Best filament for a specific project

[jabamun01 0]

Hi, I'm having some issues when printing a jug lid I designed with normal PLA plastic. There are three thin sections of the lid which need to be able to be bended without breaking apart, but PLA just breaks when I apply some force on it.

Screenshot: link (the parts circled in red are the ones that break).

My question is: which (cheap) material should I use? Do I directly have to go with ABS or it wouldn't work either? Or is it better to edit my design?

Thanks in advance and sorry for my poor English!

[Labern 774]

A form of PET or co polymer should work. Most companies have different names to differentiate them selfs from the rest by putting in additives.

CPE, CPE+, PET, nGen, XT, PETG, and the list goes on.

But with your design, its weakness is in the layer adhesion which is not the strongest way to print an item. You could make those tabs separate that you print lying down and then insert and glue them into your main lid. Or just redesign how the tabs work.

[geert_2 558]

In addition to Labern's suggestions: print slow and warm enough, and minimise cooling, so the layers do bond as well as possible.

I have made things like that in colorFabb PLA, and they worked too, if not used frequently. And only for a few months, until the PLA got harder and more brittle, after which they broke. So it may work in colorFabb PLA for a prototype to show off, or for a single snap-on fixing that is never to be released again. But not as long term solution for frequent use.

PET is much more flexible, but may also break along layer lines. You will have to try.

Editing your design to increase the traject is also an option, like adding some U-turns or sine-waves. But in my experience PLA will always get brittle over time (a year or so).

[krys 206]

I cannot see the image (my work is blocking the site), but if you are talking about living hinges, I have had success with both XT and nylon (Taulman Bridge).

Hope this helps.

[jabamun01 0]

Thanks for all the answers and sorry for my late reply! I think I'll go with PET, as I'm not going to buy nylon just for this project (so expensive!). BTW are the ones stating "flexible PLA" (e.g. this one) actually flexible as ninjaflex or are they just a PLA with a little more flexibility? Would they work for my lid? Thanks again

Edited February 21, 2017 by Guest

[krys 206]

I have no experience with flexible PLA, so I cannot help with that.

Sorry.

[geert_2 558]

ColorFabb PLA is a PLA/PHA blend (the opaque filaments) and is a bit more flexible than pure PLA without additives. But still harder than ABS and PET. So it is by no means "flexible". I don't know about the real "flexible PLA", I have never used that (so I also don't know if that stays flexible, or if it degenerates and gets brittle like standard PLA).

PET sticks way better to the glass build plate than nylon, so that may be a reasonable choice indeed.

[jabamun01 0]

Thanks! I'll then buy some PET. Where could I buy it so they ship it to Spain without making me pay like a lot of money?

EDIT: Nvm, already found it! Is 24€ for 0.75 kg a good deal?

Edited February 23, 2017 by Guest

[neotko 1,417]

Smartmaterials pet (they make it in spain) is very nice. Also, they make filament as precise as faber on diameter. Is cheap (not china cheap), works and they do a great job. Actually for pla it prints better than colorfabb, but the color selection is limited for my taste.

[Grail1973 0]

I agree with Labern to use co-polyester (CPE). I would build on edge to have the layers go perpendicular to the stress on the snap-fits. I disagree with glue as this creates an inherent weakness.