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Author Topic: 20 yr old cnc control needs replacement, and i need help.  (Read 14686 times)

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Offline Hood

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Re: 20 yr old cnc control needs replacement, and i need help.
« Reply #10 on: April 16, 2012, 03:10:45 AM »
I wouldnt go with steppers personally, they can and do work fine in some applications but by their nature they are noisy, as you have mentioned,   they are relatively slow and acceleration is poor in comparison to servos. As you have noted steppers are open loop but again as you noted if properly sized that should not cause a problem.
Regarding Servos, as Terry mentioned they have to be closed loop by their nature, where the loop is closed varies but with Mach it is in hardware. Whether that hardware is the drive or the control hardware will depend on what you have.

Few options I see for you are get something like the CSMIO/IP-A or DSPMC or Galil or KFlop/Kanalog and use your existing analogue amplifiers or get new drives that can accept step/direction or lastly go with something like the Machmotion which although basically you will end up with the same hardware it is in a kit form.

If thinking about other drives then presuming your motors are DC and fall within the current and voltage range have a look at the DG2S-16035 drives from www.cncdrives.com, they accept Step/Dir so the loop will be closed in the drives.

Which route would I take if it was me? well I think if the amplifiers were sound I would have a look at the CSMIO/IP-A. I have never used it or any of the other options of analogue control for that matter, but the specs look good, hardware looks good especially the I/O being 24v and the price is alo reasonable.

Whichever way you go is going to need some learning, the Machmotion route likely the least but also it will be the most expensive and possibly not the best as you will not be able to tailor it to suit your exact needs.

Re: 20 yr old cnc control needs replacement, and i need help.
« Reply #11 on: April 16, 2012, 02:36:33 PM »

As I understand your post, the problem with your 20 year old mill is the old DOS computer. If the motors and servo amplifiers are not burned out or malfunctioning there is no pressing need to rip them out, or change them for some other make. They have lasted this long, and are also sized correctly for the machine requirements, i.e., mass and weight of table and cutting loads.
Machmotion makes several levels of machine kit/retrofit systems. Stepper motors and amplifiers are far cheaper than servo motor/amplifier encoder feedback systems. That is reflected in the final cost you see for the different kits.

The dspmc controller used in the Machmotion 1000 controller costs over a thousand dollars, all by itself. It is a highly sophisticated, state of the art electronic system. It does all the motion control mathematics and feedback handling as a totally separate entity from Mach3. The two communicate, but the dspmc does all  the "heavy lifting."

You can keep your current Westamp motors/amplifiers/power supply, and utilize a Machmotion control kit with the screen/keyboard/controller and just wire up the existing encoder wires, reference switches, and analog signal wiring to the controller 1000, and you will have a working system. The Westamp limit switches are already wired into the amplifiers, so you do not even need to worry about them.

My Westamp motors and amps are easier to tune, smoother and faster than the original system. My rapid on the X axis is over 220 ipm on a 52" X 11" table, and I personally do not like to try to jam the machine at the highest speeds possible. This is not the fastest speed possible for a mill, but it works fine for all my machine uses. I tend to run my machines conservatively anyhow. 
If later you wish to upgrade to newer servo amps and brushless AC motors, you can do it, but it is not a necessity to have a working machine. The newer AC drives and motors are faster, more powerful, and of course off-the-shelf, but that is all a personal choice. If you decide to change motors and amps, you will be into making new motor mounts, couplings, motor power cabling, new seal-tite cabling,new encoder cabling and wiring. All of this is in addition to the basic cost of the parts. Not a trivial task.

If you choose to go with the touch screen option that Machmotion offers, you will have a system that is akin to the best industry has to offer. A touch screen plus an MPG will result in very user-friendly machine, and they look great too!

