Shoptask CNC Lathe and Mach3: Gcode delima

[Ron111]

Borrisl,
I forgot to ask, what kind of backlash did you have before you added the new ballscrew and ball nuts?

Ron

[borrisl]

Before I had about .0012-.0015 backlash with the single ballnuts. .050" on the Z axis.

I think the problem would be having to replace the bearing block on the table with something that was threaded for the second ball nut. I'm sure it probably could be done though. I certainly am not the expert in this matter. I'm frankly having difficulty getting all my backlash out. I really don't like the idea of backlash just because it's a limiting factor in my learning experiance in getting a precision product.

The limit of backlash, precision bearings and upgrading the motors has greatly improved my rate of material removal rate. I can use a 1" end mill in 6061 T6 aluminum taking .125" at 12 ipm. That's about the machines extents. Any more than that it started having a seizure. Lot's of rigidity issues.

[borrisl]

About axis orientation on a 3 in 1 machine. I've considered swapping the pin configuration in Mach3 to orient the axis in more traditional arrangments. Then in lathe functions it would be as it is now, mill mode would have the x axis along the table and the y traveling the bed.

[mute]

Ive pretty much given up using the mach3 turn. Im programming everything on the mill to do my turning. Its working out a lot better now.

Just seems like my back lash changes day to day, or sometimes even by the part. Using lead screws now but will be going to ball screw I think...

[Ron111]

I've upgraded my motor to 2HP 3450 rpm and with a fresh (4 flute) (about 1800 rpm )cobalt .500 I can take .070 to .080 at 12ipm and that's about all.

Back to Jim's original concern, I thinking pin reassignment in a Mach3turn config file may do it.

Borris,

I do have to ask, how did you get the .050 backlash out of the Z. without limiting the z axis travel even more? (I know I getting off the subject of the thread.)

Ron

[borrisl]

.050" is about standard on the Z axis stock. The worm spline drive on the spindle allows for lots of backlash.

[KaptainKarst]

Thanks for all of the replies!

I was able to change the Step/Direction pin assignments in Mach3 turn and produce the desired results.

The old X (right to left) direction of travel in Mill Mode is now the "Z" axis in Lathe mode. The old Y (in and out) direction of travel in Mill Mode is now the "X" axis. I dissabled the old "Z" (up and down) in Mill Mode settings so I only have to deal with the two axes (interesting thing about the English language: axes like in multiple things chopping wood is spelled exactly like axes as in more than one axis but yet pronounced different).

I then calibrated the motor tuning section and set the backlash.
By the way, someone ask about backlash settings. I'm using the factory ACME screws and the backlash for the X (or Z in lathe mode) is .012". The backlash on the Y (or X axis in lathe mode) is .015". Now what I have not done yet is to possition the carrige on opposite ends and the middle of the long axis and measure the backlash to see if it is constant along the entire length of the axis (just happy to be making stuff at this point).

I was however able to make an outside "dome" on the end of a piece of 1" 6061 using the O.D. Wizard in Mach3. It turned out nice (except that I need to center my cutting tool better because I had a very small nipple in the center of the dome).

My next quest will be to learn how to use CAD and SheetCam to design an entire job using arcs and radiuses (not just one operation as the wizards do) and get it posted to G-code that is correct for the axis layout in Mach3 turn.

This is step #413 in my quest for world domination..... :-)

[KaptainKarst]

Ron111.
Sorry for forgetting about answering a question you posted earlier.
I am using 640 in/oz NEMA34 steppers. However, at this point I went with a constant current (not chopper like Gecko) type of controller using 3 12 volt power supplies. It works, but my top end rapids are only about 6ipm. which for my small projects has been fine thus far (I'm not using flood coolant either, just a can of SprayOn brand cutting fluid).

The wood CNC router that I built from scratch is using the Gecko drivers, 60 volt power supply and 240 oz. NEMA 23 motors and I get 30ipm rapids. I should be able to do even better than that if I change out my .75" dia. X 10 tpi ACME screw to something smaller in dia. with less pitch......

thanks for your help.
Jim

[Ron111]

Kaptain,
Excellent debreifing, glad you have the situation under control. I do like the Mach3 Widzards. They work good for me.

Ron