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Hypotenuse
12-13-2015, 12:16 PM
I am having trouble cutting anything just over 4", with a Z limit error coming up.

Only thing in the ShopSabre manual is that G37 sets lower Z limit and calibrates switch. Poorly worded or I'm just dumb.

The center of the chuck on my 4th axis is about 4 3/8" so it must be possible to go up to 8"or so. Haven't used it yet, maybe on Xmas break.

Trying to surface a 4.5" thick burl. I have material set to 4.5 machining from the top in Aspire by Vectric.

Any suggestions appreciated. Did manage to cut a canoe hull portion last night.

DigitalOi
12-13-2015, 10:20 PM
I am having trouble cutting anything just over 4", with a Z limit error coming up.

Only thing in the ShopSabre manual is that G37 sets lower Z limit and calibrates switch. Poorly worded or I'm just dumb.

The center of the chuck on my 4th axis is about 4 3/8" so it must be possible to go up to 8"or so. Haven't used it yet, maybe on Xmas break.

Trying to surface a 4.5" thick burl. I have material set to 4.5 machining from the top in Aspire by Vectric.

Any suggestions appreciated. Did manage to cut a canoe hull portion last night.

http://www.camheads.org/showthread.php?p=41942

This thread might help. Camaster uses wincnc as well.

Hypotenuse
12-14-2015, 07:46 AM
Well it mentioned disabling limits in the Camheads thread but it still got a Z error when I typed in L21 (disable) it automatically ran L20(enable) in the code following the error message.
I'll email ShopSabre today.

islaww
12-14-2015, 08:48 AM
You don't state if your error is a +Z or -Z error. I assume with the thick material it is a +Z error. This is usually a result of Material thickness + Bit length + Safe Z setting that is higher than the machine can physically move. Check your design software to see if you can lower the safe, or rapid Z setting

Hypotenuse
12-14-2015, 04:32 PM
OK looks like I had the Home /Start position going from the spoilboard but I guess it references from the material top, duh on my part !
This is my own CNC I recently bought with Aspire, I'm used to AlphaCAm and an OSAI controller.
I'll try cutting the burl tonight and post results.

Hypotenuse
12-14-2015, 11:01 PM
I managed to surface my burl tonight, thanks for all the help! It weighed 75 lbs before machining. I tried a few different approaches to get the best surface finish.

Climb and conventional, offset and raster. I used a new but really cheap 1" dia 2 flute straight bit. Tried 12,000 to 15,000 rpm.

It was hard to notice much difference. Its down to 3" thickness, but before machining it was quite irregular so I used a hand power to trim a few high spots.