[Alex_Cole]

I want to start by saying that I would not be at any point of this conversion without the help of someone I met on this forum. He has helped me termendously with the driver cards for the servos and the electronics of this converison. I will not name him here but he knows who he is..and again I say Thank you.

Well I figured I would post an update to my conversion of a Dyna 2400 CNC mill. I purchased this mill and found that it had some issues after getting it home. It did not display these issues when tested initially but I decided to keep the machine and fix it up. It started as a stepper driven system with it's own onboard controller unit that wasn't real friendly to use anyhow. Here are some pictures of what I had to work with.



it's not a bad looking machine as seems to be nice and rigid. It has a 10k rpm spindle but I am having some issues I am working out now with it.



The steppers were driving the lead screws via this delren gear. I had to figure out how to eliminate this in my retrofit plan.









Here is a view of the machine with a cigarette pack for scale...sorry it's all I had around. I need to quit and I am in no way trying to endorse smoking. It kills...and it's killing me..I know.


This machine has a built in oiler system and an added power oiler built into it...This is nice!


This picture shows the lead screws...they are not ball screws but they have a quality adjustable nut system that allows backlash adjustment.


Home switch for Y axis


Overview of right side of machine showing placement of Estop


Well this is the machine. As you can see Dyna went with a different design of having the stepper drives actually mounted at the end of the axis with the stepper that it drives. All of this hardware must be removed.



So having mulled it over a whole bunch I decided that I would go with a servo drive for this machine. I am intending to do high speed type machining with this mill (if I get the spindle issues sorted out) and I felt that servos would be the best thing for this. I have used a stepper driven machine in the past and really had a hard time with lost steps.

I looked at several places to get servos and most were too much for what this machine needed. I ended up getting servos from www.cadcamcadcam.com I do not have the machine up and running under servo control yet but driving current to the motors to move the axies I am happy with the results so far.


Issues I have completed so far.
1-remove all old controller components
2-design new motor mounts and build them
3-figure out how to drive spindle controller board so I could use spindle.
4-figure out how to reverse spindle direction(it was going backwards) easy fix
5-figure out how to make couplers work with lead screws. I had to turn down the od to remove weight, then bore the ID to allow the locknuts for pressure on the thrust bearing
6-make spacer for inbetween coupler and thrust bearing
7-re-wire existing home switches(temporary until I mount new limit switches)


Issues I still have to address.

1-fix spindle motor and drive (it's currently a mess, motor isn't running right)
2-figure out how to fit all driver boards into the controller cabnet
3-get contuit routed and mounted for running power and encoder wires to each axis.
4-make mounts for new limit switches + and - on each axis
5-make new plate for side of controller cabnet for new ports and cable inputs
6-considering adding dc amp meter for each axis inline with each servo motor to monitor driving amperage...(so I can try to not burn these little motors.)
7-Find gas assisted spring to counter ballence the Z axis head


Here are pictures of where I am at now with this project.


THis is the spindle drive motor getting ready to go to the motor rebuild shop. It needs some TLC


This is the head assembly removed and stripped down a bit. I suspect the potentiometer(spelling?) is bad but am waiting until the motor comes back before replacing


X axis servo mounted and ready to go...except for encoder wires and power wires


Y axis servo mounted and ready to go...except for encoder wires and power wires


Z axis servo mounted and ready to go...except for encoder wires and power wires


Close up of drive coupler. This motor mount bracket needs adjusting still to close the coupler. Thats another thing I need to add to my list.


Controller cabnet. not a lot of room once the other power supply gets mounted. I need to tidy up all of this wiring still and make room for the new controllers.


Close up of one side of the existing X axis home switch


Close up of the other side of the X axis home switch


Close up of the nut assembly visible from back side of the Z axis


Different view of Z axis assembly


This is just another view of the XY slide.

I will try to update this post as things progress. I still have a lot of work to do.

I wanted to make this post as there is not much info on here or the net about converting this machine. I can and will try to help those with questions but I will say that this is my 1st machine conversion and I really don't know much about the electronics side...but I will try to help.

AC

[project5k]

looks to me like your doing a first rate job.. keep thoes beautifull pics a-comm'n

[Alex_Cole]

Well I received some not so great news about the spindle motor. It seems that it may be toast. They are going to try to fix the commentator but whoever owned this thing before put lots of new brushes in it but never had it serviced...so the brushes have eaten there way through most of the comm.

Does anyone have any sudgestions on what I might be able to do to replace this motor?

