Will Acorn work on my little VMC

[craigc]

I have purchased a Little VMC without the original PC based controller (missing), it was sold in North America under the Rockford name but it is a Hercus machine manufactured in Australia in the early 2000's.
There is no support and very little info on the model I have.
It has
- a 8 position carousel ATC with a 24VDC servo motor on a pneumatic swing arm with a index micro switch and a AMT 102 encoder. 32 motor revs per 1 rev of carousel 32:1.
- Baldor / ABB spindle servo and servo drive, belt driven BT30 spindle. The spindle servo has a resolver and the drive can output encoder signals based on the resolver. I would connect that to the Acorn. Spindle is 6000 rpm but spindle servo is 3000 rpm. I "think" the 1:2 drive ration should still work. I don't think it would work in 2:1 ratio. Pneumatic tool grab / release with manual release button as well as a solenoid for NC controlled grab / release.
- 48VDC servo motors on X,Y and Z axis driving ball screws on the 3 axis
- flood coolant system
- I removed the 4 original undocumented servo drives that drove the 3 axis and ATC carousel and purchased 4 Gecko G320X servo drives as well as upgrading all the encoders to the new AMT-102-V encoders.
I bench tested the new G320X drives with original servo motors and new encoders and it works nice on the Acorn

I'm not sure if my Acorn and Ether1616 is capable of running the Little VMC, do I use the 4th axis to drive the carousel and hope I can drive the spindle with the Acorn 0-10V analog signal and program the spindle drive to use a DI for direction?. Or should I use the 4th axis to use step and direction to the spindle drive and figure out another way to drive the ATC. The Spindle drive is a ABB microflex and I have used the ABB Mint software to tune the drive but that's the extent of my knowledge.
I think I can set the drive to position mode and hopefully have the spindle "orientate" every time it stops for use with the ATC, I'm just guessing, no experience with this stuff.
I can get photos, more info on the spindle motor and drive if that will help.

Thanks in advance

Micro_drive-25.pdf

(1.28 MiB) Downloaded 66 times

[martyscncgarage]

I have purchased a Little VMC without the original PC based controller (missing), it was sold in North America under the Rockford name but it is a Hercus machine manufactured in Australia in the early 2000's.
There is no support and very little info on the model I have.
It has
- a 8 position carousel ATC with a 24VDC servo motor on a pneumatic swing arm with a index micro switch and a AMT 102 encoder. 32 motor revs per 1 rev of carousel 32:1. Are you sure it is a servo motor with encoder and not a DC motor to turn the carousel? Does the carousel have sensors on it? Can it detect each tool position?
- Baldor / ABB spindle servo and servo drive, belt driven BT30 spindle. The spindle servo has a resolver and the drive can output encoder signals based on the resolver. I would connect that to the Acorn. Spindle is 6000 rpm but spindle servo is 3000 rpm. I "think" the 1:2 drive ration should still work. I don't think it would work in 2:1 ratio. Pneumatic tool grab / release with manual release button as well as a solenoid for NC controlled grab / release. Acorn outputs 0-10VDC [or 0-5VDC) analog output typically used on most VFD's. You will have to see what kind of signal your Baldor/ABB drive requires or how it was running previously if you want to retain it. Option is to replace with a small 3 phase motor and VFD
- 48VDC servo motors on X,Y and Z axis driving ball screws on the 3 axis Servo drives must take step and direction signals. Post pictures of the servo drives and servo motors along with make and model numbers and links to their manuals
- flood coolant system Not a problem
- I removed the 4 original undocumented servo drives that drove the 3 axis and ATC carousel and purchased 4 Gecko G320X servo drives as well as upgrading all the encoders to the new AMT-102-V encoders. It would be helpful know exactly how the ATC works and why it had 4 "SERVO" motors.
I bench tested the new G320X drives with original servo motors and new encoders and it works nice on the Acorn Properly tuned, the G320X works well.

I'm not sure if my Acorn and Ether1616 is capable of running the Little VMC, do I use the 4th axis to drive the carousel and hope I can drive the spindle with the Acorn 0-10V analog signal and program the spindle drive to use a DI for direction?. Or should I use the 4th axis to use step and direction to the spindle drive and figure out another way to drive the ATC. The Spindle drive is a ABB microflex and I have used the ABB Mint software to tune the drive but that's the extent of my knowledge.
I think I can set the drive to position mode and hopefully have the spindle "orientate" every time it stops for use with the ATC, I'm just guessing, no experience with this stuff.

Moving axis is the easy part. Your spindle drive and your ATC is doable, its whether or not you can use the original motors and you need to verify exactly what kind of motors were driving the ATC. Are there any YouTube videos on this machine?
I can get photos, more info on the spindle motor and drive if that will help.

