Messages

3841

General Mach Discussion / Re: incresing speed on stepper motors

« on: January 23, 2011, 08:46:49 AM »

Here is his machine and some more info:

http://www.machsupport.com/forum/index.php/topic,16875.msg114422.html#msg114422

RICH

3842

General Mach Discussion / Re: incresing speed on stepper motors

« on: January 23, 2011, 08:08:19 AM »

Have a look at the motor curve....if one is available for your  particular motor. It will provide a torque to motor pulse /rpm curve based on some voltage and also for different wiring of the stepper.
From that you pick where you will have the most power or where you will be on the curve. That tells what can be expected in terms of  torque to motor rpm. You need to relate that to your intended use of the machine. You have what you have and cannot compare to someone elses machine and can only do so much. Speed is useless if there is no reliability.

Now if you were starting from scatch, you define the intended use of the machine and design accordingly.
IE; - define the desired axis feedrate / IPM
     - define the desired resolution
     - define the cutting that will be done
     - find a motor which can provide for the above ( a stepper may not work and you need to go to a servo )
     - based on the above, check that the other parts of the system ie; computer, power supply and drive are correct for the application
All the above may not work so it becomes a compromise of them all.

Have a look at this for a flavor of the above:
http://www.machsupport.com/forum/index.php/topic,12484.msg80824.html#msg80824

There is nothing wrong with duplicating someone's machine that is very similar to yours but one needs to understand any differences between the machines and how it
may affect your outcome.

RICH

3843

LazyTurn / Re: Inscribed circle, what am I missing?

« on: January 22, 2011, 06:28:17 PM »

Glad you could afford the trip and hope you'll enjoy the ride.
RICH

3844

Share Your GCode / Re: Looking for Ferrari Emblem G code or DXF file

« on: January 21, 2011, 08:00:31 PM »

The dxf dosn't work when tried with a few programs on this end.
RICH

3845

General Mach Discussion / Re: questions

« on: January 21, 2011, 04:22:06 PM »

1/21/11 THIS FOLLOWING WAS REMOVED FROM "DID YOU KNOW THIS" THREAD

Hi Rich,

I have a Hobby cnc 3 axis  controller by Dave Rogotti using Mach3.  All three axis are working and I am now controlling the Sherline cnc rotary table by switching the y axis with the a axis.  My problem is getting the table to run smoothly.  Also it will only run at a certain f speed ( 35 ipm )  I have tried to tweak it through motor tuning but it still oscillates unless it is at the 35ipm speed. 

If you need more info, I will try to provide it.

Thanks for any help.



Songlight

3846

General Mach Discussion / Re: Help ! "Radial Cut with Zdepth" toolpath from mastercam makes Skip steps ??

« on: January 21, 2011, 10:09:19 AM »

What your after is the code grouping where the big gouges occured.
From that code extract the pathing for a complete rough along one radial out from the center,add the next radial for a complete
rough to the bottom, make a loop out of it in a sub-program. This way you can just vary the number of loops and observe.
This way the file will be very small.

You can do the same for the finish pass.

What is causing it can be a number of things.

RICH

3847

General Mach Discussion / Re: Help ! "Radial Cut with Zdepth" toolpath from mastercam makes Skip steps ??

« on: January 21, 2011, 06:38:27 AM »

Calico,
You are loosing position at a number of spots along the way. So it is not only the roughing. You can see it in the pictures.
I wanted to find the worst / first ones that were causing the gouging and that seems to be in the roughing.
Seems that first gouging accurs, approx, after each 1/4 of code run at a particular  depth level when roughing.
So it would be nice to just have that grouping of code to help find the problem, call it a test file.

Then you confirm  that there is no error in the code for the Z depth cuts.
You then air cut with the test file and confirm you are not loosing position.
Have a look at the code and make note of approx how much material is being remove and do some manual straight cuts
in some scrap and see if you loose postion.

I think that over a period of time, you are heating up the stepper motor  and causing the gouge in roughing.
You could reduce the rough cut depth so the motor is not working as hard.
In the finish passes it's also time related as every 1/3 to 1/4 of the code group you are out of position.

Maybe,generate code for a piece half the size and depth and see what happens.

Maybe someone can be more definitive.........

RICH

3848

General Mach Discussion / Re: Help ! "Radial Cut with Zdepth" toolpath from mastercam makes Skip steps ??

« on: January 20, 2011, 09:42:49 PM »

Calico,
Based on the pictures "seems " like it's gouging somewhere in the first 2000 to 4000 lines of code.
I assume you have a viewer, so find find where the rough is commanding the moves to that level.
The pic attached shows the rough progression to about 2000 lines.

Deleting all the code past that level would allow you to run a much shorter program to analyze the problem.
Hopefully it's repeatable
RICH

3849

General Mach Discussion / Re: questions

« on: January 20, 2011, 07:49:25 PM »

Songlight,
What problem are you having with the rotary table?
RICH

3850

LazyTurn / Re: LazyTurn

« on: January 20, 2011, 11:50:55 AM »

Marty,
Threading works fine in Mach Turn. Threading is not part of LazyTurn as you use the Wizards to generate the code.
RICH