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Messages - BluePinnacle

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Different arrangement here, 4hp 3-phase motor driving the spindle through an expanding-sheave continuously variable drive system. A stepper driving the sheaves would be a tasty upgrade later in life, has anyone tried this before?

General Mach Discussion / Re: phantom limit switch
« on: March 11, 2008, 05:41:15 AM »
I have this as well, on G00 the motor spins up fine then clunks and bangs horribly. I slowed it down and it stopped doing this, was it just going too fast or do i need to be cleverer? mine's quite a big machine so i could do with a decent fast-move rate.

1 - adjust out the play where you can
2 - If you're using mach3, use software backlash compensation.

Why not cut a spiral on an aluminium drum, fit a clock spring and a length of steel bowden cable to it and use linear motion to drive a rotary encoder? these can be had for comparatively little, compared to linear encoders at least.

I imagine a far easier option would be to use a different pin for the spindle.

The charge pump safety is another good trick, and I've sorted my spindle lockout safety as well. It'll disable the spindle while a switch is turned on, and - here's the clever bit - if the spindle is given an m3 or m4 command while the safety is engaged, the relay stays on and keeps the spindle locked out until m5 is issued and the spindle shut off. Then it's open to m3 and m4 again. Just stops the spindle running up the moment the safety is disengaged. it also locks out the drawbar motor and brake release as well, making sure the operator gets into the habit of using the safety.

A no-volt-release switch in line with the spindle would be a failsafe way of ensuring your fingers stay on, and very very simple. But I'd use a different pin anyway. You must have a couple spare.

 ;D Grand.  Much better.

I'm headaching out a small but effective spindle safety circuit which will lock out the spindle and enable the brake release, drawbar etc. to operate. Ideally the safety guards around the machine should lock-out the spindle contactor, but not everyone can easily fit this much guarding. :(

a good point, printer drivers are pretty dumb. I've never had this problem but then I set up my CNC box from a bare disk, and I've never installed a printer on it.

use a different pin? pin 1 is usually reserved for the strobe line.

A good point. I've seen no end of nuisance caused by lots of single phase equipment running together on different phases. It all stopped when we got our customer to fit it all to one phase only.

I've got all my 240v control gear, contactors, lamps etc. and 9V control supplies running off L1. L2 and L3 only do motors. So far i've had no problems doing anything despite pretty crappy shielding.

I'm very fond of my pin 1 strobe safety, which locks out all power to the contactors unless it can see 12.5KHz on its pin - And since mach3 starts in Estop mode, it hasn't clunked once since i wired the thing in. I could hear a few clunks and grumblings from the relays and contactors before i fitted the strobe safety, it's dead quiet during startup now. I'm also putting in an interlocked safety for tool changing so that not even an M3/M4 command will start the spindle while a tool's being changed. Worth doing since i won't be the main user of this machine... other people's fingers are VERY expensive.

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