Bridgeport Manual to CNC conversion...

[Davek0974]

Ok, did some tests, first was to measure slack in the z axis at the adaptor in line with the high speed spindle - I have 0.02mm vertical (with reasonable force) and 0.15mm rotational around the quill - no doubt the source of my trouble.

Left cuts in the first picture below was at the feed recommended by my S&F calculator shown in the last post, 2 passes of 1.25mm ea, top cut is with me applying pressure to the motor while cutting to remove slack, the lower cut is with it running free as normal.

Both cuts look fine, no burr on the lip and pretty much perfect.

The right cuts in the first pic show results of a single 2.5mm DOC pass, same feed rate, again with hand pressure on the top pass and free on the lower.

Both cuts are acceptable this time but they show signs of vibration on the bottom surface - this is not an issue here as this tool is a roughing tool and will cut right through on these parts.

the second pic is just a closer view of the vibration on the second cuts.

Seems I just have to back off on the fast pedal a bit and let her do her thing, plus fit a bungee cord to remove the slop.

[redtom99]

Ok, did some tests, first was to measure slack in the z axis at the adaptor in line with the high speed spindle - I have 0.02mm vertical (with reasonable force) and 0.15mm rotational around the quill - no doubt the source of my trouble.

Left cuts in the first picture below was at the feed recommended by my S&F calculator shown in the last post, 2 passes of 1.25mm ea, top cut is with me applying pressure to the motor while cutting to remove slack, the lower cut is with it running free as normal.

Both cuts look fine, no burr on the lip and pretty much perfect.

The right cuts in the first pic show results of a single 2.5mm DOC pass, same feed rate, again with hand pressure on the top pass and free on the lower.

Both cuts are acceptable this time but they show signs of vibration on the bottom surface - this is not an issue here as this tool is a roughing tool and will cut right through on these parts.

the second pic is just a closer view of the vibration on the second cuts.

Seems I just have to back off on the fast pedal a bit and let her do her thing, plus fit a bungee cord to remove the slop.

[Davek0974]

Started modifying my conversion - I am powering the knee with a servo so i can send it tool length offsets, this will give me full Z travel with any length tool, hopefully.

Got the motor mount fitted today, hopefully get the limits and home switch fitted tomorrow:)

[Davek0974]

Got the limits and home switch fitted today, moving switches and fixed cams so I could do it all with two switches :)
Top switch is limit and bottom is home.



had to alter my plan of homing to top as with the vise fitted the bed will crash...



All the way down, a lot of cranking....



Wired the limit switch into the loop, just the home to take back to cabinet...

[Davek0974]

I'd forgotten how busy it was in the cabinet :)



The knee axis servo drive will have go on the right-side wall i think.

Hopefully get the drive temporarily fitted tomorrow and powered up the day after.

[Davek0974]

Ok, got it wired and powered up.

Little snag to start with, i'm a bit rusty here....

When you take Mach out of reset, the servo starts creeping without command, anyone give a pointer as to where i start digging??

It does not creep for long as you get an ePid fault.

Thanks :)

[m_c]

It sounds like the drive is enabled, but not under closed loop control, so it's creeping until a following error gets triggered.

The drive shouldn't be getting enabled until the servo loop is active, and able to control things.

[Chaz]

Ok, got it wired and powered up.

Little snag to start with, i'm a bit rusty here....

When you take Mach out of reset, the servo starts creeping without command, anyone give a pointer as to where i start digging??

It does not creep for long as you get an ePid fault.

Thanks :)

Enable 'HV Enable' in Mach3 CS Labs plugin. Use the output to drive a relay that enables your drives.

If E Stop or limit is hit, HV Enable will go away and by default your drives will dead stop (remove enable from them). This is what I do on Thor and I have done on other conversions.