I need some help with a slipping open loop mill.

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?

Check acceleration try to decrase it, high acc demand high tourqe.