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Author Topic: Bridgeport Knee Mill Conversion?  (Read 159138 times)

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Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #190 on: May 27, 2016, 05:13:25 AM »
Lets re-visit this nugget while i'm planning wiring stuff...


I want/need two spindles here - the main mill quill and a bolt on high speed one - this will be clamped to the main mill quill for starters. Yes it will reduce the Z travel a bit but lets see how it plays before version 2. The aux spindle will only be doing thin stuff and engraving etc so smaller Z travel is probably not an issue.

Obviously when i clamp on the aux spindle it will stop the main Z home functioning so i need two Z homes, maybe two Z++ limits as well?

Ideas -
Two Mach profiles will work - The speed setup will be different for each motor, as will offsets probably and other stuff.
A switch for spindle 1 / spindle 2 - changes limits, motor control, vfd power, vfd control lines etc.?

Will only ever use one spindle or the other. I can definitely see two profiles being needed.

Looking for ways to switch all the lines needed -

Vfd supplies
vfd control and fault lines
vfd speed lines
limit switches for Z axis in two positions
homing for z axis in two positions

probably others....

The programming for the CSMIO plugin I hope will be specific to each profile?

This is a big part of the job - I need two spindles. Control is the issue i think - switching the system from one to the other. No problem doing a cold-start for the changeover - it's a boot-up decision.

Maybe choosing the Mach profile can control the spindle choice?
« Last Edit: May 27, 2016, 05:15:26 AM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline mc

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Re: Bridgeport Knee Mill Conversion?
« Reply #191 on: May 27, 2016, 06:22:51 AM »
E-stops can be a pain to implement.

I opt for limits forming part of the physical E-stop circuit, so if that circuit gets broken, the main power to the drives/spindle/anything else mains powered i.e. coolant pump gets removed.
I then have the KFlop monitoring the e-stop, and should it get triggered, it activates inputs to the drives that trigger them to stop. However, the KFlop has the benefit of being programmed to do this within milliseconds, so it's not reliant on asking the computer/mach what to do.

I know Hood likes to use Safety Relays, that when triggered, will trigger the stop input on drives, then after a small time delay kill all power. This has the benefit the servo drives should remain powered long enough to do a fast controller stop, before power is removed.

I suspect the issue dude1 is trying to mention, is the feature of DC powered drives where they dump excess power back into the DC supply during heavy deceleration, which can cause a voltage spike resulting in over-voltage damage. This doesn't apply to the type of servo drives you're using (it would apply to regenerative drives), but it could cause the drive to trip out with a DC-bus overvoltage error, as they do dump power back into the internal capacitors. If the error did get triggered, all that should happen, is the drive will error out and let the servo freewheel to a stop.

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #192 on: May 27, 2016, 06:34:50 AM »
Ok so the limit chain is N/C and part of the hold-in circuit for the contactor that feeds the main drive, servo drives, coolant, but not the CSMIO and control circuit PSU's. This contactor would have a set of contacts connected to the limits input on the CSMIO to feed back an E-Stop situation..

One issue i can see is that there will be a massive inrush when pressing the reset button as it will be bringing in three servo drives and a VFD in one go - certain to pop breakers i think.

May need a timed start-up?
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline dude1

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Re: Bridgeport Knee Mill Conversion?
« Reply #193 on: May 27, 2016, 06:49:23 AM »
yes
yes
yes

correct

Offline mc

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Re: Bridgeport Knee Mill Conversion?
« Reply #194 on: May 27, 2016, 06:54:45 AM »
I've never had any issue with inrush currents, but you won't know until you try.

Drives/VFDs get powered up when the e-stop circuit is completed and power applied, which is when you're likely to have any surge problems as the internal capacitor banks get charged.
Drives shouldn't be activated until you hit reset, and the VFD should only get activated when you finally turn the spindle one, so everything after the initial power up should be fine.

Offline dude1

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Re: Bridgeport Knee Mill Conversion?
« Reply #195 on: May 27, 2016, 07:07:51 AM »
nc same here but was told off for killing the power to the drivers and the controller, the bob I use and drivers both have a enable so killing that was what I was told was safer, no inrush, no signal no motion.

everyone has different ideas

Explain please, my terminology....

Controller - CSMIO  yes
Drive - the servo amplifier units  yes 
Motor - the servo motor itself   yes

Offline mc

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Re: Bridgeport Knee Mill Conversion?
« Reply #196 on: May 27, 2016, 07:17:19 AM »
There should be no need to kill power to the controller.

Under normal use, the E-stop circuit should always be live, as it should only be activated as a last resort. During normal use, Mach should only be disabling the drives when entering reset.
Continually cycling the power to drives/VFDs can damage them, but that should never happen under normal circumstances. If it is, then you have a problem.

Offline dude1

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Re: Bridgeport Knee Mill Conversion?
« Reply #197 on: May 27, 2016, 07:21:15 AM »
the enable not the power if i turn the bob of it turns the driver enable off, it's probley wrong, I have had some bad advice in the past any way I like hoods idea

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #198 on: May 27, 2016, 07:28:07 AM »
Ok so we'll try all-on in one go - drives and vfd.

yes e-stop circuit always live.

The e-stop circuit is activated by pressing a "Reset" button, this circuit is held in by a loop consisting of as many red e-stop buttons as needed plus the axis limits. Any limit hit or e-stop mushroom pressed would drop the circuit out and disconnect power to the drives and vfd only AS WELL as telling CSMIO that a limit has been hit.

The e-stop would have to be in a run condition BEFORE mach could come out of reset due to the limit input being down until in a safe condition.

Sound ok?
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #199 on: May 27, 2016, 09:53:33 AM »
Back to the OP Panel buttons...

I have ...
cycle start
feed hold
cycle stop
spindle FWD (manual)
spindle REV (manual)
spindle OFF (manual)
coolant AUTO / OFF / MANUAL
SAFETY RESET
PC POWER
FRO knob
SPO knob

Jog wheel will be remote pendant type with axis select and multiplier ratio built in.

Now, bearing in mind I have the keyboard and track-ball, should I leave REF-ALL and AXIS DRO ZERO options to the screen for safety or should they have physical buttons?

For Z axis touch-off I would guess a touch-plate etc would be in use so I'm fairly certain a Z-Ref physical button would be good?

Any more
« Last Edit: May 27, 2016, 09:55:10 AM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives