[moto21]

Hello all. I decided to start a project log for my new mill conversion. I started out building the controller before I knew what I was putting it on, yes I do that a lot. I’m using a 24VDC, 6.5A power supply that powers 3 gecko G201 drivers and cooling with a 4" ac fan. As for motors I’m using automation directs 434oz-in Nema 34 steppers. .I am using mach 3 for control through a winford dbl25 breakout board. I’m getting excellent torque out of this setup with good motor speed. As for my mill I bought a Cummins mini mill. I just received the mill Monday and I’m finished to clean it up. My plans are for now to use the current lead screws until I build up some funds again for ballscrews plus that will give me the setup I need for the ballscrews. I also plan on installing a two speed belt drive and add a spindle lock in the near future. Any suggestions, questions, or complaints are welcome. Any thing you want to see more detailed just ask. I’m more that happy to help.
~Brad

[JFettig]

looks like a good project, but you may want to consider automation directs smaller steppers, if you take a look at the torque/rpm curve, the 272oz-in motors pass up the larger ones quickly.
although if you go with the stock leadscrews it is likely it wont be that big of a difference, but youre likely to get higher speeds with the 272s on ballscrews.

Jon

[moto21]

To late. I already have the 434's but Im happy with them. I have already got the main plates done for the x/y axis. Its coming alone nice.

[JFettig]

How do you plan on doing the z-axis?

You might find that you will need ball bearings in the y-axis. with the 272s on the the recent mill I converted, I couldnt get more than 12ipm out of the y-axis with regular mount, but with ball bearings I was pushing 40+IPM

Jon

[moto21]

For right now I plan on using the rack and pinion gear on the Z. Just to play with for now because I to wait and do the z axis When I have the ball screws. When I do get the ballscrews I plan on running the z axis alone side the dovetails or maybe down the center. I'm planning on doing ball bearings on all the axis but not right away. I want to get the main setup done and then make improvements from there. Thanks for your input Jon, I look at your mill alot to get ideas.

Brad

[moto21]

Little update. I worked some extra hours this weekend and got some money around so the mills on hold until wensday when my ballscrews and nuts come. I also have ball bearings for the ends of the leadscrews coming. Its fun being broke.

[jjwl89]

Your conversion looks good so far. Where are you geting your screws from? Will you be machineing the ends yourself?

[moto21]

I got them from mcmaster-car. Im doing the maching myself. I have a fair size manual lathe and mill. I should be able to start maching them tomorrow as long as they show up. I also have the z axis almost done excluding ballscrews and mounting. I'll have some new photos soon.

[moto21]

Well I just got done Grinding the ballscrews on my lathe. They came out Very nice. I still have to make the ball nut mounts before I mount them. Well I'm off to the hardware store.

[moto21]

Got the x and Y axis mounted to day with the motors and running smooth. Im still working some bugs out of the z axis but thats also almost done. Im also currently cleaning up my wiring in my controller box because the wiring for testing was a bite messy. Im aslo adding some little things like a e stop, indicator light, and heat sink. well back to work. So much to do so little time. (nuts)

[acondit]

Moto21,

Where did you get your Lovejoy connectors? What did they cost?

Alan

[moto21]

I got them from ENCO. Heres the link. Remeber you need 2 hubs and 1 spider two make 1 coupling when you order.

[JFettig]

Alan, you can also get them at mcmaster, along with different kinds of couplers, I personally like the helical beam couplers, but they are more expencive.

Moto, how are you holding the screws in position? are they nutted against the bearings?

Jon

Jon

[moto21]

Locking collar. It takes up the space between the bearing and the coupling and then the coupling also locks down. Works alot better then I though it would.

[moto21]

Hey all. Sorry for the delay on the update but I’m very busy. We just had our yearly fishing trip, PA Archery season starts Saturday and I’m going hunting in Illinois in the first week of November that I have to be ready for, O and plus work. Anyway I finished the z axis and it works great. I’ve also finished rewiring my new control box. After about 2 hours of adjusting mach3 to perfection I had it up and running. I made my first cut with it today and it worked great even thought it was only in wood. Next I plan on wiring in limit switches and mounting some encoders. Here are some new pics and I also plan on uploading some movies of it cutting. Well talk to you later.
~Brad

[moto21]

Well I made a couple cuts with my mill and it work really well. I had the program feed rate a little high and got some burring on the edges but all in all good. Im also getting vibration from the way I have it clamped because Im wait on my clamp kit. Heres some pics.

[JFettig]

Looks good but I think the vibration is from the ungodly long end mill, you should typically be using end mills with the length~3*diameter

Jon

[acondit]

Brad,

I agree with Jon on the long end mill being a possible source of the vibration, but it looks like you are clamping down on to a piece of wood. That could also have some give in it that could add to the vibration problems. If you are going to use wood, I would suggest that you use something like hard maple, but I would tend to use a piece of sacrificial metal, like another piece of aluminum.

Alan

[nervis1]

Next on the list...clamp kit, the way those washers are clamping they are flexing the part at the center, making it bow up. You need to clamp over something solid to eliminate the flex. Also the tip of the clamp surface should be in contact with the part, not the base of the clamp like that washer arrangement, that will also get rid of the flex.

Then, regular length end mills. Try clamping in a vice, if you need a spoil board under the part use aluminum, it will flex much less than that 2 X 4.

Also try using some cutting fluid especially with aluminum, get those chips out of the way with an acid brush. Your part finish will be much better.

Nice job on the conversion.

[moto21]

Thanks for the input everyone. I agree with everything your saying and as a matter of fact I have pusched a vise and a clamping kit but they have not arrived yet. The board was there in case something was wrong the endmill wouldnt go crashing in to the table since it was my first cut in metal. In the future I will be using 1-2-3 blocks for anything that wont fit in the vise. Im planning on hooking up a coolant system but I need to make a enclosure first.
Thanks again I like hearing everyones ideas and input. Keep it coming.
~Brad