HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Dec 22, 2013, 12:52 AM
Registered User
United States, HI, Paauilo
Joined Dec 2007
260 Posts
Discussion
HPDE verses aluminum

I am getting a tad tired of aluminum bending on me (so do I remove the motor, desolder the esc, remove the arm, then use the mallet, or do I remove the motor, and straighten it with the rest attached lol!) and was thinking of HDPE.
I'm not sure what forces are involved with a crash but I was (hardly as it's hard to do!) bending strips of HDPE and it appears that during a crash it will merely flex while not having enough give for the FC to pick it up during flght.
What are your thoughts in me doing a one piece HDPE quad?
I made some drop in replacement Armattan 255 arms from the stuff, they are .4" thick, yet weight 20% less than the aluminum ones. They will snap but that's with two pairs of pliers, and a LOT of force. I can't try them out for some time, and the idea of HDPE torments me enough to ask you guys here
jm82792 is offline Find More Posts by jm82792
Last edited by jm82792; Dec 22, 2013 at 02:04 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 22, 2013, 06:45 AM
bobepine's Avatar
Joined Jun 2011
7,602 Posts
I'd like to see pictures.

Best,
Chris
bobepine is online now Find More Posts by bobepine
Site Sponsor
Old Dec 22, 2013, 08:07 PM
Registered User
United States, HI, Paauilo
Joined Dec 2007
260 Posts
CAMBam is quirky to use so it's taking time to figure out how to do what I want. The center plate is getting there but here are my first attempts of cutting HDPE with the wrong bit (downspiral is bad for plastics and promotes chip packing) and with a spindle with dead bearings since my good one is down right now. Also I left a .5MM skin of plastic which is apparently a bad idea since plastic isn't wood, a dremel fixes it, and but it also widens everything else up which isn't desirable.. Accuracy isn't a concern initially with this stuff but eventually with a bit of thought it will come. I used an old cutting board, and did all of this at 10PM at night so consider it some ugly monster that can't be broken with a hammer easily

A small update....
Mechanical engineers may laugh but apparently the material doesn't enjoy shocks.
I snapped two arms with a sledge hammer, so there is a limit
How much will an arm encounter in a crash and will it break is now the question.
It took a good 10 pound hammer and some force to snap it...




jm82792 is offline Find More Posts by jm82792
Last edited by jm82792; Dec 22, 2013 at 08:28 PM.
Reply With Quote
Old Dec 23, 2013, 02:22 AM
Registered User
United States, HI, Paauilo
Joined Dec 2007
260 Posts
Edited
jm82792 is offline Find More Posts by jm82792
Last edited by jm82792; Dec 24, 2013 at 02:23 AM.
Reply With Quote
Old Dec 24, 2013, 02:22 AM
Registered User
United States, HI, Paauilo
Joined Dec 2007
260 Posts
I thinned out the arms and they now weigh about half the amount of the aluminum ones yet are a bit thicker.
My curiosity no resides with am I wasting my time when compared to CF?
This is me messing around here so I'll inevitably try the HDPE frame when I get the time for the center plate,
yet if CF almost never snaps, and the plastic does then obviously all I accomplished was some CAD practice here.
jm82792 is offline Find More Posts by jm82792
Reply With Quote
Old Dec 24, 2013, 04:54 AM
Registered User
Joined May 2012
13 Posts
Get yourself a copy of Aspire, it made my life much easier I made the mistake of leaving 0.2mm skin on sluminium once thinking it would poke through easily :P It never...

Good work on the HDPE, I may try it after the holidays.
PhillyF is offline Find More Posts by PhillyF
Reply With Quote
Old Dec 24, 2013, 05:14 AM
bobepine's Avatar
Joined Jun 2011
7,602 Posts
I thought you were going to cut Titanium? Or do I have the wrong person, here? Am I confused?

I suppose CF could de-laminate and snap, but I have not sold a single replacement arm yet, and I sold a whole lot of CF frames.

