Machsupport Forum

G-Code, CAD, and CAM => G-Code, CAD, and CAM discussions => Topic started by: ausplex on July 02, 2013, 04:15:39 AM

Title: Squares Are Not Square
Post by: ausplex on July 02, 2013, 04:15:39 AM

Hi,
I have an interesting problem with my CNC router.  I create drawings in AutoCAD, generate the CAM files with SheetCam, and drive the machine with a SmoothStepper.
I noticed that the inner corners of some square shapes I was contouring were more rounded than the radius of the cutting tool.  When I slowed the Y axis right down on Mach 3, the squares were no longer squares. 

After slowing the Y axis down, the router cuts in the Y direction, and while the gantry decelerates before it gets to the corner the X axis starts moving.  So I get a parallelogram rather than a square.

I would expect that when cutting a square that the routing on one axis should complete before the other axis starts to move.  Very peculiar.

Help/advice appreciated.

David

Title: Re: Squares Are Not Square
Post by: Tweakie.CNC on July 03, 2013, 01:27:39 AM

Hi David,

Try increasing your Acceleration settings in motor tuning - this should do the trick.  ;)

As an alternative you could always select the 'Exact Stop' Motion Mode (Config/ General Config).

Tweakie.

Title: Re: Squares Are Not Square
Post by: ausplex on July 03, 2013, 02:44:08 AM

Hi,

Exact Stop worked.  I hadn't taken note of this setting before.  The problem had never showed-up on any previous jobs.

thanks

David

Title: Re: Squares Are Not Square
Post by: opelomega on April 19, 2016, 02:36:21 PM

Thanks Tweakie. Had exactly the same issue and your fix did it for me also :)

Cheers

Bob