Re: 20 yr old cnc control needs replacement, and i need help.
« Reply #12 on: April 18, 2012, 08:18:51 PM »
im back! i have read these posts over and over, i think the necessary path is becoming clear.  i am competent mechanically, but an electronics noob.  the only way i could get into modifying my current system with pc parts that i would need to wire myself would be if there were a mentor close to me in the s w NH area.  that would be a great experience and education, in lieu of that, i think i need the "kit" solution, where i will mostly just do the mechanical install.  i do have electric/electronic help available, but he has not done a pc based system.  it is very attractive to anticipate having a modern computer, control software, brushless motors & new amps, and i am pretty sure with a lil help my vfd, mpg, mist and oiler will integrate nicely into the system.  but i cannot see trying a pc part electronic install by myself, i can close my eyes right now and see the blue flash and smell the ozone!   :o

i am still puzzling over Machmotions required inclusion of the 1000 controller with the servo lathe systems but not at all with the servo mill systems.  i will talk with them soon im sure they will clarify.  their systems are the priciest of those i looked at, but not so bad considering nearly everything is already there and appears to be top shelf.  it took 4 months of part timing eves in the garage to put the $$ in the cookie jar, it is there and its time to sh** or get off the pot.  with both of my "good" machines down, i have been making stuff on my chinese 7 x 12 lathe, and mostly on my rong fu 40 round column gear head mill.  i am damn tired of counting dial revs, esp with .03 backlash screws, loosing x, y & z each time i move the head and hand cranking the machine, it will be so nice to mdi type g1x10y2f5 and push the button again, not to mention being able to do multiple features in a shot rather than putting the part in and out of the vise for ea feature!!!

i will need to fairly (to buyer and to myself) price the old westamp amps and motors coming of the mill, and the fanuc stuff coming of the lathe, to refill the cookie jar for when the mill is done and its lathe time.  i do want the mill and lathe on the same brand pc based control, the thought of the expensive fanuc man having to head to my shop lugging expensive fanuc parts is scary.  my mill had a couple years of light duty on it when i bought it, and the nardini fanuc had 6 years of the same, in 8+ years of running both, the mill was noticeably less trouble far as little breakdown issues, even though the mill ran about 2x as much.  so i am a fan of systems built from available items rather than proprietary stuff.  if i get a blanket order someday for 100000 widgets, then maybe a "real" control is in order.

thanks again for your input!!

Re: 20 yr old cnc control needs replacement, and i need help.
« Reply #13 on: May 31, 2012, 07:54:12 PM »
an update for those who care.

the fellow who was helping me with the old 486 tried a few things including building a customized motherboard from some of his old stuff, not so good, we eventually sourced a couple old lightly used pentium boards, and dumped the old hard drives in favor of an ide interfaced compact flash card reader.  i have a full spare motherboard and 2 spare cf cards that are cloned to the one we're using

its in the machine and the oem software is up and running the machine.  not real well tho, im getting a lot of what i think are encoder based errors "position" "end point precision" "following error".  the x and y axis on lights will wink off and back on quickly, then come the errors.  the machine does not like to be driven by the jog keys or handwheel, these errors pop up after a lot or a little movement.  but go to jog increment mode and set a distance of 1 or 2 or .25 inches, and the machine seems fine with it.  run a program and the errors pop up after 5 or 6 or 8 lines, run a program with a lot of tiny spiral moves and it seems the errors come quicker

the machine did sit 8 months thru a cold unheated winter and a warm wet (humid) spring.  im wondering if letting things get warm and dry again and running the machine a bit will clear this up.  also going to unplug and replug as many related connections as i can, maybe some corrosion in the contacts.  write some test programs with different types of moves and try to pinpoint what causes it the most.

as before im all ears to suggestions, and even tho it seems still wounded, it is nice to see it alive again.

after reading a lot about the mach3 interface, im wondering if it will run on this machine as is (less the problems), i like what i see compared to the oem system


Re: 20 yr old cnc control needs replacement, and i need help.
« Reply #14 on: May 31, 2012, 09:47:13 PM »
it just may be that simple. corrosion of a terminal or connector. before i converted a bridgeport r2e4, i had tried a few things to get it to work. been a while  but the manual had directions for removing boards and washing . let dry and reconnect. also about corrosion at any ic chip sockets. push on the chips carefully.
Re: 20 yr old cnc control needs replacement, and i need help.
« Reply #15 on: May 31, 2012, 10:06:52 PM »
Hello again Metlcutr55:

As said, there are lots of little connections to corrode. Good advice on connections.

