Smooth Profile Cuts

[ecope]

Hello group,

I am using a Taig CNC mill with Bobcad v20.7 software and Turbocnc. Please tell me if all cnc machines either large or small has this same problem since I haven't been around many cnc machines.

I am doing a 2d profile cut with arcs, circles and straight lines. Every time the machine finishes an arc, circle or straight line the machine stops briefly then starts on the next geometry and finishes that geometry and stops briefly.

Every time the machines stops for that brief moment it leaves a smaill but noticeable machine mark (indention on the part) where it has cut into the part from stopping.

Is this something that happens on all machines and controllers? Is there a way to have a smooth cut so I do not have to do any sanding afterward?

Thanks for any help!

Eric

[ger21]

With Mach3, you can use Constant Velocity mode, which will not stop between movements.

I think the next version of TurboCNC is supposed to have it, but it's been in the pipeline for several years now.

[The Blight]

TurboCNC will have this feature in the next version. Don't know when it will be out though.

Check out Mach3 or EMC2.

[Larken]

Looking at the turbocnc code, he does some serious floating point calculations between lines and arcs. This causes the delay.
Most modern controller programs precalculate a trajectory (velocity and distance to go for each axis) and simplify it to integer so it can be setup faster between segments as the machine is moving.
(Integer is what the final cutting is because Step/Dir is a incremental digital movement.)