My name is Andrew, I have just completed a course in CNC machining at Tafe (Mainly programming and cam modules). I would like to pick your brains in regards to a preposed purchase of equipment to retrofit an existing mill.


I have owned a:-


Mill Drill Machine


CODE : M130

MODEL : RF-31

CAPACITY : (X) 435mm

(Y) 190mm

(Z) 300mm


RF-31 BELT DRIVEN MILL DRILLING MACHINE


GENERAL MILL DRILL FEATURES


• Fine and coarse hand wheel-operated quill feed

• 3MT spindle with 75mm diameter quill

• Adjustable table and drill length stops

• Rack and pinion wind-up rotating head

• Rear slide way cover and slide clamps on all axes

• Optional power feed fits straight on the table

• Stand to Suit (M135)

http://i2.photobucket.com/albums/y50/Pandyo/cnc/16446.jpg

I was looking at using the following equipment to retro fit the above mill :-


**3 Axis 7amp stepper Motion controller with 4 internal opto relays (240vac ONLY)**

**NEW!! RAPID 55vdc / 700w Tolroid Coil Power Supply (240vac ONLY)**

**Jog Pendant Remote (Ver.3) ROUTER TYPE**

**(3) NEMA 34 / 1200oz.in DUAL shaft Stepper Motors including 8ft pre-wired leads**

**Quickstart CDRom, Printer Cable and instructional setup Leaflet**

**(3) Motor Couplers**

**MACH 3 Licence registered to**

http://i2.photobucket.com/albums/y50/Pandyo/cnc/Milling--Machine-MYCOM-3axi.jpg




I have the following questions though


Will the above items run the mill o.k. or am I wasting my time?
Will I get way with using the acme screw on the slides or will I have to purchase liner / ball screws?
If the acme screw can be used will mach3 compensate for the backlash?
When talking backlash, this is the movement that the handle moves prior to the bed moving? Yes.
Many of the photos and example of small mill have servo’s running them. Why?
Servo vs. Stepper what better in this application?
Direct Drive or Timing belt drive what’s better in this application?
If I can use stepper motors/direct drive, can I put it on the z fine feed.


Understandbly it would be better to purchase a new cnc mill outright buy i would like to use what i have if possible.

Your assistance in this is most appriciated

thanks
Andrew

Hi Andrew,
I have cut some from your post and will try to answer a few questions.

I have the following questions though


1.Will the above items run the mill o.k. or am I wasting my time?

It looks good but a web address would be helpful.

2.Will I get way with using the acme screw on the slides or will I have to purchase liner / ball screws?

It depends on how much play is in the acme screws. You should also have a way to remove additional play as the machine wears in. There are a lot of machines this size running acme screws. Ball screws are much nicer but are more expensive.

3.If the acme screw can be used will mach3 compensate for the backlash?

If it is under .010" Any nore and it is not the best from what I understand.

4.When talking backlash, this is the movement that the handle moves prior to the bed moving? Yes. Yes it is.

5.Many of the photos and example of small mill have servo’s running them.
Why?

Servo's tend to run faster rapids and have feedback to the drive. If you run steppers within their limits, they will work just fine.


6.Servo vs. Stepper what better in this application?

How deep are your pockets?:) Either will run this size machine.

7.Direct Drive or Timing belt drive what’s better in this application?

Do to the difference between a stepper and a servo, direct for the stepper and belt reduction for the servo.

8. If I can use stepper motors/direct drive, can I put it on the z fine feed.

I am not sure but sometimes the play in the fine feed mechanics can be very tough to eliminate