# Anyone Using An Ajax Dm45nc Mill?



## SEK_22Hornet (Jul 15, 2015)

Looks like I'm about to become the owner of an Ajax DM45NC CNC mill. It is currently dead, but the machine itself is really solid. I won't be able to get it home for a couple weeks - not sure if he is going to be able to find the manual or not, so I may be starting from scratch. I'm only into it for $800 plus the trip to go get it (about 150 miles round trip).  Looks like an ATX motherboard, solid state drive of some sort, and a PLC driving brush type DC servos. Nothing powers up, so I'm hoping it is a power supply problem. I won't know until I get it home. In the meantime, it was built in 2005. Sounds like it is running Linux CNC. It has a single floppy for program transfer. Anyone using this mill or the equivalent Ajax conversion? They list posts for Mastercam, but I have not looked for BobCAD, which is what I have access to. Just curious what kind of rabit hole I'm about to go down!


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## JimDawson (Jul 15, 2015)

I don't know anything about that particular setup, but it sounds like a fun project.  For $800 I would buy it.  Since nothing powers up, that normally means an easy fix.  The ones that drive you crazy are the partial failure, or the dreaded intermittent issue.

Best of luck and keep us posted.


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## SEK_22Hornet (Jul 15, 2015)

I'm certainly hoping for a power supply issue or some other easy fix!


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## SEK_22Hornet (Jul 20, 2015)

Just a quick update and some questions - it looks like I'm headed to get my mill tomorrow. I've been on the Ajax support forum and have had some encouraging feedback - including the software manual and some troubleshooting suggestions, so I'm anxious to get it home and plug in the controller and see if I can get it booted up! The question I have is this - anyone know of a reasonable source for BT 30 tooling? Should I bother getting a drill chuck or should I plan on using collets to hold drill bits? He had two end mill holders - one 3/4" and one 1/8", and one ER16 collet chuck with a set of collets up to about 3/8". I know I'm going to want several more holders - Bolton Tools has collet chucks for about $30 each and collets for around $5 each. So far that's the best option I have found. Dedicated holders run about $42 each.


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## SEK_22Hornet (Jul 21, 2015)

Got my dead CNC mill home today and had it running in about a hour - it just needed the memory card re-seated, and then it came right up - so I have a CNC RF45 style mill for $800 plus the trip after it. I have not applied spindle power yet, but the table and column work fine. Now I just need to figure out how to set it up and run it.  I just ordered 3 BT30 collet chucks from Bolton tool - along with 5 collets, the total was about $120, so not too bad. I'll be set up for 1/4", 3/8" and 1/2" mills plus 3/4" with the single holder that came with the mill. Here are some photos of my prize -


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## JimDawson (Jul 21, 2015)

I would say that you got a deal on a CNC.


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## bpratl (Jul 22, 2015)

Great find and a super price. Is this your first CNC machine and are you going to upgrade the PC and software? Bob


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## SEK_22Hornet (Jul 22, 2015)

This is my first CNC - I actually was looking for a larger manual mill when this popped up - and I felt that the price was too good to let it go. I have done (and do) some CNC programming using both BobCAD and a proprietary software package on CNCD wood routers, so i have some basic CNC knowledge, but the Milling application is totally new to me. Read up a little last night in the Centroid manual for the V2.70 software, which is the only manual they had on line. As for upgrading, I am limited to using a micro ATX motherboard with a serial port and a PCI slot that will run the Linux program unless I want to rip everything but the servos off and replace it all, so I may at least upgrade to a later version of their software and find a later PC board. Hopefully, I will at least be able to get to ethernet or USB for file transfer, instead of the floppy.


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## bpratl (Jul 22, 2015)

I'm sure that you gain lot of experience by converting old CNC to newer CNC.
I have used linuxcnc on my lathe and Mach3 on my mill.


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## mattthemuppet2 (Aug 7, 2015)

wow, congratulations! that'd be a deal for a manual rf45, let alone cnc. sounds like you're getting an awesome shop together, especially with that cnc plasma table. is this part of a business plan or just for the fun of it?


