***RESOLVED*** Constant Feed Rate

All things related to Centroid Oak, Allin1DC, MPU11 and Legacy products

Moderator: cnckeith

Randy
Posts: 13
Joined: Thu May 05, 2011 9:55 am
Allin1DC CNC Controller: No
CNC Control System Serial Number: (0122100131)
DC3IOB: No
CNC11: Yes
CPU10 or CPU7: No

***RESOLVED*** Constant Feed Rate

Post by Randy »

Ajax mach 3 mpu 11
the controller will not maintain a constant feed rate on corner radii
for instance I have a feed rate of 10 ipm then at the corner radii it reduces to .7 ipm

Also, at the end of the program when returning to a set position (x3,y2,z1)
The readout says x3.002, y2.0029,z1.0028

I can not seem to repeat this occurence manually,when using MDI.
diycncscott

Re: Constant Feed Rate

Post by diycncscott »

Where are you reading the velocity (feedrate) info from? How small is the radius?
Velocites are generated by Mach as is the displayed current feedrate - the feedrate is
calculated by Mach and may not be the actual feedrate of the machine for the current vector


Regarding returning to a position after the program ends:
Is there still power to the motors or has the motor power been released for some reason(Estop etc...)?

The fact that you can't repeat it in MDI makes me think it's either in the program or motor power is
being released. There is absolutely no difference between and MDI command and a program move.
Releasing motor power will allow your axes to "spring" out of position - a couple of thous is not unusual
if your ballscrews are slightly misaligned, the ways are dry/sticky or gravity is acting on the axis.
Randy
Posts: 13
Joined: Thu May 05, 2011 9:55 am
Allin1DC CNC Controller: No
CNC Control System Serial Number: (0122100131)
DC3IOB: No
CNC11: Yes
CPU10 or CPU7: No

Re: Constant Feed Rate

Post by Randy »

I get the feed rate reading from the control screen.
This thing is running at very high velocity 10-20 ipm,
then almost comes to a stop .7 ipm
I notice it on what appears to be corner radii generated by mcam
I thought it was the programming but it doesn't do it with the same program on a different machine.

As for the positioning there is no loss of power to the motors,at least not indicated by the typical "loss of power" warning.
This thing is off sometimes as much as .008" .The program is very specific and it does it with all programs not just one.
I only notice it with the end of program line because it stops at a specified point. But it very well could be doing it on every move
throughout the entire program.

I know there are software controls to maintain constant velocity while moving multiple axis and circle interpolation
Also are there deceleration controls that are maybe not working?
Do you think I need to reload the software?
diycncscott

Re: Constant Feed Rate

Post by diycncscott »

I doubt you need to reload the software. I'd also check your CV settings in Mach - as I said, there is no difference whatsoever in an MDI command or program move but have I've seen the Mach CV settings step on the geometry in a multi-line move. (CV settings wouldn't apply in a single line move)

You'll need to post your program and geometry or send it in to tech@ajaxcnc.com so I can check it
I notice it on what appears to be corner radii generated by mcam
Are you saying Mastercam is unexpectedly generating corner radii?
Randy
Posts: 13
Joined: Thu May 05, 2011 9:55 am
Allin1DC CNC Controller: No
CNC Control System Serial Number: (0122100131)
DC3IOB: No
CNC11: Yes
CPU10 or CPU7: No

Re: Constant Feed Rate

Post by Randy »

The mcam generates a corner rounding move when transitioning from one axis to another.
When cutting a square instead of simple linear moves it will cut a tiny radius in between.
This is when I notice the Velocity change , 10 ipm becomes .07 ipm
The radii is somewhere around .025.
This machine was working fine and no changes have been made to any parameters.
I ran line by line to see if I could notice anything,
The machine was totally cooled down when I did this.
The axis consistently were off .0002 on both X and Y. (motors cool)
The feed rate changed on every corner radius move.
I ran the last lines of a 20000 line program to see where it would stop at,
It went to exactly x3,y2,z1
Where I told it to go.
This same program when run start to finish will return to x3.002,y2.0019,z1.0009,
And,different numbers each time.
Apparently there is some affect when the motors are heated up through a long program run.
Like I said I did see as much as .008 one time.
I will send you the program.

All axis are acting the same on the positioning
This problem with the velocity started at the exact same time as the positioning
They are obviously interrelated.
Attachments
WEEP WINDOW ELEC CAV B 3.txt
(154.94 KiB) Downloaded 268 times
diycncscott

Re: Constant Feed Rate

Post by diycncscott »

This problem with the velocity started at the exact same time as the positioning
They are obviously interrelated.
Are you saying that this was not an issue in the past?

This same program cut correctly in the past on this machine with this control?

Did you the problem begin after an update to Mach?

A new POST?

A change in parameters?

Please send us a copy of your machajax.xml file in c:\mach3\ajax.

Please send us a copy of your Mach3Mill.xml file in c:\mach3
diycncscott

Re: Constant Feed Rate

Post by diycncscott »

Can you clarify what you mean by "readout"? Is this the DRO position being displayed in Mach or are you referring to a Scale based DRO?
Randy
Posts: 13
Joined: Thu May 05, 2011 9:55 am
Allin1DC CNC Controller: No
CNC Control System Serial Number: (0122100131)
DC3IOB: No
CNC11: Yes
CPU10 or CPU7: No

Re: Constant Feed Rate

Post by Randy »

Are you saying that this was not an issue in the past?
This was never an issue in the past.

This same program cut correctly in the past on this machine with this control?
Yes

Did you the problem begin after an update to Mach?
No

A new POST?
No

A change in parameters?
No

Please send us a copy of your machajax.xml file in c:\mach3\ajax.

Please send us a copy of your Mach3Mill.xml file in c:\mach3ajaxscott
I can not find a directory in C: called mach3
I have "CNC11 Mill V3.01 DEV TEST,Rev 12"


Can you clarify what you mean by "readout"? Is this the DRO position being displayed in Mach or are you referring to a Scale based DRO?
This is the DRO displayed by Mach.

I initially stated the problem appeared to be on circle interpolation, but actually it does it on linear moves as well.
Where it shows up is on small programed moves,just say generally less than .025",
So, all moves with radii less than .025", and all linear moves less than .025".
If they are larger moves there is no reduction in feed rate.
I watched a program and noticed that all axis moves are approx .002" off.
If it is programmed to go to X1.750, it rests at X1.752.
Apparently the encoders are doing there job.But, for whatever reason the contoller is not receiving the
information or just doesn't care.Obviously the motors are under full power,The motor stress meters under the DRO are minimal.
diycncscott

Re: Constant Feed Rate

Post by diycncscott »

This is the DRO displayed by Mach.


But you are not using Mach? ->
I have "CNC11 Mill V3.01 DEV TEST,Rev 12"
Please update to the latest CNC11 software available here:
http://ajaxcnc.com/tech/downloads/softw ... /index.php

Please post your system ID so that I can confirm your hardware configuration (F7-Utilities->F8-Options)

After you have updated, re-start.
Randy
Posts: 13
Joined: Thu May 05, 2011 9:55 am
Allin1DC CNC Controller: No
CNC Control System Serial Number: (0122100131)
DC3IOB: No
CNC11: Yes
CPU10 or CPU7: No

Re: Constant Feed Rate

Post by Randy »

How do you install the software update.
Its on my usb drive as a zip file but the update command in utilities doesn't recognize it.
By the way I have Linux, Is this the right link for update?

System ID JICGBBAFG (0122100131)
Locked