yellowshark

... watch the print, you may find that 40% or 60% will kill the retraction

.. retraction problem. That is one reason why I often use 100% infill !!!!!

Hi I think you mean " the version BELOW" printed at 203? I would normally agree with George that a difference in temp of 7 degrees is not going to make a great difference BUT I have found with whites that reducing from 210 to 205 can make a large difference, in terms of correcting over extrusion. Reducing from 40% to 30% infill will not improve your print - but may make no difference either. It has been my very limited experience that using a layer height < .100 can prove problematical when covering sparse infills with solid layers. With .100 you may even get away 20% infill but I do not really know as I normally use 100% and never go below 40%. In certain cases 100% gives you faster speed as there is no retraction. I do not use the flow setting either I think you said you were using solid layers for a depth of 0.8mm. If you want to go to thinner layers I think you will find that increasing that to 1.2mm minimum will help (to a certain extent dependant on the infill %) Anyway the last picture looks good so pleased to see that you seem to have got there!

My feeling is that .06 layer depth, 20% infill and 70mm/s print speed are not a good match. IMHO for the geometry you have there I doubt that using such thin layers will give you any advantage. I suggest you go to at least .10 layer depth, raise your infill to 40% and drop your print speedS to 30mm/s. That will probably fix it and then you can take it from there. No idea what your extruder temp. is but you can probably get away with the same temp. for those changes. Personally I would print them at 200-205 depending on filament (never used UM blue).

Transitioning between sections i.e. where layer height and/or print speed and/or extruder temp and/or flow rate etc. are changed. There is a fundamental principal comes into play here, filament pressure. This is controlled by the drive mechanism and is dependent on the settings controlling the amount of filament to be printed and the speed at which it is deposited; typically the layer depth and the print speed plus the extruder temp. which is the balancing mechanism controlling the viscosity of the plastic to provide perfect (or not) extrusion. When you change settings they do not all happen in the same nanosecond. Which means for a period of time your pressure will not be correct nor will your extruder temp be correct for delivering the optimum flow to match the pressure. You only have to change your extruder temp. via your printer controls to see how long it takes for the temp. to stabilise at the new temp. Whilst your flow mechanism is out of balance there may be a risk of artefacts being deposited. It will of course depend on a number of variables including the magnitude of the change(s), the filament and the geometry. I am not suggesting that this happens all the time but it can happen. I started life using Slic3r which has more variable options than Cura, such as different bed and extruder temps for layer 1, different speeds e.g. for infill and perimeter walls, different accelerations for infill and perimeters etc. Since changing to Cura the quality of my prints has been noticeably better, not just because of the aforementioned, I have always found Cura to be far better on retraction. I have always wanted to try S3D but I will not support a software company that fails to provide demo/trial software; a bit like buying a car without sitting in it and driving it. Being able to change settings for different parts of the print is awesome but just how well does it work? If you want to change print speed from 60mm/s to 20mm/s do you just do it or is it better to make two or three incremental changes rather than just the one.

Is the print doing lots of retractions? If so pull out the filament and see if it is squashed/has lots of teeth marks. If so this will be causing it to foul in the Bowden tube and cause under/no extrusion. Typical symptom is that it prints OK at the start and then fails later during the print. Solution (in my experience) is to reduce the pressure of the drive teeth on the filament.

Sorry I missed the word "casts". You should still though check the regulations - no idea if the dental industry is happy with sticking any old plastic into a patient's mouth. You can get customised filament - we have just taken delivery of a filament where we requested a 3% mix with an anti-microbial additive which prevents/mitigates against the transfer of nasties from one person's skin to another - addmaster.co.uk

Probably not. This is a specialised area and I am 99.9% sure that the material you need to use will have been certified by appropriate health bodies and quite likely not available for FDM printing.

Faberdashery - orders for 100 mtrs come on a spool. All other quantities come loose. I usually order 50mtr quantities to avoid receiving a spool

IMHO the pressure of the drive teeth on the filament come into play on the retraction point. If that is what "increasing the extruder tension" means then you probably want to reduce the tension not increase it. Anyways I had a similar problem a couple of months back and reducing the pressure did the job for me; I am assuming that it is adjustable on the UM.