I cannot seem to find any .5hp 90v dc motors that are this size. The area for it to mount is about 3.5dia max by about 4.5Length. This may be a show stopper if the rebuild shop cannot fix it.

I am open to any great ideas.

Would possibly a servo motor fit in there? Anyone?

Thanks
AC

[pastera]

MCG ID33001
4.69 lb-in @ 6000 rpm ~ 0.44hp
The length is 4.78 so you may not be able to fit it


http://www.mcg-net.com/electric_moto...rush_motor.pdf

Aaron

[Alex_Cole]

Thanks for the info. I will look into those and see if they might work.

Thanks again.

AC

[Alex_Cole]

UPDATE:

I had removed the spindle motor due to an issue with the speed and torque variance while cutting (manually turning couplers at this time) light passes in aluminum. I found that the motor was in very bad shape.

I now have the newly rebuilt motor in the spindle and I cannot believe the change in performance. This little motor now has way more RPM than it had before and it has power to spare.

I now have great concerns about the bearings in the spindle itself. If the bearings in the motor were this bad then I bet the ones in the spindle cannot look much better. Although the spindle feels smooth in rotation by hand I think I will tear it down for a full inspection to make sure there are not any issues. I do not want to take any chances at 10,000rpm.

I recommend to anyone who has aquired one of these Dyna 2400 mills to tear down the head assembly and check the motor and spindle bearings. These machines are setup for 10,000 rpm running and by the looks of the motor in mine they do this and they can do this for a long time! When I bought this machine there were 8 available from the place that I bought it. I took my time and picked the one that was in the best mechanical and cosmetic shape. It was a lot cleaner and looked like it had been maintained much better than the other machines. These little machines in my opinion are built extreemly well and are made to run for a long time. I find that many companies have used these over the years to produce some amazing production type parts. This means that when you get one you should go through it throughly and inspect all mechanical components.

The thrust bearings on my machine seem to be in good shape as well as the gibbs and backlash nuts. I have seen one of these machines online where the thrust bearings have been in peices when the user removed the end motor mount to inspect them.

The built in oiler system in the base of the machine(the XY casting) seems to hold oil and works well. I have inspected the oil lines and they all seem to be free of clogs and not leaking. I will be inspecting the automatic power oiler system as this project continues.

I decided to use a flexible conduit type hose to run the encoder cables and servo power lines out to the end of the motors. This will serve to protect the lines from oil, dirt, and chips generated from the cutting process. Over time oils and solvants will break down and make the insulation of these wires brittle. Although this takes time...lots of time, I feel it is worth the extra work to protect these lines.

Over the next week I am planning to map out the controller cabnet as to where each of the components will be mounted and where wire will be routed. This is going to be tricky as I need to make sure the airflow is going to be optimum for all of the components in the case.

Thanks for reading and I am open to any ideas and suggestions any one has with this ongoing project.


PS sorry no pictures this time.
AC

[ScottC]

Hi there, I have just picked up a dyna 2400 myself and am in the process of a stepper conversion. Have you been able to get an increase in useable bed travel by removing the original motors?

regards

Scott

[Alex_Cole]

Scott, At this time I am using the exiting screw mounts and I have not yet figured out how to increase the bed travel as the bed currently limits out flush with the end of the gibbs in each direction. Creating new screw mounts and replacing the screws you could I guess increase the travel but the issue I see with this is you will then be starting to expose the top of the gibbs and this has grooves cut into them for distribute the oil. You could then get chips into this area as the way wipers would not be working.

If you wanted to increase the travel in X I think you would need to make a new table and longer gibbs/ways to stay in contact with the way wipers to keep from getting chips into the system. I could be missing an option as I have not really looked into this and I am just going from memory here.

I will try to answer any quesitons you have along the way if you need any assistance.

AC

[woodturn]

Hi Alex, found your thread. Looks awsome. So for those of you out there, I am rebuilding a Dyna 2200 benchtop VMC. My first CNC project, I have new steppers, new xyoltex drivers, and a breakout board from cnc4pc.

Here are my questions

When I run the C11 breakout board in conjuntion with my driver, I can barely get the steppers to turn, anyone got any tips on that one? So I bypassed the breakout board, which I am starting to belive was a waste of money anyway, and things are running smooth.

Does anyone know where the wires from the limit switches go? Can I plug them into the xyoltex driver, or do they need to go into the breakout board?

