I’m thinking of making one of these to hold down small aluminum blanks. Looking for input.
It would be like a low profile electromagnet with a super thin wasteboard on top, then the aluminum blank.
Good idea or is a vacuum table superior?
What you will do is create a lot of heat in your part because of all the eddy currents developed. The parts have to be really close to the core, too. Useful AC magnetic fields are usually directed and confined.
The other disadvantage is that AC fields will demagnetize things around it if the things move in and out of the fields produced. However, if you ever turn that thing off without the magnet field current being zero, you will leave nearby ferrous items magnetized.
The main thing you will do is waste a lot of energy.
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I second what @CrookedWoodTex said and would add that you would need to make your magnet and copper core close to the size of t he pieces you are going to try and hold. Not sure if you get a big enough electro magnetic field would you possibly interfere with the stepper motors which are electro magnetic fields themselves.
The vacuum system might be simpler in the long run and you can buy vacuum pumps at Harbor Freight relatively cheap. You can buy larger pumps but the price goes up accordingly to the amount of vacuum you can pull.
What type of material are you interested in machining that methods like painters tape and super glue cannot hold. I have made jigs to hold round objects that worked quite well.
and odd shaped pieces like a big tree cookie with a combination of cam clamps, wedges, hot glue and basic clamps sold by C3D.
So there are many options to hold round and/or odd shaped pieces without a lot of engineering expertise involved.
However the reason men climb mountains is because they are there. So if you have the engineering know how to make an electro magnetic fixture then go for it. Be sure to test it to make sure it does not interfere with your stepper motors or cause unwanted phenomena in the shop.
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Thanks for the advice fellas.
I’m working with around 90% aluminum 5% hardwood 5% acrylic.
Seems like a bad idea to move forward on that project. Not only what you guys mentioned but I just randomly thought while walking my dog ‘wait, if the magnetic field is strong enough to hold down an aluminum plate, won’t it also hold down chips’.
I have a pretty good fence system in place. The issue is I think it warps the bed when I clamp pieces down. The wasteboard was surfaced with no ridges, but when I make cuts and the end mill touches the wasteboard I get pretty significant uneven depth. I’m ordering new screws to make 100% sure I’m not touching the bottom wasteboard and wedging things up.
I think I’ll work towards a vacuum table setup. Tape and glue method is ok but too time consuming, it’s also a bit messy.
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