Bridgeport Manual to CNC conversion...

[Davek0974]

Ok set speed for 2500 and acceleration for 400, moving right along - servo tuning.

Have done nothing on these apart from an auto-tune in CSMIO setup. I thought the results were ok, but having spent a few hours today scouring the 'net it seems they were pretty bad really. The first video here shows one axis after an auto-tune. Now, I have zero experience with servo's, being stepper builds up to this build, so I stand to be fully corrected but, i think the graph shows pretty bad over-shoot or oscillation?



So, throwing caution to the wind, i dived in and removed all of the "I" and "D" parameters as well as the "ff" or fudge-factor i think its called. That seemed to improve things so i started increasing the gain in steps of 1,000 and the graph seems better to my untrained eye?

The following error is lower, dead-band is reached faster and the dials on the machine no longer overshoot and slowly wind back to a stop - this was a concern as i could see it affecting cut quality etc.

This video was shot after my messing around...



Now, please feel free to rain on my parade, but does the last video look happier than the first?
Is there any issue running with zero "I". "D" & "ff" values?
I can't hear any grumbling from the motors, there is no visible 'hunting' at idle, following errors are down and the dials now stop on a dime as shown.

The Z axis would not tolerate as much gain and did go into permanent oscillation once so i backed off a fair bit but still no "I", "D" & "ff" values.

Suggestions?

[Davek0974]

Some short videos of the conversion in operation, 15mm Alu plate, full recommended speeds and feeds in use...

2d pocket clearing...


2d Adaptive clearing...

I have massively increased the non-cut return speed since this video was taken :)

So far its working well.

[njhussey]

Looking good Dave, always good to see chips flying!!!

[Davek0974]

Thanks, its good to watch:)

USB Issues?

I need USB in the control pendant, USB keyboard/trackball and USB socket for code loading.
Currently i have a cheap 4-way hub and extension but windows is not happy and i get multiple "new device found" chimes every time i start up or plug in a USB stick

Is it best to try a powered hub or run separate extensions to the PC??

The length needs to be 5m to reach.

[Clive S]

Dave can you not transfer files over Ethernet

[Davek0974]

I don't really transfer, the code runs direct from the stick and the rest is just keyboard/trackball

[Davek0974]

USB Issues solved - it works well without the hub and just having two extensions, i have ordered another extension and some clip-on ferrite blocks to suppress any interference.

Also, at last - the adaptor I have mucking about with for the last couple of months is finally done Admittedly it took so long as i was building the machine to make it and figuring out how to operate it but in the end, after ironing out all (so far) of the bugs in tooling, offsets, post-processing etc it really only took a couple of hours.

It's also the first part designed in Fusion 360, that was a learning curve!

It fits the mill snugly and as long as the high-speed spindle motor fits ok, should work beautifully, still got some jobs to clear before i can strip that down though.

Total cost in Z axis travel is 22mm - not bad i thought - that leaves me about 95mm to play with but on a small spindle with tiny tooling that should be ok i think.

Thanks for all help guys

[Davek0974]

I have a tapping head, TapMatic SPD5 - http://www.tapmatic.co.uk/products/p_12.php

It's a self-reversing unit in mint condition.

But it was for a manual machine - you feed in to a quill depth stop, the thread pulls the tap down which disengages the clutch then you pull up which engages reverse and the tap screws out. You need to pull up slightly more than the thread pitch in order to keep reverse engaged.

Now, I don't have rigid tapping, probably never will on this machine, so is it possible to create the feeds/retracts to use this device in CNC or not?

Or, other options?

[komatias]

I have a tapping head, TapMatic SPD5 - http://www.tapmatic.co.uk/products/p_12.php

It's a self-reversing unit in mint condition.

But it was for a manual machine - you feed in to a quill depth stop, the thread pulls the tap down which disengages the clutch then you pull up which engages reverse and the tap screws out. You need to pull up slightly more than the thread pitch in order to keep reverse engaged.

Now, I don't have rigid tapping, probably never will on this machine, so is it possible to create the feeds/retracts to use this device in CNC or not?

Or, other options?

Yes you can, but you need to figure out the depth you are going to end with. I had trouble with Vertex job.

Personally I prefer the tread milling approach. Quicker and cleaner.

[Davek0974]

I have a lot of M6 holes to thread - can you thread-mill that small?