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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Quote Originally Posted by Jim Dawson View Post
    One thing about grounding that is confusing is what is being called a ground. There are commons that are called ground, but they are more properly returns. In other words, they are just the other side of a power supply, for instance, +5vdc and it's common or return. It is just 0 volts relative to the 5vdc +, or the other side of the circuit, but not necessarily earth or machine grounded. A true ground is just that, connected to the machine then to the earth at some point.

    It really just requires some experience to translate what the heck they are saying. The grounds referenced in your attachment are digital returns, to pins 4, 9, and 11, which as I remember it, are connected together internally.

    The high pitched whine from the motor is from the PWM chopper running at around 4 KHz. In that system there is no way to change the chopper frequency. A choke between the drive and the motor might help. I have one that does the same thing, drives me nuts.
    The more I think about it the more I believe that DM was using that pin 8 I mentioned for disabling the amp when not driving the spindle. I could be wrong, but it makes sense to me. Before I removed all the electronics I played around with the machine quite a bit, and not once did I hear that sound. Actually, I did hear it, during a tool change, when the spindle was turning very slowly, slow enough to hear it. But not any other time.

    If the motor/amp combo was being used for an axis it would make sense to leave the amp enabled even when not commanding an axis move, in order to keep it in place. But being used for a spindle motor, when the spindle is not running, you want to be able to turn the spindle by hand for tramming parts (well, us old time machinists do anyway, I know there's other ways like using an edge finder, etc.) and with the amp enabled it's not possible. When I jumpered pin 8 to 9 (ground) it cut the amp along with the noise and allowed me to turn the spindle. It's not a permanent disable either, that is, it doesn't require a reset, so once the ground is removed the amp is re-enabled automatically. I think this is what I'm going to shoot for, using an output on the parallel port (tied to the 'spindle on' command) to ground the pin until commanding the spindle. I'm thinking I'll need a small relay for that, not sure.



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Quote Originally Posted by Marty_Escarcega View Post
    Hi Jim, it had a good sized choke. That's why I asked Dan if he left that transformer looking device in the bottom of the csbinet. It lies between the SD3060 and the motor.

    I'm not sure what Dan is asking about grounds. Grounded conductors are as you point out, Commons or returns. Grounding conductors are chassis grounds. Dan can you clarify your question?
    Yeah, I have a pretty good understanding of returns on circuits, etc. Here's an example of the kind of thing that just leaves me shaking my head--on the 5/12V PSU that came with the machine there is a terminal labeled 'acg' (third from the bottom) and another one labeled 'fg'. I left this in place as original, so the wiring is original. The bottom three wires are the input from the main power supply, so the ground wire (acg) is connected to main supply and cabinet. The fg ground looks as though it's supposed to be separated from the main ground, so I figure that's a return for anything using that power supply. But if you look close you'll see there's a jumper tab connecting both ground terminals, so effectively the return ground is the same as the machine ground. What's the point of having separate terminals on the PSU if they're going to be connected anyway? Maybe there's some other application that requires it, but not in this case?

    Attached Thumbnails Attached Thumbnails Build log-drhanger's DM4400 electronics retrofit-2017-02-26-06-05-42-jpg   Build log-drhanger's DM4400 electronics retrofit-2017-02-26-06-05-32-jpg  


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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    It is not uncommon to tie power supply commons with chassis ground. Keeps everything at the same potential.



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Things are coming along pretty good now. I've been busy this past week setting up the spindle circuits and gotten it working really well now. I've attached a photo of a small signal/power distribution board I designed in Eagle. I've made several boards like this in the past, not really what I'd call an electronic circuit board, but a nice, neat way of tidying up loose ends. I had all the wiring for the spindle in a temporary rat's nest, so this makes it really nice. I rarely design a board so it's difficult to learn Eagle all over again and takes a lot of time, but what I hate more than that is having a lot of untidiness, so in the end it's worth the effort for me.

    I did end up using a board mounted SPDT 12V relay for the #8 pin grounding technique I mentioned earlier. I designed the circuit to have the pin grounded through the NC pole of the relay so when the machine is powered up the spindle amp is disabled at the beginning. The relay coil is connected to one of the MX3660 outputs that I've tied to the spindle 'on' command in Linux, so when the command is given the relay opens the #8 pin circuit and enables the spindle amp. Works perfectly, and now there is no whining while the machine is idle, and the spindle can be turned by hand. Very happy with the results.

