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Lathe Feedrate Problem
« on: March 06, 2013, 02:42:11 PM »

Hi, A couple of months ago my lathe computer died and I replaced it with another with similar specs.

I decided to install Mach3 version 43.066

I noticed that when programming a G95 the feedrate was alot slower if I set F0.15 the feedrate in the dro would be showing F0.09
The machine motion would be moving at F0.09 also.

I have been messing around trying to solve the issue but to no avail. I installed version 43.022 and also 42.040 but still have the same problem.

Things I have discovered,

When running any of my cnc files and G95 is read the feed rate is slower until about 12-15 code lines later the feedrate returns to the correct value commanded.

I can fool the problem by coding a G95 F0.30 if I really want F0.18 and then 12-15 code lines later set the feedrate to F0.18 but this isn't perfect as sometimes I end up with one or two passes moving at F0.30 which really upsets my machine.

This slower feerate problem only seems to be when reading the first commanded feedrate in my cnc files as later in the code the feedrate is changed and the machine moves at the correct commanded feedrate.


Any help would be welcome.

Offline Dan13

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Re: Lathe Feedrate Problem
« Reply #1 on: March 06, 2013, 03:18:07 PM »
Go in ports and pins and under Spindle set sufficient time for spin up and down.

Also ver .066 is reported to be bad so wouldn't suggest using it.

Dan
Re: Lathe Feedrate Problem
« Reply #2 on: March 06, 2013, 05:15:04 PM »
Hi Dan, I did at some point reduce my spindle spinup time, that could be it. I'll give that a go tomorrow and see if it helps.

As for the version 066 I have yet to find any problems with it even with threading and I do a lot. It also seems to have more zoom on the tool path display which is really helpful. I've read the problems occur with faster computers, mine is only 1.2gHz.

Offline Dan13

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Re: Lathe Feedrate Problem
« Reply #3 on: March 07, 2013, 12:40:58 AM »
See this thread for the problems with the current version:

http://www.machsupport.com/forum/index.php/topic,23835.0.html

Dan
Re: Lathe Feedrate Problem
« Reply #4 on: March 07, 2013, 01:23:04 PM »
Hi Dan, Thanks again, very helpful. I set the spindle spinup back to 5sec and the feedrate problem went away.


Cheers
John

Offline Dan13

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Re: Lathe Feedrate Problem
« Reply #5 on: March 07, 2013, 01:33:40 PM »
Hi John,

Glad you got it solved.

Dan