Very very odd Print head error Ultimaker 1

[ddegagne 0]

Okay I have this ongoing problem with a file I'm trying to print. Only way I can describe it is the head seems to come out of alignment during a specific layer of the print causing what looks like a banding error.

Sorry best shot I could get holes are 2.5mm x 4mm and the banding is .4 mm or less. My guess 1 pass of the print head.

Hoipefully you can see that picture where the banding can be sort of seen. It starts at the the hole at the top and goes right. The piece on the right hand side is a leg from the model.

Also you can see below where there are 2 holes it starts at the left most hole and goes past the 2nd hole and down the leg. As it gets to the tip of the leg the missing area disappears.

The head travels from left to right and to the left of the holes you see it lines up. also where there are no holes its fine.

Now this error does not show up on the layers view mode. Ever it looks perfectly fine on the screen. It also looks fine on http://gcode.ws/ view, and on reprier host. I normally print from an sd card as the file is too large and usb connection is too slow to print from laptop.

it looks like the head travels a little to far inside the object missing the outer path in that area. Not a y axis problem because when I rotated it 180 degrees it did the exact same thing. if it had been a mechanical error it would print out from the edge by a similar amount. I have also rotated it 20degrees same error. Just doing 90degrees atm. will know in an hour or so.

Now I have tested and ruled out a lot of possible printer causes.

-The model is about 150mm tall and there are no other areas with this problem.

-I have printed almost 20 samples of the model all with the same problem. it is not random

-I have tried 3 different filaments. all pla. not the problem

-i have never seen this before. other prints I've done before and after do not show similar problems

-If I remove the holes from the stl file it prints fine.

-I deleted the legs and left just a stub to print. that printed fine with the holes.

-The file was done originally in solidworks then exported as stl. this is the 3rd version of the file where the holes were added. the 2 previous versions worked fine. it is not solidworks

-I took an older version of the file and added the holes using sketchup instead. Still does not work. not solidworks

-I have passed it through netfabb and print before and after samples. not stl format

-I have rotated the file 180 degrees on the x,y

-I have rotated the file on the z access as the legs have a 5 degree climb. so I elevated the back part to align them and as well see what happens. same error

-I have printed at differernt speeds. same problem.

I have printed it with different fill percentages and different wall thicknesses.

I also filled in the front of the model holes in sketchup leaving the back 1/2 hole still in it to print. same error though the holes printed as should. the front was recessed by same amount,

-I have tried ver12 13 and 14 of cura

-I created a very primitive version of the model in sketchup with the legs and the hole in the same spot printed fine. Though the sample was not hollow like the original. And so the hole I made isn't a hole technically. it would be more of a pit.

-I'm down to the idea that there is something with the arduino gcode translator but I have a lot of doubts as I can't imagine what would cause something so specific and why its not been noticed.

-I do not have any other slicer software setup except Repetier host which comes with a version of slicr. But I have no idea how to set up all the parameters to slice for an Ultimaker.

Just not sure why the problem would not show up

I have maybe 3-4 more ideas to try but those are just shots in the dark and I'm running out of ideas.

Any suggestions at all?

 

[illuminarti 18]

It could be a back lash-related error, causing the head to be positioned in correctly. It's visible by the holes, because the head path changes to print the holes, compared to when the it's all just a seamless layer. Do you see any signs of infill and perimeters not lining up on the first layers still? Certainly in some of your older pictures on flickr, bakclash is pretty evident on the first layers. If so, be sure to tighten the short belts, by loosening the motors, pushing them down firmly, and re-tightening.

Alternatively, do the walls have infill? It could be due to the head emptying of filament during internal travel moves. Be sure and turn off 'enable combing' in Cura's expert settings for retraction, enable retraction, and see if that makes any difference.

 

[ddegagne 0]

Tried last night to send a reply but it went awol so I'll try again.

I did tighten the short belts just to make sure they're tight. But those pictures you saw of the models at the first couple layers are some of the first ones I printed over a year ago. Also the error is so specific to that one model in that one area and it occurs no matter what the orientation that I have strong reservations that its only a mechanical issue. As well several other tests I done with a model that I deleted the legs from and another that I built as a test sample. worked fine.

I did find out that the tip of my extruder is only measuring 174C when set to 200. not sure what the difference is expected to be as the thermo is not in the actual head but in the heat block above it.

 

It could be a back lash-related error, causing the head to be positioned in correctly. It's visible by the holes, because the head path changes to print the holes, compared to when the it's all just a seamless layer. Do you see any signs of infill and perimeters not lining up on the first layers still? Certainly in some of your older pictures on flickr, bakclash is pretty evident on the first layers. If so, be sure to tighten the short belts, by loosening the motors, pushing them down firmly, and re-tightening.

Alternatively, do the walls have infill? It could be due to the head emptying of filament during internal travel moves. Be sure and turn off 'enable combing' in Cura's expert settings for retraction, enable retraction, and see if that makes any difference.

 

[illuminarti 18]

If you want to http://mailto:gcode@fbrc8.comthe gcode, I'll take a look at it, and see if I see anything wrong with it.

 

[ddegagne 0]

Also there is infill but the walls are only 3mm so most of the area has none even at 33%. With combing always have that on thats something I will try now. I always have retraction on