Confused...

[alan412]

I am trying to print this ( http://www.thingiverse.com/thing:662447/#instructions ) and I don't get what is happening. It lays down a perfect skirt, then when it goes to the inside nothing ends up on the bed and it becomes one huge blob being drug about by the nozzle. I don't get it.

I am using Slic3r 1.1.7

I am quitting for today, but I'll appreciate any suggestions of things to look at. I have used these same settings for some simple little red hearts that have worked great.

This is on a Simple Metal with Heated Bed.

This is with a Dark Red PLA from Printrbot.

I have attached the GCode. Any help would be wildly appreciated!!!!

Thanks in advance!

--Alan

[Jdublu]

There is nothing in the gcode that looks like a problem. can you take a picture of the skirt? What layer thickness are you using? I'm guessing your Z axis offset needs to be adjusted. What bed prep are you using, tape, hairspray gluestick?

[alan412]

Unfortunately I cleared it off to print something else. I'll take a picture of the skirt on my next attempt. I am using a 0.2 thickness layer (except for the first layer which I have set at 0.3) For bed prep, I am printing straight on Kapton tape with the bed heated to 75 degrees on the first layer (dropping to 70 for subsequent layers.)

Would you guess that the Z axis is too low? I could try modifying it up just to see if it makes a difference.

[RetireeJay]

nothing ends up on the bed and it becomes one huge blob being drug about by the nozzle. I don't get it.

That's an indication that you don't have adequate bed adhesion. I'm printing that geared heart right now, and it took me three or four tries before I got the bed clearance EXACTLY right. If you are too close to the bed, no plastic comes out on the first layer. If you are too far away, you don't get a good "smoosh" down onto the bed and the adhesion is inadequate. The first layer should not look like a cylindrical thread sitting on top of the bed; it should be flattened, smooshed down onto the bed. Also, of course, bed preparation is critical. Wipe the Kapton down with isopropyl alcohol so it's nice and clean before starting a print.

[alan412]

I was getting no plastic coming out on the first layer. Can you help me understand what is special about that design that makes the clearance so critical? (I am trying to learn so in my designs I can allow for larger tolerances.)

[RetireeJay]

This design starts out with five separate pieces on the bed: three gears, three gear axles, and the heart outline. The heart outline has a very long, thin footprint on the bed, so you need excellent adhesion. The clearance between the gears and the other gears and the gear axles is very small, so if your first layer is smooshed TOO flat and wide, they won't be separate; they'll be welded together. In my opinion, it's one of the more challenging designs to print successfully. Or, to put it another way, it's a good exercise for you to get to know your printer and all its settings very well!

[alan412]

The isopropyl alcohol worked like a charm. Now the first few layers look great, but after that they smoosh too wide such that the gears fuse onto the post. any idea what might cause this?

[RetireeJay]

Tweak your Extrusion Multiplier down a tad. I printed the thing and it works - pretty amazing because the clearances are very tight.

[RetireeJay]

Let me clarify my last post. The geared hearts did NOT come off the printer working perfectly. I had to use an X-Acto knife to pry loose each gear from its shaft, and I also had to break a bond between two of the gears. These bonded points were pretty much all on the bottom layer, where I have lots of smoosh to get good bed adherence.

[alan412]

I got it to work!!!!!!

I should probably not be this excited about three gears turning. But this is the result of a LOT of effort. I wanted to upload a video, but it won't let me upload a MOV file. Oh well, it isn't that exciting unless you are the one that got it to work....

[teicher]

I got it to work!!!!!!

I should probably not be this excited about three gears turning. But this is the result of a LOT of effort.

Yes you should! That's one of the best feelings I know, success after struggling and trying different things and learning from each step along the way. You're gonna experience that a lot in 3D printing. Congratulations!

[RetireeJay]

Yes, congratulations! Getting that print right means you've really learned a lot about your printer.

[Mooselake]

You can upload the video to youtube, then find one of the stickies that tell you the format to embed it in a post. The link has to be a specific format, not just www.youtube.com/<something>.

Kirk