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IndustryArena Forum > MetalWorking Machines > Dyna Mechtronics > dm 4400M retrofit - How many parts are reusable?
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  1. #41
    Join Date
    Mar 2019
    Posts
    21

    Re: dm 4400M retrofit - How many parts are reusable?

    Im begining to think that eproms was changed to newer versions on my machine and that might explain why some things aren't documented like these U-axis switches.. but I'm just guessing.

    It would have been nice if someone else also was activly looking into one of these machines. Right now it seems to just us two.


    I got them to home. I managed to input tool change macro and next is to test it.

    Havent really tried the spindle yet. That's also on the todo list soon

  2. #42
    Join Date
    Nov 2012
    Posts
    361

    Re: dm 4400M retrofit - How many parts are reusable?

    So... dumb question here, but.... How many amps do you have in the cabinet? The one next to the CPU cage should be an MR-S12, which is really two amps in one; it services the X and Y axis. The amp in the middle is an MR-S11, which services the larger Z axis motor. To the right of that is the spindle drive. There are some mounting holes and such directly below the CPU cage which is where the U axis would be found. You don't happen to have a U axis amp installed do you? I ask because I'm curious why you would have a PLC switch for it. Maybe the machine came with a U axis when it was originally sold?

  3. #43
    Join Date
    Mar 2019
    Posts
    21

    Re: dm 4400M retrofit - How many parts are reusable?

    There is no additional U-axis amp in the cabinette. I have also been thinking in the same direction. On the front page of the manual there is a sticker ad of the original seller. They are still in business. I might give them a call to see if they have info left.

    There is also some notes manually written in the manual. Part 2.12 plc servo parameter - m_param 12. 1/1. The manual says "not used". So I wonder why...

  4. #44
    Join Date
    Nov 2012
    Posts
    361

    Re: dm 4400M retrofit - How many parts are reusable?

    It isn't for the feint at heart, that is for sure! I have made progress, but I'm not there yet. I can't get the darned motor to not oscillate.

  5. #45
    Join Date
    Nov 2012
    Posts
    361

    Re: dm 4400M retrofit - How many parts are reusable?

    Did you ever get your 4400M running? I've made good progress all of a sudden, after months of screaming. Now I have a 4th axis amp that gently spins and even finds the home index. Well, that one is a little strange. It homes in two spots that are 180 degrees out of phase from one another, so don't quite get it. I'm tempted to take a scope back on the drive and see if the index pulse is at one of them. My guess is, however, that this might be a particular transition in the UVW tracks of the encoder (?). Anyhow, the point is.... I'm making good progress. I have a U axis now on the display that dutifully responds to the encoder as I spin it by hand. I've got the servo driving the axis nicely too (that was a chore, but Mitsu helped me out with a gentle nudge while tuning). I even have an extra HA33 motor that I picked up for pretty cheap, which is cool. All in all, things are looking up.

  6. #46
    Join Date
    Jul 2009
    Posts
    85

    Re: dm 4400M retrofit - How many parts are reusable?

    Mr metric you mentioned several people getting the old servos to work with new amplifiers.

    I’d be very interested in knowing what amps will work with the ac servos.

    Duke

  7. #47
    Join Date
    Nov 2012
    Posts
    361

    Re: dm 4400M retrofit - How many parts are reusable?

    Hi Duke,
    I think you are either misreading something I may have said, or I said something that I should not have. Therefore, let me clarify a bit....

    There is nothing special about the servos or encoders. There isn't a whole lot in motor design that differs from one model to another, excepting power, the world over (other than the obvious differences between AC and DC servos). Ditto can be said about encoders. Sure, there are different counts, index pulses, differential outputs, etc. But, the encoders on the 4400m are actually a bit of a superset of typical encoders. I say that because in addition to the standard high resolution outputs, they also have a second set of outputs that are (my assumption) used for sequencing the coil energizing. This set is used by the servo amplifiers, which I'm guessing the high resolution tracks are used by the control). Many more modern amplifiers seem to be able to use the high resolution phase quadrature outputs for the AC servo sequencing instead of requiring these additional tracks. But that just means you do not need to hook up the encoder outputs to those amplifiers; it won't hurt the encoders if you are not using the outputs.

    Now, I'm not sure if this is what you are after, though.... My hunch is that you comment is teasing a different thread, namely using the original Mitsubishi control with new servo amplifiers. That is something that I cannot help you with. Further, it is something that I think is a far more difficult nut to crack. That big (50 pin) header connector has a lot of interface lines in it and a whole protocol that would need to be addressed. To "fool" a control into thinking it is talking to an MR amplifier is certainly possible from a technical perspective, but it is not going to be an easy task to accomplish. I think it would probably not be worth the effort.

