3D Printers

[Gasman]

Noticed on the news today that a father of a child who had lost an arm had made 9 different artificial limbs for his son with his 3d printer, how cool is that !!.

Can there be a more useful 3d project ?.

Steve 

[calli]

2 hours ago, Chriske said:

 
The absolute winner was PLA that had nearly no deformation after months in full sun.

 

 

Hehe, yes thanks for that other mythbusting post!

I also tried similiar and busted the "UV and composting" myth (for me at least). A sample single wall piece was exposed to the sun/weather and the other one in my compost heap. Nearly two years and no degration (other then cosmetically)

EDIT: Also used a (grey) PLA 1.25" to Nikon Adapter which holds my Nikon D5100 to the scope, worked even while Merkur Transit for hours into the summer sun (germany tho).

Carsten

Edited January 1, 2019 by calli

[upahill]

2 hours ago, Chriske said:

The absolute winner was PLA that had nearly no deformation after months in full sun.

This is really interesting. When I printed my pier adapter in PLA, with 70% infill, 1.2mm walls I was basically called a nutter by some. The general consensus being that within a few days of sunlight PLA would warp and my mount would come tumblin' down. In my defense it was supposed to be to make a mold for a cast or acrylic part but its been so good I haven't bothered.

Im now probably 6 months in, through a moderately warm summer with zero noticeable deformation or reduction in stability. All bolts are still tight, no UV degradation, no cracks and still maintaining very good polar alignment and guiding results. It has had the mount on for weeks at a time and whilst the mount was covered the adapter was exposed.

[upahill]

1 hour ago, Gasman said:

Noticed on the news today that a father of a child who had lost an arm had made 9 different artificial limbs for his son with his 3d printer, how cool is that !!.

Can there be a more useful 3d project ?.

Steve 

Combined with some of the neural mapping techniques for controlling there are some very cool projects out there.
If you have a printer and want to give a hand (to use their own pun) check out e-nable - http://enablingthefuture.org/

[JamesF]

20 minutes ago, upahill said:

This is really interesting. When I printed my pier adapter in PLA, with 70% infill, 1.2mm walls I was basically called a nutter by some. The general consensus being that within a few days of sunlight PLA would warp and my mount would come tumblin' down. In my defense it was supposed to be to make a mold for a cast or acrylic part but its been so good I haven't bothered.

This is quite reassuring from my point of view.  I want to print replacement parts for much of my weather station (wind direction vane, anemometer cups, perhaps even the main housing) and wasn't sure that PLA would really be up to the job (though I've already experimented with printing the cups in PLA just to see how they'd come out), but I think it's definitely worth going for now.

James

[Gina]

I'm planning to make a mount for my widefield imaging rig using 3D printed parts.

[upahill]

3 minutes ago, JamesF said:

This is quite reassuring from my point of view.  I want to print replacement parts for much of my weather station (wind direction vane, anemometer cups, perhaps even the main housing) and wasn't sure that PLA would really be up to the job (though I've already experimented with printing the cups in PLA just to see how they'd come out), but I think it's definitely worth going for now.

James

I think if we had really high temps here it could be an issue, but im talking months of 35+ temps which isn't going to happen.

The three concerns seem to be:
Softening due to temperature
Degrading due to UV exposure
Strength

Chriske's experiment seems to allay the concerns with all three, and the second could be further protected against with a coat of something like perhaps. Im seeing mostly anecdotal evidence that suggests PLA is fine for outdoor use, and I think the UV instability is more a reference to the colour pigment of the filament than it actually biodegrading. If layer adhesion is good then I can't see it delaminating either so really think the concerns with PLA outdoors are a little unfounded and probably just assumed because its 'biodegradable'
 

[Stub Mandrel]

My meteor detecting Yagi is made from 6mm aluminium alloy tubes mounted in black PLA holders.

It's been up since august, it will be interesting to see how long it lasts.

Biodegradation shoudl only be an issue if it is kept wet and unable to dry out.

[Chriske]

Hold your horses guys...!

I ONLY tested whether white PLA would sag or deform under constant sunlight. Nope it doesn't, not at all. It does what it suppose to do, for me. It hold its shape.

What I did not test is whether PLA would degrade under sunlight. UV surely will degrade almost everything in sunlight..!  PLA or other filament is no exception to that.
Can someone name me one other plastic that does not degrade at all.
To prevent printed parts from degrading under UV you'll need to paint it. Using parts, say a telescope, most of the time during nightly observations don't bother, it'll hold for many years without painting.
As a matter of fact all things, except bricks a, concrete, we paint everything that needs protection, why would PLA be an exception...?

And btw, I only buy white PLA and PETG...

[upahill]

2 minutes ago, Chriske said:

UV surely will degrade almost everything in sunlight..!

I think you are right - everything is going degrade over time - my issue is that a lot of people would tell you that PLA is useless for outdoor use - and as yours, mine, and others experiments have proven that's just not the case (within reason, and providing your use case isn't extreme or unreasonable)

I used to be a healthy, fit, athletic teenager - you only need to look at what UV exposure did to me to see the risks ?

[Chriske]

10 minutes ago, upahill said:

 you only need to look at what UV exposure did to me to see the risks ?

