CNC Shark Forum

My preview in VCARVE show square corners but when loaded and cut the G code shows G3 commands to radius the corners. A simple square being cut out will have a square corner at the start location and the other 3 corners will be given about a 1/8 to 1/4' radius corners. These are outside corners. Not an inside corner that will have a radius from the bit. I just tried the new molding tool with 8.5 and did a miter corner with sharp corners option chosen. The cut preview shows a crisp miter joint. When cut it rounds the corner at about 1/8 to 1/4" radius. Nothing as large of a radius if you don't pick the sharp corner. I'm use a 1/4" spiral bit when it does it and it does it when I use the 1/4" bit for rough and 1/16" ball nose tapered bit. The right bits are being used per what VCARVE is being told. I have been at this problem for over 2 months. Am I just missing a setting or what. Any help would be great.

It sounds like a bit size problem.

VCarve produces g-code to go around the corner in an arc according to the radius of the bit. The result is a crisp, 90-degree outside corner. It's a little counter-intuitive, but if the g-code used perfectly straight lines around the outside corners, it would actually overcut into the excess material a little more than is actually needed. By generatic arcs at the corners, it ensures that one point of the bit is in contact with that sharp corner at all times, rather than cutting past the corner, then coming back. (This is difficult to describe clearly without a diagram.)

Check the size of the actual bits to see if they're slightly smaller/larger than you're anticipating. There may also be a path option to disable this behavior, but I don't have VCarve installed on this machine to check.

In the profile tool path when generating tool path there is a box you can check to give you sharp corners. Its in the box where you create tabs. its a tab all the way to the right and it says corners open it up and check box next to sharp external corners

I had the same thinghappen to me. Called another user here in AZ. He said to run any updates there might be. Sure enough, it fixed it. No more round corners

Both Vcarve and the controller are up to date on up dates. Most my files are DXF format drawings but used Vcarve to draw a square in a square. Checked square corners. Profiled outside cut and inside cut. A square donut. Using a 1/4" upcut bit. I still get rounded corners on the outside and a larger than bit radius on the inside.

That's more egregious than I'd expect. I don't know why it would do that.

Both Vcarve and the controller are up to date on up dates. Most my files are DXF format drawings but used Vcarve to draw a square in a square. Checked square corners. Profiled outside cut and inside cut. A square donut. Using a 1/4" upcut bit. I still get rounded corners on the outside and a larger than bit radius on the inside.

When you say "Checked square corners" is this what you have checked/selected?? Note Image below What post processor are you using to save your toolpath??? I use CNCShark-USB Arcs (inch) (*.tap)!

Sharkcutup

Inside corners can never be square it will always have the radius of bit being used

SHARKCUTUP Thanks you found it. The post processor was set at CNCShark-USB 3D Contour (inch) (*.tap)
Changed it to Arcs and got my square corners. Never looked at that setting. Would have save me a lot of time on the last 450 pieces I just cut out. So is Contour used for 3D cutting (STL files) and Arcs for everything else?
Thanks again

Glad I was able to help!!!

So is Contour used for 3D cutting (STL files) and Arcs for everything else?

I am not really sure because all I have ever used is the ARCS Post Processor! I have not yet had a need for 3D Contours Post Processor. Maybe someone else out there on the forum can answer that for you.

Good Luck!!!

Have a GREAT Day!!!

Be SAFE around those AWESOME Machines!!!

Sharkcutup