Best,
Chris
bobepine is online now Find More Posts by bobepine
Site Sponsor
Old Dec 24, 2013, 12:37 PM
Registered User
United States, HI, Paauilo
Joined Dec 2007
260 Posts
Titanium would be astounding but the cost would be very high and I'm guessing I'd need a $$ machine to handle it(or it would take hours to cut it with tiny passes). All I can recollect is I mentioned is HDPE or high density polyethylene I was thinking would work since it's cheap, flexes, and I've yet to see much playing with it. Furthermore, since it's softer yet doesn't put out a tenacious dust you can 3d profile it, pocket it, and everything else.


PhillyF I want to get Aspire, but it's hard since most of my $ work is MeshCam (as I feed it 100MB STLs and it doesn't croak like everything else), and I just get by with FEngrave for my VCarving needs.CamBam is obfuscated at times, but I have a decent background in 3d modeling, and I seem to be able to handle the backasswardness of it all
Past the $500 I'm dumping into my current setup the next logical step for my (woodworking not this experiment!) business is a 4x4 cnc router parts kit, aspire would be like 1/4 the cost of it though
jm82792 is offline Find More Posts by jm82792
Reply With Quote
Old Dec 24, 2013, 12:39 PM
Registered User
Joined May 2012
13 Posts
I know how you feel with the cost of it, I had to spring for a new watercooled spindle last week after it died

Is the HDPE the same stuff as chopping boards?
PhillyF is offline Find More Posts by PhillyF
Reply With Quote
Old Dec 24, 2013, 12:44 PM
bobepine's Avatar
Joined Jun 2011
7,602 Posts
Quote:
All I can recollect is I mentioned is HDPE or high density polyethylene I was thinking would work since it's cheap, flexes, and I've yet to see much playing with it.
Did I not send you CAD files as you said you were going to cut Titanium? Did i send you files?
bobepine is online now Find More Posts by bobepine
Site Sponsor
Old Dec 24, 2013, 12:48 PM
bobepine's Avatar
Joined Jun 2011
7,602 Posts
Sorry. Just did a search. Wrong person. It's someone else who said was going to cut titanium. Sorry.
bobepine is online now Find More Posts by bobepine
Site Sponsor
Old Dec 24, 2013, 03:55 PM
Flippin Multirotors
Get Real's Avatar
Illinois
Joined Feb 2006
4,985 Posts
Quote:
Originally Posted by PhillyF View Post
I know how you feel with the cost of it, I had to spring for a new watercooled spindle last week after it died

Is the HDPE the same stuff as chopping boards?
Yes,Ive wanted to try using it for frames for quite a while. Currently there is a quad out made from it and reports on its durability have been very good. Kydex is another material that has had good durability reports as well for quad frames but seems to be more suitable to molded frames etc. HDPE supplier and info HERE. It seems like a good material for durability and weight with reasonable production costs to produce frames. I had some parts cut several months ago using it but not an entire frame yet.
Get Real is offline Find More Posts by Get Real
RCG Plus Member
Old Dec 24, 2013, 06:09 PM
Registered User
United States, HI, Paauilo
Joined Dec 2007
260 Posts
Quote:
Originally Posted by bobepine View Post
Did I not send you CAD files as you said you were going to cut Titanium? Did i send you files?
Yeah that's me, send me the plans as I'll try cutting one out of titanium within the next decade ! Realistically I could cut it but it wouldn't be fun since I'd have to do a lot of learning. (The plastic arms I did mill up are ugly, the plastic appears warped, and I tried to make myself feel better by taking a photo of them along with my real work.......)

