This topic contains 54 replies, has 6 voices, and was last updated by 
click 5 months, 2 weeks ago.
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Cone and benchy test, not perfect but getting there.
Moh
What’s wrong with benchy and Robox? Robox is supposed to be superior in printing dual material and yet when you browse internet you see quite neat prints on ‘inferior’ printers. Where are we going wrong?
BTW @mistsoul cone looks beautiful!
I must give benchy a go myself, too.
@click yea definitely, hopefully future AM releases will correct some of the issues we are seeing. Do post if you give it a go.
Moh
@click When I see Benchy printed on competing dual material printers, it isn’t that small. The problems I see with the dual material Benchy and Robox are all consistent with printing really tiny parts with a large nozzle. I suspect that if the Benchy model were scaled up to where the features are appropriate for a 0.4 mm nozzle we would see different results.
I operate two Betas and four Production Robox.
I am the US/Canada Technical Support engineer for the Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/benI you calibrate the nozzle openings you loose the stringing and the model will be much better.
I agree with @bhudson this model is not designed properly. When you design a model for fused filament printing you need to know the nozzle diameter and layer height. Cut the roof and you see more problems with this model.
yeah the leaking between colours shouldnt be there, tune the nozzle close.
What materials are the red and black?
@pete thanks for the tip. Before making the print, I had the nozzle opening fine tuned to the smallest amount visible when doing the calibration . I repeated the test a few time to make sure the setting was correct. The material is PET+. I did not want to set it to the point right before i see the filament because i thought the increased pressure could cause a blown seal. There are so many variables that can be tweaked but one guess is that the leak and blob could be due to water the water content in the filament in case it is not dry. I will try to dry in an oven and might give it another try if I have time. For the stringing I am not sure how to correct it, some recommendations on matter hacker explained that the non-printing travel time and retraction can be increased to solve the issue.
What other suggestion do you have ?
Moh
@mistsoul You should not need to dry PET. Water does not affect it like PLA.
The stringing is caused by the fact that the print is too small for the nozzle and the nozzle is picking up little pieces of material and stringing them out. The Robox does not use the travel time or retraction settings.
I have noticed that PET+ is very stringy and does not print well. I have run through about 2 rolls of it and got similar results, lots of blobbing and stringing so I have stopped using it. I use ColorFabb XT now and do not see the stringing and blobs.
I operate two Betas and four Production Robox.
I am the US/Canada Technical Support engineer for the Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/benI’ve been getting great dual material prints so I’ll give the benchy a go tomorrow and post the results.
STEELMANS 3D PRINT.
3D Hub: www.3dhubs.com/service/steelmans
Website: www.steelmans3d.com@bhudson, thanks for the clarification. I used PET+ prior with the single head before and it printed perfectly with miniature and larger parts in fine so the bump up in nozzle size as you indicate may be the issue. I do see a lot of artifacts (underextrusion and tiny holes) in my prints which were not there with the single head except in draft mode (makes it glitter a bit more than normal).
With DM - see close up of the cone above printed in normal
With Single Head - see close up of the chess box printed in draft
http://www.cel-robox.com/forums/topic/chess-set/
The prints are better in fine, so I might be able to find an optimum setting for PET+ with the DM with further tweaks. For the flow rate multiplier what is the max above 1.0 that can safely be used without harming the machine?
Moh
@mistsoul My PET+ was very early - they actually had to replace a reel because it was full of air bubbles, so that may have contributed to the issues. I haven’t used it since I ran out of all but one reel.
I would not adjust the flow rate over 105 with PET because it is a pretty stiff material and not very viscous. If you increase the flow rate, you should also increase the temperature to make sure the material has enough time to fully melt.
I operate two Betas and four Production Robox.
I am the US/Canada Technical Support engineer for the Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/benthanks, sorry the flow rate question was general, not specific to PET+, what is generally the max limit that should never be exceeded for the machine not to malfunction irrespective of the filament or what happens to the machine if it is set too high, i.e. too much material being pushed out and a blown seal?
Moh
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