Machsupport Forum
General CNC Chat => Show"N"Tell ( Your Machines) => Topic started by: engineeringpunk on February 26, 2007, 10:29:39 PM
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OK everyone. My name's Zach and I'm a Manufacturing Engineering student at the Pennsylvania College of Technology in Williamsport, PA. I have a decent electronics background as well. My school is about to throw away 2, count'em, 2 1992 Bridgeport Discovery 308 VMC's. They run the very awkward SX-16 control, made by Bridgeport. Mechanically, the machines are in decent shape. Electrically, well, they're broken. The controls are bad in both and parts aren't available. I have all but completely convinced the school to let me retrofit a control onto one of them as a project. I'm thinking very seriously about using Mach3 as my control software but am also looking at FlashCut. Any opinions on their software would be appreciated. Here go machine specs:
TRAVELS................................: 18" X, 12.5" Y & 16.1" Z
SPINDLE SPEEDS.........................: 60 to 6000 RPM
SPINDLE TAPER..........................: BT 30
FEED RATE RANGE X & Y AXIS.............: 1 to 472 IPM
FEED RATE RANGE Z AXIS.................: 1 to 295 IPM
SPINDLE DRIVE..........................: 5 or 7 HP (i'm not quite sure yet)
EQUIPPED WITH:
8 STATION TOOL CHANGER
FLOOD COOLANT
BIJUR AUTOLUBE
Tomorrow after my first class, I'll take some pics and throw em up here for you guys all to see. I've already done a little investigating on the servos. Here's what i got.
All three axis are SEM brand DC Brushed Servomotors MN:MT30U4-31
CStall Torque: 35lb/in 13.5A
Max Speed 4000rpm 125V 86A
Tacho 9.5V/1000rpm IP44 IC40
Made in January of 1992
I'm gonna call SEM tomorrow and get the manuals on them for the rest of the specs. They dont make the 31 model anymore, but they make a 26 and a 36 with specs up online.
I haven't got the lowdown on the spindle motor itself yet, but i do know this. Currently the spindle is controlled by a V400 Flux Vector AC Motor Control 4.0kW max which is made by either SECO, Danaher Motion, or Control Techniques. I'm not sure who owned who when it was made, but i'm gonna make calls tomorrow. I'm also gonna look into the types of encoders currently on the machine.
Now for my list of questions:
What kind of hardware am i looking at needing here?
Do I need to buy a PLC, if so i've used allen bradley and DIRECTLogic. Opinions?
Servo Drives? Can i use the ones already in there..as far as i know they work. Would Gecko Drives be sufficient? Any other recommendations?
I want to still be able to use the tool changer and flood coolant. What do i need to take into consideration? I have the wiring diagrams and currently there is a little PCB designated "Spindle orientation board" sitting right by the big AC motor drive. I assume i have to keep that?
After i do an initial cost report on this and present it to my school, i can start buying equipment and get this rolling. Any input you guys can give would be greatly appreciated.
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Here's some pics i have of these machines from last year...when they still worked. My buddy kevin is making something on one of them. I'll get more and better pix tomorrow
(http://home.comcast.net/~punk.rocker/1.jpg)
(http://home.comcast.net/~punk.rocker/2.jpg)
(http://home.comcast.net/~punk.rocker/3.jpg)
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If you are going to do a control like that you need to look at the Galil cards.. you could keep all the old amps in the machine (that are not all that old).
You should be able to get a 4 axis version for about 1200 and you will have a full closed loop controle.
hope that helps
Brian
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What part of my plan makes me have to go to Galil? Is it the spindle/tool changer/coolant control?
Trying to get all my ducks in a row here i need to control this much stuff:
X-axis servo, encoder, and limit switches
Y-axis servo, encoder, and limit switches
Z-axis servo, encoder, and limit switches
Spindle on/off, direction, speed, and somehow orient
tool changer engage/disengage, and index
coolant on/off
This sound about right? So this would be 3-axis, and how many input/outputs, and digital or analog? or both?
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The type of amps that you have in the machine. they are analog torque amplifiers and will not run from the P Port. BUt will run from the Galil or you at the S&D to analog cards (Never used them)
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Ok now i'm somewhat more confused. If i'm completely off base tell me, but it shouldnt matter what kind of amperage i'm dealing with in my machine. As long as i have good servo drives and spindle drive, i can choose from a bunch of controllers. What prevents me from using the same hardware everyone else uses if i have the drives to run these servos and spindle? Also, could you clarify what you meant when you said S&D to analog cards?
