View Full Version : working problems during series all the same at the same corner

Mon 01 December 2014, 07:02
Hi i had working problems during series, over a big MDF panel, i made many engraving rectangles with a ball tool, all rectangles have 3 corners equal and the left bottom corner is narrower, the root dxf design is a simple rectangle, the speed is not even fast, i really can not understanding why this is happened, someone can helping me to understanding the reasons? What i did wrong? What can i do for solve this problem? Thanks a lot to anyone.
i uploaded an picture about this problem, maybe you need to enlarge the image for seeing the wrong detail

Mon 01 December 2014, 14:43
Its difficult to see, but it looks like the base rectangle (in the dxf drawing) has a radius on three corners but not on the the bottom left corner? Is the cut starting and ending at that corner?

Mon 01 December 2014, 14:45
I think it is a problem of CV settings

Mon 01 December 2014, 15:25
i do not remember if the only different corner is the starting and ending, my dxf design is a simply closed rectangle, a corner is different repeated all over the Others rectangles

Mon 01 December 2014, 15:28
Yes, but if the first corner is right, means that the CV settings at your speed do not allow to do 90 degree angles. Check the acceleration value, speed and CV settings, otherwise try to cut with a Exact Stop instead of Constant Velocity

Mon 01 December 2014, 15:39
thanks a lot i have to try that setting, i hope to solve this problem thanks

Robert M
Tue 02 December 2014, 05:01
Another thought.... What is your cam (or G-code generator) settings ( but before, what cam are you using?)
Any other “unusual” cut behavior has ever happened before ?

Tue 02 December 2014, 05:13
Vectric aspire
Now I realized this mistake, and 'small but carefully i can see it, the CNC has repeated on many rectangle the same mistake in the same corner of all rectangle

Tue 02 December 2014, 10:12
First corner where the toolpath starts is dead on, but the CV shortens the other corners, use the Mach3 option STOP CV ON ANGLES or make a start point anywhere else on the path except in corner :)

Tue 02 December 2014, 10:23
thanks a lot

Tue 02 December 2014, 10:59
You make a very valid point on moving the start point.
Corners = bad. Sides or sacrificial area = good.


Tue 02 December 2014, 14:18
just a bit more explanation on possible implications when moving the start point out of corner when you are doing something other than profile cut.
It may leave a mark on the start / end point so do an OVERCUT, it's possible with Vectric Aspire only if you use Lead in/out.

Gerald D
Wed 03 December 2014, 01:06
A wobble at start or end of cut is also sign of a possible loose router mounting bracket to z-slide. Or z-slide loose inside its rollers.

Wed 03 December 2014, 15:02
I have seen the "Z slide loose inside its rollers" issue before. Thought it was good until I took the spring tension off the motor mount, then it was apparent.

Wed 03 December 2014, 17:07
Thanks a lot i have to check it

Mon 15 December 2014, 16:32
I tried the same gcode on my mechmate and the results are the same ...
I'm sure it's a "software" problem ... aspire or mach3 setting .... I do not have that problem with most of my files :-)