Reprap parts with PLA?

[nepaholic]

Hi guys

I want to know your opinions about printing reprap parts with PLA. Is it worth or not?

The PLA I use ( from germanreprap) is recommend to extrude at 210C and it also seem to work best for me with this temperature.

I never printed in ABS because I don't have a heat bed on my original PB so I don't no the difference.

Can I print extruder parts with PLA?

[mrsamnc]

PLA is more brittle than ABS so you may run into stress fractures and/or cracks over time. If nothing else, I would think you could print the pieces in PLA, maybe with some backups/spares, and then later print them in ABS? Heck... give it a shot and let us know.

[nepaholic]

Thanks yes it is more brittle. But anyway I thought to give it a try and I started to print parts for the adapto printer. Will print 2 sets just in case.

Cheers
Jens

[Bob-StPaul]

Or for the critical parts that carry a lot of stress - print them in nylon. With the rest in PLA.

[TutherJay]

So this appears to be the appropriate thread for continuing this discussion: PLA vs ABS (vs nylon) for replacement parts for some questionable wood structures that my PB+ v2 kit included - at least the best I've found in my attempts to search before posting...

I'm NOT pleased w/ the built-up layers of plywood for the carriage. After relatively few print jobs completed since original assembly I discovered an alarming amount of slop in the hot end - primarily in the Y-axis direction (much more than in the X) and further examination disclosed that it's not JUST the UBIS end mount into the wood structure that's the problem - it's ALSO that the linear bearings on the X rods (primarily the lower of the 2) were not gripped securely by that sandwiched LC ply arrangement. I've posted elsewhere about my serious questioning of trying to screw multiple wood layers together where all but the LAST layer are not drilled out enough so that they do NOT grab threads - anyone who has tried assembling wood thusly should have quickly discovered how that's problematic!!! Oh well - I digress - back to the topic at hand:

Just what is working out there in reprap land where working printers can THEORETICALLY replicate their own parts - as in what plastic works for what pieces? Of primary concern to me, as all I have to print with (so far) is PLA (PBHQ didn't have any ABS when I first ordered, so I had to settle for PLA and haven't yet ordered anything else from them or anyone else), is the structures supporting and in close proximity to the hot end. Can PLA stand up for the extruder and fan bracket, for instance?

While I have mine torn back down I may as well start asking, I finger. I'm going to TRY a couple quick fix things to see if I can stabilize this, but I want to print replacements ASAP if PLA will work. My batting average so far is abysmal - it seems that I get about one decent print job, whatever it is, after a real serious tune and adjust session, and then it botches things up again. Usually it's lost its Z awareness and either tears up the tape or doesn't touch down to deposit from layer 1 (this morning I awakened to find that almost nothing got on the print-bed - it had just collected a big mass around the hotend. I had found one successful print and tried to start another before I hit the rack last night, and YES, I DID recheck bed level at all 4 corners before the run. So after clearing off the big blob and relevelling, I tried again but all of the parts (all cylindrical) came out WAY weeble-fleeble (unround) upon do-over. At least they were ON the bed, not on the hotend.

So - what's the general consensus on material for replication???

(while I go back to reassembly. This took so long I don't even have the patience now to try to find discussion of how to tighten the loose UBIS end mounting)

Cheers

jm

[Bob-StPaul]

For pieces that need to be really rigid - if they are somewhat thin - I'd print in PLA. If they don't see a lot of force or stress - I'd print in PLA.

I broke my first fan mount (PLA) and replaced it with one printed in nylon (first successful print in nylon for me.) and because it's fairly thin - I find that it is very tough but just a little flexible - which makes it rather forgiving for something like the cooling fan on my jr -that hangs right out there in front where I bump it from time to time.

Nylon is very tough - I printed new feet for some deck chairs in nylon and they are doing really well - where as I think PLA would be too brittle for that application and might have cracked when I was forcing the feet into the legs. I think the OEM feet were nylon.

For me PLA is easier to print - by just a bit. So unless it's a part I've already broken once - or a part I know will benefit from the strength and forgiveness of nylon - I default to PLA.

[Tdeagan]

Mechanical considerations aside, PLA is, in many ways, the _traditional_ Rep Rap material. Key patents for it are held by one of the two original Rep Rap founders, Vik Oliver.

Additionally, it's plant sourcing and biodegradable qualities make it very much part of the Rep Rap philosophy.

Many many RepRaps are made with PLA.