Any chance we could have a photo of this polystyrol? I'm rather intrigued.
Any chance we could have a photo of this polystyrol? I'm rather intrigued.
I'd check with smarter roboteers than me, but For the chassis it might be too brittle? I am doing much the same by layering different materials for their specific strengths, but using cheapo chopping board as backfill - nothing structural, just to fill voids and stop things flexing.
I googled Polystyrol, and all I got back was polystyrene sheets. - http://modelshop.co.uk/Shop/Raw-Mate...-board/ITM4883 - There is no way that is suitable for any class of robot except maybe a flea weight I'm afraid.The same goes for the clear sheets from Wickes, which is acrylic sheet for windows and the like, very unsuitable.
https://www.directplastics.co.uk/hdpe-sheet - Are one of the main sources of HDPE for the entire community. Depending on the design you want at least 10mm on every side; this varies depending on the style of robot but to keep costs down I'd just buy one sheet and use it for everything rather than buying multiple thicknesses.
PS is used for jewel cases for CD's. Far too brittle and not good for armour or frame.
So, an update! (mainly maths)
I got 2x 250x250x8mm HDPE to use for spare material and gauge how heavy a bot made out of HDPE weighs. I came up with these dimensions and weights: Warning lots of numbers
Robot basic wedge shape 500x600x70mm with cutoff for wedge at the front
Base armour: 300x600x16mm 2742g
Ceiling armour: 300x400x8mm 914g
Side armour: 2x 70x500x16mm 1066g (wedge shape averages out 70x600 and 70x400)
Inner panels for central motors/electronics: 2x 70x500x8mm 533g
Front wedge flat panel 212x500x8mm 807g (trigonometry base 200mm height 70mm)
Rear armour: 70x500x16mm 533g
HDPE armour total 6595g (almost 1/2 the weight!)
I won't bore you all with the rest, but I have the motors and Saturn 16 gearbox weight, then I estimated the rest. Without a weapon, the robot will weigh ~9kg with the above armour. With a lifter, thats another motor, scoop, and gearbox/gears which will likely add 1 to 2kg since it's a small scoop at the front. Looks like plenty of margin for reinforcing armour or adding more inner panels.
I will add some pictures later of the parts I have so far! The radio controller looks awesome and it's the first time I have held one in the flesh.
Just don't forget the screws, wheels and stuff like that.
Really, a handfull screws is heavier than you might think.
500mm x 600mm is an absolutely massive footprint for a featherweight! There are some heavyweights out there not much bigger than that. You could save a chunk of weight by dropping the size down to something more reasonable, such as 300mm x 400mm and cutting the baseplate thickness down from 16mm to 8mm, which will be perfectly adequate for a featherweight.
I support Jamie. Hannibalito 3 is BIG compared to most featherweights, and that 's 440mmx395mmx170mm.
Thanks for the feedback, will reduce the size down and up the height a bit to make room for the electronics.
i have 10mm hdpe on my bot and it took direct hits from the mini terrorhertz at full power with no issues
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