[CPK_Jim]

Well the time has come to cnc my PM 12X36 lathe. Ive had the lathe for about 9 months now so its due date is here, lol. I luv this lathe as a manual machine and was going to scratch build a lathe to soot my needs and keep this one for use as manual. But now Im swamped with work and need a cnc lathe bad. So i made the decision to convert the PM. I ordered what should be the remainder of the parts i need last night, so hopefully next wk we convert. I cant wait.

I will be using 220w servos running at 48v driven by gecko 320x drives. The x axis ball screw i ordered is 16mm x 430mm with a pitch of 5mm. The z axis ballscrew is 20mm x 1200 with a pitch of 5mm. Both screws will be driven by a timing belt with a 30t pulley on the screw and a 10t on the motor.

I went fairly cheap on the B.O.B with a CNC4PC c35 quick setup board. I havent looked into spindle control too much yet but i think i should be able to just switch the relays in the stock control via another relay for now. When the funds are available i will swap out the spindle motor for a 3 phase motor driven by a vfd to give mach more control. I will be using something for a spindles index pulse, but i cant recall what its called at the moment its off a treadmill though.

Once all the parts arrive, hopefully next week. I am hoping to get it running cnc in a couple days. I will then add the appropriate covers and enclose to keep the chip at bay.

I think thats about all for now. I was going to upload a picture of the lathe as it sits but my card reader is not working for some reason so i will have to do that later.

[asuratman]

I will follow up your build. Now, I am planning to cnc my lathe also.

[CPK_Jim]

One more thing i forgot to mention. There is currently not enough clearence for the x axis ballnut. So I will have to make some room for it on the mill.

Jim

[CPK_Jim]

[asuratman]

Many people put on its side.

[Bubba]

I also am in the process of doing my lathe and because there is not enough room in the cross slide for the nut, I will be using a rotating nut design. The nut and pulley will be mounted on the back side of the lathe and the ball screw will be fastened to the cross slide.

[asuratman]

I will be using a rotating nut design. The nut and pulley will be mounted on the back side of the lathe and the ball screw will be fastened to the cross slide.

Its interesting.

[CPK_Jim]

i thought about the rotating nut design also but decided to just do it right and mill out the carrage to accept the nut. I will probably modify the nut a but also. I'll figure that out when the screw gets here.

I got the bob from cnc4pc already. also got the paralell port board from newegg. geckoes should be here wensday. Timing belt stuff from sdpsi still hasnt shipped. Power supply is on its way. The only thing im not sure on is the screw, but if its anything like last time it will be here this wk too. It may be on for the weekend..........

Jim

[gt40]

Looking forward to seeing this. I have a Jet 13x40 I am thinking of converting after I finish my pm45m...

[CPK_Jim]

Well its been a rough 5 days but i managed to make some parts on the lathe running as a cnc today. It prolly would have been running in 3 days but i ran into a snag with the encoders. Which i should have tested before i started but i didnt so i bit the bullet on the overnight shipping for some new encoders.

The wiring is all temporary and minimal at the moment but at least i can get a few parts out the door while i get everything figured out. I am very impressed with the servo motors, I can get 300 ipm rapids on the Z and even more on the x. Its scary fast though, i turned it back to 100 ipm until i can get comfortable with the machine and the control. Mach lathe is a little more of a challenge to figure out then i had anticipated but im picking it up pretty well.

I have a slight amount of back lash in the z axis ball nut. But I havent looked into that much yet. And i have not decided on how to attach the z axis screw to the carriage, the c clamp is filling in for now, lol. I also have to decide on swarf guarding and wire routing.

Basically i have a long way to go before its finshed including a full eclosure.......





More updates soon,

Jim

[CPK_Jim]

a lil vid of the first parts made by cnc

[gt40]

what size and diameter ballscrews did you end up with. Diameter looks to an inch?

[CPK_Jim]

The x axis is 16mm the z is 20mm.

[ninefinger]

I'm still waiting to take delivery of my PM 1236 but I definitely am paying attention to your conversion - I have plans to do an add on conversion that can be "quick disconnected" to do simple manual turning when desired.

Mike

[CPK_Jim]

I thought about the manual combination which would be easy on the x but the z is another story. I run a powder kote company and had an employee point out the fact that i haven't touched the manual mill since i built the cnc mill 3 yrs ago, so..... whats the need for manual...... I do find myself reaching for the hand wheels occasionally though, lol.

Well I have been running parts for 3 days, and I absolutely luv it! I am trying to get caught up on work again so i can finish the machine. I still have all the electronics on a sheet of OSB. The Z axis is still held together with a c clamp.... Ya there is much to be done. I should be done with this order tomorrow then i will work on the control box and wiring some more. I would also luv to get the spindle index figured out and operational as i need to be able to thread like 3 days ago, lol. I also need to figure out a good oil system for the ways, this thing is moving alot more then it ever has, lol.

Another big need is a gang tooling setup. This changing tools by hand is for the birds. I want to put stock in and come back to a finished part. It may take 6 months but ill get there......

Question.... What is too hot for a servo motor? My Z servo is getting moderately warm i didnt hit it with the temp gun but it was prolly 120 or so. Should i be concerned?

More updates, mods, and pictures soon. Sorry ive been super busy throwing chips across the shop.

Jim

[CPK_Jim]

Well I have been busy ass heck but have managed to add some swarf guarding and wire track. I have also finished the mount for the z axis so it is not longer held together with a c clamp, lol. The z axis is much stiffer now with no noticeable flex. We also removed the glass scales, old readout and mounted the computer monitor. Not sure if ive mention yet or not but i have also installed an optical sensor on the spindle and it threads awesome!!! So far i couldnt be more happy with the way it has gone. Ive had more trouble with the quick change tool post repeating then anything. No other issues at all really.... I guess im getting better at building these things, lol.

Anyways heres a pic i snapped after we powder coated all the guarding and put it back on.



I do have more upgrades planned. Im trying to get my hands on a ethernet smooth stepper to play with and may and the system. I also need to build a tool turret or gang tooling setup ASAP. I am also planning to make some sort of sliding door to keep the coolant and chips at bay.



Jm

[will gilmore]

Looks great. Can I see more details on the z screw cover?

[CPK_Jim]

The z axis cover is nothing more then a pc of sheet metal we rolled in the roll and bent in our brake. The bottom of it is open but this seems to keep most of the swarf off of the screw.

Heres a couple pics.





Jim

[will gilmore]

Looks good. I like the look of the gang tool holders that drop onto the QC post.