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## SEK_22Hornet (Aug 8, 2015)

Yeah - I still can't quite believe it - I have been playing with the on board programming and have actually made a few cuts with it, but I need to make a fixture to hold the part I want to start with - this is just hobby. I'd love to have a plasma table, but the only CNC I have is the mill right now. My other CNC work has been at my work with a couple wood routers. The BT30 tooling is bit pricey but I have enough to get me started for now. I still need a couple drill chucks.


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## mattthemuppet2 (Aug 8, 2015)

on crap sorry, got you mixed up with someone else! that'll teach me to post on meds  either way, keep up with the pics and keep an eye on cl/ eBay for the tooling.


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## SEK_22Hornet (Aug 16, 2015)

Ok - so I have the mill set up and have ran a couple test parts. On the round pockets, it looks like I have some backlash in the x axis - as near as I can tell, about .014. I know nothing about ball screws and have not started looking for this yet, but was hoping someone might give me some idea of what I might be looking for. With that much, I'm not sure the backlash compensation is adequate. The first part that I want to make has two curved profiles and I'm concerned about the surface finish and accuracy of the radius. The Y axis seems very tight. The gibs are tight and I can't find any slop in the table. So my question is - assuming the ball screw itself isn't shot, my first place to look would be the support bearings. Is there usually some adjustment to take care of backlash at the bearings? I'll have to tear the servo and mount off to see anything on this machine. It looks like there might be a belt drive, since the servo is offset from the leadscrew.


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## JimDawson (Aug 16, 2015)

Let's start here, a little primer on ball screws  http://www.barnesballscrew.com/how-a-ball-screw-works/

0.014 backlash is a lot for a ball screw, normally a ballscrew should zero backlash, backlash compensation in the software will not compensate when cutting an arc.  There are three places where the backlash can come from.  The ballnut, the support bearings, and the motor coupling.

I would first confirm the the motor coupling has no play and is tight on the shafts, we found this in alloy's machine the other day.

Next is the support bearings, leadscrews are normally tensioned in one of two ways, by putting the entire screw under tension with a hard bearing stop on each end and a nut that just puts tension on the entire screw, or one end is allowed to float in the bearing housing, and the tensioning is all done at the motor end by preloading the support bearings against the housing.

The final place that backlash can be generated is the ballnut.  The ballnut could be loose in it's housing (loose bolts), or the housing may be loose on the saddle mount(again loose bolts).  If both of these are tight the the last place is in the ballnut/ballscrew interface.

If the backlash is coming from the ballnut, then at 0.014, there is something drastically wrong.  If you have a single ballnut then there is no hope short of maybe larger balls.  If you have a double ballnut, then there is a an excellent chance of fixing it.  With a double nut system, the nuts will have some provision for tightening against each other, thus preloading them.  There are a number of different systems used to preload double ballnuts, normally involving a threaded coupling of some kind.  In one case I recently worked on, there was a shim pack between the ballnuts, that got changed over to a threaded system because the shim pack proved to be impossible to adjust correctly.

I hope this helps
.
.
.


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## SEK_22Hornet (Aug 16, 2015)

Jim - That does help - a lot! I need to tear it apart and start looking. I was pretty sure that much backlash meant I had something wrong! I'll post what I find out. It does have a handwheel on the ball screw, so that may help me isolate where the problem is (motor / drive or ball screw / mount, anyway).


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## SEK_22Hornet (Aug 17, 2015)

Made it to the shop for a few minutes this evening and did some troubleshooting. I started by locking  the gibs on the table and rotating the hand wheel. I could feel a definite click at each end of the backlash. I removed the cover from the drive and confirmed that the drive components were all tight. I removed the servo motor and placed a dial indicator on the end of the lead screw. I measured right at .014" end play. It looked like the play was in the support bearings. I started to take the retainers of on the drive end to see if I could see any numbers. The bearings did not want to push out easily, so I went to the other end and gave it a light tap. It felt solid, so I went ahead and pulled the end plate to see if there was a retainer of some sort and found a  adjusting nut with a lock tab. I released the lock tab and found there was quite a bit of slop.  I started tightening the adjusting nut and was able to adjust out all but about .002 to .003 of the backlash!


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## JimDawson (Aug 17, 2015)

Awesome! If you have a single ballnut then that's about as good as it gets unless you want to re-stuff the ballnut with larger bearings. 0.123 balls are common, replacing those with 0.125 balls will give you near 0 backlash.


