Wing Construction Testing and ABS Warping

[Ian Jones]

I've been using a not too brilliant design as a test piece for creating an ABS wing. I want to use ABS so that:

• due to the higher "glassing" temperature, if I leave the model in a hot car it should still be the same shape when it comes out as when it went in,
• it will be stronger than if PLA was used
• it will be less brittle than PLA

I've stuck with the same test piece as otherwise I would not be able to measure success or otherwise.

Most of use will not be able to print a wing in one piece so a means of joining wing pieces is needed. Traditionally we use ribs, spars, sheeting, trailing and leading edges and I wanted to experiment with how I might adapt that idea for 3D printing techniques. Feasibility is a "yes" but I can already see many improvements that I will use when it comes to it. I also wanted to test if a girder internal construction was feasible and again it's "yes it clearly has merit", though I wouldn't use the pattern I tested with.

By far the biggest problem has been warping of the ABS and at long last I can report some success with that. I had hoped that printing on a raft would eliminate it but it seems that this shape has enough shrinkage to pull the ends of the print off the raft. I enclosed the printer, that helped and tinkered with temperatures, eventually ending up with a 220 extruder temperature and 90 bed temperature. The final element to bring success was to do away with the raft and add adhesion discs. I think in future prints I will use a skirt instead but I think it could be useful to have look at the progress made so far.

Successful wing section and rib:

The difference is obvious:

With the discs removed there's nice flat edge:

Two good flat edges with a scaled own rib based on the same construction:

so adjoining panels can form strong joints:

No provision for a spar? Ah, well that's another story!

[Robert Armstrong 2]

Did you print the wing on the M180? Still think it's my first choice, but out of stock everywhere it seems.

[Robert Armstrong 2]

Posted by Robert Armstrong 2 on 24/04/2017 16:45:40:

Did you print the wing on the M180? Still think it's my first choice, but out of stock everywhere it seems.

And the reason its out of stock anywhere is that Hobbyking have discontinued the item. B****er.

[onetenor]

To join A.B.S. use plumbers cement /glue or M.E.K. applied to the joint with a fine tipped brush.Capillary action will run along the joint

[Ian Jones]

Posted by Robert Armstrong 2 on 25/04/2017 09:21:51:

Posted by Robert Armstrong 2 on 24/04/2017 16:45:40:

Did you print the wing on the M180? Still think it's my first choice, but out of stock everywhere it seems.

And the reason its out of stock anywhere is that Hobbyking have discontinued the item. B****er.

Perhaps HK will get them back in, the had a batch a short while ago at around £465 IIRC.

Posted by onetenor on 25/04/2017 10:13:14:

To join A.B.S. use plumbers cement /glue or M.E.K. applied to the joint with a fine tipped brush.Capillary action will run along the joint

Thanks I'll try those.

[Ian Jones]

Cracked it!

With the help of a sheet of PEI plastic as a build surface, Simplify 3D as a slicer and the very helpful, friendly people at Rigid.ink I was able to find the right temperatures and most importantly first layer height to ensure good adhesion to the bed and no warping.

The key settings then:

Setting extrusion multiplier to 1.03
First Layer Height 80%
First Layer speed 20%
Bed Temperature 100c (I prevoulsy used 110c and it took me ages to get the print off)

Video:

Although I'd had some success in past, I wasn't able to get ABS to consistently print well, until now. This half scale wing panel test is still prototype quality but it works:

So does this mean I'll be using ABS to print my first aeroplane?

Hmm, well it gives off alot of horrible fumes, that give me a sore throat and headache. The search goes on, but for now the matter of being able to print an ABS wing panel is settled and I call that a major success.

[onetenor]

Get a fan at least if not a proper extractor unit. Those fumes are carcinogenic. Please take care . We don't want to lose anyone

[MaL]

Have you tried PETG? It is supposed to be stronger and less brittle than PLA, easier to work with than ABS and odour free!!

[Ian Jones]

Posted by onetenor on 20/05/2017 23:15:14:

Get a fan at least if not a proper extractor unit. Those fumes are carcinogenic. Please take care . We don't want to lose anyone

Thanks, until I get something sorted out ABS is out of the door.

Posted by MaL on 21/05/2017 17:24:11:

Have you tried PETG? It is supposed to be stronger and less brittle than PLA, easier to work with than ABS and odour free!!

Great minds...

I haven't hit the sweet spot with the settings yet but I'm getting there. It's true, it's very strong, flexible, doesn't warp or smell. There's other materials I want to have a go at but at the moment this is going to get all the attention. It's naturally transparent too, well in thin layers it is. Could look really good.

[Robert Armstrong 2]

Which brand of PETG are you using? Have been trying it and have got a badly clogged nozzle. On the printer that is.

[Ian Jones]

I bought a sample from http://shop.3dfilaprint.com/ details:

        Product Code:	HDG-RED-1.75mm
         Description:	HDglass™ 1.75mm 10 Meter samples by FormFutura - Diameter:1.75mm, Filament Colour See Through Red, Filament Weight:35gms
          Item Price: 	£ 3.29
                 Qty: 	1
               Total: 	£ 3.29

That doesn't appear to be available at the moment though. I now need a full reel and will almost certainly go for this which is available in various lengths, including 10metre sample for £3.95. I have exchanged emails with several of the people at Rigid.ink and I like the informal but dependable responses I've been getting.

Clogging? I didn't get any. I believe that you should be able to clear it by heating the nozzle to the highest recomended temp for the filament you are using then feed in more filament to push the "plug" out. Perhaps this link will be useful for you.

Edited By Ian Jones on 25/05/2017 00:44:11

Edited By Ian Jones on 25/05/2017 00:45:30

[Robert Armstrong 2]

Tried the rigid ink PETG myself. Just a sample so far. Printed a little turtle from thingiverse for my granddaughter. Came out nice. Also used some of their PLA. No luck trying the PVA support filament. Strings badly. Might work better if I could set retraction for the support separately to the main filament.

Good service and helpful responses to questions from rigid ink.

The clog was rather odd when I sorted it. The hot end itself seemed to be clear but a piece was melted onto the top of the hot end, further up than the PTFE, and then broken off the rest of the filament. Wouldn't remelt to reattach to filament. Pushed out easily when the hot end was out of the print head.

[Ian Jones]

Hi Robert,

Interesting info and I agree they do seem to be a very helpful lot at Rigid Ink. Holidays etc interfered with progress a little here, should be back on track soon now though.

I've bought in the PETG I need from Rigid Ink and got some other hardware for my next project. Hope to tell you all about it in the not too distant future.