Team Pasty Build Diary: Loki

[ChrisKazoo]

Well if I'm taking requests :P







[Please excuse dodgy CAD]

[Andy]

Looks really cool, I like it

One thing I would say, maybe just have hardox on the lip rather than the whole thing, as aluminium/hdpe will go blunt quite quickly and make it hard to get under other robots, while hardox will stay sharp, maybe just have bolt on hardox lips to the rest of the aluminium arm?

[overkill]

The strongest aluminium that can be reliably welded is probably 6061. some people say that 2024 can be welded but the spec sheets don't advise it.

[maddox10]

What is the current pneumatic setup?

[Ellis]

Just a quick note, something that weighs 1.07kg in 5mm alu would weigh 2.02kg in 3.2mm hardox. So not sure where the error is, but thought I'd mention it!

[Eventorizon]

Nope, CAD is good. I have been trying to design something like that for ages that I am happy with and that looks great. What are the specs?

[ChrisKazoo]

Good idea for a Hardox lip Andy, thanks

Thanks Nick will have a look into that.

Mario I have 12 oz main and buffer paintball tanks, Trev reg, 5/2 way valve, QEV on the ram inlet, 63mm bore, 50mm stroke ram, bungee return, 10 bar. Think that's everything.


Tubing will probably be shortened once I make the chassis and get an idea of how everything will fit in. It's 8mm OD Nylon tube. The ram is my current 50mm bore ram (63mm in the post) and will have 12mm OD tubing between QEV and ram.

Ellis... yes... looked at my spreadsheet, turns out that's the mass for 6mm aluminium.... just saved 178g not enough for Hardox though

Thanks Alex, it's 4 wheel drive, s900s on 5s, 6:1 reduction, 483 x 434 x 140 mm, 15mm HDPE sides, 6mm HDPE top and front. Obviously subject to change if I find out it's lighter than I'm expecting (fingers crossed, although designing to the weight limit has not been a strength of mine :P )

[mrsam]

New Loki looks awesome Chris, hopefully the new Hatchet gets the chance to fight it. What's the size like compared to the first one? Bigger or smaller?

[maddox10]

63mm bore ram. @8bar is 250 kg force.
Volume of the ram is .155liter. Buffertank size 0.45l or closeby.
A 12oz tank is 15% larger in volume. And it looks like a standard CO2 paintball bottle. Way heavier than needed for LP.

The Trevor can be adapted to be mounted directly on the bottle if you use an on/off valve for the bottle. Saving some weight and space.
I don't see a low pressure relieve device in your setup.

I would go for FP, with a 25mm bore ram. Same force, but a lot smaller and lighter.
With FP you can use a smaller buffertank, or dispence of it.
The only disadvantage of a simple FP setup is that it's single acting, and that you'll need bungees for the return.

[ChrisKazoo]

The pressure release valve is on the right of the inlet on the solenoid valve and has been tested.

Going full pressure sounds interesting, was going to use bungee return anyway so that's not a problem. Yes it's a standard paintball bottle and weighs 650g, does appear to be a bit overkill now you've said it. My only reservations with FP was sourcing fittings and being a 4 bar the ram needs to be mounted and be able to pivot at both ends (unless someone can figure out a different way it could work).

Sam from what I remember the old Loki was about 490x490x80 (with lots of 20mm HDPE) so new one is taller but slimmer (with a lighter but less beefy chassis)

[maddox10]

I think I can find a way to make it work. And fittings, no problem, those I can't source, i make.

[Gabe01]

This looks like a good set up a few points to think on, the flow is restricted between the QEV and the buffer (pipe diameter) and I can't see a way on your system for venting the buffer after a fight?

[Gabe01]

Sorry that should read the 'flow is restricted between the QEV and the ram'

[ChrisKazoo]

I've got 12mm piping to replace the 8mm between the ram and qev, just haven't got round to it yet and there's a ball valve under the pressure gauge on the buffer (you can just see it poking out on the photo).

[Flag Captured]

You've got S900 drive on 4WD, is it belt-driven? I would assume so, but I thought I'd ask!

I'm sure there's some places you can save a bit of weight even if it's just by drilling a few holes in the HDPE or what have you. Failing that, I'd make the arm cheap and easy to snap together from parts, and get a few spares made - Hardox wouldn't bend as readily, but if you don't have the weight for it, you might be able to get away with a disposable arm and some smart driving... As long as you don't let anything hit it side on, I think you'll be alright for the most part!