Wednesday, 26 December 2012

Milling the first Cup

You may have seen the gcode i posted, it was looking great until i realized that the mill wasn't yetup to the job, the Z axis has about 2.5mm of backlash!!! that's just NASTY if your code makes this axis go up and down... really need to stop playing and attach a gas strut piston to hole up the head. get rid of the backlash, not too sure how that all works will have to find that web page that suggested it as a solution and double check what i am thinking.

So while i was setting up to cut the first of 24 coil cups for the magnetic bed i ran into a small electromechanical issue, the handle on the Z axis caught a wire which cause the loom to get pulled which in turn caught and pinched the Z stepper wires and proceeded to release the magic smoke that killed the axis' stepper driver. Not happy jan...

After i sorted that problem out i proceeded to attempt the first cut thats when i found the Z backlash to be bad, so i changed the code so it only drives the Z axis in the downward direction, making the backlash not a problem for now..

 I Loaded up the chuck with a 7mm 4 flute end mill cutter slapped a chunk of 25mm hex bar into the jaws of the dividing head and set the Z axis to be 16mm in SW and HW and hit play.. the results are below.

video
the gcode that's running in the above video is plunge 0.25 then spin then spin back then  repeat. today i have some new code that i wrote that will plunge as its rotating and not need to spin back to reset the axis.

I discovered that i really really need to mount the DRO scales permanently they have about 0.5mm of backlash in them.. i will replace the temporary double sided tape for screws.

in the video you cant quite see it but we jury-rigged an air blower up to clear the swarf from the job and spread it far and wide across the workshop..

we smashed a 7mm end cutter into a ball of brokenness when i was playing with some settings and spun the job in the chuck at a speed FAR FAR too fast the slider was reset between reboots and i forgot the defaults are still dangerous!... oh well another $5 on ebay.. i have more cutters to replace i have lunched a few while learning the limits of the mill, these cutters are dirt cheap so i dont mind..

I was meant to make the drive bolt for my printer as the first project but unfortunately i dont have the brass rod thats the right size for the job :( so i am keeping my self busy while i wait for the steel store to open :)

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