Correcting MillWizard’s feed rates       Author – Derek Mackenzie

There was no easy answer to this one – I had to write a program in VB6 to do it.

MillWizard is very good at what it does – generating raster tool paths – with a few exceptions. The worst problem was tool breakage or jamming caused by excessive feed rates.

MillWizard has a plunge rate but ignores it after the initial plunge, it also uses a single feed rate regardless of what it is cutting.

The only solution within MillWizard is to set a feed rate that is slow enough not to cause breakages or jamming (small tools break, larger ones jam when fed too fast)

I decided to write a program to work out when the feed rate was too high and reduce it.

Tricky – the G-code output is just a collection of X, X, Z co-ordinates – it was necessary to store every position on the last pass and then compare it with the current pass to see if it was cutting much deeper this time, I also needed to compare previous and future positions to see if it was about to drill a hole (replaced by peck drilling) or if was about to run into a wall. I also needed to check for various other things – so it took over six months of full-time experimentation and programming to eliminate nearly all of the problems – nothing is ever perfect and the program can occasionally get caught out.

If anyone is interested I can make the program available for the very reasonable sum of £30 (it soon pays for itself in reduced tool breakages) – it also comes with a program that displays the toolpaths in different colours for different speeds, and a program that swaps the axes for lathe control.

Call me if you are interested.