Perils of the open loop: strategies for letter engraving

[tsomer]

My version, 5.06 produces tool paths that seem to wander around the substrate like a drunken sailer, doing the descender of one letter, then a loop for another, and then rapid transfering diagonaly across the panel for an element of yet another, and so on.

I'm still not in production, and am learning the limitations of my router. In the meantime I'm having some disapointing trials. I'm evidently losing steps on Z, or else accumulating backlash error which is screwing up my work. I expect to have that fixed soon. But this error is magnified by what seems to be arbitrary, random tool path generation. Maybe there is some logic to this, but it's beyond my comprehending.

So, while I'm isolating a fixing this problem, does anyone have any advice for workarounds-- strategies for optimizing tool paths? I've considered setting limit switches close to use them as references, and periodically directing the machine to register to home. This will admittedly generate some error, but it won't be cumulative.

Now,I've tried the obvious solution of clicking regions and generating paths in the sequence I want the machine to run. This method takes forever on my machine, (1800 pentium, 500 Megs Ram) . I may as well cut by hand. I have not tried using the layers feature, and this is a possibility.

Final thought: Could an Alphabet of toolpaths be created in VM, exported to Rhino, configured and reimported to VM to circumvent processor time? Ideas about this and the other thoughts?

Thanks.

Thanks.

[jwatkins]

Tis' the plight of Horizontal Roughing. The more complex the part, the more random jumping around it's going to do.

If you just want straight letters with a single cut line for each (no pocketing), you can just bring them in from Rhino as open curves, and then use profiling. The trick is to set your stock offset as a negative number equal to half the diameter of your cutter. Then the cutter goes right down the center of the line.

If you want fancier stuff (pocketing), the best way I've found is to profile them with multiple stepovers. Setting it to "depth first" will limit the jumping around some. Sometimes the stepovers will cut into inside stuff that has to stay, like on a brush font lower case "g", or "o", but leave uncut portions elsewhere. Limit the stepover to prevent the offending move and then draw a polyine to create a toolpath that fills gaps.