Web Goblin cnc has begun

[Jonathan]

I think your single spindle mount is causing chatter/resonance looking at the edges I can see chatter lines.!

Just what I was thinking - the vertical lines are a bit of a give-away.

Definately too low feed and stepover - with only 20% stepover you need to feed much faster to attain the same chipload, look up chip thinning. This explains some of it, though it is aimed at making you buy the program...

http://www.cnccookbook.com/GWCalcFeedsSpeeds.htm

The alu also has some hard sections in it so that was why the cutting fluid was generously applied.

I was joking when I said that was generous!

I have had a look at the program file and cant see any G64 codes in it.

Mach3 may have defaulted to it anyway, it depends.
G64 puts mach3 in constant velocity mode, so that within reason the feedrate remains constant. This means that external corners will become slightly rounded - more if the acceleration is very low.
G61 puts mach3 in exact stop mode, so it stops once it has got to the point specified by each line of code, then continues. This makes the motion very 'jerky', though depending on the situation it will make the final part more accurate.

Using constant velocity makes the motion a lot smoother, and a constant feedrate is clearly faster overall and kinder on the cutter. To try it just type G64 at the begining of the program. You'll notice the most difference when a program uses lots of small lines to approximate a curve.