Printing on standard PLA

Support for UP mini. To report a bug, post with a title [BUG REPORT]. To request a feature, post with a title [FEATURE REQUEST]
Post Reply
yo3ggx
Posts: 11
Joined: Sun Nov 23, 2014 8:10 pm

Printing on standard PLA

Post by yo3ggx » Tue May 05, 2015 7:20 pm

Hi everybody,

After successfuly printing a lot of objects in ABS (both original and standard with temp mod) today I've done my first print in standard PLA.
I'm using NuNu's white PLA from Amazon.
Considering many issues related to PLA printing I was skeptical, but the result is far beyond my expectation.
After trying to print at -20degC below the PP3DP PLA default settings I've seen that the filament stucks in the extruder after first 3-4 layers and need an withdraw/extrude cycle to make it advance again.
This happen even if I try to push the filament with my hand.
Then I switched back to the default PLA temp of Mini (no mod) and .... surprise!
The print was almost perfect, using fine mode, with both raft and no raft settings. The only small issue is that the support material is a little bit harder to remove, but at the end the object remains clean.
You can see some sample pictures below. The piece is very small, so it looks even better in reality.


Image
Image
Image

Dan

roller
Posts: 1622
Joined: Sat Oct 06, 2012 9:09 pm
Location: Brisbane, Australia

Re: Printing on standard PLA

Post by roller » Wed May 06, 2015 1:32 am

Hey Dan, I would describe that as an easy print for PLA. Most of us hit issues with long prints where heat buils up in the extruder body. Some printers suffer this more than others. You may be lucky and have one of the cooler extruders or it may be just the short run on this print.

That print does look too hot (glassy finish) and this will help by reducing backpressure and limiting the tendency of the filament to buckle. You can improve print result and ease removal support by using a fan blown to blow directly on the print as it extrudes. I use a large PC fan or desk fan for high volume airflow. I try to keep this off the hotend (with a glass wool blanket on the hotend) as much as possible and focused on the extruded material. This can improve your print quality and if it hits the extruder motor too allso buy you some extra print time. Overall though it is likely using the stock extruder:

- if you do long prints the PLA will jam
- as you do many prints the PLA will jam as mini jams strip the filament and fill the extruder gear with slippery dust

There are many discussions of possible improvements you can make on this forum to buy you better prints with PLA. Use a Google search to find them as common words like PLA are ignored by a direct search on the forum.

yo3ggx
Posts: 11
Joined: Sun Nov 23, 2014 8:10 pm

Re: Printing on standard PLA

Post by yo3ggx » Wed May 06, 2015 5:54 am

Hi,
I will try this evening a bigger print. I forgot to mention that I've removed the top door of the printer to keep a smaller filament tension.
Extruder fan is in ON position.
If I try to use a lower temperature, the filament stuck in the extruder after a few layers.

Thank you for your feedback. I will try to read more on this.
Dan

roller
Posts: 1622
Joined: Sat Oct 06, 2012 9:09 pm
Location: Brisbane, Australia

Re: Printing on standard PLA

Post by roller » Wed May 06, 2015 2:57 pm

That's right ... if you get the temp too low the back pressure will also cause the filament to either buckle or slip ... both are bad. Direct extruder designs are less forgiving for PLA and the Up one is a little underdesigned for that intention with heat, tension, bite and unguided pressure path issues.

Anyway ... get a bigger fan blowing in there and that might help you enough at the current print temp to get the results you want. Hopefully you are one of the lucky ones with a cooler running extruder and you will have less jam issues. Keep in mind if you have a fail or a series of partial fails your extruder gear may clog up with dust and make future attempts fail even though you have made the right improvements. Cleaning the gear is an annoying time consuming chore when you are trying to work out your ideal settings and if you forget you sometimes pass up a positive improvement.

yo3ggx
Posts: 11
Joined: Sun Nov 23, 2014 8:10 pm

Re: Printing on standard PLA

Post by yo3ggx » Wed May 06, 2015 5:07 pm

This is another bigger print going smoothly through my Up! Mini with the same setup, in around 1h.

Image
Image

Dan

roller
Posts: 1622
Joined: Sat Oct 06, 2012 9:09 pm
Location: Brisbane, Australia

Re: Printing on standard PLA

Post by roller » Sat May 09, 2015 2:29 am

By big print I would generally mean 2+ hours and more like 4-8 hours normally. It's looking good though. Still a little glossy though maybe that's a property of the PLA your using? Did you use a fan blowing on the print?

yo3ggx
Posts: 11
Joined: Sun Nov 23, 2014 8:10 pm

Re: Printing on standard PLA

Post by yo3ggx » Sat May 09, 2015 6:11 am

I agree with you. Prints longer than 1h are not possible. The fillament stucks becuase of a very hot extruder motor. I've stopped working with PLA till the new cooler assembly for the motor will be ready.
I'm trying to build something with 2x40mm fans, one for the motor and one for the printed piece. As recommended in the forum, I will reverse the original fan, but I need some longer screws in order to be able to mount it in reverse position. I'll be back after that with my results. Thank you. Dan

Post Reply