blobs and partial skirt?

I have a AO-101

The skirt always seems to be missing the first 100mm or so and almost always ends up with a “booger” trailing the nozzle that gets drug across the center of the skirt.

In addition the nozzle seems to always create a “booger” that gets stuck in the part.

I’ve tried extruding a bit and removing the drool just before printing, but don’t see much difference.

Are things I should be doing to fix this?

Do I need to up the temperature of the bed and/or the nozzle?

Regards,
Mac

It sounds like your first layer height is not set right. Skirt is used to make sure that the hot end is primed with filament and smoothly extruding before it moves onto printing the actual part. The first 25% of my skirts are always a little sparse, but then transitions into a smooth extrusion, similar to the one pictured on page 41 in the manual found here: http://download.lulzbot.com/AO-101/documentation/current/AO-101-User_Manual.pdf

Make sure your nozzle is clean on the outside by wiping it with a cloth or something else soft and heat resistant. Do not use anything hard. If your nozzle has a lot of molten/burnt on plastic it can cause the filament to grab.

Try these settings in Slic3r:

Printer Settings > Extruder 1 > Retraction
Length: 1.7
Speed: 30mm

You will want to use the ABS and acetone solution to get great ABS part adhesion. The recipe can be found in the User Manual on page 49.

That sounds about right for the skirt then.

Those pictures are fine assuming my eye, your eye, and the author of the manual had their eyes calibrated the same… :wink:

I happen to have an optical measuring loupe so I checked what I’m actually getting. First I checked that the bed was level using the leveling file downloaded from the lulzbot web site. I used the loupe to confirm that the width of the paths was the same at all the extremes.

The width of the path is about .6mm and thickness is about .3mm. I can’t really tell from the pictures whether that’s right or not.

Make sure your nozzle is clean on the outside by wiping it with a cloth or something else soft and heat resistant. Do not use anything hard. If your nozzle has a lot of molten/burnt on plastic it can cause the filament to grab.

Try these settings in Slic3r:

Printer Settings > Extruder 1 > Retraction
Length: 1.7
Speed: 30mm

You will want to use the ABS and acetone solution to get great ABS part adhesion. The recipe can be found in the User Manual on page 49.

I clean the nozzle regularly. THere was a bit of burnt ABS on it, but the tip is clean.
It’s just kind of interesting that my first dozen prints were no problem. Then the “non stick” just appeared. :confused:

Oh…and is the nozzle supposed to ooze while it’s heating to set point?

I’ve seen and get the same as you drmacro, including the oozing while heating.
What I fine helps is to home the print head before starting heating. This stops the ‘ooze’ getting out and thus the hot end is better primed when the print starts.

Antony

This is getting frustrating. Now I get no adhesion what so ever.

The skirt is actually nothing for most of the first loop then oozes a bit and is dragged across the working area when it starts the second loop. Then the ooze that got dragged gets caught in the beginnings of the raft.

The plastic just drools along and eventually ends up as a ever growing mass of plastic strands dragging around with the nozzle.

Every time the head changes direction the end of the just laid trace peels up a bit.

Am I supposed to be using the ABS/acetone slurry all the time or applying occasionally or only for small cross section parts?
And why didn’t I need it for the first dozen prints?

:frowning:

If your machine is like mine, when I received it Lulzbot had already had the ABS juice on the bed. I use the ABS juice or hairspray on my bed all the time. Usually I can get a few prints out of my printer before having to apply the ABS juice. Try lowering your temp for the extruder 5d and see if that helps, maybe you are making the filament too hot and it is becoming to runny. I usually set mine to 230 for ABS, but some colors change that down to 220. The color changing filament requires slightly slower speeds.

If printing with PLA I have the slicers move z axis up 1mm during retract and moving to new locations, as sometimes it rubs against the previous layer pretty hard and messes up my print.

ABS/acetone makes a huge difference. It may be that your nozzle is a wee bit high above the bed too, so you could try lowering it. There are some photos in the manual that show how the extrusion should be squished against the glass on the first layer.

what brand material are you using?

Maybe it is a very viscous batch, and that is why it oozes a lot.

Normally I level the bed with a stiff business card. Once I have the bed level then I use a piece of paper to set the z limit. So far my prints print perfectly fine the first layer and stick 99% of the time. The white ABS I have been getting lately prints better at 225c instead of the normal 230c I use for the rest. They are all from the same supplier and the same brand… Also 3mm and 1.75mm makes a difference with blobs. 3.0mm has a higher pressure so if temp off will ooze more.