Is hardox absolutely necessary??

My team and I are encountering our first robot build.......a heavyweight. So were making it easy on ourselves.
We're pretty set on an invertible ram/wedge 4wd defensive bot.

Definitely a NOOB.

Being a welder/fabricator my task is to ensure we have a chassis that wont be ripped to shreds on our first encounter with a spinner.
initial thoughts when first approached were 6-8mm thick mild steel plate. However after re watching the last series of robot wars everyone was using hardox (I'd never heard of it)
I was planning a complete monocoque chassis (inc. wedge) fully welded with chamfers on each side of the wedge to minimise being struck at a hard right angle.
Basically is this possible to achieve in mild steel or is it a must, with spinners around like carbide, that hardox is used.

any ideas would be much appreciated.
Cheers.
Pep.

I think you can use mild steel if you want, but I wouldn't expect it to last long against the big spinners of today. Then again, not much does. It's fine for internal structures like bulkheads, but honestly I think you're best going for Hardox on the outside, unless you plan on doing a Hypershock and just avoiding hits on your armour.

Have a look at this by the PP3D guys: http://pp3d.weebly.com/getting-start...-and-materials

Thanks for your reply. That's a great link.....hardox does seem the way to go.

Hardox or simular kinds of steel are an affordable option. Cheaper than the less suitable stainless, and way stronger than mild steel.

But with spinner power as it is now, we're looking at 8mm+ of hardox 500 or better.
And that with as little welds as possible, all angled to deflect hits.

The other option is to use titanium , grade 5, and that is costly, with a pricetag 15 times higher per kilo than hardox.... For only a 33% weight benefit for the same thickness.

At Featherweight level, robots can get away with thick mild steel - however it ends up about as thick as heavyweight hardox.

Thus it is possible, but to get comparable results there is an offset in terms of weight.

Absolutely necessary? No. Recommended? Yes

No offence intended, but I think 8mm angled is a bit overboard. Maybe if you're intending on getting hit all over, but nobody uses 8mm everywhere. Terrorhurz' wedge was 6mm I believe, and that bounced hits away just fine until it got pried up by Aftershock from underneath, after having been on the flipper. I know Battlebots is a fundamentally different environment to Robot Wars, but you have bots there with much lighter armour, and I can't imagine stinger's front blade is that thick either. I think you can get around using thinner stuff if you play to your strengths. Carbide has 5mm Hardox around the edge to my knowledge, though it's fair to say they rarely get hit.

Valkiri 3 ripped right trough 6mm Armox 600, and thats a featherweight.

It's a case-by-case thing though isn't it? How was the armox mounted? Was it at an angle like a wedge? Where did the spinner catch? We've seen Tombstone break its blade in half on Witch Doctor's shock-mounted front scoop, and then there's stuff like Gabriel which just ignores spinners for the most-part. It almost feels like you're better sacrificing armour thickness for maneuverability​ and weapon effectiveness when most armour just gets torn through anyway. Pulsar manages an 8mm front and back because it's so small, but are there any heavyweights that have 8mm on all sides?

The damaged armor was a welded monocoque , all well angled.
In short, if you want to armor up against spinners, it will be heavy. That is why we still use HDPE for the feathers :) .

Methinks we need some new composites to come out at some point. Something light and springy, but also strong.

The issue with composite panels is replacing them. Hardox can be cut out and a new piece welded in. A composite either needs to be monocoque which means a new chassis each time or bolted on which means the bolts become the weak points.

Does anyone have any thoughts on 5mm aluminum tread plate as armour? Just been given a large sheet.

Will hold out normal ramming attacks and low power axes.
But for that weight, you can use 10mm HDPE and have weight left.

We're useing 3mm Mild steel.. But do have 12mm round bar inside the bot for extra strength.. I can't afford Hardox but will see how Griffalo goes. Can always make it smaller and add a thicker mm steel

As a reference, this is what Carbide did to the mild steel on Nuts: https://www.facebook.com/nutsrobotic...type=3&theater

Quote:

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Originally Posted by J.A.G

We're useing 3mm Mild steel.. But do have 12mm round bar inside the bot for extra strength.. I can't afford Hardox but will see how Griffalo goes. Can always make it smaller and add a thicker mm steel

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I have a load of hardox you can have FOC your local to me some come take it away Clevedon

Quote:

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Originally Posted by R9000

No offence intended, but I think 8mm angled is a bit overboard.

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Last rites bent 1" thick hardox equivalent at Robogames

8mm is definitely not overboard lol

To be fair, it did take several enormous smashes from the most destructive spinner in the game to bend that stuff. The total kinetic energy used to bend that panel must've been immense. And again, nobody has the weight for 8mm all over. Whoops! and Sewer Snake are only armoured at the front as far as I know. Whoops! even has the advantage of having no active weapon mechanism, which wouldn't be allowed on TV.

That said, I do understand that 8mm isn't overboard for more heavily-armoured sections. But I still think it is if your entire HW shell is made up of it.

With the right design 8mm will take anything really, it depends on the design and how its supported/mounted and if it is angled just as much as the thickness IMO

Its reached the point where you can't stop the spinners from cutting through your armour or bending your whole robot out of shape. The way forward now IMO is shock mounting your armour to lower the peak forces exerted by any weapons; see Beta as a great example.
Of course that has its own drawbacks and issues but even if you take an impact that lasts 0.1 seconds and turn it into 0.2 seconds you have still halved the peak force.

Regarding the question, I'd be tempted to have multiple armour pieces cut in Mild if you can't afford Hardox and just keep changing the panels. You only need it to last 3 minutes; that's still a LONG time with Carbide, but after that you can fix any damage. Just make sure you have spares!

To be honest, my thoughts towards armouring up against spinners are now more towards hardox frame and lots of HDPE+air gap - no matter how hard they hit, if they can't gouge through the armour enough to hit anything important then you're pretty much set.

Not sure on any examples in heavyweights off the top of my head, but that's definitely a good tactic in Featherweights and below. shock mounting definitely helps things out too if you can't do the above.

Quote:

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Originally Posted by katch

I have a load of hardox you can have FOC your local to me some come take it away Clevedon

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Yes please I gave you a pm