Jittery prints on flat pieces?

This is for general discussions. Also FAQ can be found here.

Moderator: speedake95

Post Reply
twicx
Posts: 105
Joined: Fri Jan 11, 2013 1:26 pm

Jittery prints on flat pieces?

Post by twicx »

Hello all,

Image

I'm trying to print the floor plate for a building I'm working on. The problem is, the bottom most layer, the one that prints slowly, seems to print with this jittery effect. I've tried a tonne of different things. I've tried degreasing the bed, raising and lowering the temperature of both the extruder and the bed, and checking things like Z wobble, but nothing seems to be making a difference. PLEASE HELP!

Lioric
Posts: 116
Joined: Wed Aug 15, 2012 1:13 am

Post by Lioric »

How is you hot end? I can't really say that I have seen that pattern but it might be that plastic is around the tip of the hotend, when melted plastic is around the outside of the tip, it pulls up whatever it touches

Make sure your hotend tip outside is clean

dognotdog
Posts: 181
Joined: Tue Sep 04, 2012 9:22 pm

Post by dognotdog »

I see that in places where the bed isn't clean enough, and/or the Z distance to the nozzle is too large.

twicx
Posts: 105
Joined: Fri Jan 11, 2013 1:26 pm

Post by twicx »

my printing seems to be going from bad to worse now :( So I'm gonna go back to the calibrating x/y axis step and have another go, and clean out the hotend while i'm at it.

It's very frustrating that after all this, its just not printing right at all.

Kjetilei
Posts: 334
Joined: Fri Mar 16, 2012 8:26 pm
Location: Stavanger, Norway

Post by Kjetilei »

I've had that problem too and what dognotdog said is most likely the problem you're seeing.

What surface are you printing on?
Have you tried printing the first layer faster (increasing the feed rate/speed multiply in Repetier)?

Don't give up. You'll get there in the end and learn a lot of stuff on the way :)

twicx
Posts: 105
Joined: Fri Jan 11, 2013 1:26 pm

Post by twicx »

Ok, so I'm not getting anywhere tonight, so I've decided that considering the first few prints were the best, I'm going to try to Ctrl+Z the whole thing :P Here's the plan:

1. Retract/clean the nozzle (I'm going to try the FLOSS-YOUR-FELIX idea, and I've picked up 2 sets of guitar strings, one of which is 8's and the other is 9's, so I'll start with 8's and try 9's if i need something thicker)
2. Check that all the motors are at set up right. I suspect that before I got things going the first time around, I had the extruder motor at slightly higher, i.e., 1/2 or 1/3 turn, instead of just 1/4, I'm not sure how much this might impact it, but no harm in seeing if it does.
3. Recalibrate the X/Y axis, i.e., re-level the table. I suspect it might be easier to actually take off the table and start from scratch rather than try to tweak whats there, but I don't know just yet.
4. Recalibrate the Z, although when I checked it last night, a piece of sketchroll (thinner than normal paper) fit in just nicely, so it's pretty damn close anyway. Still, after doing the X/Y, it'll need some adjusting.
5. Start from the recommended base point of 200 degrees / 60 degrees, and try some of the other heating points that people have found success on, such as 190/55 and 185/55. I had a look last night at the deviation between extruder and bed when idle, and it's <0.5 degrees, which seems pretty good.

Now, on point 6, I have a little question regarding Slicer and temperatures, which is relevant to what I'm trying to print. I'm printing scale models of buildings for college work. The model is pretty big on the X and Y dimensions (maybe 150 x 150mm) but it's not very high on the Z dimension (<10mm). The model consists of a number of walls, creating sort of cells. Each wall is ~1mm thick (At 1:500, they should be about .85 - .9mm) So, my question is, does anyone have any recommendations for things like temperatures, speeds, and what setting/profile I should use in SFact? I tried the various Normal profiles, such as full support, enclosure support only etc, but the results are not noticible.

So that's the plan, things are going backwards, so I'm going back to square 1. Realistically, I don't need to print any important models for about 2-4 weeks, but I don't like that my printer isn't working right, especially considering that for me it's a pretty big investment. The thing is, from what I've read here, it does seem that once I do get it working the way it should, it doesn't really need any further tweaking, and maintenance is relatively low, provided you take care of it (i.e., turn it off when finished, keep things clean, keep the fillament dust-free, replace the kapton tape occasionally, keep the bed degreased etc etc.). It's just a matter of finding that fabled sweet-spot where everything just works.

satoer
Posts: 436
Joined: Mon Oct 01, 2012 8:00 pm
Location: Netherlands

Post by satoer »

I've had these same problems. This happens when the nozzle is to close to the table. The extruder smashes the filament and widens out. Because of this, the new extruded filament pushes the "old" extruded filament away. Since there are multiple lines besides it, the only way it can go is up. This is probably not the only problem. I think you've also sticking problems to the heated bed. Make sure you clean it with acetone before each print. Or take a look at the sugar, wood-glue (haven't tried these myself) or other solutions over here:
The ultimate anti curling fix so far
What also can help is to print the first layer real hot and slow without the fillament cooler (The top cooler needs to stay at 100% at all time!)
My Felix 1.5 printed designs on Thingiverse
E3D V6 Hot end upgrade for your Felix
Tweezer bracket for your Felix
Led bar upgrade for your Felix

felix
Posts: 11
Joined: Wed Mar 14, 2012 6:34 pm

Post by felix »

twicx wrote: Now, on point 6, I have a little question regarding Slicer and temperatures, which is relevant to what I'm trying to print. I'm printing scale models of buildings for college work. The model is pretty big on the X and Y dimensions (maybe 150 x 150mm) but it's not very high on the Z dimension (<10mm). The model consists of a number of walls, creating sort of cells. Each wall is ~1mm thick (At 1:500, they should be about .85 - .9mm) So, my question is, does anyone have any recommendations for things like temperatures, speeds, and what setting/profile I should use in SFact? I tried the various Normal profiles, such as full support, enclosure support only etc, but the results are not noticible.
1mm walls tend to be a little annoying, since they're just slightly more than two extrusion widths, but not enough to put infill in between. I try to keep thin walls to integer multiples of 0.38(the felix extrusion width on 0.25 and 0.2 layerheight). In addition I use 0.2 layerheight (guillaume's "normal quality" profile) when I print thin features, it gives much better adhesion between the layers.

About your first layers: What everyone else said. Use kapton tape, degrease with ethanol, slightly higher Z distance.

felix
Posts: 11
Joined: Wed Mar 14, 2012 6:34 pm

Post by felix »

one more thing: If you still have the old bearings and are battling with lash settings, it helps to use 0/90 degree infill (aligned with the axis), instead of the default 45/135, because then the infill is independent of the lash setting.

Post Reply