[Jay C]

YouTube - High speed spindle mount[/ame]

[Jay C]

X2 Mini Mill with the CNCFusion ballscrew kit
KelingInc KL23H276-30-8B steppers
HobbyCNC Pro 3-axis driver
Homebuilt linear PS 32V 10A
Mach3 software
Drawn in Autocad, CAM using CAMBAM 0.8 freeware
Feed 6ipm for both cut and plunge
Spindle speed 4200 RPM using a KBLC driver and the Harrisson belt kit
Tools: .5" 4-flute endmill for pocket .125" endmill for the rest
Depth of cut: .025

The part is a high speed spindle mount for a Wolfgang Engineering spindle. The material is T6061-T6 .5" aluminum plate. The pocket is .25" depp, the mounting holes are .25" in diameter and the spindle hole is .758" in diameter (were it a true circle that is).

Pros:

• The tram is right on, the pattern left in the aluminum by the .5" bit looks great to my eyes.
• The machine cuts aluminum and the enclosure contained the mess
• Belt kit is quiet.
• Adding in tool changes to the generated Gcode was trivial. I do still want to build the touch off plate. I already have the signal wire connected and configured.

Cons:

• The spindle got blistering hot. I don't want to have to take it all apart but alas I will have to to replace the bearings as others have done.
• Backlash. Despite measuring and turning on backlash comp in Mach3 my circles are eggs. I am now planning on reloading the y-axis as I have .011" backlash measured. X was measured at 0" backlash before this job, but the circles are linger in the diagonal (/) so it has to be a bit of both axis.
• Using the pvc as a spoil board was ok ... but, it wasn't long enough and so the clamps pulled the front of the part lower than the rear (as viewed in the video) thus the part was "cut through" at the end of the job. I reran the last profile and as it cut through, the part was grabbed and gouged by the bit. I should have added or moved the clamp to hold the part. The gouge has no affect on the part and was easily sanded away.
• The .5" x .25" deep pocket didn't extend out far enough and I ended up with two "ears". I hand filed these away.

Jay