Quote:
Originally Posted by Joe G.
This same basic principle also applies to extrusions. Extruded frames also give the advantage of making an even more structurally sound shape, the rectangular box, available in a more weight-efficient manner than sheet metal does, in addition to being made from much stronger material as Austin mentioned. In a pure race to achieve a target strength with minimum weight and optimal design, extrusion will win on paper every time.
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I would have to disagree with you on this portion as in every building that bares weight or hold things together is either I beam or [, etc. never have I seen a square metal tube used for holding up a floor or a roof or a a building, why? because it's unnecessary weight when an I beam can bare nearly the same load. also if you have ever seen a tower-crane, they do not use a solid tube rather they use scaled up version of sheetmetal that uses webbing to give it it's strength/rigidity and it's light weight ( for heavy machinery at least) this principle also applies to sheet metal as well. "available in a more weight-efficient manner than sheet metal does," from this i'm gathering that you are saying tubing is lighter then sheet metal? (correct me if I'm wrong on this) if you are indeed saying this then i would have to disagree with you as our robot using extruded tubing this year/every year has a much heaver weight to it, then sheet metal frame (according to CAD)
as for ease of fabricating, I would agree with you in saying that it is much more time consuming if you don't have a laser/water cutter or CNC machine, and even if you do it still would take much more time then extruded tubing, that much i do not disagree with you on.