Help please

after having little success buying a hw i now have some motors and gearboxes purchased from here. i have some metal box lengths 1x 1 x 1.2mm. im not sure about welding the box section for strength, should i angle the ends to 45 degrees and just weld them like that? would it be strong enough? im using a gasless mig welder.
also my robot has a wedge on the front will i need to put some sort of small wheels on the front? i want the front to be as low as possible to get under offer robots. it has to wheels at the back, my design will be similar to firestorm.
my other question is about armour/wedge. i cant afford titanium and hardox may be too heavy. are there any other cheap alternatives? i was thinking about 50mm hdpe plastic inside and then maybe put a thin sheet of ali/steel over the outside, but what material would i need for the front wedge.
the robots that spring to mind that worry me are tiberius, kan opener and terrorhurts for causing me damage.

(Message edited by robotnut on November 19, 2008)

1 rule for box section welding, closed sections are a lot stronger than open sections. So, angled at 45° and welded then or just welded together and then the ends welded closed wont make a great difference.
But I garanty you that the box section you say you will dent and rip under the power of the machines you name.

On HDPE, 50mm HDPE weights as much as 6mm hardox or 10mm Ti. 20mm is more than enough to protect against all but hyraulic crushers and the better disks around. Ald layering a thin sheet of ali or mild steel over it, pointless.

thanks mario, so i may aswell just use 20mm hdpe for now, i was going to put a thin peice of ali/steel over it so the hdpe wouldnt get chewed up as much and to give it a nicer finish.

The thin piece of metal will get chewed up very fast. Also, it will accept blows and transmit those to the robot whereas HDPE will just get a cut or nick that with a bit of luck, will repair itself.

Also, if you want to work cosmetic, then use a 2mm sheet of disposable Polycarbonate and bolt that over the body art of the robot - and that body art can be done on paper. It will get damaged, but can be replaced without big costs, is light, and easely copied or replaced with other art.
We did so with Project II/Hexem and it worked fine.

i need all pnumatic parts for a hw flipper i am building, i want it to be full pressure. i know what a ram is, and the won i want is where it just has a hole at the top and the air lifts my flipper. my knowledge of pnumatics is really bad! i know i would need a co2 bottle is this just a fire extinguisher bottle. dont know what a burket is, or what else is needed. also can anyone tell me a suppier to buy the parts.

(Message edited by robotnut on November 23, 2008)

Burkert is a brand. They mainly do valves and such.
1 type of valve in their program is the Burkert 5405. the 1/2bsp (or simular sized NPT one) is one of the few easely available 2/2 valves with good flow and reasonable cost that can switch 750 psi.

It seems you want a basic Gravity style setup. Like used in a lot of heavy and feather flippers.

For a basic setup you need
CO2 storage bottle- buffertank (3times ram volume adviced)-1000psi Pressure relieve device (a valve that opens at 1000psi and vents the overpressure to the open air) valve to fire the ram (the formentioned burkert 5405- amount of valves used depend on ram size, below 70mm bore I say 1 above 2 or more).Valve to relieve the CO2 cought in the ram
A ram of suitable size and then a frame that can take the forces involved.

You can ask around, enough teams have experience.
Team Beast springs to mind.

and after spending the last 2 days discussing with my team, before we start cutting and welding the frame, we decided to change the design to like gravity, we believe this design works well, is relatively easy for us to make. the only thing we are unsure of, is what sort of size it should be, and standard size of a robot, we have looked at lots of robot photos but find it hard to tell. we have placed the motors, gearboxs and batteries where we want them and have an idea on space for other parts but want to be sure

u read my mind mario about gravity

On Gravity.
Dimensions, a bit over a meter long 60 cm wide and 38cm high at the end.
2 Kosbox 20-1 gearboxes with 10 kartwheels/slicks and bosch 750 motors on 36V.
Mythras Speedos, set at 75A currentlimit
Multiplex Commander 2020 transmitter and a 8 channel reciever.
3 PBQ 12V 9Ah batteries

Weapon
1 100mm bore 180mm stroke steel bodied ram.
2 2kg CO2 bottles
2 custom made buffertanks
1 1000psi PRD
2 inlet and 1 outlet Burkert 5405s.
Some assorted hoses

Arm was made from steel 60*30*3 box section. And M20 bolts acted as hinges.

As a rule I have learned the smaller the robot is the heavier the armor plate can be.
When it comes to size for a flipper I would say Iron awe is about right in probably every respect.900mm*900mm*750mm on the RR web site.

If you can buy all the big bits to fit the robot then design the smallest shape with the bits inside mocked out on a piece of wood, that would be the way to go.
Points to watch out for
1 make the robot so you can get to all the bits easily, so you can fix and adjust the robot quickly.
2 padding for batteries and other €œsoft parts€ is good.

3 Make sure any critical parts are not in a position that they will get chaffed or damaged if something comes loose. or the armor gets dented by Thz or similar.

4 Think what is the worst that could happen because it will!!!!!!! Then try to design the robot to minimize this.:uhoh: