Messages

1

General Mach Discussion / Re: How do I control spindle brake and gear shift?

« on: September 09, 2009, 08:02:39 PM »

Hm.  Now I'm confused.  Up until now, I wasn't aware that a VFD won't even work with my motor!  It's a good thing I didn't throw the spindle drive away.  I believe I have some schematics for the spindle drive (very basic ones).  Maybe that will tell me what voltages it runs at.

As for controlling gear shifts and spindle brake with PLCs...  I'll have to research that idea, as well.  I had to look up PLCs on wikipedia just to get a better idea of what exactly they are!  I am starting to think that attempting this  retrofit may've been a bad idea.  My friend bought an entire kit from MachMotion and said it was a breeze to install.  So, I figured it can't be all that complicated.  However, I might be better off just getting ANOTHER crusty old CNC mill that actually works!

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General Mach Discussion / How do I control spindle brake and gear shift?

« on: September 09, 2009, 03:42:28 PM »

Hello!

I am about to start the retrofit of an old Tree CNC milling machine.  I am at the point where I need to start purchasing the necessary equipment.  I am planning to keep the original DC servo motors and the AC spindle servo.  The plan is to use some of the new Granite drives to run the 3 axes and either a VFD or the original spindle drive for the spindle motor.  Another forum member mentioned that the original spindle drive (Fanuc) is a nice unit, but I'm not sure how I would get it set up on a PC-based system.  My goal is to come up with something that is fairly simple and very reliable.

Anyway, the main reason I started this thread is to find out the best way to control the spindle brake and two-speed geared head on the mill.  I believe that both of them use relays/selenoids that control compressed air.  Typically, are those sorts of things controlled through the I/O relay controls of a breakout board?  I'll have to take a closer look at the  head to see just how it changes gears, but I'm pretty sure it uses air lines.  The last time I ran the mill through its gear change, it did it on the fly and made an awful racket.  However, I don't think that anything was damaged (hopefully).  I've just been wondering if it would be better to just have it in high gear and use a VFD to cover the entire speed range.  I believe the original control changed from low to high around 1200 RPM (with a top speed of 6000).

Well, if anyone can give me any pointers in regard to this matter, please let me know.  As I mentioned, I've been under the impression that I could control such things through the breakout board, but I figured I'd ask to be sure.  I don't know too much when it comes to the amalgamation of electronic and mechanical systems, but I'm trying to learn!  Thank you for taking time to read my post and for any pointers you can give me.

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General Mach Discussion / Re: Hoping to retrofit a CNC mill with Mach3. Where do I start?

« on: September 08, 2009, 01:35:15 PM »

Thank you for the additional info, John!  Also, thank you for taking the time to put things into layman's terms.  I'm not the most technically-adept fellow, so it is very helpful when someone explains all this stuff in a manner that I can actually understand (for the most part).

So, I am curious about the Galil cards and how they compare to a "breakout board" setup that seems to be the standard for most CNC retrofits.  Does the Galil only provide advantages when using older analog servo drives?  I was planning on buying some of the new Granite drives.  From what I've read, digital drives are quite a bit more reliable and easier to set up than older analog drives.  I still have all the drives from the original control.  From what I gather, a Galil card would allow me to keep the original drives, but I would have to buy  some additional (and fairly costly) equipment.  The work I plan to do with this CNC machine is fairly simple (no large-scale production and no sub-.001 tolerances).  However, there may be some 3D movements involved.

Anyway, the two things that are most important to me with this retrofit are simplicity and reliability.  I don't mind having to go a little slower to get the job done, so maximum speed and performance isn't at the top of the priority list.  As I've mentioned a few times, I'm not too familiar with the intricacies of setting up and dialing in electronic equipment.  I just want to make sure that I know what I should be looking at before I plunk down any money on the necessary parts for the retrofit.  Thanks again for the additional information.  It will give me something to think about as I shop around this week.