Thanks for that Ultiarjan. Good article and I might just get away with the temperatures

.... i.e. boiling water underneath the bowl

So if you put a candle in a bowl (say)and heat it will that give you molten wax to use in a mould? Is boiling water sufficient?

"Hopefully the hypochondriacs and safety fascistas don't get to interfere with this hobby like they interfere my woodworking, metalworking, plastic casting... or just about anything else fun come to think of it." You and me both Don. I just read today that Ladybird books have given way to some d*mn lobbyist group to remove the "for girls" "for boys" from the cover page. Personally I would rather read about tigers than dolls houses.

To be honest I only skimmed the paper without focussing on all the details in the tables. But it seems to suggest ("seems" is an important word) that cooking in the kitchen is more dangerous than operating a 3D printer.

Didier that is really interesting, strikingly different. I assume that apart from extruder temp, maybe, all the settings were the same? Maybe if the extruder temp did not change you had over extrusion on the first set? - I am clutching at straws here. Yesterday I was printing a small box with a series of triangular shapes, about 1.5mm/2mm thick which due to print orientation were printed on their sides, one above each othe,r with meshmixer supports in between. All the pointy ends, apart from the bottom one sitting on the print bed, were turned up. It was scaled down to a small size and as there was so little material around the point of the triangle I wondered if the heat from the tip of the nozzle was pulling them as it moved away because there was so little material to get good adhesion. I ran it again tonight making it bigger, plus pushing the fans up from 40% to 100%, and it was fine. Maybe if you are working on a really small model then working with a thinner layer depth induces a similar problem?

Yup cubes look good to me. Some touches of elephants feet but if the filament decides its going to do that, often there is not much you can do about it - I try to drop the temp assuming I am not going at an insane speed. Lol I cannot get my brain around what I am looking at looking at your spiralise pic. The threads might be a result of going too fast, not sure, or is that area an overhang. The pitted areas would worry me probably but I cannot work out their print orientation - which applies to all the surfaces!!

.3 or .25 nozzles. I have never tried them but I would not have thought they would help resolution except maybe on the very smallest parts. To be fair they must do something or why have them. They will slow the print time. I am sure that for most parts, unless you are a dungeons and dragons freak, you will better resolution and finish by slowing down and/or going to a smaller layer depth. Thinking onwards if you are working in mechanical engineering and have to be really really precise then with certain orientations they may help - but you will probably have switched to an SLA printer or whatever by then.

Hi Jamesh, 4 up can and does help depending on the geometry. Cura will print 2 layers on a model and then move over and print 2 layers on the next model, so you are not getting the benefit of 2up because alternate layers on each model do not get the extra cooling time. I am not saying it happens all the time but I have seen it recently with 14.07 release but have not investigated.

To be absolutely clear 2up is as referred to above using two, or more, copies of the model. Typically you need about 10 secs for the layer to cool before depositing a new layer on top of it, although some people do push it to 5 or 6 secs. With really small models this is unattainable so multiple models overcome it. There is a bug in Cura though that can blows this solution away as it often sequences itself so that it prints double layers on each model, alternatively, so you still get a minimal amount of time. The solution there is to print four copies and the two in the middle of the sequencing will be fine.

As I said have you tried a different filament. It is normal for duff filament to have a length, could be metres, of sound filament and then a length of wider filament that jams the feeder/extruder path and would cause your problem

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

Just been looking at the new 3ntr A4v2 (http://3ntr.eu/?page_id=939), it has dual z-screws, water cooled extruders, optional direct feeder for flexible filament, dual extruder heaters providing a peak temp. of 415c and OMG a z plate sensor for distance measurement. Still only got dual extruders though.

... even though you said XT in your 1st para - doh! If you search on XT there are some threads on the forum with people's experience on XT

Sorry I did not realise you were using XT - best to go with their recommendation in that case not mine!!