Nomad pro Spindle sounds like it's loosing power

(Rob ) #1

I’ll try to post a video of what’s going on but I notice that the spindle sounds like it’s loosing RPM and then correcting for it even when there’s a constant chip load. At first I thought it was something funky with my material (6061-T6) but it’s had the same behavior on a few different samples. If I try to push it any harder than what’s below the spindle stalls.

Should I be taking a significantly smaller cut? It seems like the only way to get the job over with faster is to take light passes at high feed rates. I’m used to milling with a Bridgeport so my intuition is usually incorrect when it comes to the Nomad.

Tooling/Feeds/Speeds:
.125 x 1/2 LOC 2 flute ZNR coated end mill
9900 RPM
Feed rate 16 in/min
DOC .030 in
Stepover .015 in

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(mikep) #2

That’s a pretty significant cut for the nomad in aluminum - it just doesn’t have a lot of power. Try cutting the stepover to .010"

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(Vince) #3

That doc is pretty heavy and I’m showing a maximal chip of 0.0005 which is dangerously low.

Imo, start the doc to 0.010 and at least 40ipm. That will net the same MRR as your previous recipe yet will cut a 0.0013 chip. Then slowly raise speed and doc until you see too much strain, then back off 10%.

I run a mill with 70 watts as well and it takes a mix of new age toolpaths and constant loading with oldschool light doc and fast to run well.

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(Rob ) #4

Thanks all, that helps! It’s nice to know I’m not going crazy… yet

Are there any rules of thumb for trading axial vs radial DOC? Can I trade thou for thou?

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(Vince) #5

Your radial doc is the most important and needs to be calculated with chip thinning in mind if you are cutting less than 50% diameter. This is a good calculator

http://www.iscar.com/ita/Calculators.aspx?units=M#

Radial changes = actual work being done per revolution. Very important to get this in the sweet spot for a good cut. Good to start at 0.0008 for small tooling and 0.001 for larger.

Axial changes = overall load increase or decrease. Mainly effects overall material removal rate. Full width contour slotting you’ll want to start at 0.005 doc and adaptive can go quite a bit deeper.

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(system) closed #6

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