I’m following the Mark Method of building a RepRap frame, which involves using large Aluminum extrusion for the frame. The process involves cutting it, milling the faces flat, and then bolting it together. No wimpy 3D printed corner brackets here!
Adrian met me at Milwaukee Makerspace yesterday and helped me get my Aluminum extrusion cut down to size. I now have seven pieces ready for the next step. There are three pieces at 460mm, two at 480mm, and two at 500mm.
I started by cutting the extrusion to length (plus 6mm) on the band saw in the metal shop. We added 6mm so we’d have about 3mm on each side to mill down to get the final length. Cutting through the 45mm extrusion took some time but it wasn’t too bad.
I haven’t used the Bridgeport before, so Adrian got me all set up and walked though the process. I’ve used a few lathes in the past so the actual milling process wasn’t hard to do, it was mainly learning a new machine. I can see why people love the Bridgeport! It’s a nice machine that has some great capabilities. (I’ve got the old Enco mill at work, so I may need to play around with it a bit more.)
Milling took some time, but there was nothing too difficult about it. One thing I learned about milling is that it’s a messy, dirty process. I mean, the oil and the chips and the metal and all that. Being such a digital fabrication nerd probably doesn’t help.
Neat trick I learned from Adrian. Use a black marker to draw all over the face of your piece so you can easily see if you’ve milled off enough material. (I guess that’s why there’s a container full of Sharpies in the Metal Shop.)
Next in the process will be tapping the ends to accept bolts, drilling holes through the extrusion to get a hex wrench to reach the bolts, and then screwing it all together. The whole process of cutting and milling the pieces took a little under two hours. I still need to clean up the extrusion a bit, take care of sharp edges and remove little bits of metal. Adrian suggested using a Scotch-Brite pad for that.
(I’d like to thank Adrian for all the help, and Mark for the good price on the Aluminum extrusion!)