Messages

1

General Mach Discussion / Re: Z axis G1 moves get shorter with reduced feed rate

« on: July 06, 2010, 03:38:54 PM »

SOLVED!
You guys were quite correct, it was mechanical. I found some tightness in the new leadscrew.
I've cured that and also upped the gear ratio on the Z axis.
Thanks for all your help.

2

General Mach Discussion / Re: Z axis G1 moves get shorter with reduced feed rate

« on: June 17, 2010, 03:40:20 PM »

Here is a table of results, all commanded movements are 1"
Feed Rate ins/min                Actual movement
1                                        0.45"
2                                        0.62"
3                                        0.76"
4                                        0.84"
5                                        0.90"
6                                        1.00"

3

General Mach Discussion / Re: Z axis G1 moves get shorter with reduced feed rate

« on: June 16, 2010, 07:44:22 PM »

The DRO indicates the correct movement but the axis stops short. Also the amount by which it is short increases with a reduced feed rate.

4

General Mach Discussion / Re: Z axis G1 moves get shorter with reduced feed rate

« on: June 16, 2010, 03:35:15 PM »

Hi Hood
A thought has occurred to me. I originally set this system up with a small desktop PC with separate graphics card and everything worked fine. I replaced the pc with an all-in-one unit with touch screen and integrated graphics and the problem appears to be related to this change. I used the same xml file on both units. I have attached it for your perusal anyway. I will see if i can find another PC that I can use to prove this theory. The only other change was to replace the leadscrew with a trapezoidal one.

5

General Mach Discussion / Re: Z axis G1 moves get shorter with reduced feed rate

« on: June 15, 2010, 10:17:57 AM »

Hi Hood
this is a stepper system and using Mach 3 turn.
I'll swap the plugs round and see what happens.
It's odd though that the problem only seems to occur on G1 moves but not G0.
For example:-
Z=3
G1Z4 stops short
G1Z3 returns to Z=3
G0Z4 goes to Z=4
G0Z3 returns to Z=3

I'll post again with the result of swapping the axies.

6

General Mach Discussion / Z axis G1 moves get shorter with reduced feed rate

« on: June 14, 2010, 09:06:41 AM »

I am having this problem.
If feed rate is set below 6"/min then G1 move of Z axis gets shorter.
G0 move is fine
X axis does not exhibit this problem.
I am using ver 3.041 trial version.
Can anyone help?