PhillyF, I know what you mean, as I was looking at the sub $500 VFD spindle setups (how do you like yours by the way?).
After killing two Bosch Colts I found the Dewalt 611 works rather well for a sub $200 setup (router+Precise Bits Collets is excellent!) and even has a speed controller so the RPMs are controlled. I burned out the bearing on the first/current Dewalt, I had the replacement bearings, but it was a big enough pita I just ordered an one sale $75 replacement Dewalt. My TIR (maybe it's backlash, but I'm not sure but will know shortly) was getting rather sour from my observations, as my tooling was lasting 1/4 the time it usually does which is yet another thing I have learned can go wrong, and bit you when least expected.
For now I'm keeping it cheap, although it's just an endless cycle of marketing, sales, investment, growth, and etc.
I've done rather well for my first year, but it's hard to spend all you make in equipment, yet it's probably the best idea to fuel growth.

That's what I was thinking Get Real, it's a cheap plastic, it's strong, it machines easily, it can be 3d profiled(it takes a long time but it would give you rather sweet frames), and finally it's not widely used yet. Since I reside in Hawaii my best source for the stuff are cutting boards or Amazon since they ship dead weight here for free. I've resourcefully learned a lot in regards to the software and hardware related to CNC machine since I never had the fancy things to start out with. I had to solder and otherwise hack my way to where I'm at right now
Being 21 has it disadvantages as I can do rather irrational things at times;
but at least I can recognizance my stupidity from time to time.
jm82792 is offline Find More Posts by jm82792
Last edited by jm82792; Dec 24, 2013 at 06:31 PM.
Reply With Quote
Old Dec 24, 2013, 06:51 PM
Registered User
Joined May 2013
51 Posts
I have noticed some problems with anything Plastic (And I mean all sorts of them).

I can't scientifically say why, but you better use aluminium. I noticed a lot of twisting and bending with all sorts of plastic. I now only use aluminium.

I would never claim any type of plastic is unusable for multicopters, but after some serious testing I now am sticking with aluminium.

Carbon is not easily available in my country, and posses a health issue... so I am not testing this. But please, if you have the power in your motor, esc and prop to use aluminium... do so!
World Citizen is offline Find More Posts by World Citizen
Reply With Quote
Old Dec 25, 2013, 01:13 PM
Registered User
United States, HI, Paauilo
Joined Dec 2007
260 Posts
Well the plans are coming together, failure or success should occur today when I finally cut everything out of the 7.7MM HDPE I have. I'm just trying to get a few changes done but deviating much from a proven plan could be a bad idea

I realize the dimensional stability of plastics can be questionable, however, there are many applications where plastics are used in precise mechanical systems, and they do perform.
The Acme threaded drive nuts my CNC machine uses are made from Delrin(which provided hundreds of hours of use with minimal wear), many slides in mechanical systems are made from UHMWPE which is a relative of HDPE, and there are a plethora of other uses that I bet a mechanical engineer would tell me about that I'd be shocked of. Speaking of an engineer I have a mechanical engineer that's going to borrow my soldering iron ( I'm surprised he doesn't have a weller or so forth) that works in the Mauna Kea observatory, I'll ask him what he thinks about the plastic verses aluminum deal. His wife designed full on rocket engines that are made from CF so odds are I will get some constructive input.
jm82792 is offline Find More Posts by jm82792
Last edited by jm82792; Dec 25, 2013 at 02:20 PM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold JR 9503 DSMX (not the old DSM2) Heli ver zjoffe Aircraft - General - Radio Equipment (FS/W) 2 Feb 25, 2014 08:44 PM
For Sale KK2 Board, used - perfect Ver 1.5 uniquewon Aircraft - Electric - Multirotor (FS/W) 6 Dec 03, 2013 10:46 AM
Sold Align 3GX Ver 1.2 Upgraded to Ver 2.1 $70 Shipped 737 Driver Aircraft - Electric - Helis (FS/W) 1 Jul 19, 2012 08:29 PM
For Sale Droidworx MK Gear rail brackets, CNC ALUMINUM Ver 2.0, Replace the weak plastic ones patrick21x Aircraft - Electric - Multirotor (FS/W) 6 Jun 26, 2012 02:08 AM
Discussion RCAP Ver 1.1- Ver 2 Development. hihptsi UAV - Unmanned Aerial Vehicles 33 Mar 21, 2008 12:28 AM