Got a picture to verify this...?

[upahill]

7 minutes ago, Chriske said:

Got a picture to verify this...?

Some things can't be unseen. I'm now going to be blaming UV for my hairline biodegrading as well as a myriad of other things.

[Gina]

ASA filament is supposed to be UV resistant.  How much better it is than PLA I don't know I have no data.  I may nave data later but don't hold your breath...

[Chriske]

And there's one other thing about PLA : Biodegradable ..?
Yes it is,  but takes YYYYYYears to do just that. But eventually it does.

The main reason I use PLA is because (in the end)it IS biodegradable(basic ingredients : corn  + printing ABS you need to suck these micro-particles (dust) out of the printer. And it smells awful...

[Gina]

Printing ABS produces toxic fumes and micro particles!  Very nasty stuff.

[Chriske]

1 minute ago, Gina said:

ASA filament is supposed to be UV resistant.

Common Gina, you don't mean this...
I will tell you a lie if I intend to sell you my product, in fact I tell any lie to reach my goal.
Maybe, just maybe, it'll resist  a bit longer compared to other plastics. Plastic UV-resistant..? that'll be the day...

[Gina]

I certainly have my doubts!!

[Gina]

Regarding ABS, I have a fair stock of old 3mm ABS that I bought years ago when offered cheap on a certain web site from China.  I think this will be staying on the reels as it has effectively been superseded by better, more user friendly thermoplastics which are far less polluting.

Edited January 1, 2019 by Gina

[Chriske]

I'd use PETG instead if you still want to use even stronger stuff and filament that has a higher glas-temp.
It'll do for most of our projects imo

And If my information is correct ...hum...you did order 'one or two' reels of filament a few days back...?...?

[Gina]

I did - yes.  Have PETG as well as PLA.

[Gina]

I think I have enough PETG to last me a little while but planning to use PLA mostly and reckon I should certainly have enough of that for a few months.

Edited January 1, 2019 by Gina

[Stub Mandrel]

Well I'm interested to see how long my aerial lasts.

I suspect the longevity of the PLA will depend on what they use as the black pigment and how transparent it is to UV.

[tonyowens_uk]

Hopefully the technical anecdote below isn't off topic.

I think there is enormous potential for rejuvenating telescope making using the better 3D FDM materials coming onto the market not to mention low cost bureau-printed SLS parts in NY 12. See below some 'gash CAD' of the guts of a special high resolution 3D scanner we built last year (for dimensional inspection of precision mouldings). Inspired obviously by a Hubble Optics Dob prototype structure I bought some years ago and which had sat in my workshop reproachfully for several years! The red bits were 3D printed parts.

As part of this I decided to put the turntable on a goniometric tilting table. To make the thing backlash-free and cheap I designed a preloaded dovetail slide into the table and had the parts FDM printed in PETG. The pictures and notes say it all.

That was the plan! The reality was around 1mm of flatness deviation and 0.5mm of tilt error on the top mounting surface of the assembled table. The dovetail slide surfaces needed to be 'scraped' a bit too to get an acceptable fit.

Milling the mounting surface flat. I found the solid 'skin' on the plate too thin to provide a machining allowance. Should have specced it to be thicker. Live and learn. The flexures really helped kill lash in the dovetail and get the parts to conform well. A bit of Kilopoise and knurled clamp screws and the result was good - much better than I'd expected.

 

The real payoff I discovered was the combination of prototyping speed and the intrinsic lightness and stiffness of heavy section parts modeled on traditional metal castings. This gives a high natural frequency and the structural damping of filled polymers. Very interesting for other kinds of instrument building e.g. telescopes!

 

Edited January 1, 2019 by tonyowens_uk

[upahill]

20 hours ago, tonyowens_uk said:

Amazing work! I'm guessing the projector is projecting some sort of grid for the cameras to pick up? Im a little bit naive with 3D scanners but have looked into some photogrammetry stuff and done some full body scanning with an xbox kinect to print replicas of myself (albeit smaller).

The problem I'm having right now is designing stuff for printing that are so over complicated its unreal. Where usually a piece of steel bar would do the trick. My latest over-designing project is to hold the motor to my focuser. Its good practice with solidworks at least.

[tonyowens_uk]

Yes its a DLP structured light scanner not a laser one. Blue light filtered to reduce IR noise effects emanating from ambient solar lighting and with pretty mature software from a Russian developer using thermally-stable steel artefacts for calibration. A genuine metrological scanner not a toy. Its still significant work to run a scanning job but we found the fixture gave us big productivity benefits where small batches of supposedly identical parts are to be inspected.

Nothing odd about your motor mount IMHO. The adaptations I had to make when designing for 3D FDM and SLA printing involved abandoning concerns about material use/thick sections and focusing more on feature access, incorporation of living hinges and flexures, deprecation of threaded fasteners, and the usual FDM printability concerns (overhang angle, scaffolding, surface texture, access for finish machining). Initially I felt like a dog with two tails but now I just want to embed and extend the process to facilitate making rapid investment castings in nonferrous alloys. I'd like to connect with anyone who has done this at a professional level BTW.

Last year we invested in one of these:

from Mass Portal but we are still waiting for a delivery date.

Tony