I need some help with a slipping open loop mill.
I’ve got a MaxNC 15 open loop desktop mill that I’m using to route out some oak for a project. It’s feeding at 4in/min with a spindle speed of… err… full speed, I don’t know. I just crank the knob up all the way; I’ve never measured it.
By this point in my post, you have probably already realized that I am neither a machinist nor a wood worker. I’m an EE and Computer nerd. So I don’t REALLY know what I’m talking about, I’m learning/making it up as I go.
When routing oak with a .500" router bit and a .250" depth, it keeps slipping steps. By a lot. A 4" travel slipped about .150". I was able to use this same bit and feed rate to route pine with much less of this kind of slippage (though not zero.)
My question to the community is: What can I do to this mill to make this better? With my limited knowledge, I can see 4 options, in order of increasing cost:
1: Slow down the feed rate even more, but great gravy it’s already agonizingly slow. I’d like to avoid this if I can, and am willing to spend some money to do so.
2: Get better motor drivers. It’s currently running a 12v system, which won’t give a lot of torque at high feed speeds. I could retrofit it with something like this: http://www.ebay.com/itm/280911250280 that would be able to push more current more quickly through the coils, giving it more torque and hopefully have it slip less.
3: Close the loop. Put encoders on the feeds. This would require new electronics too, since the current electronics don’t support encoders. If I’m going to replace the electronics, I might as well do #2 above while I’m at it.
4: Given up on the MaxNC and buy something better. Lots of dollar signs here.
Is there something I’m missing? Any other suggestions? Recommendations on electronics packages?