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Most of us are using small motors with homemade power supplies and Gecko drives for the motors. This will not accomadate the requirements of you motors. The S&D to analog convertors would take the step and direction pulses produced by Mach and convert them to an analog signal. This would allow you to use the drives you have now. Don't take my word for law, let someone verify this before you proceed.
Brett
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engineeringpunk,
Sounds like a very energetic project.
S&D is short for step and direction. If you use the same amps (refering to the amplifiers - or - servo motor drivers) they are probably analogue input, not the step/direction input type.
Most cost effective would to use as much of the hardware that you have and still is functional, but that will not be the simplest way.
It will require interfacing mach3, which does step & direction outputs via the parallel port to your analogue cards (the biggest hurdle), there are some interfaces that do this but I can't help you there.
The simplest way would be to purchase servo drivers with step & direction inputs, if a Gecko is large enough to handle the power requirements of your existing servos (they are pretty good drives). Then the next hurdle is all the other IO you have for limits, tool changer, coolant etc. You will quickly run out of points on your parallel port, even if you put in an additional parallel port card. With your knowledge of PLC's you would probably want to put the less time sensitive IO on a PLC and communicate via ModBus with it. There will be a time lag between sending and receiving these ModBus points due to scan cycle time and how often Mach looks at the modbus.
Things like e-stop, limits & spindle index(1 pulse/rev index signal) you will want to keep on the parallel port for timing reasons. Tool changer, coolant, maybe spindle start, stop, direction could probably all be done on the PLC. Spindle speed, I am guessing you probably have an analogue input to the VFD, you can use a mach to output a pwm signal on the parallel port - convert that to analogue and feed it to your VFD.
Lots of info in these forums, you should have a good time with this, looks like a very worth while project where you will learn a lot.
Arnie
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I have had good luck with the pixies (http://www.skyko.com). They convert step/dir to analog out using the encoder on the motor for feedback.
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Hello EngPunk,
I think you need to have a look at what is in the machine now and what you can save. You will find that it is not as simple as loading new software :( But it is doable and it is a ton of fun to make it work with new software. You need to have a very good understanding before you start taking parts out of the mill.
Posta pic of what is in the boxes on the mill and we can tell you what you have ;)
Thanks
Brian
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I took a bunch of pictures today that i will put on when I get home tonight. I also have a call in to Gecko about whether or not their drives will adequetly power my servos. If i do end up having to keep my servo drives because it would be not cost effective to purchase new ones, i like the looks of those pixie boards. I also have a copy of the wiring diagram i will put in PDF format and post so you guys can check it out. I also got ahold of the users manual for the spindle drive that i can post in PDF format. It's a Control Techniques V400 Flux Vector AC Motor Control and Drive with a max capacity for 4kW motors. That means my spindle is likely 5HP, or maybe 5.5HP. Tomorrow morning i'm gonna take some of the paneling off to get a better look at the inner workings of the tool changer, the limit switches, and the spindle motor.
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OK, here goes pictures and then I will explain all i learned today.
here's pics of the 2 machines from the front. They're identical. I think the serial numbers are even close.
(http://home.comcast.net/~punk.rocker/4.JPG)
(http://home.comcast.net/~punk.rocker/5.JPG)
Now each machine has 2 control cabinets, one on each side of the machine. Here's one side. It houses the spindle drive, some contactors and relays, and a big honkin ass transformer. Then there's a closeup of the spindle drive. I have the manual on it. I actually had to call 3 different companies and make my way up to "level 3" tech support before someone could help me. The level 1 guy didnt even try and the level two guy tried a little but then admitted he had no idea about the product i was trying to get info on.
(http://home.comcast.net/~punk.rocker/6.JPG)
(http://home.comcast.net/~punk.rocker/7.JPG)
Here's the other side. It houses the actual control components, axis drives, DC power supply, a smaller transformer, and a buttload of wiring.
(http://home.comcast.net/~punk.rocker/8.JPG)
Here's a closeup of the axis drives. I actually took one out and got some info that was slikscreened onto it. i shouldve taken a pic when i had it out. It's made by Motion Science, Inc. of San Jose, CA. I think they have been absorbed into Cleveland Motion Controls who i plan to call tomorrow.
(http://home.comcast.net/~punk.rocker/9.JPG)
Here's a pic of one of the axis servos, the Z axis particularly. It has a tachometer and a 3 channel differential encoder. I will call SEM tomorrow as well to get some more info on it, since their website, http://www.sem.co.uk, sucks.
(http://home.comcast.net/~punk.rocker/10.JPG)
Lastly we got a pic of the inside of the machine looking up at the tool changer.