Here is my biggest question. The anti backlash nuts on this machine seem to be a spring loaded plastic, maybe derlin? I don't like em. I have an acme lead screw which I think is 1/2" by 10, but I am not sure because the major dia of the screw is .475" or so. It looks much like Alex's lead screw. I can get the steppers to go about 40 ipm, but only for a couple of inches then it sound like the lead screw is binding in the nut. I wish to keep the existing acme and remount a different nut, on the cheap by the way, afterall I am new teacher. Your ideas are very welcome. Alex suggested the rolled ballscrew homeshopcnc.com. But too pricy right now. Like I said, I am a teacher, not a Trump. I was think two steel nuts with a pre load of some sort, but the machine did not come with a oiler.

By the way, Alex, you are doing an amazing job, I will try to get some pics up soon.


dave

[Alex_Cole]

Woodturn, If your screws are like mine and are origional then they should be a 2.5mm pitch that is .098425197 per revolution. With the way they have the end bearing mounts setup and how the backlash nuts are mounted I would be supprised if they were binding but you never know. I would try to see if this was the issue by loosening up the gibb adjustments and also the anit-backlash nut and reomove the stepper you have mounted. Then try turning the coupler you have installed by and to each end of the travel of the table. Does it seem like it is binding? THen slowly start to tighten everything back down in small incriments while turning the coupler from one end of the travel to the other. I know this will get old but it is the best way I figure to track down if you have a binding issue in your setup or not. If you removed anything just make sure you get all peices back where they were when you re-assemble.

As for the limit switches. If you are using Mach software you will be running the limit switches to the computer. This means through your breakout board. I believe the Xylotex board has terminals for you to use for inputs. So in that case you would run them to the Xylotex board. There documentation should describe this. You also need to keep in mind how many pins you are going to use up in your limit switch method. If you loop the (+) and (-) switches together then you will only use up 3 input pins for your six limiti switches. But if you want to have independant + and - inputs into mach then you need 6 available input pins into the computer. THis may mean a 2nd parallel port card in your pc. This is the method I am most likely going with due to other inputs I will be using.

I attached my wiring diagram that I am going to use for my new limit switches once I get the new mounts made. I ran it past the electronics guru that is helping me on this project and he said it looked like it should work good. It uses a continuous +5v signal through the switches. That way if a switch gets tripped or wire gets cut the machine will stop. If you use a +5v when the switch is activated then you run the risk of a wire being cut and you not know it and the machine runs through the limit and crashes. ...That would be bad!


Last night I got the power supply mounted back into the controller cabnet and I preped for mounting the drivers. I just need to go pick up some standoff material and I will have the drivers mounted and set to go.

Hopefully I will get this done tonight.

AC

[Rico55]

I also have a dyna 2400 mill that I am in the process of converting. I was hoping to use the original stepper motors, but it looks like I might end up replacing them with something a little more precise. Has anyone come across a stepper motor model that will bolt into this machine without too much work?

[woodturn]

So I got my steppers from automationdirect.com. about 19 bucks a peice. They are NEMA 17s and have about 83 ozin of torque. they mount up OK with some screw that I bought at Ace Hardware, but I forgot the pitch of the screws. The steppers are nothing special 1.8 degree four wire, but so far they seem to work well with my xyoltex driver. If you mico step your drive, you can get a higher resolution, but then you will probably want to get rid of you gear reduction. Oh, I also had to cut the arbor of the stepper to put my drive gear on it. I hope this helps. Oh by the way, I did not use the original 8 wire steppers were impossible to get the spec sheet on so that is why I went with the four wire from automationdirect.com.

Back to my lead screw issue... I pulled off the X table and the ways seem to be in good shap and slide easy when the lead screw is out. When I thread the lead nut on the lead screw it feels as if the nut is a lock nut, it is really stiff, so I think that I will make an antiback lash set up if I can find a nut that fits. By the way AC, I think my lead screw is the same as yours a 12mm 2.5. The distance between peak to peak is about .100, which translates into 2.5, assuming my math is right. Do you know where I can find a lead nut that will fit? Thanks

On the electronics issue... I will deal with the limit switches after I get my lead nuts figured out, but thanks for the info. I think I did waste my money on the breakout board, I hate wasting money!!! But who knows, it might be useful later on.

Well I am going to try to find a lead nut, maybe dumpstercnc.com??