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## countryguy (Aug 18, 2015)

Wow-  I missed an Ajax/Centroid CNC post.  Man -  I am busy!!!  What you have there is a very sweet deal.  I paid abour $3K for my AjaxCNC upgade.    you have the DC-AIO (all in one) module as the guts .  I have the same thing.  This PLC is run from the Centroid system on a PC. There were early Linux versions but they have discontinued them.   Do you know what version you have?    So far-  after using this for 6months -  I love it.  Just intuitive and fun.      Let me know if you have any issues.  I do have a print for the DC-AIO and yo ucan download the whole print.    Keep us posteded.


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## countryguy (Aug 18, 2015)

OK- I poked thru the posts a bit slower.   If the PC is running the Centroid Linux version  - You should still be fine.  Just that you need to know Linux (Unix) to navigate around the OS outside of the canned Centroid platform.  I wonder if you can upgrade for a cost to the newer PC version.


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## SEK_22Hornet (Aug 18, 2015)

I have version 1.02 and would like to at least get it up to the last version of the Linux software - 2.72, I believe (working from memory here). I have read the upgrade info and downloaded the install disk, but have not yet tried to make a new flash card or boot drive. I have a couple bootable flash card readers on the way off of ebay.  I will probably add more RAM to the motherboard and have even considered trying to use a SATA solid state drive in place of the flash card. It looks like there are some pretty significant differences in the hardware between the Linux and Windows versions, so I doubt if I will try to go to Windows. I'd love to get to where I can use a flash drive to transfer files, but my version only supports floppy discs. CNC was one of those things I always wanted to do, but kept running into too many roadblocks - so when this thing showed up - even my wife said to jump on it! The on board CAM software seems to work pretty well and is pretty easy to use, so far (at least for 2.5 D work). This winter I hope to start learning Autodesk's Fusion 360 for more advanced projects. Oh - one of the programmers where I work is a real Linux lover, so I do have some support on learning what I need to there!


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## SEK_22Hornet (Aug 26, 2015)

Ok - been working with this new beast and have written a couple programs that ran just fine in aluminum. I went to run a piece of copper and the spindle kept shutting down. No error message until the x or y axis would error out for full power with no movement. Hit the E stop, and raise the spindle and hit start and it would start up again. It got worse the longer I worked - eventually shutting down for no apparent reason (no load, just sitting there running) - still no errors. Nearly impossible to get to shut down when I have a meter in my hand, in true intermittent style! Running idle, the 2 hp motor is drawing 1.4 amps per phase and the three phases are running about 250 volts from phase to phase and about 175 from each phase to ground.  The current readout matches what I measured with my clamp on meter (1.4 amps). I'm guessing the VFD is shutting down, but it must be a failure, since I can't see any external cause. The VFD is an automation Direct GS2-2PO 2 HP running on single phase input. Anyone know anything about these VFD's? I am starting to go through the manual now. It is rated for something like 7.5 amps. Is that the sum of all three legs or per leg? Not familiar how three phase is rated current wise. By the way, neither the motor or the VFD felt or smelled hot - just slightly warm to the touch, so I don't think it is excessive heat.


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## countryguy (Aug 27, 2015)

The guys on the CNCzone AJAX forum are the best bet.  I know there are some diag dumps and settings to help but do not know them.  Something smells amiss (obviously).    I supposed just getting into the motor Xformer and checking connections and leads up to the serveo just to check and.or just issue a reconnect?   Sorry I cannot help more but that system is very elaborate w/safeguards. Some you can mess w/  some you cannot.   post to the AjaxCNC guys on the zone.    or the free Ajax support forum (old php forum) but it opens a service ticket w/ Centroid. You'll see "countryguy" all over that board!!! .  A great bunch!


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## countryguy (Aug 27, 2015)

I know if my hunyang does fault I get an error condition on a pair of Alarm contacts.   1 for alarm and 1 which is interlocked to the PLC to STOP the mill.   So you could check for those VFD alarm contacts and see if they are wired up. They should be.   As I just followed the print.     The latest manual has a explicit setup for your VFD as it is 99% identical to mine and it's the setup I followed.