Thanks in advance

IMG_20210912_134130_0.jpg

IMG_20210912_134113_6.jpg

IMG_20210912_134100_8.jpg

PXL_20210429_132839998.jpg

PXL_20210429_133108074.jpg

PXL_20210701_203202754.jpg

PXL_20210701_203117229.jpg

s-l1600.jpg

Micro_drive-25.pdf

[martyscncgarage]

In looking at your pictures again, I think you could run the ATC by adding one sensor and a trigger for each tool position. Reuse the DC motor to rotate the ATC.

I see it has an encoder. Any markings on it? Possibly a manual on line?
How does the ATC move in and out? More pictures?
You could use a pneumatic cylinder with sensors on each end of its travel, would be carousel in and carousel out

[craigc]

Thank you for looking at my post,

This machine has had very little use, there was a bit of wood shavings in the chip tray. It has never had coolant in it either.
I have replaced all the encoders on the 3 axis as well as the ATC motor shaft, they were the old HEDS type. I replaced all 4 on the machine with the new CUI AMT-102-V encoders.

amt10-v.pdf

(925.82 KiB) Downloaded 57 times

There were 4 servo drives originally but zero info on them, 3 were labeled as X,Y,Z and TC (ATC) each had the respective HEDS encoder connected to each servo drive as well as the limit switch for each connected to each drive.
X,Y and Z had 48VDC connected and TC (ATC) had 24VDC. TC servo drive in my hand.

The 3 axis servo motors are working fine with the new Gecko G320X drives and new encoders, I bench tested them with my Acorn DB25 connector. The servo motors are Electrocraft S240-1AB which are a earlier version of below.They are amazingly powerful for their size and run almost silently.
https://www.electrocraft.com/products/pmdc/DPP240/
They are still sold but out of the UK.

Here is the X axis servo motor with a grey plastic cover over the old HEDS encoder. There is very little room for the servo drives in the mill.

The ATC carousel motor is a Johnson HC970, I cant find anything on the Johnson website for HC970 but did find this today.
https://www.directindustry.com/prod/joh ... 17083.html
Maybe it is just a DC motor, I just presumed it was a servo motor because it had the exact same kind of drive as the other 3 axis.
There is no sensors on the carousel other than the encoder and the index microswitch on the driveshaft of the carousel that seems to be indexed to tool 1.

The ABB spindle drive can take +/- 0-10V or step/direction, I will have to see if I can program the drive to use 0-10V and its digital input for direction.

The spindle drive is a ABB FMH2A06TR-RN23W Microflex
https://new.abb.com/products/3AXD500000 ... 06tr-rn23w

There is VERY little info on this machine, there is a little for the benchtop Hercus lathes. I have looked for months, I even joined the Hercus facebook group. A couple of people have mills similar to mine but don't have the enclosure or ATC.

Thanks again for your time

[martyscncgarage]

Here is the drive I find for your spindle drive:
https://search.abb.com/library/Download ... ion=Launch

It looks like it takes +/- 0-10VDC analog signal.
Acorn will only give you a +0-10VDC analog signal for forward control

You might consider getting it going that way first. THEN consider the C89 controller from CNC4PC. It will give you what you need along with Acorn to be able to reverse your motor.

I would consider keeping the DC motor on the carousel and use a NPN NC Proximity sensor to detect the head of a bolt, placed precisely each tool position. Would be good if the proximity sensor has a little adjustment.

Get the axis and spindle going first, then work on the ATC last. How does the carousel go in and out of the tool change position?

[craigc]

Hi Marty,
In reply to your second message about the ATC moving in and out is exactly how it works now. The pneumatic cylinder has magnetic reed switches at each end. A picture of the pneumatic control solenoids for the ATC is in the first group of pictures I posted in the first post.

[martyscncgarage]

I see everything now. I also see there are holes right behind the keys on the ATC. Is there anything in them? You might be able to use them for tool counting.

I see the keys now, you say you use BT30 tools and there are locating keys in the carousel. So, the control must have noted the encoder position, and subsequently when called to orient, it would rotate the tool to that position. This is why it is important to completely understand how the ATC system works.

Marty

[martyscncgarage]

You could treat rotating the ATC as an axis, but then you loose the ability to have a traditional 4th axis...

[craigc]

I was just going to ask about that, With a C86 would the mill be capable of rigid taping? if so I will use the 4th axis to drive the ATC. Its a hobby machine and I'm just learning It will be some time before I'm capable of using a traditional 4th axis. Maybe Centroid will come out with a 5 or 6 axis Acorn by then.

Thanks again

[martyscncgarage]

I was just going to ask about that, With a C86 would the mill be capable of rigid taping? if so I will use the 4th axis to drive the ATC. Its a hobby machine and I'm just learning It will be some time before I'm capable of using a traditional 4th axis. Maybe Centroid will come out with a 5 or 6 axis Acorn by then.

Thanks again

Sorry, I meant C89 board from CNC4PC:
https://www.cnc4pc.com/c89-10vdc-analog ... board.html

It will provide +/- 0-10VDC analog output.

To do rigid tapping, you need to have a line driver differential encoder belted at 1:1 on the spindle.
Is the SERVO motor belted at 1:1 with the spindle?
You still have to work out spindle orient...