44w - Discrepancy between Vectric estimate and 1F toolpath time

I upgraded from the 7w laser to the 44w. I had a toolpath that that I’d created for the 7w that took 6 minutes and 33 seconds. After I installed the 44w I experimented with a lower power output and a much faster move speed. VCarve shows that it should take 1 minute and 38 seconds but when I load the new, renamed file, it still takes 6 minutes and 33 seconds on the 1F. Nothing I do in VCarve affects the speed that the 1F runs. No matter how I adjust the settings, it still takes 6 minutes and 33 seconds on the 1F. What am I doing wrong?

VCarve is using a simplified method to calculate run time that doesn’t account for acceleration/deceleration of the axes. If it’s s told to run a tool at 100 in/min, it assumes that speed throughout. Take a look at your actual feedrate while your laser is operating, and you’ll see that it’s not constant.


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The problem isn’t the estimate I get from Vcarve; that seems to be correct. What is puzzling me is that no matter what I change the settings to, the 1F still runs at the same slower speed. I can’t seem to get it to move faster. Originally, I had it set (I believe) to 50 inches/minute. I increased that at one point to 150 inches/minute but nothing changes. It still runs at 50 inches/minute. It’s as if the speed is maxed out.

So, it looks like Dan kind of hit on the answer. It would appear that the issue was my ignorance of how the 1F works. The project I’ve been trying to engrave is only about 6x1 inches. It would appear that the 1F can only operate up to a certain speed within that space. There just isn’t time to ramp up to speed in that small of a distance and therefore with a project that small, it just isn’t able to run any faster no matter what speed I set. My only option is to experiment with the laser intensity rather than the move speed. Kind of dumb on my part but at least I learned something.


Have you tried turning up your acceleration?

You can turn it way up from the factory settings.


I’ll look into this. I don’t know how but hopefully it isn’t too difficult to figure out. Thank you.

I have found arcs are the real time killer at high feedrates.

What is the feedrate and are there a lot of arcs or curves the toolpath is taking?
On the buildbotics controller the feedrate for arcs and tighter curves is slowed down a lot.
Yesterday i did a carve programmed at 350ipm feed - the CAM package said it should take 28 minute. It ended up taking 1 hour 11 minutes. The toolpath was mostly arcs.
I changed the toolpath to get rid of most of the arcs. The actual cut time dropped to 29 minutes.

By watching the screen it appears that somewhere around 50ipm for a .250" radius toolpath move is the fastest the controller can go.


The real problem could be the number of nodes in an arc. Lots of nodes will slow down the toolpath.


That’s an excellent point. I should have considered that. I’ve had to optimize toolpaths before for that reason. Since this one was small and simple I didn’t think of it.

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