    If you have a good control, and good motors, but bad amplifiers, then my approach would be one of two directions. First, I would be on the hunt for some amps. I actually managed to find some spares to "prep" for just this situation. I *may* be able to help you with that, if necessary, although I'm not horribly eager to sell off my own spares. The other option would be to retrofit the whole caboodle. This would mean that you replace the control and the amplifiers. There are a lot of amps to select from now. I even have some Granite Devices amps that might work for you. There are also a lot of controls. You could roll your own with LinuxCNC. You could buy one of those Chinese things that are sold on eBay (they actually seem to have a fairly good feedback, although the displays are tiny, they are all step/direction based, and I doubt you'll have long term support). Or, you could buy something like an Acorn or its parent's products (those have a good reputation too, although Centroid, as a company, has a reputation for being one of those "everything is an option that costs way too much" type of company). If you decide on putting in a new control, then you will have to replace the amps for the reasons stated above. However, that is probably not an issue because a bad amp is probably the reason you are thinking about all this in the first place.

    The last possible thing would be to repair the amp(s). I'm an electrical engineer so I've got some experience in this area, but I do have to say that I shudder at the thought of doing any work there if I were to be in a predicament. There's a boatload of components on those amps (a modern equivalent would be about 1/20 the volume of an MR), no schematics, no support from Mitsubishi, and, worst of all, a huge number of the components are Mitsubishi branded "custom" devices for which there is no datasheet. My own perspective has been that if I have an amp that dies, and I don't have a spare, I'm most likely going to retrofit. One big caveat there.... It is entirely possible that a fault exists in the stuff below the main boards. That is where you have the large capacitors and transistors that are used to synthesize the high voltage output to the servos. On a good day, all of the electronics on the control boards may be perfectly fine, and you simply have to replace a few select components (often with holes in the side after having blown up) in that chassis area. Don't discount looking at that. Oh, and don't ignore the error codes displayed on a faulty amp; it might give you some good ideas too (such as... if you replaced an amp and nothing works, are you sure you set the ID of the amp? If not, the control can't find the amp and the control will fault).

    I don't know if any of this helped, but I'm hopeful I've at least peripherally touched on some of the areas you are thinking about. If not, feel free to ask questions. I'll do my best to help. All of this is a hobby for me, and I always enjoy the discourse.

    Alan

  8. #48
    Join Date
    Jul 2009
    Posts
    85

    Re: dm 4400M retrofit - How many parts are reusable?

    Alan,

    Thank you for the Detailed response,

    I am very interested in getting different amps set up with completely different controls, as the machine I have was a basket case.
    I purchased it nonworking with the plan to completely retrofit it.
    I would like to keep the motors as my understanding is they are a pretty good overall motor. (although they are almost 30 years old so I may be better off just replacing them as well)

    I already own a centroid acorn board, and license that were originally purchased for a cnc router (taken off and replaced with UCCNC due to it being better fit for a router)

    the centroid acorn does seem like it is a pretty good system for a Mill, so since I already have it, will probably go that way.

    I have built half a dozen arduino GRBL based control boxes.
    also built 3 UCCNC systems 2 plasma and one router.
    have Mach3 running on a Sieg X3 mill and a router table that I'm trying to sell.

    So I have enough knowledge to be dangerous using both open loop steppers and closed loop steppers with multiple controls.

    what I need is some direction on what I need to learn about AC servos and how to decide what amplifier ( control) I should look at to dive into.

    Now all of that is going to be held up by the absence of a drawbar on the basket case mill.
    I have a spindle, but its missing the drawbar.

    from what I understand the DM4400m had a proprietary pull stud on their cat30 tool holders, so what I am researching, is possibly replacing the entire cat30 spindle.
    unfortunately the bt30 spindles that I find on aliexpress are almost universally 90mm and the barrel of the spindle on the dm4400 is 95mm
    also most of what I have found for bt30 spindles have mounting holes that are 105mm apart and the Dyna is 115mm making use of an adapter somewhat tricky.

    I do like the idea of changing the spindle out entirely but unless I can find something that I can make work, this entire project is going to be on hold, as it doesn't make much sense to get a perfectly running machine without a drawbar to hold the tools in the spindle.

    So I could use some direction on what I need to know about selecting and driving the AC servos with new drives/amps.

    Thank you

    Duke

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