Spot welding is a process by which two pieces of metal are joined together in a permanent manner at a number of points (aka ‘spots’). This is done when an electrical current is passed through the point at which the weld is desired and the resistance creates heat, thereby melting the two points together. Frankly, after months of dealing with things like rhino and spider joints, it’s a relief to come across something where the name is so clearly indicative of the actuality.
“I’ve used spot welders for a long time in metal shops. I was a machinist and metal fabricator for a couple of years coming out of college,” said Borgatti. “I did a lot of the metal coursework in industrial design at Rhode Island School of Design and that became my career for a while. Now that I have my own independent shop, I have for years focused on digital fabrication doing 3D printing and laser cutting to get work done and as I’m trying to increase my powers of prototyping I realized that there was some additional equipment that I could use.”
“I realized that when I passed a dead microwave on the street that I had everything in my shop, plus that microwave, to build my own spot welder. I own a laser cutter, I’ve got a 3D printer to do the brackets, I used the fastenings that I had around and I made electronics with what I had in my scrap bin,” he said.
In an interview with 3Dprint.com, Borgatti detailed the process for creating his microwave spot welder:
“I do a lot of SolidWorks stuff, it’s my program of choice. I started with bench tests, pulled apart the microwave, put together temporary circuits to run the transformer. Rewound it, first using a heavy gauge cable that I made by stripping thinner gauge cable and folding the copper together as a proof of concept. When that worked, I invested in heavier duty cable. I took measurements of all of the important components, figured out how I wanted it to behave, put it into SolidWorks and worked with a bunch of different iterations to try out a number of versions.”
“I built a bunch of corner connectors out of the 3D printed PLA on my Ultimaker2. The way that I designed everything was to minimize the number of additional fasteners. So, I tapped the PLA parts, they had a high wall thickness and a heavy infill to have more meat to tap, then I tapped them with an M5 and then I also had the laser cutter actually cutting out the pilot hole for tapping,” Borgatti explained.
He hopes to be able to use the microwave spot welder’s ability to weld sheet goods together to continue to add to his tools.
“I would like to create a CNC desktop plasma cutter that I think I’m going to lead my shop in that direction for creating holding mechanisms for stepper motors, for creating structural elements for CNC machines. I think this is a good direction for a small fabrication studio, especially because the kind of work I do through my company SuperReleaser is generally equipment design. I’ve worked, for example, CNC plotter robots that move pens around reproducing people’s handwriting and other strange projects. This spot welder allows me to really combine traditional metal working techniques with the digital fabrication,” said Borgatti.
Borgatti has made the files for the scrap microwave spot welder available for download on Thingiverse, as well as details on the build on his website, so you can try your hand at making your own. Let us know what you think of his design, and if you decide to create your own in the Spot Welder forum thread over at 3DPB.com.