We have really enjoyed getting to know him further and we think you will really enjoy seeing how he is using the LumenPnP to help manufacture the products he sells. From 3D printing to injection molding, he does it all in-house and loves every minute of it. In this article, please enjoy learning more about what he does. It is really interesting! 


Tell us a bit about yourself and what you make.

I'm Randy Cox, the CEO of Virtjoule, Inc., which is based in Sonoma, CA. (Yes, we make more than wine in Sonoma!) I design, manufacture, and sell a cellular sensor that monitors amperage and demand control switches on HVAC equipment for a large utility.

I am also the top seller of soldering iron tips that are specialized to insert brass inserts into plastic, primarily used by people with 3D printers to make parts stronger.

I'm a maker at heart. I own three 3D printers, a CNC milling machine, a CNC Swiss lathe, a soldering robot, a wire crimping machine, a fiber laser, a small injection molding machine, and two PnPs, and you can imagine all the other things that might go along with them.

What are you building with your LumenPnP? 

My sensor is a carrier board architecture with an ESP32 at its core. I designed and made the carrier board, a 4-channel linear amplifier board, and a 2-channel RMS to I2C board. It uses an XBee cellular module for communications. The carrier board has a rectifying power supply that takes 24VAC and regulates to 3V3 and 5V.

Did you build or buy a LumenPnP? Have you made any modifications from the original build?

I bought the LumenPnP with 25 feeders. I only had one part that was in 16mm tape and everything else was fed with the Lumen feeders. I have two parts using the 12mm feeders. There are no technical mods, but there are many usage mods.

I put it up on 4x4 blocks to help with the spent tape, peel tape, and to make it easier to get feeders in and out. All my work holding is done with custom 3D-printed jigs. I wish I had time to redesign the tooling plate to make more room for boards.

How many boards a month do you produce with your machines?

My board production isn't really a flow, but a once a year production based on the demand from my main client which is spring-time once a year. By the time my current build is done, I will have built around 1,200 boards and roughly 36,000 placements. That's over about four weeks of production time in the last few months.

How were you building these boards before the LumenPnP?

I still own a CharmHigh 36VA, but it hasn't done anything but hold up extra parts reels since I bought the Lumen. Things can go wrong in a hurry with that machine, and they do.

What is the single most important piece of advice for running an SMT line?

Get your bare boards ordered, tested, redesigned, reworked, and reordered five more times before Chinese New Year starts.

What's your solder paste of choice? Any advice for others?

Kester NP545 and Loctite GC10 SAC305T3


You can find Virtjoule at  
To keep up to date with Randy & Virtjoule,
check out their YouTube, Twitter, and Randy's LinkedIn Profile.