printing with PET - a first glance

[fablab013 0]

 

Tday we received a first batch of PET at the lab. Since we haven't been able to find much info on this new printing material we'll give you a quick review :

 

 

 

PET - the stuff plactic coke bottles is made of

 

The problem with materials like PET is that we have all handled it before and it's been perfected in the industry to create disposable consumer containers like bottles and crates. Since PET as a simple bottle is so perfect in strenght, clearness, weight & safety it was easy to get our hopes up high ..... waaay high ..... when we received our first spool of 2.85 mm. PET.

 

As fablab prototypers we know better though .... first see ... then believe ....

 

Cool but not impressive

 

 

Our first print with PET went as expected. Intuitively we set the temperature rather high for a new material and we hit the sweet spot around 232 degrees for printing PET.

 

Surface adhesion on standard blue tape worked well, similar to PLA, and printing was smooth and uneventful. PET is sold as clear / translucent material, and it is, but due to the printing proces we'll never be able to achieve window-pane like clear materials as the layering in our prints will always scatter the light. So ..... no see-through bottles ... not even with PET.

 

Our print came out clean and very smooth. Upon close inspection we must admit that the surface of the PET bottle was surprisingly smooth with light bumping. No signs of the usual layering (on the surface).

 

 

A simple break-test revealed that PET also simply snaps at the first weak layer, not unlike PLA, but further temperature test may still hold a secret strenght-sweetspot. We haven't found it (yet) so strenghtwise we rate it along the lines of PLA.

 

PET when printed is not brittle and hard, but somewhat silky and flexing. No flex like nylon, but it gives a bit and boinks right back.

 

short conclusion :

 

PET is still new and undiscoverd. Up till now we are unimpressed. Apart from the silky textured surface and potential resistance to certain acids/materials we have not seen anything that made our jaws drop. It's still expensive and we haven't found a specific use for it yet. At any rate, being able to add a new material to the filament list is always a good thing.

 

We'll move on to masonry style filaments next ... sounds more exciting ... stay tuned.

 

fablab013 - Tilburg

 

[owen 19]

Thanks for the info. Do you know the Glass Temperature for PET?

 

[fablab013 0]

PET glass temp ? hmm ... I'm guessing 70 degrees ?!?

 

[edis 0]

http://en.wikipedia.org/wiki/Glass_transition

 

[Daid 305]

Glass-transition-temperature is simply put the temperature where materials go a bit soft. For PLA this is really low, around 45C, which is why PLA and hot cars or hot water give problems.

 

[owen 19]

Yep, I'm looking out for filament that has a higher Glass Temperature the PLA but isn't ABS due to the hot car problem.

 

[thingster 0]

Yep, I'm looking out for filament that has a higher Glass Temperature the PLA but isn't ABS due to the hot car problem.

 

Then you should give Polycarbonate (PC) a try. Its glass transition temp is about 150 °C. Much higher than PLA und PET, and even higher than ABS.

[Daid 305]

The problem with PC is that it warps like crazy, worse then ABS or the 618 Nylon.

 

[owen 19]

The problem with PC is that it warps like crazy, worse then ABS or the 618 Nylon.

 

That's what I don't want.

 

[thingster 0]

The problem with PC is that it warps like crazy, worse then ABS or the 618 Nylon.

 

There is no "ideal material". Each material has its pros and cons and one downside of PC is that it warps a bit. That's just how it is.

[Daid 305]

There is no "ideal material". Each material has its pros and cons and one downside of PC is that it warps a bit. That's just how it is.

 

True, but then list both the pros and cons, or you will set false expectations.

 

[grpiotr91 10]

Did anyone of you experience PET sticking to nozzle?

In my experience, sometimes, material which was accumulating got pulled by printing element. You can imagine that this unwanted material causes problems like loosing steps, pulling away the element from the platform.

[shipto 0]

On 6/12/2013 at 7:51 PM, fablab013 said:

Hi I am almost a newbie to 3d printing and have more failures than successes with PLA. However I am doing a scooter up for my daughter and decided rather than buy a rear light I would print one so I am printing the PET for the lense as I type this, I started at 232C but slowly increased it as the print progressed and currently its sitting at 245C and the result is pretty good resionably clear.