Thank you in advance
dave

[Alex_Cole]

It sounds to me like your ainti backlash nut is adjusted too tight. There is an adjustment screw on the backlash nut that is used to adjust the tention on the screw. If it is adjusted too tight then the screw will be hard to turn. If you scroll up look at the picture of the Z axis nut assembly. The big allen screw that is sticking up is the adjustment screw. Turn it CCW to loosen the tention and CW to take up the backlash if I remember correctly.

I have looked over the anti-backlash nuts that are in place on my machine and although the inners are some sort of delren or the like they seem to be real solid. There are lots of thread engagement to distribute the weight and I have taken some test cuts in 01 tool steel at about .035 deep with an .125 flat endmill and it seemed to hold fine without feeling weak at any point. NOTE: I was turning the couplers by hand to try to feel the rigidity(?spelling) of the machine. I was quite impressed as the machine didn't seem to have any issues with cutting the steel and left a pretty decent finish.


As for an update on the progress of my machine I received the aluminum that I will be using to make the wiring mount plates. I have not figured out the complete design as my origional plan was scrapped by a clearance issue with the chip pan. Oh well I guess it's back to the drawing board there. I am however now ready to get the control cabnet cut to allow the wiring to come into there.

I have one controller board mounted and I have both power supplies mounted back in. I have the holes ready for the other servo controllers ready but I have to get the right standoffs. We are going to use plastic ones not the ones shown in the pics.


Well I'm tired and going to bed. See ya'll later.

AC

[woodturn]

I wish I have the same system as yours, but there is no adjustment for mine, I'll try to get some pics tonight, got to go,
dave

[mike944]

Woodturn - since you have a 2200 machine, you have different anti-backlash nuts than Alex does with his 2400. the 2200's have spring-loaded nuts, the 2400's have screw-adjustable nuts.

The only suggestion i have for you is try oiling your screws. That might allow higher speed. You could also try replacing the spring in your anti-backlash nut with a less powerfull one.

If you're dead-set on replacing them, i would look for a similar nut as the 2400's use. believe it or not, plastic threads would be my first choice, followed by brass/bronze. steel would be a last-resort option. Likely to gall on your screws.

[woodturn]

[IMG]file:///C:/Documents%20and%20Settings/Dave%20Stevens/My%20Documents/My%20Pictures/Img0029/lead%20nut.JPG[/IMG]Here are some pics, I hope they went through
dave

[woodturn]

I am glad my pics went through. I have tried to take the screw off and run the nuts by hand, but my hand gave out about a quarter of the way in, it feels like I need to wench the nuts on. I am debating on getting rid of the back half of the screw and facing off the other half to have less thread engagment, but then I will not be able to find a replacement if it does not work, I can't find these #$%$### things anywhere

AC, are you sure that they are 12mm with a 2.5 pitch? I can find a source for these.

What type of lube would you all use,

thanks again.

dave

[mike944]

Something definitely sounds wrong there. Running them on by hand should go pretty smoothly.

Did you try running each half on independently? does one half run on better than the other?

By the way, i don't know if this is just how you took the picture, but that nut looks like it's not assembled correctly. You shouldn't be able to see much, if any of the thread in the middle of the nut. The 2 halves should be closer together. Unfortunately, this will make the preload higher, and make it even tighter. Perhaps the 2 nut halves are clocked 180 degrees, and maybe that's causing it to bind?

[Alex_Cole]

I will have to go back and check my notes when I get home today. I do know the ones I have are for a fact 2.5mm I called dyna and asked them specifically about them before. You can always contact DynaMechtronics and setup a support account with them and order parts through them. They may be able to get you the type of leadnuts that the 2400 has with adjustable backlash.

I guess if I were going to do it I would probly just save up and replace the existing screws and nuts with nook. As I said before I don't think the work envelope of this machine would justify the expense of ground ball screw.

You could easaly replace the lead screw with a new one. Just get a more common screew and have the ends turned down to mount and you should be set. At least that way you would be able to get parts easier for it. checkout this site and search on ACME lead screw.

http://www.mcmaster.com
AC

[woodturn]

Yea I think you're right, nooks would be the best in this situation. I plan on installing half of the nut and do some careful adjustment of the gibs and call it like it is, when I get more $$ I will probably retorfit the machine to nooks or something like it...I wonder it I should get some gaint NEMA 43 steppers??? would that solve this problem.... with say 750 ozin of torque?? Probably not the best fix, but it's fun to think about kind of like putting a V8 motor on a chainsaw. OK enough of that, time to get back to work.
dave