Author Topic: What Material Should I Buy for a Structure?  (Read 1856 times)

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Offline Warhawk87Topic starter

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What Material Should I Buy for a Structure?
« on: June 01, 2010, 07:01:04 PM »
Hey guys,

I am asking for Robot parts for my birthday so i can build my first robot, but I dont know what I should ask for in terms of building a structure.  In my FIRST club, we have premade metal beams that we build with, but I want to build this robot completely from scratch.  So what can I use to mount everything onto?

Thanks in advance!

Offline Admin

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Re: What Material Should I Buy for a Structure?
« Reply #1 on: June 01, 2010, 10:32:47 PM »
http://www.societyofrobots.com/materials.shtml

I admit those articles are really old and need to be re-written, but it should be good enough!

Offline Warhawk87Topic starter

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Re: What Material Should I Buy for a Structure?
« Reply #2 on: June 02, 2010, 03:46:39 PM »
Thanks for the link!

I actually did some looking around and i liked your post about the HDPE or whatever the initials are.... I'm going to do some looking into that... Thanks again!

And if you would be so kind as to check my post about microcontrollers, i would be quite grateful  ;D

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Re: What Material Should I Buy for a Structure?
« Reply #3 on: June 02, 2010, 08:19:16 PM »
If you aren't poor and willing to spend more for better quality/stronger material, I recommend Acrylic/Delrin.

HDPE flexes and screw holes wear out too fast. It also scratches easy. Its easy to cut however and super cheap . . .

Offline Soeren

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Re: What Material Should I Buy for a Structure?
« Reply #4 on: June 03, 2010, 05:26:58 PM »
Hi,

[...] I want to build this robot completely from scratch.  So what can I use to mount everything onto?
Scratch of course  ;D

Aluminum profiles (right angle, round, tubing etc), 1.5mm to 2mm aluminum plate,  carbon fiber rods, tubes and foil/plates for low weight (expensive), plywood (cheap) etc.

More practical wishes (better understood by old Aunt Agnes) could be stuff like motors, wheels and so on, i.e. a couple of levels up from scratch, but I don't think you want to make your own motors from scratch although it's quite possible.

Even more understood is tools, so Granny will probably feel better giving you a set of screw drivers or a Dremel and you'll need tools to handle all the scratch.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline Warhawk87Topic starter

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Re: What Material Should I Buy for a Structure?
« Reply #5 on: June 03, 2010, 07:09:42 PM »
I fully intend on getting premade motors lol

thanks for all the suggestions ill look into them all!

Offline Anoroc

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Re: What Material Should I Buy for a Structure?
« Reply #6 on: June 03, 2010, 08:13:04 PM »
Holy Cow!

Not to hijack the thread, but I just priced out some 1/4" delrin. a 24 x 24 sheet was like $225! Does that seem right?

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Re: What Material Should I Buy for a Structure?
« Reply #7 on: June 03, 2010, 09:36:38 PM »
Holy Cow!

Not to hijack the thread, but I just priced out some 1/4" delrin. a 24 x 24 sheet was like $225! Does that seem right?
Delrin is really strong. Try for 1/8th (or 1/16th) on a 12"x12" sheet, it'll be a lot cheaper. Also look at acrylic and nylon which is nearly just as good.

Offline Anoroc

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Re: What Material Should I Buy for a Structure?
« Reply #8 on: June 03, 2010, 09:46:26 PM »
I use acrylic alot, but Im not a fan at how brittle it can be. We've had machine parts made out of delrin (tapped parts) and I really like it. I suppose I just want to try cutting a new sheet-good other than acrylic or PVC :P I fount an 1/8" sheet 24"x24" for less than a quarter of the cost of 1/4". I think I'll start there :)

Offline voyager2

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Re: What Material Should I Buy for a Structure?
« Reply #9 on: June 03, 2010, 11:41:30 PM »
I made the $50 robot recently.
To make a chassis I used cardboard.

Take some thick strong cardboard and spread some PVA glue around on it.
Make sure the glue seeps into the cardboard, making it slightly soggy.
Sandwich the glue with more cardboard.
Leave to dry for a day or two(at least double the recommended dry time)

The  result should be incredibly strong.
Try breaking it over your knee (ouch!) 
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Offline MechHead

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Re: What Material Should I Buy for a Structure?
« Reply #10 on: June 05, 2010, 08:22:51 PM »
A material that I am partial to is ABS.  It's stronger than HDPE but a bit more expensive.

