MakerGear Forum

Can anyone tell me what is going on here?

There are three images below. The first is the SketchUp wireframe view of my model. The second is the Simplify3D view of the obj that it's supposed to print. The third is the garbage that I'm getting.

On the last picture there are three prints. The first two on the right were done with a different model. I thought there might be something hidden that I couldn't see in my model so I recreated it from scratch in SketchUp. The brand new model did the exact same thing.

Does anyone have any idea what is going on with this? It gets to roughly the 2" mark and just wanders off on an angle for the rest of the print until I stop it.

I've only had this thing together for a week but I've already printed models taller than where this drifts off.

The belts are are all firm, when I home all axis they move to the correct location.. The only problem I've run into is that the Z: motor doesn't like to go up once it's all the way down.

Also, the model is NOT sliding on the glass. It's well adhered.

I found this post and have adjusted the 'z hop' (i think) in Simplfy3D. Print running.

viewtopic.php?f=7&t=1965&p=9161&hilit=angle#p9161

uncharted.services wrote:Can anyone tell me what is going on here?

Two clues:

1) In the bottom picture, the two models on the left failed exactly the same way, while the one on the right failed differently in the same region.

2) In the middle picture, all that weird red junk in what should be open space suggests a bad model.

Given that the models came from Sketchup, I'd lay long odds that they're severely non-manifold. Those geometric errors confuse the slicer into producing bad G-Code.

Preview the G-Code in http://gcode.ws/ and I predict you'll find the printer is doing exactly what the G-Code calls for.

Although some folks seem to be able to build 3D-printable models with Sketchup, the process looks a lot like a steel-cage death match.

OpenSCAD is an acquired taste, but for designing simple objects like that, it can't be beat. Other folks around here have been using various 3D CAD programs to good effect, too. Whatever it takes, ditch Sketchup and your results will suddenly improve...

The "weird red junk" is just Simplify3D's way of showing travel moves. It might be model related issues, but I'm betting it's a mechanical issue that's causing you to skip steps in one axis. Post your STL here (zip it up to attach) and we can see. (I hesitate to judge people's choice in software, but I agree with Ed that SketchUp will end up causing more pain than it's worth.)

Oh, one quick thought is that you mentioned your Z axis doesn't like to move. How old is your printer, and if you've had it a while, when's the last time you lubricated it?

I have seen things go badly from model to S3D, but once S3D has it, it's view of the path planning is always accurate, from what I've experienced. If the S3D slicer screws up, the screw-up is there to see in the path view.

If the offsets are in the X direction, then a cracked motor mount is a possible cause. Check if the nozzle is no longer perpendicular to the bed. If it's still sitting perfectly vertical to the bed, then it sounds more like a belt slip issue, such as with a loose set screw on the motor shaft.

When something is loose and just at the point of slipping under gentle pressure, then it often starts looking like a modeling issue; this is because certain parts of a model, like an overhang, say, will warp slightly and push up a little more than the rest of the model. The nozzle then runs into the raised spot every single time in exactly (or almost exactly) the same spot, and the offsets can be cumulative.

I found a similar effect with the dual extruder, where the 2nd extruder bumps into some raised spot on a print, but that causes the 1st extruder to mimic the movement, which creates a duplicate error at the separation of the extruders. Depending on the size of the print, you can end up with a whole chain of duplicate errors.

First thing I would do to diagnose it, is try to print some other file that is taller than the problem area on this one. (You said you'd printed things taller than this, but you didn't say if you printed those first, or after you had problems with this file. If the other taller file also goes off kilter, then the problem would have to be mechanical.)

Otherwise, i would know it is just the code for that specific file causing the problem, and I'd look for something there. (At which point i would very carefully try to understand what these guys said. )

Tim wrote:If the S3D slicer screws up, the screw-up is there to see in the path view.

Pleased to be wrong! A second opinion from http://gcode.ws/ would confirm all's well with the slicing.

Compared with Slic3r's garish-but-definite tool path preview, S3D's seems rather hazy...

I added .5mm of 'z hop' and slowed it down a bit. The edges are still curling up and i'm working on that but it did print. Little things like this piss me off soo much but man, I love this printer. This is soo much fun.

Yay!

jsc wrote:The "weird red junk" is just Simplify3D's way of showing travel moves. It might be model related issues, but I'm betting it's a mechanical issue that's causing you to skip steps in one axis. Post your STL here (zip it up to attach) and we can see. (I hesitate to judge people's choice in software, but I agree with Ed that SketchUp will end up causing more pain than it's worth.)

Oh, one quick thought is that you mentioned your Z axis doesn't like to move. How old is your printer, and if you've had it a while, when's the last time you lubricated it?

I bought it in December but have only recently had time to put it together. It's freshly lubricated.

uncharted.services wrote:I added .5mm of 'z hop' and slowed it down a bit. The edges are still curling up and i'm working on that but it did print.

That's a little surprising. Edge curling usually happens with PLA only on overhung surfaces, and your model has none of those, except for the holes which printed successfully. Have you tried an extrusion multiplier calibration? viewtopic.php?f=3&t=1964