6mm Aluminum plate cut quality

[dovrosenberg]

I just finished building my CNC Plasma cutter table using plans from JDs Garage. I have a PrimeWeld Cut60 I am using. I tried cutting some 1/4" (6mm) aluminum plate but a lot of bad things happened. According to the PrimeWeld manual - for that size plate, I should use 45 amps at 1365 mm/min. My GRBL used 1600 mm/min - the setting I used for 1/8" steel plate. Some issues I see in the attached pictures:

• The holes are tapered - wide at the top, narrow at the bottom

• The holes are not round

• the cut marks look like they are angled too much

• The piece got so hot in places it seemed like it almost welded itself to the table

• The cut quality in general was a lot rougher than the steel bracket I made

I used Fusion 360 to generate the gcode. Thanks in advance for any insights. This is my first time using a CNC and plasma cutter

[acourtjester]

If you cut a square are all sides tapered?? or only on 2 sides. This will tell you if the torch is not square with the metal surface. Hole seem to be cut better with a reduced speed from straight cuts. When piercing there should be only a slight delay before the torch moves on the the cutting operation. this may be why your rewelding the hole, Aluminum cutting is a totally different action then steel. 1600 MM seems to be faster then you should be moving for 1/4" I have not cut aluminum but cut 1/4" steel are 1200 MM. Holes not being round is caused by distance differences in the X and Y axis movement. You need to calibrate the X and Y axis travel distance.

[robertspark]

with grbl I suspect you will run into acceleration limitations.... your cuts will be ok (better than hand cut) but never production quality because of acceleration