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Reducing Layer Blobs

Posted: September 18th, 2016, 11:15 am
by Chaco
Good morning folks
Been reading a lot and thanks for all the good info. Thanks specially for the marlin firmware settings which made my printer work much better

But if i may ask your experience with layer blobs
Since the beginning i have had big blobs (the layer start/end) on layer changes... It was bad at the beginning but came to make my current status and cant seem to get it any lower or less noticeable.
If i print a 20mm test cube, the zits are barely noticeable.. If i print a normal piece, its very noticeable. Let me show u some pics

Currently i have 3.5mm retraction at 60mm/s. Print temp is right on range for filament. Noticeable if i print layers first or layers last...
I know it has to be software related. The .hex file HIC gave me, has very little blobs, but as u know, i really cant open it to check the settings.
If i change the layers to random, it really makes it look bad, as u got zits everywhere rather than linear. If i use craftware, it also has smaller blobs than slicer. But i really like using a host, and not have to be using an SD card all the time.

What else can i change in firmware to make it less noticeable?


Setup.
HIC 3DP-08
Print at 0.2mm and 65mm/s with external perimeter at 75% speed
PLA @ 210 (Inland with recommended temp of 205-225)
running Marling RC6 from Chip (modified Z steps since i got 8mm leadscrews)

Thank you very much ladies and gents.

Re: Reducing Layer Blobs

Posted: September 18th, 2016, 4:15 pm
by Izzy
The problem occurs as the z height changes, I can't remember how to reduce it in Cura, I've been using Simplify3D for a little while now and have not noticed it recently.
No doubt if you give it a few days one of the guys will give you a better answer, but welcome to the forum in the meantime.

Re: Reducing Layer Blobs

Posted: September 18th, 2016, 8:39 pm
by Chaco
Thank you kindly, I have learned a lot lately for sure. You fine folks sure have a lot of knowledge, and i just want to learn the "dont's" from the best :)

I just trying to keep my prints from showing this ugly vertical scar along the layers

Re: Reducing Layer Blobs

Posted: September 18th, 2016, 9:38 pm
by LePaul
I bet if you print at 40-45 mm/sec a lot of those banding lines go away

Re: Reducing Layer Blobs

Posted: September 19th, 2016, 8:11 pm
by Chaco
Thanks for the feedback. ill give it a shot and see

Re: Reducing Layer Blobs

Posted: September 20th, 2016, 1:43 pm
by Izzy
:roll:
To true on the print speed, just because you car can do 100mph doesn't mean that's what it will drive at all the time.

For PLA I rarely go above 50mm/s and I prefer 0.1mm layer height, I get good quality prints almost every time.
For ABS I may increase to 70mm/s but I usually stick to 50mm/s, and for flexi materals I am usually bringing at about 30mm/s.

OK so it may take longer to print, but unless I am doing a quick prototype test ay 0.2mm layer height I am happy to except that that's how long it will take!
There is nothing worse than pushing the limits for an important print, having under extrusion and having to scrap it.
No matter how fast we can get our beloved machines to print it will never be quick enough for some people, life is a journey that we want to enjoy.

Re: Reducing Layer Blobs

Posted: September 23rd, 2016, 2:45 pm
by Chaco
I have been playing with 40 & 45mm speeds... so far so good, blobs are a bit better..... helps that i got Craftware to work again on SD cards... had a problem there for a min where it will stutter on first layer and make blobs,.. seems gone for now.

I really liking craftware as their supports tend to come off super easy and with minimal or any trace... i may have to compare it now to simplify3d and see


Izzy, considering my stepper motors, 4 start 8mm leadscrews etc, i cant print at 0.10 without being off a step. So, i had assumed 0.12 was my lowest setting... should i venture and try 0.08mm? that would be my next step down...or will considering 0.12 would be best?

Thanks gentlemen.

Re: Reducing Layer Blobs

Posted: September 23rd, 2016, 6:18 pm
by Izzy
Hi Chaco,
I would try each layer step you can to test the performance, on my UM2 after an initial base layer of 0.1mm I have printed at 0.04mm layer with a 0.15mm nozzle.
It depends what you want to use as your definition, I want to experiment with the very small, Carl has a 0.1mm nozzle I want to get and test some very small prints on so I need to test very fine layers, but I also want to improve my print quality of the 0.6 and 0.8mm at 0.2-0.4mm layers but obviously they are for larger points with less definition.
Unfortunately my zopen University courses start again in a weeks time so my spare time to play with the printer is going to be limited for a while.
I would surgest getting a nice little test piece such as the robot or the treefrog and run various varations on the layer size to see how you get on, the treefrog is great for retractions and overhangs so you will see the layer stepping across the back and the belly.

Re: Reducing Layer Blobs

Posted: December 7th, 2016, 11:08 pm
by Chaco
I have found what i think was the problem. And i am comfident it was the stock hot end .
The heatbreak part of the extruder is too big and too much filament was too soft... I am using an E3Dv6 now and these blobs are gone. Not to mention i did use wipe settings, and retract a bit more and faster now.

Thanks everyone