How to build a pneumatic ram from scratch

[technoclub]

We are currently building a robot for robot wars and want to use a flipper for the primary weapon. We have a low budget and therefore cannot afford to purchase one. Can any one give us some tips for making our own?

[ewan]

How to build a pneumatic ram from scratch

DO NOT make pneumatic rams from scratch, CO2 in any form is extremely dangerous (one of the reasons why I havent used it in my robots). You can build a pneumatic flipper, but as you are first-time builders, you MUST buy most of your pnematic parts off the shelf. I guess you do not have enough expirience to mod a scrap ram, which if not made safely would be extremely dangerous.

When building Pneumatics for the first time, look for direct help from someone with full expirience.

Cheers, Ewan
http://www.micro-maul.co.ukwww.micro-maul.co.uk

[kaideejee]

How to build a pneumatic ram from scratch

Building for robot wars may not be a valid target any more with the likely demise of Robot Wars as an institution, although building for robot combat (i.e. live events) is a valid aim. If youre building something light e.g. a 12kg featherweight bot you may be able to follow the original Rexs Robot Challenge idea of using a bike pump at max pressure around 50psi (I imagine it could go higher), although I couldnt tell you exactly how they modded the pump for this (Id be interested to find out however.)

I bow to the more superior knowledge of others (Mario?) on the specifics of pneumatic ram building however.

-- Kev

[fluppet]

How to build a pneumatic ram from scratch

Speaking as someone with no practical knowledge:

If you cant afford to run a high pressure ram, look at a low pressure (possibly larger bore) one, but bear in mind the price of the regulator, buffer tanks, etc.

If thats not going to work for you, have a look at an electric lifter? You can probably make one of those for less (unless your names Ed or Carlo), and itll be safer.

To make your own ram, start with a decent lump of steel, the metal lathe you obviously have, a good knowledge (I recommend a degree course) of fluid dynamics and a load of moderately specialist components to make the plunger, seal, end caps, etc. Dont forget to make two so that you can destruct test one and get a pressure rating. Try not to autodarwinate while doing it. Oh, and dont get it wet. In other words: best of luck, but of all the reasons to make your own ram (or at least, get one made - talk to the Bulldog Breed team to find out who they used?) saving money is unlikely to be a practical one. Economies of scale amongst people who know what theyre doing, and all that.

Sorry to be harsh - Im just trying to impress on you not to try to do this.

Alternatively, hang around in the for sale section and save up (preferably not in that order). Which is approximately what Im doing. :-)

--
Fluppet

[maddox]

How to build a pneumatic ram from scratch

A flipper.Lots of questions to be answered.
Knowledge you posses?Metal working experience?Budget?
If you dont have sponsoring, and wanting to have a real flipper-like Chaos2,or M2 Im afraid this will be difficult on a limited budget and knowledge.And then Im not talking about the new generation of Launchers -with Gravity as example.

I did make several rams, and started with a 127mm bore 180mm stroke 10 bar version.
I garanty you that it aint cheaper than lurking around on Ebay,or trying your luck in the for sale tread on this forum.

In any case, if you need more specific knowledge,mail me.
Basic formula to build a robot
Time*money= Robot
The larger the amounts of time and money, the bigger the chance that the robot will do well-if the basic idea is good.

[Guest]

How to build a pneumatic ram from scratch

you should get a ram from on of the for sale threads much cheaper than it would be to build one from scratch try http://www.leebay.fr.fmwww.leebay.fr.fm or the for sale thread on this forum

[fwsorg]

How to build a pneumatic ram from scratch

Sorry to break the mold, but i found making my ram and fun and educational experience.... that is untill I over-bored the cylinder and so the seals stopped to function in the manner their name suggests.....

On a more serious note, I know the Ceros guys (http://www.ceros.org.ukwww.ceros.org.uk) have loads of low pressure rams for sale. Theyll be well worth an email.

[Guest]

How to build a pneumatic ram from scratch

Instead of building a dangerous and difficult full pressure flipper, why not settle for a nice pair of titanium ramming spikes?
Alternatively, could you look at sodastream bottles? I Robot Wars banned them, but they may still be useful for live events, that will become much more prevalent (please can someone post the rule about this).

[woody]

How to build a pneumatic ram from scratch

8.3. The compressed gas shall be stored in a commercially manufactured gas cylinder of appropriate design, specification and certification. Except where the maximum storage pressure is less than 50 psi (3.4 bar). N.B. Some events may have further restrictions on bottle sizes/weights used please contact the event organiser for clarification
8.4. The gas cylinder must incorporate a burst disc or pressure relief valve with a relieving pressure of 190 bar. Exemptions from this requirement are where the manufacturer or manufacturers agent fills the gas cylinder and applies an integrity seal / wrapping, or the storage pressure is less than 50 psi (3.4 bar). Event organisers may wish to check integrity seals prior to their use.
8.5. Gas cylinders charged to pressures of greater than 50 psi must incorporate an isolation valve that can be operated from outside of the robot.
8.6. Gas cylinders that do not incorporate a valve (for example: the gas is released as soon as the cylinder is screwed into it€™s mating pneumatic connection) such as found on disposable welding bottles and €˜fizzy drinks€™ machines must have an additional remote isolation valve accessible from outside of the robot.

[swedemac]

How to build a pneumatic ram from scratch

Sorry to burst (he he) in like this in the thread but I have a question about the 190 bar releive valve rule.
As far as I know the european standard releive pressure in fire extinguishers now are set to 250 bar? Or is that only we swedes that have read the EU rules to closely again?

[m2xt]

How to build a pneumatic ram from scratch

Markus, there is no intention to raise the FRA rule for burst disc rating to above 190 bar. This is because many of the older regulators, valves etc. are only rated to 230 bar. If you have an extinguisher to EN 3 with a 250 bar disc, you will need to change the disc to a 190 bar rating. We will however, monitor the situation.

Paul Cooper
FRA Technical Team

[swedemac]

How to build a pneumatic ram from scratch

Good thing then that we have a Technobots 2 litre 190 bar burst disc refurbished extinguisher .

Techno club: I do agree with the advice the people above have given. Its probably more cheaper and smarter in the longrun to buy a used ram from someone around here. Good luck with your robot.