I have some 6" x 6" x 3/8" thick aluminum that I am using to make a few jigs from and need to cut a 3" O.R. on one of the corners of each peice. What is going to be the easiest method and tooling to use to ensure an accurate and repeatable process? This could easily turn into a large qty item to produce. How about inside radius?
Thanks in advance.
Dan
A good quality wood cutting bandsaw with 6 TPI or more bi-metal blade will do it. Accuracy is up to you, but you should be able to cut within 1/32"of the line if the saw is in good tune and you are reasonably skilled. If you can drill a small hole in the plate at the radius center, a matching short pin in the saw table will make the OR very easy to do.
Randy
A waterjet might be the best for quantity production. 3/8 aluminum is well within the efficient operating range. Not sure if the finish would meet your needs, but it would be better than plasma cut, which is another alternative.
Richard
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Dan wrote:
Several ways:
A bandsaw or a plasma cutter would be good for small runs. A circle jig or a template works good for the plasma torch by hand. A fixture would be needed for the bandsaw. I DO NOT recommend this, but some grades of Al can be finished to size with a router (Warning: very noisy and not great for the tool- safety gear is a must, as the chips fly. I DO NOT recommend this as a general procedure, but have done it in a pinch) or with a mill. Will require a fixture for this.
For heavier production, a plasma cutter with a template and fixture for the part is good, or plasma cutter with circle jig part of a fixture (key thing: fixture- takes a bit of work to set up, but worth it for more than a few parts)A small CNC mill could also be used, if available, or a mill with a fixture that allows for turning the radius under the tool.
Real heavy production: plasma table, die, or laser. Not usually worth doing yourself for even reasonably small runs, unless your time is free. A specialty shop is usually quite reasonable for simple jobs, once you get into even the hundreds. For the low quantity end, laser is likely the most reasonable if you don't wnat to invest in a plasma table. The tooling cost for a die can be high.
If you have a lot of plate pieces of varying design in small runs, the plasma table is very cost effective. Program it, run it. Can be just about as good as laser, with only a little cleanup.
Or, perhaps better yet, is to just buy a bigger sheet, and run them all at once without any special fixturing. This would be a lot faster.
Depending on the brand of waterjet used, you can expect tolerances in the neighborhood of 0.002", with decent edge quality. Repeatability is usually right on, but that depends on the brand of machine doing the cutting.
For a list of waterjet job shops that can do the work for you, visit:
If you need accurate, don't have too many to do, and have access to a mill, this could easily be done with a small rotary table, and an endmill. Wouldn't be all that hard to set up a couple stops on the rotary table to allow easy and accurate insertion of the 6"x6" blanks. With a good setup and coolant you would likely be able to make a sandwich of 2, or maybe 3, at once.
DLGlos
Hi Dan,
Another way is to have them water-jet cut. Provided you can tolerate the draft in the cut, and the sandblasted finish on the edge.
A router also works, but it is more productive, and prudent to have a very powerful model, and to use carbide end mills of good quality. I often use a Porter Cable 7539 3-1/4 hp to cut aluminum rounds and hoops from flat stock. It is fast, cheap, easy to set up, flexible, and repeatable. It does produce vast amounts of shavings.
Guy
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