I am in need of advice about my MHP mill I purchased. It uses the Hydropath III controller. When I got it home and connected the power and the air, the machine came to life fairly easy. I was worried because it had a rough ride on my trailer for 100 miles or so.
After playing with it for a few days and finally figuring out most of the buttons, and learning how to do a tool change something changed. I started to get following errors on the x axis. I have a complete set of manuals for the machine, but there is not a lot of information about the “Following Error”. If I jog the machine really easy, then I can make the x axis move, but any faster and it faults out. During the few days playing with it, I cut a 2 inch hole in ½ plate, and by using calipers it is 2 inches. There no bumps in the cut when the axis changes direction. I did not have a chance to do any more tests on run out or backlash before the problems started.
Here is what I know about the machine-- It has a 10 HP spindle, with a pneumatic hi/low changing gearbox (50 to 5000 RPM). It has a 22 tool changer that uses BT 40 collets. It has an automatic oiler. It has a Toshiba variable frequency drive, it has some way to control the location of the spindle orientation because the spindle stops at the same position every time. The servos are 94 volts DC ( I think) and use resolvers. The z axis also has a brake on the axis.
I started to do some simples troubleshooting on the x axis tonight, and here is what I found. With the servo disconnected from the ball screw, the servo is still getting errors, and is also jerky. The ball screw appears to be in good shape, and the ways are in great shape. They are boxed ways if that matters.
I am planning on swapping the x and y servo driver just to see if the following errors follow the drive.
Now for the questions---
Should I continue trying to fix the x axis, or plan on starting swapping the electronics out and re building the mill?
I have successfully built a 6 x 12 cnc flame table, and the hardest part for me was figuring out what electronics to use. After swapping parts and have problems, I ended up using granite devices servo drives, US digital encoders, the BOB from candcnc. I also tried the smoothstepper (which I still have) and the c23 BOB (still have this too) from cnc4pc. Power supplies from Jon at Antek.
So what should I buy? I have been reading up about Ajax, and the DSPMC controllers. I would like to stay with the granite devices servo drive. The only reason is that I can order 1 extra drive and use it on either machine. I would also like to use and industrial PLC. I work with AB, Mitsubishi, Fanuc, Motoman, Toyopuc (Toyoda) and a few others at my day job, so I am very familiar with PLC controllers and the Ladder Logic.
I am planning on spending between 2000-3000, to get it running.
Man am I jealous. I had an MHP 83-3000 when I had my (full time) shop and it was a tank. Congrats on a great purchase. I am not electrical, but I could provide names of two companies that still service the MHP machines.
BTW - mine had multiple offsets using E1, E2,...E6 - six work offsets(!), which i used to advantage on more than one occasion.
I would think they are dc servos on this machine.May need the carbon blowing out from the brushes and the motor and tach brushes may need replacing.Something you should check anyway.A dirty comm on the tacho will also cause jerkiness.Clean it with a pencil eraser.
Mark.
I did not know about the brushes on the tack. I was/am planning on removing it to check for a loose set screw or loose wire. I will clean the brushes when I remove it.
Underdog-
It is built like a tank. That is why I purchased it. I figured I would have to replace the electronics sooner or later. Can you send me the name of the two repair centers?
sbfp... is the INDUSTRIAL DRIVES power supply, not a servo. this is a 19" card rack unit that you plug the servo drive cards into. they are part numbers like sbd2-.... they will be different for each axis so you should NOT swap motors or drive cards w/o knowing details of each. We can share this info with you as we actually have spare parts in stock for these still. We build exact duplicate replacements for these also for large aerospace companies using new drive compnents - not something you would be interested in with $$ you want to spend on it. but perhaps we can help you get this puppy back on its feet....
the motors DO have tachs; the bds2 and bds4 drives cannot run without them. what u see is probably a add on encoder mounted on the back of the motors. the motors have tachs built inside their rear motor endbells; 19.8v/krpm units. yES if you are careful you cal try to clean the comms with erasor - good plan mentioned earlier in thread. that very well could be the problem since it ran for a bit before starting to give xcess error.....
the bds drives have green and red lites on them as well as full part nos on sticker on the side of the slide out alum angle bracket. get these and motor part numbers (like TT-5301-102-B-12-C and we can tell u all about them too.
hope this helps u get it going! I can email you drive and motor data and manuals; just ask if you want. Mike@KilroyWasHere.com, Kilroy Corp, (937) 660-5313.
I used to work at MHP ( long time ago)
There are still some guys in the Buffalo area who may be able to help you. I will try to dig up #s for you.
