Messages

11

General Mach Discussion / Re: Trouble cutting accurate parts

« on: December 18, 2013, 02:15:40 PM »

Well, so far it has been a bit frustrating.

I started mapping the ballscrew and recording values as I went, which by the way were a lot better than I was expecting, but nothing showed up in the graph on the screen, just a red horizontal line. It might be because the extremes of travel were in the .5" range, while my errors were in the 0.001" range, but it looked flat lined and I couldn't find out how to adjust the graph vertical range.

Anyway, I went with that, sent the mill to 0 and enabled the X mapping correction. Unfortunately Mach3 X axis DRO read +1.#QNB, I'm not sure what it meant.

Sending X back to 9.000 resulted in an inch of travel, then the motor started seizing and rattling like it was having a heart attack, and the table stopped moving. I did this a few times then I mostly gave up on the mapping idea.

Obviously I'm doing it wrong, or mapping is not working right (it's probably the first option).

12

General Mach Discussion / Re: Trouble cutting accurate parts

« on: December 18, 2013, 11:34:39 AM »

I agree 100% with you Rich. I'm just trying to get the best possible setup without throwing more money at it (for now).

I'll try the mapping thing, then let you all know how it went.

Merry Christmas and/or Happy Holydays to you all.

13

General Mach Discussion / Re: Trouble cutting accurate parts

« on: December 18, 2013, 10:32:36 AM »

Fantastic!   I'll go play with it right now!

Thanks a bunch.

14

General Mach Discussion / Re: Trouble cutting accurate parts

« on: December 18, 2013, 08:20:34 AM »

What your seeing is mach rounding the movement to the nearest step your machine is capable of making. Take for instance the 3.0035"....another step up or down of the motor, would have put you beyond the 0.0035 length, therefore, 3.0035 was simply the closest that could be achieved.

Thank you for your prompt answer Rich, but I respectfully disagree. Perhaps I need to offer more details to allow you to appreciate my assessment.

First is the fact that I can manually step the X axis to the any number I choose, so in this example I can step it all the way back to 3.000" after its initial commanded movement.

Second, mechanically the resolution is 0.0001" per step, but obviously not the accuracy. My screw is Roton #5932, not a particularly accurate one, but ok overall. It's a 0.200 inch per revolution which combined with my 200 steps per turn stepper motor, plus 10 microsteps per step, gives me 10'000 microsteps per inch.

So, I can physically move the table at increments of 0.0001", that's just a fact. I cannot however place the table where I want it using an X#.#### command because the spiral screw is not consistent throughout its length (my assessment).

This is where the idea of mapping the screw comes in.

Now, I've seen a few people mentioning it, but never anyone actually doing it, so I wonder at this point if it is an actual feature of Mach3, or not. If it is I would like to take advantage of it, as it would allow my somewhat inaccurate screw to achieve much better positioning, at least as accurate as my mill's DROs can measure. Who wouldn't want that?!

15

General Mach Discussion / Re: Trouble cutting accurate parts

« on: December 17, 2013, 05:00:18 PM »

Well, my ballscrew is a bit erratic throughout its movement. I'll ask X to move one inch, and the mill's dro will report 1.002", then I'll ask to go to the 2" position and it will be spot on 2.000". Then the 3 inch might go 3.0035", but then the 4 might be 4.000.

My backlash is around 0.003", but this problem is a little different, it's more cyclic in nature.

My Roton ball screws are not very precise, but for my first CNC built I didn't want to go too expensive. I think I will eventually change them, but for now I'd like to train Mach 3 to recognize my ballscrew inconcistencies.

16

General Mach Discussion / Re: Trouble cutting accurate parts

« on: December 17, 2013, 04:15:00 PM »

Maybe you need to map the leadscrews with Mach's mapping feature.

I've been trying to find out how to map my ballscrew. How do yo access Mach's mapping feature?

17

Mach4 General Discussion / Re: New people welcome !! Come in here and introduce your self!

« on: December 10, 2013, 11:29:53 AM »

Hi, my name is Marco, from Virginia.

I have a mini-mill that I am upgrading to CNC, 2 axes done with Z in progress. I'll be using it to make parts for my full size 2 seat airplane project. I've been using my mill and lathe for the past 2 years, and enjoy making things.

I'm still dealing with the CNC learning curve, but it gets a little better every day.

Can anyone point me to how to map my Ball-screw in Mach3?

Ciao

18

Mach3 under Vista / Re: Running Mach3 through usb port rather than paralell printer port

« on: December 09, 2013, 06:12:11 PM »

I use a UC100 USB to parallel interface with my Mac running Windows 7 on Boot Camp, check it out at http://www.cncdrive.com/UC100.html

I haven't had any issues whatsoever so far with it, it pretty much worked right out of the box after installing the driver.

Good luck to you, Marco.

19

Mach3 under Vista / Re: MACH 3 and windows 7 setup and testing.Help!

« on: December 09, 2013, 06:06:11 PM »

I'm just a new guy myself, but I did get my mill running using a USB device attached to my Mac running Windows 7.

I use a UC100, check it out at http://www.cncdrive.com/UC100.html it works great and didn't need any setup beside installation.

As far as wiring, I used a Gecko 540, so my wiring was spelled out for me, if I were you I'd check out http://buildyourcnc.com/CNCElectronicsandWiring.aspx

Good luck, Marco.

20

General Mach Discussion / Re: Origin position -x keeps creeping when returning back to Zero----HELP !!!

« on: December 08, 2013, 08:33:42 AM »

One more thing...

Snugging the couplers' fasteners allows you to run faster motor acceleration before they start slipping again.

Run a few cycles of "air cutting" with the motor acceleration set to minimum, then GOTO ZERO, compare Mach3 with your machine DROs, and see how high you can push your motor's acceleration before slippage occurs again.

Good luck, Marco.