Mini Using CURA, Issues with Erratic Infill Shaking

Hi guys,

This is my first post on this board, as I just received my Lulzbot Mini a couple weeks ago. This is my first venture into 3D printing, but I have been a CAD junkie for the past 10 years and do solid modeling on a daily basis at my job.

Getting started with this machine has been a breeze straight from the box, nearly all my first prints have been done using HIPS and the built in “quick print” profiles for either normal or high quality. I have been taking alot of my automotive related projects and parts, and scaling them down for fun at the moment. I am an Engineer for the Roadster Shop (http://www.roadstershop.com) where I get to design cool things like this all day, but in full scale obviously. The parts have turned out great, as I started with some larger parts with a decent amount of thickness for clean infilling. Here are some examples below from my instagram ( http://www.instagram.com/3d_magic_mike ) :





My latest venture has been to make a nice enclosure for around my Mini. I am making plastic bulkheads for stringers of 3/4" wood dowels to secure into, and acrylic panels will box in all sides from mounts on the bulkheads. I am still using HIPS at this point, not with the “normal” quick print HIPS settings.

These parts have thinner walls in some areas, and I am noticing that after the outlines are created on a new layer, the infill is extremely violent due to the short span it has to move from one side to the other of the boundary layers. I believe this is an infill issue and not a “fill small gaps” issue since i don’t think this version of CURA has code for it, at least there is no option to manually control it anywhere I can see.

I have been running these parts in Peak Green Lulzbot brand HIPS now for about a day straight non-stop, each bulkhead takes about 4 hours to complete. With all the violent shaking from the infill, I have been noticing that print quality has slowly been degrading on the parts, and I can now stat to hear considerable dragging/binding sounds from the bed axis. I think that due to the shaking from the infill speed, fasteners are coming loose and or components are becoming unstable and miss-aligned.

The picture below is the first part where I first started to see issues. Its not bad, but a bit inconsistent compared to what I am use to:

Quite a few parts down the road, and things are devastatingly worse. I dont know if most or all of it is contributed to the angles and circularity, or the insane infill jarring:

Here is a part that is printing currently, with results that dont make sense compared to similar parts that truned otu beautiful earlier using the same settings and filament:




I have seen some posts where people have described that the bearing blocks for the bed axis rails can have their screws come loose over time and cause these issue and noises, and I should take the auto-leveling washers off the bed and lift it to see if I can carefully tighten that hardware. Is there any other mechanical locations that are suspect to loosening or issues from shaking of this level? I have added a video below of the shaking. The video doesn’t do it justice, in real life you can see the entire machine and table it sits on shake from the violent movement. The bed axis sounds also are not captured on film (of course they don’t make the sound when I am filming and need them to), but the sounds are an off/on issue that seems somewhat random but is limited to bed movement

https://youtu.be/vjfBRxS6AJM

Are there any other comments or suggestions for this? If this is an issue that is directly relevant to parts that have walls this close to each other, that is a bummer since it seems parts of this caliber would make up a lot of what I want to do with this printer. I don’t seem to have any issues with larger prints where the infill can cleanly make the honeycomb center section between large spaces from the outer boundaries.

To help alleviate this, I think I am going to try printing on some of my own advanced settings. From what I can derive from lulzbot’s “normal HIPS” print profile in their text INI file, the normal settings call for 50 infill speed and 20 fill density. Would changing either of these help? I was thinking of drastically lowering the infill speed to closer to 20 or 15 and see how the machine copes. I would think scaling the infill down by that amount would make a sizable change in the machine’s jarring during the infill procedure. I don’t mind waiting the extra time, it doesn’t scale the overall time of the print by as much as I would think.

One last thing. (sorry, I tend to write a book as I go) I have been recommended to Simplify3D by quite a few people, which I wouldn’t mind paying for it has sizable more control over settings as I get more experienced with things. Does Simplify3D have an interface pre-built for the lulzbot mini that uses the auto-bed leveling and wiping process, and automatically corrects the code for the bed level during every print? That is my only real concern with using a different program, I would like all of that to remain automated if possible.

Thanks everyone,

-Mike

Slowing down the infill speed should help with the vibration. I would check all the fasteners, it doesn’t take long and with that much vibration I expect some have loosened. I found my mini needed a few tightened. I was getting some minor movement on the Y as well.

Simplify3d is nice and has more settings. The bed leveling and nozzle cleaning works. I copy the end gcode from Cura. The reason is that the Simplify3d version doesn’t wait for the bed to cool and move it forward. It’s a small thing, but once you’re used to it…

The other thing it doesn’t come with is a good HIPS profile. Just ABS/PLA. I posted one in the filament forum that’s worked out well for a couple of us.

Thanks ttabbal. I lifted the bed last night after the last print had finished, and sure enough most all the fasteners that secure the bearing blocks for the y-axis rails to the aluminum bed needed about 3/4 of a turn to snug them comfortably. I didn’t crank down on them as it seems Lulzbot uses alot of brass press-in inserts in the plastic sections, so I didn’t want to pull them out by over torquing anything.

I haven’t had a chance to run a test print yet to see if this resolved anything, I want to take this time to go over all the fasteners and components, and give the machine a good cleaning. I’m also going to try a section of the print to test out using CURA on my own settings with the slower infill, and see how the machine behaves. I’m going to look more into Simplify3D since it seems that their interface is considerably more controllable than CURA’s, which will be helpful when I get more experience with fine tuning setting for different materials and prints.

Thanks,

-Mike

ttabbal helped me quite a bit with S3D setting on my Mini using HIPS (thanks again!). I’m still learning, but S3D is more of an advanced user software. I printed garbage using S3D at first, so I decided to stay with Cura until I understood it completely and could make better and better prints using small test objects, adjusting one parameter at a time until I hit the sweet spots. I’m a novice at best, but once I finally got comfortable enough with Cura, I was able to move into S3D and modify it to make good prints and understand what I was doing. Now I’m using S3D pretty much for everything and comfortable enough with HIPS settings to move into different types of filaments and experiment with those. Once you’ve nailed down Cura, the move to S3D will be easy and open up much more control of your printing process.