Hello Guest it is October 26, 2020, 12:40:01 AM

Author Topic: Rotary Setup / Feedrate questions  (Read 1434 times)

0 Members and 1 Guest are viewing this topic.

Rotary Setup / Feedrate questions
« on: July 11, 2017, 10:31:41 PM »
Hi,

I setup a 4th axis on a china cnc 3040 cnc.  Everything is working after replacing all of the electronics and building a new control case to fit everything in.  I have 10 steps per unit and 75000 and 25000 in the motor tuning page.  I command A 360 in MDI and get 1 revolution and decent speeds when jogging so it seems all is well but when i run a program with a and y together at a feed of 100 the axis are barely moving (like 1 min to move 1/8 of an inch).  I currently have a feed rate of 7000 with FRO set at 250 to get a 'normal' speed.  Is there another setting somewhere that needs to be turned on?  mach 3 version .066 running through parallel port and setup units are in inches and program is inches.  Also i have set the federate to radius option under tool path and set radius to 1 inch on the settings page.

Thanks,

Matt
« Last Edit: July 11, 2017, 10:48:26 PM by mrmatt68 »
Re: Rotary Setup / Feedrate questions
« Reply #1 on: July 12, 2017, 04:18:51 PM »
Would a video help?

Offline rcaffin

*
  •  1,034 1,034
    • View Profile
Re: Rotary Setup / Feedrate questions
« Reply #2 on: July 12, 2017, 07:01:18 PM »
No, skip the video for now.
What you need to do is to present far more detail. For instance:
I command A 360 in MDI and get 1 revolution
What do you mean by this? Is this a G0 or G1 command. Critical differences.

Remember: if the machine works at all, then it is likely that Mach3 is doing what it has been told to do. That means it is most likely that you have some really wrong figures in the motor settings. These can be fixed.

Side comment: consider changing from V.066 to V.062, as the latter is generally considered more reliable. But that won't be the problem.

Cheers
R ger
Re: Rotary Setup / Feedrate questions
« Reply #3 on: July 12, 2017, 08:33:23 PM »
Ok well I guess I should have specified the MDI command was a rapid move but either way it's one revolution.  The other moves in the program are feed moves at a rate of 7000 inches per min. with the feed rate over ride set at 250 so something is obviously set wrong.  I just don't know what it is beyond the radius option.  I will try .062 version to see if that makes a difference.  The 75,000 and 25,000 seem absurdly high but that's what it took to get reasonable speeds on the a axis when jogging.

Offline rcaffin

*
  •  1,034 1,034
    • View Profile
Re: Rotary Setup / Feedrate questions
« Reply #4 on: July 12, 2017, 09:09:23 PM »
> a rapid move
In that case Mach3 has the right calibration for the angle of rotation.

> decent speeds when jogging
In that case the system is mechanically able to rotate at a sufficient speed.

> feed moves at a rate of 7000 inches per min
Not so fast!
7000 UNITS per minute, but if you are using the A axis, that will be 7,000 degrees per minute. That is 7000/360 revs/minute, or about 20 revs per minute. That is 3 seconds per rev. Does that sound about right?

This is a problem when working with a rotary axis. Degrees/minute are very different from Inches/minute. In most cases the A axis will be the limiting factor in any operation. When I am programming g1 moves I do keep using different feed rates - depending on whether there is an A movement or not.

Keep experimenting - with all this in mind.

Cheers
Roger
Re: Rotary Setup / Feedrate questions
« Reply #5 on: July 12, 2017, 09:19:19 PM »
Oh wow so yes that explains it....yes it looks like about 20 rpm.....in the program I just have an feed line with a and y at a rate of 7000(thought it was ipm but I see that is not the case).  So next question is how to post a file from aspire when using the rotary and straight line moves together?  Machine won't move x y or z axis at that federate.

Thanks again
« Last Edit: July 12, 2017, 09:28:59 PM by mrmatt68 »

Offline rcaffin

*
  •  1,034 1,034
    • View Profile
Re: Rotary Setup / Feedrate questions
« Reply #6 on: July 12, 2017, 11:27:51 PM »
I have no idea!
But can't you tell Aspire to use different feed rates for moves with and without the A axis? Surely!

I don't use CAM. I write my own g-code from scratch, and my production programs are in kilobytes, not megabytes. But I am not carving faces on a router; I am machining metal in 4 axes on all 6 faces.

Cheers
Roger
Re: Rotary Setup / Feedrate questions
« Reply #7 on: July 13, 2017, 07:50:19 AM »
Quote
But can't you tell Aspire to use different feed rates for moves with and without the A axis? Surely!

I have not seen that setting but it might be more a function of the post so i will definitely find out.


Thank you for getting me on the right path,

Matt

Offline rcaffin

*
  •  1,034 1,034
    • View Profile
Re: Rotary Setup / Feedrate questions
« Reply #8 on: July 13, 2017, 08:34:44 AM »
Ah - yes, in the post for sure. Something along the lines of:

If command involves A axis then
  feed = 2000
else
  feed = 200
endif

Cheers
Roger