Corner Bulge

tomtom

Hey guys,

I finally found some time again to run my A5s again and am motivated for some projects. But I'm not satisfied with my Corners. They have big Bulges and I would like to make a assembly in the future so they need to be better. Using the Community FW btw.

I stumbled across a video wich sounds promising, even it may not is exacly what is my problem. 

https://www.youtube.com/watch?v=AKTvykTPjQw

At 09:45 it shows pretty much what I'm looking for. At least it looks promising.

Now I checked my firmware settings and they say:

M201 X1200 Y350 Z100 E500 (these should be the Default Community FW settings as I don't remember to have changed them!)

I think it will have a reason why they are so "low" (in comparison to the 1500mm/s in the video) and was wondering if it even makes sense to adjust them or am I making everything worse if I do so?!

Wall Speed is Inner 50mm/s/ Outer 30mm/s
Jerk is 20mm/s

I also havent tried Coasting successfully.

Thanks a lot for your Ideas or maybe recommendations!!!

Cheers Tom

tomtom

Thats how it looks right now.....

tomtom

Also I stumbled across the jerk junction deviation value on the Display and am wondering if that is in conflict or prohibits higher jerk values in Cura. Currently I'm trying around but it all so far does not really lead me to where I want to be. 

Also if I got the same values for Outer Wall-speed and jerk it doesnt help.....but actually it shouldnt slow down in the corners like that?!

Btw I already did recalibrate my E-steps and Flow values.

Samuel Pinches

Looks to me like the linear advance K-value needs tuning:

http://marlinfw.org/docs/features/lin_advance.html 

I can't remember if junction deviation or linear advance are enabled in the firmware by default, I don't think linear advance is - sorry I don't have more time to look into this at the moment. May be worth building your own firmware and seeing if linear advance helps?

tomtom

Thanks a lot....I didnt think of that!!! That sounds really promising!!

No worries!! Thanks a lot for the tip....I do not know  if building firmware is a bit too much for me but I'll think over it!!!

Can I use the community firmware to edit it or do I have to start from scratch??

Samuel Pinches

If you follow the instructions on this page it should walk you through compiling the firmware. There's a few awesome people (thanks @eyes )  who have taken my early build configuration and updated it for the latest marlin 2.0 - you might want to ask them for help so that you can start from a more recent build. See this thread here.

ishtob

I turned on linear advance, the corners looks great now, but print time has been increased by 2-3x the estimated value on Cura (where it was only a few minutes off before the linear advance.)

Stephen Todd

I've not bothered to do anything about it, but my print times are also wildly different from what Cura says it will be

It seems that it is due to having settings in Cura that the machine cannot match in real life - i.e. over-optimistic configuration

Maybe some tweaking is called for?
http://lokspace.eu/how-to-make-cura-accurately-estimate-the-print-time/

ishtob

LA messes with he accelerations, so cura print time remains underestimated. unfortunately since the speed changes are calculated by the printer, the slicer has no way to account for it.

tomtom

Thanks for the comments, 

I still want to use it but I'm stuck with a broken x-axis motor meanwhile... But I'll try on.
I don't bother too much about the time as long as the prints get better!!!