the mystery of the wonky corners

[kingcreaky]

if I put G61 at the beginning all is fine.... what is that all about then? why all of a sudden is it playing up?

only thing I can think of is I greased the Y ballscrew the other day and havent cut anything since.. perhaps im experiencing the momentum of the Y now it moves easier?

[Jonathan]

if I put G61 at the beginning all is fine.... what is that all about then? why all of a sudden is it playing up?

Looks like it's something to do with changing the acceleration settings then. Go into your mach3 folder (probably C:\Mach3) and find and copy the .xml file for your machine and post it here, then we can check the settings. It'll be called whatever the name of the machine profile is, which you click when loading Mach3, with .xml on the end. Or just post a screenshot of the X and Y motor tuning settings, but the whole thing is better.

[stirling]

4 clues... you said...

see how its rounded the edges of two of the corners but not of the other two?

only thing ive changed today is... .... and ive increased the acceleration on X

looking at both the photos X is vertical... Y is horizontal

if I put G61 at the beginning all is fine....


What you're seeing is the classic behaviour when in G64 with unequal accel on X and Y. If your accel was equal but "poor" you'd get 4 rounded corners. If equal but "good" you'd get 4 sharper corners. If you'd increased your accel on Y instead of X it would be the other two corners that rounded. The rounded corners will switch to the other 2 if you reverse cut direction. etc. etc.

[Jonathan]

Yes, just what I was thinking...I'm expecting that if we get the configuration file it will show that the acceleration on one of X and Y is lower than the other. Perhaps a typing error was made and the acceleration has actually been reduced significantly (decimal point in the wrong place) since it would have to be very low to make the large difference we're seeing here.

[stirling]

Given the cut direction (from the code) and the statement that X is vertical and Y is horizontal on the pictures (curious but what was stated) then X accel HAS to be greater than Y. So if the accel HAS been accidentally REDUCED then it would HAVE to be Y that was changed and NOT X (as stated) otherwise the rounded/sharp corners would be swapped.

[kingcreaky]

thankyou all for your help.

appears xml is an unsupported attachment type so it can be found here
http://pensys.co.uk/cnc/Mach3Mill.xml

[JAZZCNC]

Try lowering the CV Dist tolerence In Mach go to General config and in the CV Control section and "CV Dist tolorence" to lower number and see how it goes.?. . . .OR . . . Try setting the "stop CV on Angles>" to 90 deg.
Both will have an affect just in different ways depending on the G-code.

If it works then basicly your trying to go too fast round the corners.? Go read this . . http://www.machsupport.com/docs/Mach3_CVSettings_v2.pdf