Yes the weight limit and dimensions, 500mm x 500mm max.
Regarding the bit of wood, it was actually quite a large piece of wood flying around - and I remember Will getting a bit concerned as the arena was not exactly spinner proof! :eek:
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Yes the weight limit and dimensions, 500mm x 500mm max.
Regarding the bit of wood, it was actually quite a large piece of wood flying around - and I remember Will getting a bit concerned as the arena was not exactly spinner proof! :eek:
So, I got the latest update on the final stages of the build which unfortunately are not looking good
Yesterday they managed to complete the robot to a working state in terms of drive, and the pneumatics were working (apart from some minor leaks!) So I was feeling confident that by today it would have been combat ready.
But this afternoon, after finalising the build and taking it out for testing it refused to move...dead! My brother is thinking the receiver went bust, but with no time to buy one looks like its grounded!
Only hope is they borrow one from I don't know where!
Guys I'm having a hard time getting this build within the weight limit!
I have gone through plans again and trimmed it further,(for now on sketchup obviously!) But I'm still off the mark by about 500 grams.
One of the heaviest pieces is the base plate which is 3mm thick Aluminium, thats 1.5kg. It is also the part which worries me most as being 1000 series Alu its soft and prone to bending with a good impact.
I was thinking of cutting some pockets in it, but not yet convinced about that, first because it will further weaken the base and secondly it will expose the internals when upside down...
Any ideas of what could be done, or maybe different materials, or maybe I should just risk it!
Attachment 4245
A 10-12mm HDPE base would save you that weight easily, and would be more than enough protection against the ram's power; we use 10mm on Skyfall, it stands up to FP fine.
10mm HDPE would actually be about 250 grams heavier than the 3mm alu. I have this problem in my machine, too, as in, the baseplate eating up a huge portion of the weight limit. It depends on how structural your base is, but I have been able to drop mine to just 1.2mm ti (only has to hold the electronics in). I wouldn't trust that to handle all of the forces of the ram on its own, unless it's supported around the base of the ram well, but point is, it'd save ~500g.
Saying that I'm not sure how much more I'd trust soft 3mm alu to support those forces, so it's probably a much for a muchness. If there is some sort of strut (some lengths of the 3mm alu on-edge perhaps) support under the ram then I'd expect it to be fine.
3mm angle ram braces would be the way, then you can also mount armour and electronics of them also
The problem with 10mm hdpe is that the base would weigh approx 1.7kg, still 200gr more than 3mm Alu. I'm not concerned about the ram's power, as its not mounted vertical, its horizontal...I'm more concerned that the whole base would warp with an impact from a spinner or from getting a good flip.
One option is going 5mm hdpe - which would be a last option as the previous build was based on that and it was too flexible for my liking...
The other option is replacing the base with thinner aluminium say 0.09" but of a stronger grade (say 2024 or 7075), problem with that is its hard to source and expensive!
Ahh bloody weight!!!:angry:
Is there anywhere else you can loose weight? It seems that your base is locked down for your design to work. You might be able to pocket out your HDPE bulkheads (I am assuming the machine is much like the one in the picture).
If Sketch up will let you, there is a tool in solidworks that allows you to view cross sections of the design, allowing you to move through and find large blobs of material that you may not need.
Its very much similar yes to that (have a look here: http://www.fightingrobots.co.uk/thre...d-diary/page15 for pictures of the internals)...
My primary concern with the base, as I mentioned is its ability(or lack of) to take punishment from external forces rather than from forces from the ram etc. It ties all the parts together taking a major part of the load, so if the base material distorts and does not spring back, then that will be the end of it!
Ellis, titanium plate at 1.2mm will of course be ideal, but I cant find a piece 500x500 in grade 5 form...apart from that, God knows how much it'll cost me!
Alex, I could probably look elsewhere for weight reduction, but I have to be careful not to weaken the whole thing... The other parts that come to mind are the hdpe sides which are 20mm thick, I could maybe drill holes in them to half their weight (they weigh 0.5kg each)
Might be worth getting a quote from these guys on the offchance: http://www.firmetal.com/titanium-sheet.asp
I got one for a conceptual Tormenta 3's 4mm titanium armour (quite a lot of material) in grade 5, and it was surprisingly "cheap" compared to other sources.