[PLA stops coming out 1/2 way through the print of a fractured bone]

If you've thoroughly checked and are happy that your feeder works okay & your filament (2.85mm) isn't being tangled on it's route - which is friction free, the bowden tube is clear & your nozzle is clear... there's little left mechanically that can cause a problem.

Sorry to bang on - but you've not checked your isolator have you? You're certain that's ok then?

The isolator will deform over time and cause you problems. Replace it & I'd put money on that solving your problem. 50p bet? :smile: (I win either way)

 

Having received the UM2 pre-built, I am not familiar with the parts. I assume that the build instructions are online so that I can work out what the isolator is. What should I look for? Is it easy to change?

MM

 

[PLA stops coming out 1/2 way through the print of a fractured bone]

I have not changed any part of the UM2. I have had it for a few months

I have cleaned the nozzle with the Atomic method many times when I was having adhesion problems and the PLA accumulated around the nozzle leading to a block

MM

 

[PLA stops coming out 1/2 way through the print of a fractured bone]

There is not the grinding as I have had when the print loosens and then the accumulation of PLA around the nozzle blocks it completely. It seems to be stuck retracting and advancing

I am using the "standard" settings of 50mm/s and 0.1mm layer

I will try heating the nozzle to 240C

Thanks

 

[PLA stops coming out 1/2 way through the print of a fractured bone]

I have been successfully printing out models of fractured bones that I have converted from CT scans.

I now have a model of a fracture that I need to print out to help with decision making. The model is quite big when full size in spite of selecting as small a region as possible. The stl file is 16Mb. The print is meant to take about 6 hours

I have tried printing three times now. On each occasion the print seems to go fine for about 1/3 of the print time and then the PLA stops coming out the nozzle and the print head is following its path in mid air. The filament seems to be simple shuttling forwards and back rather than advancing.

I did a material change and the PLA comes out the nozzle and so seems not to be blocked

I have looked at the model with xray in Cura and there are no red lines

Can anyone help me understand what has gone amiss?

I would be ever so grateful if someone could look at the stl file and see if it works for them? I can put it into a dropbox

This is quite important for me as I need to make a clinical decision based on the model - once I get the wretched thing to print

Many thanks

MedicalModeller

 

[Print failure possibly because the bed not hot enough]

Dear All, Thanks for the support/advice

I have not been using glue on the bed! In fact I have been cleaning the glass with isopropyl alcohol and almost all the prints seem to work fine. But as I posted, not all prints stick.

I will try a thin layer of PVA glue.

As as aside I wonder why the nozzle blocks after the print becomes loose. Is it because the PLA accumulates around the print head and so it does not get hot enough and the filament then solidifies inside the print head? Certainly I have become expert of the Atomic unblock method!

Thanks

MM

 

[Findings model errors]

Thanks

Without wishing to appear completely dumb, when you say validate in the slicing view, what is it that will show the errors exactly?

MM

 

[Print failure possibly because the bed not hot enough]

I have been printing large models of bones. The prints have been failing due to failure of the print to stay stuck to the heated plate (UM2). I have wondered if this is partly to do with keeping the UM2 in a room with the heating on low so that the room is rather cool. Anyhow, I increased the bed temp to 70 degrees and the print came out perfectly (showing the fracture nicely)

Is there a way to make the default bed temp anything other than 60 degrees to avoid having to tune every print??

Thanks

MM

 

[Findings model errors]

Can someone kindly explain the xray function on Cura. Am I right that if I click on Xray and the model is all blue that all is well and does not need repair in NetFabb

If I click on xray and there are lots of red lines, this is bad and I need to repair the model in Netfabb? If I do repair in Netfabb is the standard repair sufficient?

Sorry if this is all too obvious

MM

 

[Printing tiny gears - resolution not good enough]

Would exchanging the .4 nozzle size for a .3 nozzle help improve the resolution? Is .3 the smallest nozzle size you can go?

 

Did not know one could change the nozzle size! Printing "2 up" certainly improves the resolution. Will try 4 up now

MM

 

[Printing tiny gears - resolution not good enough]

I would probably print at 20mm/s, certainly no more than 30mm/s. Probably worth trying fan on at 100%. Difficult to tell the size but you might want to print 2 up to ensure you have a decent minimum layer time

 

I had printed at 25mm/s

What does "print 2 up" mean?

The gear is 13mm in diameter

Thanks

MM

 

[Printing tiny gears - resolution not good enough]

I am printing some gears for a mechanical device. The gears are quite small. As a result the definition between the teeth is not good enough for the gears to mesh.

I am using the default settings on Cura so the nozzle is set to 0.4

What are the suggestions to make the teeth better?

Thanks

MM

 

[How do I stop parts being filled in that should be open?]

This model is not something that I have made. It is a model of a real boat and I asked the boat builders for a file with which to make a model. They sent me a file in .3dm format. I have had to convert it to .stl. So these errors have arisen somewhere in the translation

MM

 

[How do I stop parts being filled in that should be open?]

I have tried to print without any "fix horrible" checked and the print failed after one hour. The nozzle blocked and the printer was printing air - just like my heel bone that has internal errors.

When you say clean up the model, what is the best way to do this. Back to Meshmixer?

Many thanks

MM

 

[How do I stop parts being filled in that should be open?]

Thanks. You were right that one of the fix horrible options was selected

When I look at the xray view - there is a lot of red. What is a "defect" in this situation? Is it a void that might be intentional?

MM

 

[How do I stop parts being filled in that should be open?]