    I actually ran the first real program yesterday morning, that was to drill the holes for the circuit board. So at this point the machine is now in a usable state, although there's still a lot of loose ends to work on. The next stage is getting the tool drawbar in operation. I've been using a cordless drill attached to the presser motor, which has a shaft extension at the top, it's a bit cumbersome but works fine. I'm really leaning towards attaching a pneumatic cylinder with a simple pneumatic valve attached to one of the drawbar buttons on the front panel. Does anyone know how much force is required to press the drawbar? I'll need some idea so I can calculate what size cylinder to use.

    Attached Thumbnails Attached Thumbnails Build log-drhanger's DM4400 electronics retrofit-2017-03-05-13-17-38-jpg   Build log-drhanger's DM4400 electronics retrofit-2017-03-05-13-18-02-jpg  


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    Quote Originally Posted by drhanger View Post
    Things are coming along pretty good now. I've been busy this past week setting up the spindle circuits and gotten it working really well now. I've attached a photo of a small signal/power distribution board I designed in Eagle. I've made several boards like this in the past, not really what I'd call an electronic circuit board, but a nice, neat way of tidying up loose ends. I had all the wiring for the spindle in a temporary rat's nest, so this makes it really nice. I rarely design a board so it's difficult to learn Eagle all over again and takes a lot of time, but what I hate more than that is having a lot of untidiness, so in the end it's worth the effort for me.

    I did end up using a board mounted SPDT 12V relay for the #8 pin grounding technique I mentioned earlier. I designed the circuit to have the pin grounded through the NC pole of the relay so when the machine is powered up the spindle amp is disabled at the beginning. The relay coil is connected to one of the MX3660 outputs that I've tied to the spindle 'on' command in Linux, so when the command is given the relay opens the #8 pin circuit and enables the spindle amp. Works perfectly, and now there is no whining while the machine is idle, and the spindle can be turned by hand. Very happy with the results.

    I actually ran the first real program yesterday morning, that was to drill the holes for the circuit board. So at this point the machine is now in a usable state, although there's still a lot of loose ends to work on. The next stage is getting the tool drawbar in operation. I've been using a cordless drill attached to the presser motor, which has a shaft extension at the top, it's a bit cumbersome but works fine. I'm really leaning towards attaching a pneumatic cylinder with a simple pneumatic valve attached to one of the drawbar buttons on the front panel. Does anyone know how much force is required to press the drawbar? I'll need some idea so I can calculate what size cylinder to use.

    Try this as a starting point for pneumatic drawbar
    http://danielbauen.com/make/index.php/tormach-milling-machine/tormach-power-draw-bar/

    Watch the stroke of your cylinder. Ascertain how much of a stroke there is on the presser bar set up. Too much stroke and you could damage the bellville washers

    I would use a 24vdc solenoid valve so its read should you pursue the ATC. You also need switches at the top and bottom of the stroke so the control knows when the tool is released and when the tool is retained.



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    No news is good news? :-)



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Quote Originally Posted by Marty_Escarcega View Post
    No news is good news? :-)
    Pretty much, yeah. The machine is in a 'high functioning' state, but not very user friendly yet. I don't think I've posted this video yet, first part run:



    I'm working on a couple of things to make it easier to use:

    1. The part in the video is a Delrin bracket for a temporary tool changer arm. I removed the original presser motor and assembly, and replaced it with this bracket and a pivoting arm on a fulcrem, using a pin between the arm and the drawbar when I needed to change tools. This arrangement aided me in getting a rough estimate of the force required on the drawbar. I used a spring scale at the end of the arm to determine the amount of torque required-about 600 in/lbs. The fulcrum pin was about 2 inches from the drawbar so I got about 300 lbs. of force on the drawbar. I found a nice air cylinder on Ebay--2-1/2 bore x 13/16 stroke, nearly perfect. The lowest my compressor drops to is 90 psi, so at the least I calculate 440 lbs. of force, more than enough. I made another bracket out of aluminum at just the right height for the cylinder to extend the same amount as the old presser to prevent excessive stroke on the bellevilles, found a 3 way, 5 port hand control in a pile of junk and hooked it all up for the first time yesterday. Worked perfectly, now I have a simple and quick manual tool changer. I think the bellevilles are probably worn--with a tool holder in place, if I grasp and twist hard I can make it rotate in between the drive keys. I can see the tool pulling out on a drill cycle with packed chips, so I'll have to keep that in mind. For now with light loads it should be okay, but I'll have to address that eventually.