If there are no fault alarm connections, then check the OpCodes for the VFD and set it to runthe relay.  (I think that was code driven?)  maybe hook up a small alarm.  I guess we can see if that goes off?   

I guess I am saying that on mine-  If the VFD faults,  The alarm outputs are wired into the PLC as interlocks to halt the machine.


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## JimDawson (Aug 27, 2015)

Set up the programming on the VFD to you can run it from the keypad to see if the problem is in the VFD or in the controls.  I've never had a GS-2 fail, and I've used a lot of them.  My guess is the problem is in the control wiring.  If the stop switch is a NC push button, check the contact block.


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## SEK_22Hornet (Aug 27, 2015)

I actually had not thought of setting the drive to manual mode, but I will do that. I did see the #2 relay wired into the harness, which would default to an inverter fault. I have no manual on this machine, so I'm using the CNC10 install manual from the Ajax website. It shows a typical spindle fault connection. I have ordered a replacement drive, but obviously I would need to record all settings if i change it out, so I guess that is my next step - check to see how P3.12 is set. It also looks like I may be able to read out the last 6 faults in P6-31 through P6.36. Does anyone know if these are retained on power down or not? This may give me a clue as to what is happening. I ordered a new drive, just in case.


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## JimDawson (Aug 28, 2015)

I think the faults are saved on power down.


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## countryguy (Aug 28, 2015)

+1 on that.  But I believe only until the next condition that may overwrite it.   ahhh chasing bugs.  The hunt is always a bunch of fun too.  Learned my 3:1 inside and out that way.   I found literally most every wire and junction blck w/ loose screws on the wires.  poor connections.  grounds not grounded properly, and just plain poor upkeep. 
So if you run the VFD manually as-in just turn it on and move the spindle around w/o the PLC going. Observe to see if the VFD faults.  I will lean towards it runs just fine.  (....and now it's in printed form... will probably go the other way around. :- )       do you need me to send anything along from my DVD?  I can send the part w/ the GS2 fault interlock.  It runs to one of the PLC of the relays.    All Relay and I/O outputs can be observed from the main screen of Centroid OS.  I think it's the ALT-i key?  Its listed in the main manual anyway.  It is like the mach 3 diagnostics screen and will offer good insigt into what may have tripped on this condition.  (as I thought about this issue last night)      You'll find it!


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## compsurge (Sep 11, 2015)

I don't think I can contribute other than suggesting MariTool BT30 holders. The ER collet holders are about $100 each. Made in USA as well. I think they are cheaper because they are only balanced to 20k rpm.


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## SEK_22Hornet (Sep 12, 2015)

The machine has had lousy upkeep. The bellows chip guard foe the Z axis is in tatters, so I tried to get a replacement. NLA, so I tried Grizzly - nothing available - tried PM, no luck. I found one at Tormach,  but it is too wide. I think I can make it work. The backlash in the X axis was in the bearings and I adjusted it out. Just did the same for the Y axis tonight. The Z will be a lot tougher, if I need to adjust it. I programmed the drive to control speed using the pot on the drive and wired a switch in parallel with the control for forward rotation and when it drops out now, I can flip the switch and keep it running. I am losing the drive speed control voltage and the forward control signal when it drops out. I have info from Ajax on how to monitor the control inputs and outputs, but so far it is still running. As near as I can tell, a heavy cut with a lot of vibration triggers the fault. I need to use it and monitor the controls to see if I can find out the actual fault. Need to check out the CNC zone Ajax forum but just have not done it yet. I have been on the Ajax support forum with mixed results. Did manage to finish my copper project after rigging my bypass switch and moving on to some work with brass, which is machining much nicer! I'll be making some nice heavy cuts in a little while, so I'll find out if the problem comes back. I did prove that there were no faults stored in the drive, also. I also accidentally proved that a drive fault will shut things down (I won't go into the embarrassing details on that).  As for holders, I ended up buying several from Bolton tool for about $30 each (I ended up with an ER25. another ER16 and 4 ER20 holders and a couple drill chucks (one with 3/4 straight shank, one with a 1/2" and one BT30 shank). I know they are cheap Chinese, but they will work for me for now - they are actually very nice looking, but I have not checked the run out. I picked up a few collets from Bolton and several off ebay.


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