I have a model of a boat. In the mid part of the model, there is a recess which is the cockpit where the wheel goes. On the view in Cura, the cockpit is clearly seen (arrowed). I have set Cura to 0% fill but the model comes out with the cockpit covered over with a layer of PLA. I have taken the layer off and the cockpit structure is not there . I have also printed with 20% fill and the end result it the same.

Can someone help me get the print to look like the representation on Cura?

Thanks

MedicalModeller

 

[Printing stops due to blockage after 2 hours out of 7]

Many thanks for all this. Most of the other bone models that I have made have been tubular bones with little in the middle. In contrast the heel bone is quite solid. I think that is the basic problem. I will try to get another heel bone scan and see if the same thing occurs. If it does, I will have proved a limitation in getting from CT scan to 3D model

I will also try and follow you advice and see how I get on

Many thanks for your time

MM

 

[Printing stops due to blockage after 2 hours out of 7]

Used Meshlab to make the model hollow and again reduced size of x,y & z to 0.5. Re-printed and it stopped and blocked at about the same point again. Back to the Atomic unblock again..........................

The last bone that I printed was a fracture of the upper humerus. the stl was (only) 14Mb. It printed fine. Maybe this heel bone model is just too big/complex with an stl of 80Mb

All very frustrating for a simple bone fixer. Happy to dropbox the stl if someone wants to play and see where I am going wrong.........

Thanks

MedicalModeler

 

[Printing stops due to blockage after 2 hours out of 7]

Netfab basic is free,

or you can just go here and upload your model for automatic repairs.

https://netfabb.azurewebsites.net/

 

Ah ha! Now downloaded Netfabb. My STL has 1,686,572 triangles. Is that a lot?!

Now struggling to work out how to reduce the number of triangles

MM

 

[Cura cannot cope with big file?]

Could be (another) memory related issue. What happens if you double the layer thickness? (just for testing reasons)

 

I reduced the size of the model to x,y, and z each 0.5 of the original size. I assume that reduces the memory. Still an incomplete print.

MM

 

[Printing stops due to blockage after 2 hours out of 7]

I think we need to get some idea of the settings which were used for this print. E.g. print speed and temperature, and whether the feeder was grinding or skipping (making the chock sound).

 

I reset the settings back to default

Layer height 0.1

Shell thickness 0.8

Enable retraction

Bottom/top thickness 0.6

Fill 0%

Print speed 50mm/s

Touching build plate

Brim

Nozzle 0.4

Initial layer thickness0.3

Temperature is whatever the machine defaults to when loading new filament and selecting PLA.

Once the nozzle blocks then the feeder is grinding the filament of course

Is there a shareware program that can split a model into two equal halves

Netfab is not cheap. Is there a trial version or a shareware alternative?

What do I look for in the layer view that would be odd?

Thanks for everyone's input. Please excuse my ignorance, but I am new to 3D printing (obviously) but trying to perfect getting from CT scans of bones to reliably printed 3D models

MM

 

[Cura cannot cope with big file?]

What happens? does the model load in the 3D area or not? Does the progress bar start or not?

 

The model does load. The progress bar starts but rarely finishes.

MM

 

[Cura cannot cope with big file?]

do you need all the polygons? Or would a decimated mesh work, generated by Zbrush for example.

Usually you can reduce polygon count by about 80% without having a noticeable difference in quality of the model.

 

I do not think I will spend $795 to find out if zbrush helps!

MM

 

[Cura cannot cope with big file?]

Actually, it's addressed in the test version, not the 14.09 release:

http://software.ultimaker.com/Cura_closed_beta/

 

Thanks

I downloaded the test version, but the problem remains

MM

 

[Printing stops due to blockage after 2 hours out of 7]

I have posted this at the end of another thread but then read that it would be better to start a new thread for a new problem. So please excuse double posting....

So I have a 2 week old UM2. I have printed out 8 large gears (2 hours each) and a model of a upper end of humerus without a problem. The latter took about 7 hours to print and was/is perfect.

 

Then I tried to print a heel bone which was a big file 80+Mb when in stl. I reduced the size to print 50% of true size. It was meant to take 6 hours to print. I have tried repeatedly to get a complete print but the filament stops flowing after 2 hours and the print head carries on printing air. I have now done an Atomic unblock on 3 or four occasions. Each time the nozzle blocks after 2 hours or so

 

 

I have Cura set to 50mm/sec and all other settings to default

 

I have done the extrusion test with the print head set to 240

Here is the result

 

It seems that extrusion is not the problem - or is it?

 

This is so frustrating. I feel like sending the printer back if it is this difficult to consistently get a good print

 

MM

 

[UM2 extrusion rates revisited]

So I have a 2 week old UM2. I have printed out 8 large gears (2 hours each) and a model of a upper end of humerus without a problem. The latter took about 7 hours to print and was/is perfect.

Then I tried to print a heel bone which was a big file 80+Mb when in stl. I reduced the size to print 50% of true size. It was meant to take 6 hours to print. I have tried repeatedly to get a complete print but the filament stops flowing after 2 hours and the print head carries on printing air. I have now done an Atomic unblock on 3 or four occasions. Each time the nozzle blocks after 2 hours or so

I have Cura set to 50mm/sec and all other settings to default

I have done the extrusion test with the print head set to 240

Here is the result

It seems that extrusion is not the problem - or is it?

This is so frustrating. I feel like sending the printer back it is this difficult to consistently get a good print

TP