    2. I bought a touch screen and got it working somewhat, but being in Linux makes it a little less than Plug and Play, so I'm having issues with that. I did get it to work but the touch response is erratic at best. I suppose it needs to be calibrated, but haven't had time to mess with it yet. Right now I'm using a mouse and keyboard perched on the old controller pedestal, it's cumbersome but gets the job done. Once I get the touch screen working I plan to build a mount for everything on the old pedestal, having most things under touch screen control will really improve the 'user experience'.

    There's an issue that came up that I believe is related to the higher voltages I mentioned before. I only noticed it when I was first playing with the spindle speed control, before I had the spindle brake set up (remember before I mentioned that I was just leaving the spindle brake energized when running the machine). If I command a lower speed while the spindle is running already, or just a spindle off, the overvoltage protection circuit on the driver shuts it down. I remember the DC voltage at the driver was just under 180, right at the edge of tolerance, so I think that the spindle inertia while slowing down is just enough to trip the circuit. I went ahead and set up a relay circuit for the spindle brake so now it's under CNC control, and when I command spindle off the brake is fast enough to prevent the overvoltage problem, so as long as I don't have a program that lowers the spindle speed while already running it shouldn't be a problem. I think I'd feel better if I could bring the voltage under control, though, just for the sake of the system as a whole. The machine was originally spec'd for 220VAC, but my voltage is around 245, so I need to do something to condition that better I think. What would I need to do that? Some type of transformer I suppose?



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Oh yeah, forgot to mention--I checked for backlash on the X and Y, got between 0.0007" and 0.0012" and entered those in the backlash section of LinuxCNC. I circle cut a 1.4" hole, took it in to the shop I work at and checked it on our CMM. Got a TIR of 0.0004" on the hole (probed in 12 places), which I thought was amazing for how old the machine is. I had to look very carefully to see the axis reversal marks on the cut, couldn't really even feel it. Very happy to see that.



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    Community Moderator Jim Dawson's Avatar
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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Looking good.

    You would need a buck/boost transformer wired as buck.

    Build log-drhanger's DM4400 electronics retrofit-bucking-png



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Hmmmm...that looks suspiciously similar to a set of transformers that I pulled out. Maybe it was already set up that way originally, and I ended up bypassing that. I'll have to look at that when I get home. I do recall that the smaller transformer was a 12V Radio Shack, the larger one is a Siemens 300VA.

    Attached Thumbnails Attached Thumbnails Build log-drhanger's DM4400 electronics retrofit-2017-01-28-09-09-26-jpg   Build log-drhanger's DM4400 electronics retrofit-2017-01-28-09-09-36-jpg  


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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Quote Originally Posted by drhanger View Post
    Oh yeah, forgot to mention--I checked for backlash on the X and Y, got between 0.0007" and 0.0012" and entered those in the backlash section of LinuxCNC. I circle cut a 1.4" hole, took it in to the shop I work at and checked it on our CMM. Got a TIR of 0.0004" on the hole (probed in 12 places), which I thought was amazing for how old the machine is. I had to look very carefully to see the axis reversal marks on the cut, couldn't really even feel it. Very happy to see that.
    Excellent news Dan! Congratulations on get it to make parts again!
    Marty



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    WOW! That is accurate.



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Quote Originally Posted by Jim Dawson View Post
    WOW! That is accurate.
    If I wasn't the CMM expert at work I might be inclined to question it. I also checked it with a dial bore gauge just for confirmation, got exactly the same result.



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    So Dan,
    How are things going with the DM4400? Still running well?
    Did you get the other one in storage going?

    Marty



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Quote Originally Posted by Marty_Escarcega View Post
    So Dan,
    How are things going with the DM4400? Still running well?
    Did you get the other one in storage going?

    Marty
    Hey Marty, been a while. Yes, I've got it running pretty well now. Haven't made any money with it, but I've made quite a few parts for my astronomy project. Never did get the ATC working, didn't even try. I'm fine with that for now. I am right now in the process of changing the axis motors to something different. I was never able to reliably get it past 72 ipm rapid with the stock steppers, which wasn't bad I guess considering the original machine spec was 100 ipm. I removed the old motors and belts and retrofitted some larger steppers and made it direct drive instead of belt drive. I'm not sure why they had a 1:5 belt reduction except to maybe increase the resolution of the drive--since steppers lose power the faster they go it really put an upper limit on the whole thing. My requirements were not for such high resolution, so no problem to go direct. I made some new housings/adapters to mount the new motors directly on the ball screw shaft and managed to get a reliable 132 ipm on it. Below is a video making one of the new adapter plates (nothing special about the video, the same as gazillions of other people's cnc videos). In the video you can see when I pull back the camera the blue air cylinder I mounted on the spindle for the manual tool change. I thought about the Clear Path servos when I started the retrofit but decided it was overkill for me right now.