Offline amando96

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Re: What Material Should I Buy for a Structure?
« Reply #11 on: June 06, 2010, 02:01:32 AM »
Acrylic isn't expensive at all, quite strong, clear, it looks really nice, I recommend it.

Use a program to draw the template first, and make a prototype with cardboard, if you have any misaligned screw holes, you'll notice, and correct it for the acrylic.
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Offline Warhawk87Topic starter

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Re: What Material Should I Buy for a Structure?
« Reply #12 on: June 07, 2010, 07:22:35 PM »
Seems like the vote is for Acrylic!  Thanks a lot guys!  Now with the Acrylic, is it easy to mold into a shape or do i need big expensive equipment to put a crease in it?

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Re: What Material Should I Buy for a Structure?
« Reply #13 on: June 07, 2010, 07:48:08 PM »
Hmmmm a hack saw can do it, but I'd recommend buying/using powered tools.

Offline MechHead

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Re: What Material Should I Buy for a Structure?
« Reply #14 on: June 07, 2010, 07:51:09 PM »
If you need to drill holes in it, it helps if u put a piece of wood above and below it.  Tends to reduce chances of chipping.

Offline Warhawk87Topic starter

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Re: What Material Should I Buy for a Structure?
« Reply #15 on: June 07, 2010, 08:55:59 PM »
If you need to drill holes in it, it helps if u put a piece of wood above and below it.  Tends to reduce chances of chipping.

if i have to add more material to reinforce this material, then it does not sound like a good material for my purposes... Im looking for a small robot, not a 10 pound plastic-metal-wood infused 10 lb monster.... Although 10 lbs is no where near a monster 0.o

and i dont mean just cutting, like a hacksaw would do... Would i be able to bend it at 90 degree angles? Ive see robots that were made of one piece of aluminum bent into shape, or a heated piece of plastic molds into a shape...  Does acrylic allow me to do that or would i have to cut it up and mount it with screws to get the desired shape?

Offline chelmi

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Re: What Material Should I Buy for a Structure?
« Reply #16 on: June 07, 2010, 09:22:01 PM »
If you need to drill holes in it, it helps if u put a piece of wood above and below it.  Tends to reduce chances of chipping.

if i have to add more material to reinforce this material, then it does not sound like a good material for my purposes... Im looking for a small robot, not a 10 pound plastic-metal-wood infused 10 lb monster.... Although 10 lbs is no where near a monster 0.o

You don't leave the wood, just use it when you drill the hole...

Offline MechHead

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Re: What Material Should I Buy for a Structure?
« Reply #17 on: June 07, 2010, 09:57:57 PM »
You can bend acrylic if you heat it up first.  I believe you can heat it up hot enough with a heat gun.  Preferably you will want to have something to bend it against at the right angle and clamp to it until it cools.  Also the masking on the acrylic can get kinda stuck if you don't take it off before heating.

Offline paulstreats

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Re: What Material Should I Buy for a Structure?
« Reply #18 on: June 08, 2010, 12:45:29 PM »
Acrylic can also be glued with things like Acetone and Cellulose (easy to come by). Once set the join is virtually as strong the original material. Its easy to make right angle mounts and stuff by glueing it with solvents. It is easy to work with, the tip about using blocks of wood while drilling is just to protect the Acrylic during the process. Its a good idea to use this technique when drilling holes in most thin materials at home.

There is a material called Sintra, its closer to HDPE in properties (as in softer and less brittle than Acrylic). Sintra can be melted at low temperatures between 60 and 80 C. So just put it into some hot water or bake very low in the oven. Unfortunately if your robots going to be left on your windowsill in the sun then the sintra can warp etc.. because of its low melting point.
(Sintra is expanded PVC with a thin layer of non expanded PVC over the surface)

Offline Warhawk87Topic starter

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Re: What Material Should I Buy for a Structure?
« Reply #19 on: June 08, 2010, 12:57:36 PM »
Sorry i didnt pick up on the taking the wood off part lol

It looks like im going with acrylic then... Thanks!

 


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