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General Mach Discussion / Re: Hoping to retrofit a CNC mill with Mach3. Where do I start?

« on: September 07, 2009, 06:03:52 PM »

Just a note on the Fanuc Model 3 spindle motor...keep the drive for it if you can as it's a servo drive and should give you excellent controll of that motor. Those Fanuc spindle drives are super reliable and have good safety devices inbuilt in them to stop any major damage if something goes wrong. The drive will do orientation for tapping and tool changing.

I have two machines with the Fanuc model 3 motor on and they will tap holes no problem with a tension compression tap holder.
Is the drive an A06B-6044-H07 ..?

http://www.dnc-electronics.co.uk/fanuc-drives/6044_fanuc_spindle_drives.htm

The Fanuc stuff  might be old but it's damn good quality!!

By the way there is a nice 8 axis Galil motion card on ebay at the moment that would control your  servos and drives..would also control your spindle drive too! It will do analogue 10V or torque mode or even steppers...
The Galil section has all the info!

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230366526511&_trkparms=tab%3DWatching

Thank you for the info, John!  I do still have the spindle drive.  Unfortunately, I chopped the wires from the bottom of it.  However, I kept all the plugs that went to/from it.  I assume that it would have to be configured differently, anyway, so it may be of no consequence.  It is an A06B-6044-H007.  To me, it just looks like a complicated mess of electrical components.  It appears that the going rate for these things on fleaBay is around $2500.  I never would've guessed an old spindle drive would be so valuable.  Would the performance and reliability be much/any better than a VFD?  I'm no expert when it comes to electrics and electronics.  The VFD just sounded like it would be a fairly simple solution to spindle control.  However, if the Fanuc drive would be just as reliable (and not too much trouble), I might just go with that.  Would the spindle control or the breakout board control of the spindle break and geared head?

As for the Galil unit...  It seems a little bit complicated.  I'm not sure, but I get the impression that it has a LOT of features that I will never need (or even know how to use).  For me, simplicity and reliability are going to be key to getting this retrofit done.  I assumed that the Granite unit would be best for the Granite drives.  However, I could very easily be missing some very important understanding of these components (which may be obvious from reading my posts).  Thanks again for the valuable input!

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General Mach Discussion / Re: Hoping to retrofit a CNC mill with Mach3. Where do I start?

« on: September 06, 2009, 05:06:54 PM »

I am bringing this old post back to life as I am hoping to start making some progress on the retrofit project.  Since I last posted, I have removed all of the control components from the mill.  The servo motors and spindle motor are still in place (as are the limit switches).  I should probably go ahead and start purchasing the necessary components.  I am planning to buy some of the new 160V Granite drives.  I was also looking at their breakout board.  Would it adequately complement the servo drives?  My mill has a two-speed geared head and a spindle brake (both controlled through electro-pneumatic relays... I'm not sure if that's the right term for them).  Typically, does the breakout board control such things, or would I need another component for the PC to control any other relays?

Also, I was hoping someone might be able to recommend a good VFD for me.  My mill has a 7.5 HP (5-6kW?) motor.  I'd like to find one that is reliable and fairly easy to use.  I have no experiences with VFDs, but it sounds like it shouldn't be too terribly hard to interface with the PC control.  If anyone has any recommendations on a breakout board and VFD, please let me know!  Thank you for your time.

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General Mach Discussion / Re: Hoping to retrofit a CNC mill with Mach3. Where do I start?

« on: June 13, 2009, 03:09:58 PM »

I've been busy with other projects for a few days, so I haven't been able to stay on top of this.  Are ballscrews typically made in even increments?  Do I just measure OD of the screw and get an estimate of the pitch?  I figured that most screws are fairly even measurements.  My only question is whether or not the dimensions of this old machine will be metric or standard.  Will I need precise measurements and specs for the retrofit process?

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General Mach Discussion / Re: Hoping to retrofit a CNC mill with Mach3. Where do I start?

