Joe90's BIG RAT Build.

**JAZZCNC** · 27-06-2020

Originally Posted by Muzzer

JAZZCNC - I've never knowingly used cast plate - where do you get yours and what grade is it?

Recently bought some 15mm plate from Poland and assumed it was rolled. That was EN-AW 2017 T451 and it machines very nicely. Also pretty flat.

Cast plate tends to be mostly tooling plate and is very flat with a shiny machined surface or ground surface in most cases. It's easily identified from a rolled plate which tends to have a dull finish and is rarely flat.
Also, Cast plate is heat-treated and annealed to relieve stress as part of the casting process so it's very stable and cuts completely different to rolled plate. The chips that come off are like little balls rather than stringy chips because of the grain structure which is much finer, it also doesn't have hard n soft spots as the rolled plate does.

I buy mine locally and the grade is 5083. You can buy Cast plate from Aluminium warehouse and Ecocast is their trade name for cast plate but I believe it's 5083 grade.
You will also find it under the name Mic5 or Mic6 which is basically 5083 or 6082 grade. 6 series cast plate isn't so common and much more expensive usually and to be honest I find little difference between the two in machining terms, obviously, if you need the 6 series properties then that's different but I find 5 series more than good enough for any CNC use.

I buy mine locally and it's 5083

**joe.ninety** · 29-06-2020

Jazz, what's you recommendation for plate thickness for a standard z axis build? Is 15mm thick enough? I'm talking about for a desktop machine and not something huge, so say a 6040 cutting area.

Cheers

**JAZZCNC** · 29-06-2020

Originally Posted by joe.ninety

Jazz, what's you recommendation for plate thickness for a standard z axis build? Is 15mm thick enough? I'm talking about for a desktop machine and not something huge, so say a 6040 cutting area.

Cheers

Personally I use 20mm mostly but 15mm would work for a lighter Z-axis. Just remember the Z-axis is handling all the cutting forces so if it vibrates then the tool vibrates with it and you get a shitty finish, excess tool wear and even breakages if bad.! . . . Some areas you don't want to skimp on and Z-axis is #1.