A following error means the axis is not where it is supposed to be at any given time. Could be a lot of things. Check to make sure the ways are oiled.
so you can swap the axis cards to try if you want and not hurt motors or drives. 29360 is another name for a 2936 motor - just newer model no we went to to identify some small change in brushes or something non important to you.
actually remember if you swap the motor leads you also have to swap the tach feedback leads and control command and feedback leads too or the control will run away. be ready on the estop button when you fire it back up swapped around!
I swapped the servo drives and the jerk or glitch or whatever you want to call it stayed with the x axis servo motor. I think that is a good thing. I also applied a piece of tape to the x axis servo motor shaft, so that I could watch it spin. The jerk was not consistant with the rotation or rpm speed of the motor. It appeared to be completly random.
The person I bought the mill from had an old encoder in the control cabinet. I am not sure if it is good or bad, but here are the specs on it--
Opal Encoders
pn- 625-x1xsc1-5600625-5-2-21
it also had a sticker on the side that had
PN
70988
If I go and try to clean the brushes on the tack, is there anything I need to be aware of?
There are 4 plugs on the side of the motor, and i am assuming those are the brushes for the motor. Is that correct? or are 2 for the motor and 2 for the tack.
RAndom shakiness is often tach comm that is dirty yes so cleaning is prob first step.
The Opal digital encoder is for position cnc feedback and most of the time this device either works or does not; seldom does it give your symptoms so I would not bother with it.
4 caps around outside of TT2936x motor are motor brushes and not likely to give your symptoms.
Tach is inside rear endbell. You will need to take encoder off; you probably should try to mark shafts so you put it back same orientation as before dissasembly in case the marker pulse location is important to the cnc.
Let us know how you do. We try to stock tach parts for these motors.
I was able to take the motor apart, and I did not find anything that stood out. I cleaned all four of the brushes, and wiped the commutator (I think that is what is it called) off. There were not any burned spots or shinny spots.
I reinstalled all the pieces and parts, and fired the machine up. I turned the percent of the axis speed down and started to jog the x,y,and z axises. Everything moved as it should. I slowly increased the percent to 100 and still everything was moving good.
I decided to run the home function, and the mill moved to Home. Now the x is back to jerking again.
So I am starting to think the problem might be in the motion controller.
Someone tell me if this might work, or will I let the magic smoke out.
Can I take the servo drive inputs for the x and y and swap just those? This way when the mill jog y axis button is pressed, the physical x axis will move. I know the limit switches will not function, and I am planning on starting slowly and gradually work up the speed.
it does not sound like you cleaned the TACHOMETER commutator just the motor comm... the tach is the little motor like thing in the BACK of the motor - about 2" diameter with its own little commutator and set of brushes. We used a couple different part no tachs on those motors but mostly TGF-2030-A models - it will be marked right on the side of the tach in the back. You gotta clean it not the motor.
that said, if you do it and no improvement then swapping axes is a possibility but NO u cannot just swap the commands u gotta swap the encoder feedbacks too......
Looks like I may have found the problem. On the diagnostic page there is a configuration set-up table. Somehow this table was way off from what is written on the enclosure door.
I changed the settings and all is good (kinda)
I was getting a file editor error, so according to the manual I did a complete reset of the program tables. I think that did the trick. I can now save programs.
I still have an INM Job Directory Checksum Fault. Anyone knows what that is?
Ok time for my first question—
I need to change the battery on the S5 board. I have found several websites that explain how to do this. I am worried about getting the battery off of the actual board. It appears to be glued down then soldered to the board. It looks like I am going to have to break the battery off of the board, then soldered the new battery in. Any suggestions on this?
Question 2
While playing with the settings today, I noticed three different settings for the axis. There are XA, XD, XC, the same for Y and Z
I figured that XA was for Absolute, and XC was circular, but what is XD? Which should I leave it on?
Last question (for now)
I can figure out how to make simple programs for xyz movement, spindle speed, coolant and stuff like that.
Once I get a simple program written and saved, how do I get the xyz readout to zero once I jog the mill to the start point of the program? An example is if I want to drill a 1 inch hole in a piece of plate clamped in the vice.
What you're talking about is a fixture offset. If I remember correctly they are activated in the program with an "E" code (from 1-6). The physical distance from the machine home position to your part zero must be entered in the fixture offset table. Then when you program calls out E1, your part zero is now the zero point for all X & Y coordinates.
The Z coordinates are usually controlled by tool length offsets.