Team MedBots

[Laser]

Hi, max

We had a play with our oneumatic system last week, and it all went well, one thing you may have to concern is that if you try and increase the pressure by turning the endcap when you have got it connected to the bottle and gas flowing throw it, is that it gets very hard and the high pressure seal may leak.

As for your higher pressure problem, when you turn on your bottle the pressure does go about 1 bar higher than the disired pressure as the reg was starting up, your PRV should blow then and your system should return to your desired pressure.

Have a look at my videos I took whilst during the testing:
... ature=plcp

[Bodge Job]

Oh sorry, got it wrong

[Max]

2 questions today,
Would 2mm steel be ok for base and armour? It would be well supported.

Also how do you full pressure flippers guys attach a pipe to your bottle, more specifically ones with a co2 nut type thread? I don't understand how you attach a pipe to the co2 nut.

[Bodge Job]

I think that 2mm will be way more than enough!

[Max]

Hi all,
I've spent the 3 hours just discussing with my dt teacher how my flipper design it wrong rather than getting on building it
But I do see his point, because the ram is mounted nearly horizontally the force going upwards should be almost zero (cosine of angle times force . if angle is 90 then times force by 0!)
He suggested using a elbow shaped linkage which should mean most the force goes up but it has a lot more parts to go wrong and break and it makes the robot bigger and using the ram in reverse so a bit less force and one of the pivots has to move in a slot.

Also he recons you only need 70mm movement at the tip but I think you want at least double that, what do you guys think?

[mightymouse]

Max

Just found this post, have you sorted the regulator? From what I am reading it sounds like the O-ring is faulty.

You should be able to fit the reg onto a bottle, vertically. Wind the cap until it is loose, turn on the bottle pressure, wind the cap in until it vents throught the outlet. Wind it back out again and the flow will drop and eventually stop, If it doesn't then there is a problem and you should return it to me. If there is a leak in the reg you will be running at full pressure and will damage your system.

As for your ram, your teacher is looking at the system as force vector problem, when the major concern is gas flow. If the ram moves too quickly it will not have the ability to keep the pressure high, that is why when you look around the pits other machines look mechanically inefficient - it is for a reason - slow down the ram and your gas supply can keep the pressure in the ram.

Pm me about the regulator.

Trev

[Max]

Thanks trev, I'll have a look at that today.
I just splashed out £1 for a old soda stream hoping there was parts usable in a robot. I know people use the co2 bottles but is there anything else I can use?

[kane]

The bottles are not really suitable for robot use; they are heavy and should not be refilled.

[Max]

Don't some people use them as high pressure buffer tanks?

[kane]

That would be a possible use. There are lighter alternatives though.