New Featherweight Robot (Beginner)

**R9000** · 24th October 2016, 18:43

Any chance we could have a photo of this polystyrol? I'm rather intrigued.

**lowndsy** · 24th October 2016, 18:50

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.

**Eventorizon** · 25th October 2016, 06:39

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.

**leorcc** · 25th October 2016, 07:08

PS is used for jewel cases for CD's. Far too brittle and not good for armour or frame.

**COAESystems** · 25th October 2016, 22:17

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.

**Runsler** · 26th October 2016, 03:57

Just don't forget the screws, wheels and stuff like that.
Really, a handfull screws is heavier than you might think.

**RogueTwoRobots** · 26th October 2016, 06:50

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.