Hi Gene,
The Z axis ball screw attachment is a bit weak and is not very
consistent. It attaches to the quill with a 1/4" screw and another one a
bit bigger. And the X ways have a bit of wear so the saddle dips a bit
in the middle.
JT
On 5/28/2017 10:25 AM, Gene Heskett wrote:
On Sunday 28 May 2017 08:20:24 John Thornton wrote:
I wish the BP knee mill Z was good enough to 3D print I'd give it a
try... I just need to get on with making the CoreXY printer.
JT
Whats the problem with it John?
With the weight its carrying, I wouldn't think dropping 10 thou to put
down the next layer would be a problem, even with an acme screw in it.
All that should mean is that you'd need a 4x bigger stepper to lift it.
This is much the same problem as I had in a scaled down size, with
lifting the head on the g0704. It turned out that whoever suggested I
replace the 1600 oz-in nema 34 with a 950 oz-in nema 34 was quite
correct. The low current, very high inductance 1600 quickly ran out of
torque going up, so about 27 ipm was the best it could do. Replacing it
with a 960 oz-in 8 wire, and its driver and power supply with an
integrated driver/$upply, and it can now do 70 ipm up the tower.
And it runs 50F cooler doing it.
So, since I had them, that motor and driver are on the Z screw of the
Sheldon, where it can do even with some geardown in the timing belt,
something it the 65 ipm range. But I am not impressed with the dm860
driver, its step to step size is plumb doofy, one step in the 8 its set
for cannot be heard or felt, and now that the stuff inside the lid of
the power electronics box will be gone, I'll have room for a taller
auto-tech k6080 to replace it, 6 amps at 80 volts. I've around 65 volts
to bang it around with, and I'll bet the improved smoothness will let it
do 90 ipm. Now if I could do the same with the 8 wire, parallel
configured nema 24 on the X screw, I'd be happy. Thats a small, unk
pitch 8mm screw of unk make, and its out of steam and may stall with a
2/1 geardown, at 37 ipm. Same screw is on TLM's x, direct drive, does a
g76 retract fast enough I can cut threads at 400+ rpms. But on the
Sheldon, which will be turning slower most of the time, I traded speed
for holding, or being able to program any taper I want by having enough
twist to move it under cutting loading.
On 5/27/2017 8:54 PM, andy pugh wrote:
On 16 May 2017 at 14:27, Gene Heskett <ghesk...@shentel.net> wrote:
Has anyone put a printhead on a std moving table milling machine,
and used it to do some 3d additive printing?
https://www.youtube.com/watch?v=NEyL6cVWlo4
So, it clearly can work.
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Cheers, Gene Heskett
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