    The other one is still in storage--I've used it to replace a few bad parts on the garage one so it's not going to be useful except for replacement parts.

    Dan





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    Quote Originally Posted by drhanger View Post
    Hey Marty, been a while. Yes, I've got it running pretty well now. Haven't made any money with it, but I've made quite a few parts for my astronomy project. Never did get the ATC working, didn't even try. I'm fine with that for now. I am right now in the process of changing the axis motors to something different. I was never able to reliably get it past 72 ipm rapid with the stock steppers, which wasn't bad I guess considering the original machine spec was 100 ipm. I removed the old motors and belts and retrofitted some larger steppers and made it direct drive instead of belt drive. I'm not sure why they had a 1:5 belt reduction except to maybe increase the resolution of the drive--since steppers lose power the faster they go it really put an upper limit on the whole thing. My requirements were not for such high resolution, so no problem to go direct. I made some new housings/adapters to mount the new motors directly on the ball screw shaft and managed to get a reliable 132 ipm on it. Below is a video making one of the new adapter plates (nothing special about the video, the same as gazillions of other people's cnc videos). In the video you can see when I pull back the camera the blue air cylinder I mounted on the spindle for the manual tool change. I thought about the Clear Path servos when I started the retrofit but decided it was overkill for me right now.

    The other one is still in storage--I've used it to replace a few bad parts on the garage one so it's not going to be useful except for replacement parts.

    Dan

    I think I would have gone with the Clearpath SDSK NEMA 34 brushless motors.
    I used 6000rpm DC brush servos on mine.
    Good to hear your machine is running well.
    Did you finish rebuilding the spindle on the other one?



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Marty, I did not do the spindle bearings yet. I was glad to see you asked the other guy about his, that thread will come in handy when (if) I get to it.



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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    Marty/Jim/both/anybody--

    I've been getting a lot of good use out of the machine, and have been thinking off and on about working on being able to reverse the spindle. If you recall I did not try to get reversing working, just getting the machine in service.

    Marty, back in this post (http://www.cnczone.com/forums/dyna-m...ml#post2007868) (I've reattached the SD3060 manual here) you pointed out that on the SD3060 driver there is a jumper (A/B) that allows you to use a differential input to the spindle so that a positive signal can be used to reverse the spindle. So instead of directing the 0/+10V input signal to pin 2 of J1, direct it to pins 1 and 2 of J2. I thought I would mess around with this for a while to see what I could accomplish. Not setting up any switches/wiring yet, just moving the input signal manually.

    First I moved the A/B jumper to position B. Then I pulled the wire/pin from the connector at J1 pin 2, and put it back in at J2 pin 1 and restarted. Commanding M3 Sxxx successfully gave me a reverse motion spindle at the commanded speed. Shut down and moved the wire/pin to J2 pin 2 and restarted. Commanding M3 gave me a forward motion on the spindle, but the spindle speed was reduced almost 50%. I can't find anything in the manual that might address why the speed gets reduced. On page 13 of the manual, at the bottom, the A/B jumper is described, where it says for position A (single ended input) it uses J1 pin 2 'with respect to' J1 pin 4, which is how I've been using it. For my experiment I did not change J1 pin 4 but left it as is. Position B says 'J2 pin 1 with respect to J2 pin 2'. I wonder if I need to have the common connected to one of the two pins when I reverse them. I would try that but thought I should get some advice before I do.

    Dan

    Attached Thumbnails Attached Thumbnails Build log-drhanger's DM4400 electronics retrofit-sd_3060-pdf  


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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    The single ended input takes +/- 10 volt. You do not have the use the differential input, the single ended input (pin 2 I think) will give you FOR/REV.

    Jim Dawson
    Sandy, Oregon, USA


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    Default Re: Build log-drhanger's DM4400 electronics retrofit

    The problem being that I only have +10, not -10 available. At least with my current equipment....



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