How to Line Up Parts Perfectly for a CNC Table
Sometimes Kevin has to improvise. He's currently building a large sound sculpture. It has 5 big arches with bells hanging off of them. He needs to cut out the parts for the metal arches, or branches. They range in height from 8' tall to 6-1/2' tall. His CNC table is only 4' x 4', though. He's not going to cut them out by hand - that's why he brought the CNC plasma cutting machine!
Kevin uses a Dynatorch 4' x 4' CNC plasma table. It comes with 2 programs: 1 runs the table, while the other you put on your computer. The 1 on the computer is Sheetcam. You use that program to set all of the parameters in your DXL files. The parameters are settings like the type of metal, how thick it is, how fast to cut, etc.
Then you run the file in the Dynatorch host program, which is out by the CNC plasma metal cutting table. The host program communicates from the computer to the table so it can cut the metal.
Kevin is sure somewhere in these programs there is a way to index, or line up, a 4' cut with a another 4' cut so you can put the two together. He hasn't figured it out yet, though, so he came up with a workaround.
On his computer in Sheetcam, Kevin shows one of the arches for the bell sculpture. He shows how to edit the design. He puts in a reference marker, then draws a rectangle that is only about .64" thick across the width of the metal arch. He uses the program to trim both ends of the rectangle, in effect cutting the arch into 2 pieces.
Kevin saves the top portion and the bottom portion, giving him 2 separate pieces to go the metal cutting table. He shows how the ends meet up perfectly, where they will be welded together with a little brace, or gusset, on the back side of the weld to help keep the metal nice and stiff.
Where should you cut a piece of metal that is longer than your plasma table? Remember, you need 4 of these pieces: top and bottom, left and right. Now you have 4 3' pieces to lay out. Having pieces that are a little smaller can sometimes help you nest them so you can get the most out of your metal. If you have one 4' piece, it will take a big chunk right out of the middle of your 4' x 4' sheet.
Back at his workbench, Kevin shows the two pieces of metal cut out. He shows the top section and the bottom section, and where the two meet up. He shows the small piece of 1" x 1/8" steel he'll weld on the inside of the metal arch as a gusset to help keep that joint nice and tight, smooth and flat. After sandblasting, you won't even be able to tell it was welded.
Kevin hopes that helps point you in another direction - there is always a way to "cheat," a way to work around things. He appreciates you watching this video. Please leave any comments below.
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Kevin Caron is ready to go back to work, but you might want to stick around for another moment to see the program say "no" ....
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