Frame

Is 10mm steel bar sufficient?

What kind of robot are you building, that will be the main factor...

Going by the word Frame I would guess you are making an external chassis and then mounting the parts inside rather than going for sheet construction like most robots. If so then 10mm would be ok but the welding area would be very small at each end, going to 20x20mm box with a 2mm wall might be better but as I said it depends on the robot type

10mm steel is very heavy and probably ott for a fw frame

Are we talking solid 10mm steel or 1cm*1cm steel box section? What type of robot? Particularly big or small as FWs go? Armour or chassis? (or both?)

LP flipper, box section 10mm, 10mm hdpe and 3mm ali, just under 500mmx500mm base, yes I do mean frame like that, as in a steel cage.
So not instead of armour, but to keep the shape, as can be seen in grim reaper and bitza build diaries. Armour goes on the outside of the bars.

500x500 base? thats gonna be massive!

It's hard to say either way, but I'm inclined to think that 1cm box section would be a bit spindly. It depends on the wall thickness of the stuff but I'd suggest maybe trying to use a sturdier size. If nothing else, such small box section will limit attachment methods. Plus, a 50cm long piece would likely flex quite a lot.

Then again, with a well built and strong design, you could build a featherweight out of cheese. :lol:

I agree that 50x50cm baseplate is pretty big!

A 10*10*1 box section is tin foil.
A 10*10*2 box section is not as strong as a equaly heavy 20*20*1 box section.

I prefer 40*20*2 of 30*30*2 box section for the main member of the Tframes used in the Hannibalito's.

If you would use a mix of inner steel frame and armor combination of 10mm HDPE and 3mm Ali... why use the steel then?

There are several machines that use 10mm HDPE for a monocoque design (frameless).

My idea , just use the 3mm ali angle to connect the HDPE plates.

The featherweight Seraph (the big green wheel robot) has no chassis and is made of HDPE plastic.
Thickness from about 8mm too as little as 3mm! apart from some vertical spinners none of the other robots have been able to penetrate it. also it is largely held together with 4mm bolts!!

serph is the exeption to the rule :)

I tend to disagree on the comment that Seraph is an exception to the rule.

On the other hand, the hannibalito's ain't HDPE monocoques. I needed metal to contain the flipperforces, so a minimalistic frame resides in that HDPE shell.
But that shell is pure welded and bolted HDPE.