« on: June 06, 2009, 01:54:17 PM »

Hm.  I'll have the research the ballscrew pitch/size.  As chance would have it, that is one thing that isn't specified in the literature I have.  I can probably take some crude measurements with a caliper and figure it out.  The servo motors are geared down (via belts and pulleys).  I imagine this information is rather important when it comes to setting up a retrofit.

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General Mach Discussion / Re: Hoping to retrofit a CNC mill with Mach3. Where do I start?

« on: June 06, 2009, 12:26:25 PM »

The data chart for the servo motors has quite a bit of information on it.  However, I'm not sure how much of it pertains to the current drawn by the motors.  The "Continuous Rated RMS at Stall" is shown as being 12.5 amps.  From what I've been told, old DC motors aren't the most efficient.  Is it a common issue for new drives being unable to support enough current for old servo motors?

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General Mach Discussion / Re: Hoping to retrofit a CNC mill with Mach3. Where do I start?

« on: June 06, 2009, 01:21:55 AM »

Here is some of the information I've managed to gather from the literature.  The maintenance manual for the machine gives a pretty good description of the various components.  I'll include any information that seems pertinent (even if I have no clue what it denotes).

Axes servo drives - Gettys N360 SCR   They are 3-phase half-wave drives.  I have the factory manual for the drives.  It includes diagrams and schematics, but some of it is tough to read because an obvious printing error jumbled up some of the text and placed some of it on the schematics.

The axes servo motors are Gettys permanent magnet motors.  The tachometer produces 9.5 VDC for every 1000 RPM, and the armature voltage at 1000 RPM is 34.2V +/- 10%.

The encoders are 500-line optical incremental encoders.  The literature gives a bunch of specs for them, but I have no idea what most of them mean.  For example, the outputs are described as quasi-sinusoid or square wave single channel or dual channels in quadrature.  I sure hope I don't have to understand such concepts if I am to be successful with this retrofit!

The spindle uses a size 3 Fanuc AC spindle drive and motor.  If I understand correctly, it is a servo-type motor.  It is rated at 3.7 kW (5 HP) continuous and 5.5 kW (7.5 HP) for 30 minutes.  The base speed is 1500 RPM and the max is 6000.  The input command voltage goes between +10V DC (max speed) and 0V (halt).  Power supply is 200/220V +10% / -15% at 50/60 Hz +/- 1 Hz.  Velocity feedback is provided by a pulse generator.  The Fanuc part numbers for the spindle motor and drive are listed, but I assume those are not necessary.

Anyway, I hope that some of this information will be able to help move me in the right direction.  As I said, I just assumed that it would be best to replace the servo drives.  This is mainly because they are so old (from the early 80s).  There is a factory-installed 4th axis on this machine.  So, there is a spare drive on hand.  The original rapid speed was 200 IPM (with feeds topping out at 100 IPM), so changing out the drives probably wouldn't turn a fast machine into a slow one.  If more detailed information is needed, please let me know.  The literature I have seems quite detailed, so there is a good chance it will have any info that might help.  Thank you to all for taking time to read my posts and help me with this project!  I'll be damned if I'm going to end up like these guys.

http://www.youtube.com/watch?v=x3RgyZRgshA

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General Mach Discussion / Re: Hoping to retrofit a CNC mill with Mach3. Where do I start?

« on: June 05, 2009, 12:44:12 PM »

I would not be in a big hurry to trash all the drives unless they just don't work. I refitted an older Bridgeport 308 and left all the drives in place. A Galil card noes nicely to control them.

The reason I figured I would get rid of the drives is because they are so old.  I would rather have the reliability of something newer.  If I did the retrofit and kept the drives in place, I would be worried that one of them would fail at some point.  Are servo drives usually quite reliable?  Basically, I just want to end up with a machine that is reliable.  Right now, I've got a 4500-pound paperweight.  I will get getting all the specifics on the drives later today.  Hopefully, it will help figure out what exactly I need to do with this machine.