(http://home.comcast.net/~punk.rocker/11.JPG)
Now onto what i've learned today. I dont think gecko drives are gonna cut the mustard with these servos. I have, however, found Rutex R2020 drives, at only a little more $$ per pop to be a little more beefy. 200V at 40A beefy. So i think i'm gonna buy 3 of those guys. I still don't know whether or not i wanna do mach3 or flashcut. Flashcut looks more user friendly, but mach3 looks more versitile. I've downloaded mach 3 to start playing with it. That takes care of my axis drives.
I'd still like to use a G-rex g100 motion controller to deal with all my ins and outs, limits spindle speed and communication with the rutex drives. Anyone see a problem with this that i dont? It should have enough to deal with everything. tool changes, coolant, limits and homes, and the spindle. i hope.
Later on i will PDF my wiring diagrams and the manual to the Vector drive that i worked so hard to get and post them up here for all to check out. This is turning out to be very interesting.
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Honestly I would use the pixies. The motors and drivers are a tuned matched set. Save some money and the headache of rewiring. You will gain nothing by going with new motors. Then you have to spend time to tune them if you use new drivers.
Either that or a Galil card. That will give your analog out to the drivers.
The VFD should take a 0-10v in. I used a little card from http://www.cnc4pc.com that converts step/dir signal into a signal for the vfd. You should be able to use the analog output of the grex for this as well. Or at least someday.
I just spent the $ today and ordered my Grex.
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i think if you saw these axis drives up close you would understand why i wanna replace them. they are notoriously unreliable. very expensive to replace. the one that i pulled out had replaced resistors on it from some prior repair job. I like the SEM motors, but i think i want rid of these drives. I'll keep the big DC power supply for the motors. as far as i know it works ok, and i'm not sure where to find a high voltage, high amperage DC power supply. I'd rather buy my whole new control knowing that all the pieces will mesh well and retune the motors than base my whole control off of the fact that i have analog motor drives from 1991 that are going to be near impossible to replace if one goes for good. If i put in Rutex drives, and one breaks, a replacement, even if it isnt a rutex, wont be difficult to locate. If my logic is crappy here, please tell me.
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If that was me I would do the following...
Go to automation direct and look at there 1kw med inertia drives, motors and cables. it will be about 1500 and axis but you will never have an other problem if you do this... OR you could look at the CNC Teknix drives. I will be testing one soon on an SEM motor like the one that you have.
Best of luck
Brian
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Zack,
Your logic on putting drives in that you can find replacement parts if they fail is right on the money. Might cost a bit more in the short run but it wouldn't be a very good project if you retrofitted interface and then the old drivers burnt out and now you would be stuck.
I am a hobby user of Mach3 and would recommend you go with it. The reason is simple, it has a lot more user controllable configurations, down to the point of customizing it using visual basic, and custom screens. It might have a little steeper learning curve but that is mostly due to the numerous ways you can configure it.
Arnie
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I think you are wasting your time with these machines, you would be better crating them up and sending them to me for proper disposal ;)
Hood
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I would try a (galil or baldor) pci-2 card, a pc, and if you need new motors you can get them on eBay... You can buy big servos cheaper than smaller ones... If I had to have a new motion controller I would use a galil... I have a new system from Low Cost Retro, it runs mach 3, I have a 4 axis galil running camsoft... I like them both... I am also in the process of doing the same as you except my project is a Fanuc S-420 robot.
The Mach 3 will run galil so the software is not any more that the small hobby guys use..
Have a great day (weekend).
BTW: I have vista on a new lap top and it is no good... I guess for an office guy it would be great... It does not like doing multiple tasks..
Later PC
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Also look in the BP, I think they used a galil... or it is a delta tau.
If it is a galil you could just run it from Mach3 and not rewire the mil ;)
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I was kind of wondering if this ever whent anywhere? I have the same will in my lab that we are giving to another department and I am going to retrofit it for Mach III. From reading this and other posts about the Galil 18x2 boards and Grex, it looks like the Galil might be the way to go. The Grex analog outputs are only 8 bit resolution so I would have to us it's SD outputs and something like Pixe's to control the analog drives. Considering that fact that both the Pixe's and Grex would want acccess to the encoder signals (I think Grex does) I can't see how that would work; please correct me if I'm wrong. (I think I'll contact Gecko and ask :) ).
Here is the cost breakdown of both options as I see it:
Gecko: $400 Galil: DMC-1842 $1200
Pixe's: (4) 320 64 bit I/O expansion 200
------ ---------
720 1400
So from a initail price the Galil is about twice as much but the Grex might not be able to do the job, any input?