Nylon 6 Vs HDPE

[Bodge Job]

Nylon 6 Vs HDPE, that is my BIG Question.
I dont know whether to use nylon 6 for the frame or HDPE for the frame and armour? Nylon 6 is twice as expensive and I think its alot stronger (correct me if im incorrect) and it machines easely, HDPE is half the price but is it weaker, less flexable and harder to machine?
I need to beable to tap a thred in to the frame to beable to build my design, but can they both have threds taped in to them?
please give me some advice.
thanks

[craig_colliass]

Re: Nylon 6 Vs HDPE

It's always hard to know what to suggest without seeing detail plans of your project, as to my own experience of HDPE Seraph is made almost entirely of HDPE it has been hit with MD's hammer and spent a while in the pit with Little Hitter doing it's best to knock a hole in it. Neither did any real damage,

I would not advise tapping into any plastic, this has been a problem even on THZ, use angle brackets, Blind hole captive nut or bamboo bolts (this is a stud (threaded) bar that goes through the whole robot with a nut on each end that holds everything under compression.)

[elobire]

Re: Nylon 6 Vs HDPE

bodge job, what type of design are you going for?

[RogueTwoRobots]

Re: Nylon 6 Vs HDPE

If I can afford it, I prefer to use Nylon 6 for the chassis and if I want cheap armour, I tend to plump for HDPE. Having said that, I have used HDPE for a chassis before and plan to use it for the first chassis of Drumroll II so I can afford to have it ready for the champs in September (will rebuild it from something more durable after that)

HDPE can work for a chassis if you have no major load-bearing points, otherwise it will deform. On the previous Kaizer, I attached my lifting forks to an HDPE bulkhead but it simply bent whenever I tried to lift anything, so I had to brace it with a length of box-section steel. I replaced the HDPE with a bit of polypropylene in the current version and got rid of the steel and the results were much better. There is still a bit of flex in the material, particularly if it's lifting something heavy, but it is an improvement over the HDPE. Replacing the polypropylene with Nylon would be a further improvement still.

Tapping into both HDPE and Nylon can be done. Many people advise using wood screws over bolts when tapping into HDPE but I've never had a problem using the latter. There are loads of tapped holes in the Nylon chassis of Drumroll and only some of them are beginning to slip in their threads; that's after three years and numerous times being screwed and unscrewed.

The machining properties depend on your definition of machining. I would say that if you're using hand-tools such as a saw (or jigsaw) or cordless drill, then HDPE is the easier material to machine. But if you are getting it machined by mill or CNC machine, then I would imagine that Nylon 6 would be the better material to machine (although I could be wrong on that).

Here are a couple of data sheets to compare the properties of each material, and also a page of data graphs:

HDPE - http://www.directplasticsonline.co.uk/p ... asheet.pdf
Nylon 6 - http://www.directplasticsonline.co.uk/p ... truded.pdf
Graphs - http://www.directplasticsonline.co.uk/graphs.html

As the others have said, if you let us know what your design plans are it'll give us a better idea of what would work better.

[banana_man]

Re: Nylon 6 Vs HDPE

Having recently been playing around with both Nylon 6 and HDPE on my micro mill, I have found that the Nylon gives a much nicer finish for the same cut, but the HDPE allows far deeper cuts, allowing it to be rough cut quicker. Not sure if that is at all helpful, but here it is anyway.

[Bodge Job]

Re: Nylon 6 Vs HDPE

I'm going for a box design with 4 blue wheels powerd by 4 cordless drilll motors. we have estmated it to weigh 9.5 Kg with a battery so we can add a weapon later. this is a basic design, all the plastic is 20mm apart for the top and botom which is 5mm HDPE. I have drawn the design full scale but it was not clear on the camera (my scaner is to small) so I vagly drew on it using Paint (the computer program). the middle space is for batterys and esc's and the recever.
thanks for your help allreddy

[Bodge Job]

Re: Nylon 6 Vs HDPE

so nylon 6 or HDPE

[RogueTwoRobots]

Re: Nylon 6 Vs HDPE

Is cost an issue?

If not, go for the Nylon. If you'd prefer to save some money and/or have an easier-to-work-with-using-hand-tools material, then go for the HDPE.

[Metal Demons]

Re: Nylon 6 Vs HDPE

Nylon is a much better material for anything structural, just remember when tapping into it to use the coarsest thread you can.

If you can get hold of UHMWPE - some chopping boards are made from it, else order from somewhere like directplasticsonline.co.uk - it's extremely tough (and somewhat flexible) and light, and a good thick section of it would do great as armour.

Chuck a dirty great steel wedge on the front and you're set

[gravity]

Re: Nylon 6 Vs HDPE

how about designing with a weapon ?
otherwise its just another boring box...

[Bodge Job]

Re: Nylon 6 Vs HDPE

Im designing it so I can fit a spinner or eletric lifter on the front, back or sides because i'm tapping holes on the outside too so I can add weapons or extra armour later, A change-o-bot if you like. That means I can change weapons inbetween battles if they are damaged or or ineffective against the robot i'm going against next.

[gravity]

Re: Nylon 6 Vs HDPE

yes, but since you're building a feather... you will be up against 12 other feathers...

[elobire]

Re: Nylon 6 Vs HDPE

you also want to remember that some events dont allow spinners. also making a changeable weapon might cause design flaws.

[Bodge Job]

Re: Nylon 6 Vs HDPE

at first the weapon will probably be a wedge as I can't aford a moving weapon at the moment, even if I do build a moving weapon at the moment it would be held on in a similar way to how I'm intending to build it now.