The feedback to the control is not 100%. The motor feedback is the tack signal, which goes to the amplifier, and the encoder feedback goes to the control, and it is only a 5v signal. The older encoders used an LED, or a tiny light bulb, interacting with a glass scale. There is a lot of old electronic hardware, which must work 100%, or the machine positioning is toast. I would also check the 5v supply, and test the 5v at the encoder itself, for each axis, when you jog, and the axis is moving. This is best done with two people.
I recently had a 5v power supply, that would put out a clean 5v, and then 10 minutes later nothing! Nearly drove me nuts trying to find the problem.
Re: 20 yr old cnc control needs replacement, and i need help.
« Reply #16 on: July 27, 2012, 07:18:09 PM »
hey guess who's back?

still having issues bad enough to not be able to run this machine.  all the issues are in x and y, z is fine

it loves mdi moves, in rapid or in feed.  doesnt like the handwheel per my last post in this thread.

wrote a program that just does a rectangle 1 x 3 (2) times.  all the fails come at corners

run this program 20 times, it will run ok 7 or 8, the rest of the time x or y will fail at a corner
the "axis on" light will go out, stay out a half second, then come back on.  no other pattern detected
very random between x and y

same fellow is coming to help tomorrow, he had some thought that the new pentium board is fast, maybe
too much.  something to do with "interrupts?"  he asked me to do the program again with a small pause between ea move.  i put a 1/2 sec pause
between them, no changes

wrote a circle program, one again it fails on corners.  motors just dont like to change direction.  i wish they didnt every time
its the 35-40% of the time they work fine that makes the troubleshooting harder.

just throwing his out there, the fellow helping is a great legacy computer guy but not a cnc man.  and im just a good machinist
that is slowly learning this stuff.  always welcome you guys input.
Re: 20 yr old cnc control needs replacement, and i need help.
« Reply #17 on: July 28, 2012, 02:15:20 PM »
and here i am again!!!

legacy computer guy has come and gone,  we fooled with it for a while, various things, no luck.

we had talked about the machine as i bought it years ago, with a new 386 motherboard driving it, and how
replacements had been made, to a 486 then to a pentium 90, all successfully.  he was the guy who put the p90 in
for me.

he decided to slow this board, which was 166, down by moving some jumpers, and dropped it to 133.

i have been running test programs i wrote and old part programs for the last 45 minutes without a single failure.   ;D

i think we have it licked, time to tool back up and make something!!!   ;D

i will not be gone from this board, soon as the mill makes me a lil $$$ it will be time to pull the fanuc off the
nardini lathe and get that onto a pc control.  ill bet that will cause me to generate a few threads here.

the fanuc has lost its mind from sitting too long this winter i guess.  even tho i put a new battery on and fired it up 2x a month for a charge.  i get some type of parity error that the local cnc fellow says indicates the unit is fine but has forgotten its software.  a fellow on the internet has been kind enough to share his nardini fanuc files with me but i think i am tired of fooling with fanuc and want to go pc based.

i look on ebay, fanuc pc parts seem to command pretty fair money.  my question to you folk would be:  do you think there is any added value in trying to sell this
control system complete, from the servo motors on back?  or would it draw more $$ pc parted out on ebay?

thanks again for reading!

« Last Edit: July 28, 2012, 02:26:41 PM by metlcutr55 »

Offline Hal

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Re: 20 yr old cnc control needs replacement, and i need help.
« Reply #18 on: July 28, 2012, 03:54:21 PM »
I am glad your mill is up and running.

Watch the Fanuc parts to see if they are selling, and not just listed. If you part it out you could be left with white elephant parts ono one wants. If the servos work keep them. There are seveal motion control board that will work. Are the drivers digital or antilog?
Re: 20 yr old cnc control needs replacement, and i need help.
« Reply #19 on: July 28, 2012, 08:54:35 PM »
hi Hal thanks for commenting

i wont keep the servos, they are fanuc items and i want out of fanuc as much as some folk seem to want them.  i run a fanuc controlled workcenter at my day job,
the $$ the folk who come to repair them get is beyond ridiculous as are replacement parts.  my mill is analog with brush dc motors, i think id like the new ac brushless stuff, but if the mill is going to run well, i think i may try to keep the lathe replacement parts as close to the mill as possible, to share as many repair parts as possible. and i have read that the fanuc red cap motors are a hard match up to any of the pc based systems out there.  Machmotion and Ajax are being looked at, there is other stuff out there, Motiontek, Kanalog, DSPMC, but a lot will depend on who can help a guy like me who has little electronic knowledge, i am capable of following instructions, and thats about it.  a lot will also depend on the input i get from the good folk on this board.  i am sure i can handle a mostly mechanical installation, but might like to try to do as much as i can electronically, it will help in my retiring years to have as much knowledge of the internal workings as possible.