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yellowshark

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Posts posted by yellowshark

  1. Assuming your filament diameter IS set correctly - you do not mention checking your feeder knurled wheel. Over time the teeth will get impregnated with filament and the wheel and filament will start slipping against each other producing the extreme under-extrusion you are displaying.  Having said that the 3rd pic is confusing. Was that model printed soon after the previous two? With the same reel of filament? Anything else printed in between the 2nd and 3rd pic?        

     

    Have you tried printing the same models with a different reel of filament - the filament could be jamming on the reel, even randomly.

  2. Load your model and select it. At the leftmost side of the screen you will see a column of seven icons. Place your cursor over the 2nd icon down and you will see it is the "Move" tool. Click the icon and you will see three rows for the x/y/z axes. They should all be zero but your z axis probably has a value. Set it to zero and problem solved.

  3. Lol I have been asking myself that question for the past 4 or 5 years. The good thing is it sure motivates you at an early stage to get your bed adhesion absolutely optimised😎.  Never seen that "Optimise shell printing order" before, but I am only on 2.7




























     

     

  4. I will assume there is nothing really wrong with your printer and that is has decent dimensional accuracy, i.e. a maximum tolerance of 100 microns.

    So firstly, your screw/bolts and the screw holes in the lid and box. These are circles; circles never print accurately; 3D printers do not prints circles they print straight lines; so a circle is made up of very many small straight lines and it is the method used to print them that causes the dimensional error. Now if you have two holes, a screw and a screw hole you might expect them to have the same error and therefore fit, but as you see this is not always the case; what hidden law of physics is acting there I have no idea. Mine are normally smaller and if I am printing a hole for a steel bolt to go through I will normally start with the diameter of the hole modelled as bolt diameter + 300 microns. But this will not always work first time so yes it is somewhat suck and see but with some experience you can get it spot on pretty quickly.

     

    The box/lid alignment really should not be a problem; at the worst a quick file on a print defect in the wrong place should do the job. If the designer has a) designed with wall widths of 400 microns and b) left a100-200 micron (gap between the two mating surfaces) and c) you are doing nothing silly with your nozzle width and wall width, then it should fit. 

     

    In my experience which is predominantly PLA based, PLA is fine

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  5. I suspect you need to change the Machine Setting for your printer. Take menu option Machine/machine settings and select your printer. You will see machine centre 0,0 on the left side. Change that setting and hopefully all will be well.

  6. Yes often a tricky one; you have an inherent problem caused by the required change in pressure which does not happen instantaneously, it takes time to settle down. That is why 99% of the time I print with all speeds set to the same value.

    With regards to your last comment, I have often wondered why Cura does not allow you to specify the speed change to happen during the last part of the infill.

     

    I am only on 2.7 and so not aware if there have been subsequent changes that would help. All I can think of is to print the wall inner to outer and if need be add an extra wall. I normally go outer to inner because that is meant to improve dimensional accuracy which is normally important for me.

    Also if you are printing something, maybe a bust, where there is a definite rear which will not be seen, then use the “user specified” option of the Z Seam Alignment to start the layer on the rear section.

  7. The secret with small things in PLA is to go as cool as you can, lol I bet you can drop 5 if not 10/15 degrees and go as slow as you can. You may have to play with both parameters to find the sweet spot. And filament make/colour may play a part too although I have never really investigated that for this question - although for general use I know my best 2 or 3 filaments

  8. OK if you have not done so already, you should check the measurements in Cura to ensure they exactly replicate the measurements in Tinkercad.

     

    On the X/Y axes; afraid I have to disagree with @Smithy, who does have some good stuff above, but if you are doing engineering stuff and dimensional accuracy is vital then your measurements are poor. You should be able to better 100 microns easily and quite frankly 50 microns too. I can better 20 microns but have never been able to do so  consistently, so in our T&Cs we guarantee 50 microns but prefer 100 microns as that allows us to work faster and cheaper.

     

    You need to research and I mean hours and hours of testing; which filament(s) gives you the best results. We go to one of two filaments if dimensional accuracy is tantamount. Play, in a disciplined manner, with your Cura settings to establish what produces the sweet spot and then stick to that. I had always had the strong view that slower was better. But a month back I printed something for myself, used 60mm/s and was really surprised at how accurate it was. So I now have to find a few days of free time, test and test whilst re-evaluating my views.

      

    Then of course you have e-steps. I am guessing you have  pretty new printer with not that many hours of use, so mechanical wear and tear should not be an issue. I am sure I read somewhere that part of Ultimaker's QA process is checking the e-steps; which infers that for any given printer the manufacturing process, when everything is pulled together, can result in performance differences. I may not be 100% correct on that but I will add that when I first got my printer I spent a lot of time focused on dimensional accuracy and everything was good.  Six months ago, following a period of 18 months(?) when I did not need to worry about it, we got a job where accuracy was vital. On the first run the dims were appalling. That was when I taught myself how to recalibrate e-steps and it is all sweet again following that work.

     

    The z-axis is a bit different. Additionally you have your nozzle to bed distance set during your bed levelling. If you like to have your filament really squashed down to get great adhesion well your first layer will not physically be 0.300.Your Z-axis measurement is your most accurate and it is shorter not longer, quite possibly resulting from your z-offset. You may find that if you increase your gap marginally you may improve on that 60 micron variance. But you are pretty reasonable so be careful otherwise you will make it worse

     

  9. Lol modelling in clay etc. Use the camera  then the software and let technology do it for you. OK the software you want is Autodesk 123D Catch. Autodesk is one of the top 3 CAD software companies in the World and they have a range of free software for 3D modelling on their website. Catch is just brilliant, so easy too use and really good results. Yes you need more than one photo! Maybe a dozen will be OK, maybe 30 or so.

     

    Now I have just been on their website and see the software is no longer available. Now it may have been absorbed into Autodesk 123D, which I think used to be Autodesk 123D Design. So could be worth downloading that and checking? Catch may be available on some other download sites? Ask some forums on the net how to get it?

     

    Or if you have some cloud storage I can drop the software file there for you.

  10. Your Retraction Distance looks awfully long at 9mm. I say that because mine is 0.9mm and I do not suffer from travel lines. My retraction settings are 

    image.png.c942e4d2cf8f7ab4ae6d5d8345c3c640.png

     

    With PLA I found 5.5mm for retraction distance to be fine but I changed it to 6.5mm for nGen material.

     

    I always print with Combing Off

     

     

     

     

     

    image.png

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