Bridgeport Manual to CNC conversion...

[Davek0974]

Found a local company to move the bores and counter-bores on the Y axis bracket - so annoying having to get stuff done outside when it would have taken me about 15mins to do, I had to leave it most of the day, make two 30min trips and stump up £40 :(

Anyway, done now and fits nicely, also mounted the motor plate using some spacers to pick up on the bottom of the counter-bores at the top face is not flat. Had to make a shim for the bearings to give a bit of pre-load but not bind up. Next job is to turn up a spacer tube for the pulley-to-bearing gap and then fit the belt - one axis finished.

Will also be planning limit switches this weekend, metal has not arrived so can't make the X axis plate yet :(

[John S]

Still got this step speed head unit with a brand new 3Hp 1425 rev motor and conversion plate, you just need a VFD to run it.
£300 to get it out of my way ?

[Davek0974]

Hang on to it a little longer, lets see if this one will survive, if not i'll be in touch ;)

[Davek0974]

Got X-axis motor plate fully fitted...



Limit switches next, Y-Axis Limits and home switches...



From the left we have Y--, Y-Home, Y++.
The home switch remains tripped once it trips so that i can home even if the switch is triggered, a home-offset value will take care of the switch position.

Then the X-axis, a bit harder this one, first idea...



From the right we have X-home then a dual-direction X-- & X++ switch. The picture is not quite right - imagine the right-hand switch is another roller type like the left one, I have one somewhere, just got to find it ;)

The only down-side I can see is that it blocks the chances of using flood coolant again as the switches are in the way of the left drain hole.

Still thinking on this one.

[Davek0974]

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I hooked the rebuilt head up to my VFD today, sounds a hell of a lot better, for some unknown reason it runs a bit warm around the top bearing plate though.

Its not quite right though yet as the vari-speed system seems to do nothing in the higher end when in back-gear, but is ok in normal gear??

[Davek0974]

Nearly got the x-axis motor fitted, once that's on I can lash-up the drive and controller and do motion testing :)

[Davek0974]

We have motion In 2 axes at least. Done some basic servo tuning, cut the top speed to 5000mm/min as 7500 was just too scary. Got homing and soft limits working nicely. Homing is silly-accurate with index-homing turned on - about +/1 0.01mm or better as far as i can measure.

Next I fitted up the Spindle VFD, expecting serious issues with my complex manual/auto speed control idea. I was totally amazed that I have perfect control of speed from 40rpm to 3000rpm within about 25rpm tolerance! It tells me to choose back-gear or high-gear and high or low speed-pulley setting depending on speed chosen by code.

The only issue it does have is that if it is set for say 100rpm in back-gear low range, and the code calls for 2000rpm in high-gear high range, it will spin up the spindle and then tell me to change gear - this cannot be done without smashing the drive.

I have all the code in SpindleSpeed.m1s - can it also be made to stop the spindle and restart it after pressing enter without wrecking the code-flow etc ??

My bench-top lash-up, well it's not a bench but the plasma-cutter but here you go ...



Going to need a pretty big cabinet.