[jonrya91]

I'm getting chatter when boring a circle. Mostly 10 oclock to 2 oclock and 4 oclock to 8 oclock. A solid guess would be the x axis? I know i have roughly .0008" backlash on the Y axis and a bit more on the x, but the majority of the vibration feels like it's in the head.

Is this typical of spindle bearings going bad - or would i get chatter everywhere if that were happening?

Also a side question:

When i'm in DNC and i have to either feed hold or stop the spindle, is there a way to restart or even continue the program? It seems as though when i do this i have to reboot the machine to get it to do anything besides jog. It won't even do an MDI move.

Thanks,

Ryan

[Floriptoolworks]

Ryan,

I'm not sure why you'd be getting chatter but I think you may be right in considering the spindle bearings. I have two of these machines and one has head vibration at higher rpms. I suspect bad bearings. Looks like replacement bearings can be found at a reasonable price point.

Does the machine have a tool changer? If not, I'd retrofit the electronics. I tried DNC a couple times using the Centurion V and it was a pain, always waiting for something to go wrong. I had transformer issues a couple weeks ago and decided to dive in for a quick upgrade. Now that the machine is up and running, I am kicking myself for not doing it a long time ago. One of my main problems was the maximum file size I was able to upload. Most of my code is CAD/CAM created. Unless it was a very simple part, I wasn't able to use this machine.

My retrofit cost around $700.
Parts I used:
Gecko DC servo drives (3)
ESS Smoothstepper motion controller
C25 breakout board
CUI encoders (probably could have used the stock encoders)
Mach3 as the controller
Lower voltage transformer

Gecko Drives-
These drives are limited to an 80volt maximum. My machine was running much higher than this. I replaced the transformer and used the original h-bridge and capacitors. Remember, whatever voltage you're pulling out of your transformer must be multiplied by 1.4 in order to determine what your DC voltage will be after it runs through the capacitors. My system is around 72 volts after the capacitors. Another option is to keep your transformer and run the output voltage through a variac transformer. These can be had for under $100 on ebay.

There are other aftermarket servo drive manufacturers out there that can handle higher voltages. I've used gecko in the past and decided to stick with what I know.

Motion Controller-
I went the route of the smoothstepper and Mach3. I did this because I already have another machine in my shop that uses Mach3. I've used it for years and am really happy with it. Another option would be to use the Centroid Acorn and their controller. I went the Centroid route with my lathe project and am happy with it.

Encoders-
I bought some encoders online and made an adapter shaft at the rear of the motor. I could have probably used the original encoders...I thought I was having feedback problems with the original encoders so I replaced them. I now think I had a couple wires backwards. Using stock encoders would have saved a lot of time.

All said and done, the project was done in a weekend. My machine is making parts once again and the controller (in my opinion) is more user friendly. Most importantly, I can run any size of program.

Another plus is that aside from mechanical components, no part of the machine will cost me more than $200 to replace and the parts are available for delivery within a couple days. No outrageous repair quotes from the manufacturers.

Your machine has a number of original/valuable parts. I am selling the old parts on ebay, they will pay for the entire retrofit and then some.


Having lower voltage drives does affect the maximum speed of the machine. I have the axis's setup with a maximum of 175ipm. This is still plenty fast for me.

Hope this helps.

Erik