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Smithy

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Posts posted by Smithy

    Custom Supports (3/4 normal filament, 1/4 PVA)

    in UltiMaker Cura

    Posted

    That's right, every possibility to avoid or minimize supports is better than fiddling with all the options. PVA is a great material and due PVA we have a lot of possibilities, but it can be a pain to print with it and it is very expensive compared to normal PLA.

     

    But the support roof normally works fine, but I haven't mixed it up with PVA, just PLA for everything. The roof is normally 1mm thick and it gives good support for the surface of the model above. The drawback is, that is it harder to remove.

    S5 Build Volume?

    in Improve your 3D prints

    Posted

    When you use both print cores then the build volume is smaller. So if this is a single extruder print you can try to disable the extruder 2, to get a bigger build volume. The shaded border will get smaller.

     

    You can disable the extruder in Cura menu -> Settings -> Extruder 2 -> Disable Extruder

    Unterextrusion direkt am am ersten Layer

    in Deutsch

    Posted

    9 hours ago, FrankyB said:

    vielen dank für die Information. Tatsächlich hatte ich das übersehen.

     

    nichts desto trotz hatte ich das gleiche Verhalten auch mit 2,85mm Filament davor. 

     

     

    Da müsste dann aber trotzdem ein signifikanter Unterschied zu sehen gewesen sein. Weil der Slicer (Cura) sagt dem Feeder, transportiere x mm Material und da ist eben ein enormer Unterschied von der Menge (Volumen) ob nun z.B. 20mm 1.75 Filament oder 20mm 2.85mm vorgeschoben wird. Daher wichtig, nur 2.85er Filament verwenden, der Drucker (Feeder, Bowden Tube und Düse) ist auch nur für 2.85 ausgelegt.

     

    Aber wenn das vorher auch schon so war, dann arbeite einmal die Tipps von Digibike ab, mache einen neuen Testdruck und poste ein paar Bilder damit wir das sehen können.

     

    Required Humidity % for printing Hygroscopic materials (PVA, NYLON)

    in Improve your 3D prints

    Posted

    You can bake it on the heated bed or in an oven, both are possible. The time depends on how wet your filament is, overnight is a good starting point and then you will see if it was enough or not. I don't know the temperature for UM Nylon, but you should always stay below the glass temperature, otherwise, the filament gets soft and you can ruin the spool. As far as I know, the UM nylon has a lower glass temperature than other brands, round about 50°C, so I would start at 40°C for the drying process, but with lower temperature, it will take longer. 

     

    There also commercial solutions available like the DryBox, but it is nothing more than a normal food dryer which is much cheaper than the Drybox solution. But a heated bed and covered with a towel or an oven is also a way to go. When you use an oven, be careful and heat up the oven without the spool, because ovens mostly overshoot the target temperature when heating up.

     

    My Polybox has humidity inside between 11% and 20% and that is fine. I also think that humidity below 50% is a way too high, especially for storing. I guess UM means that you print the material when below 50% but for sure not for storing. And when you have a long-running job, 50% can be too much. There is no other general rule how much humidity is acceptable, but keep it as low as possible.

     

    Your hack box has maybe also too few silica packs, so you could give it a try to put 2 500g or 2x 250g packs in the box. The very small ones are not working fast enough and due to the reason your box is not airtight enough, too much air comes in and the packs cannot absorb the humidity quick enough.

     

    Every box which is more less airtight and which contains enough or big packs of silica packs are ok and useable. The Polybox is just a commercial solution, which works well, but you can also make a box on your own to achieve the same result.

    • Thanks 2

    Required Humidity % for printing Hygroscopic materials (PVA, NYLON)

    in Improve your 3D prints

    Posted

    You will have to bake the filament from time to time regardless of where you store it. Storing dry is very important, but not always to only way to keep the spools dry. So option 1 is something to do when your prints are not nice or you hear a sizzling sound.

     

    Option 2 or 4 is a must-have in my opinion to have a consistent quality also for a longer print job. I prefer the Polybox, it is nice, small and keeps 2 spools in a dry environment. But it is nothing more than any other box you modify. I don't care about the NFC reader it does nothing else than select the material for you, so I can select it manually too. (But be careful, because then you have to choose the generic material in Cura and not the UM one, otherwise the printer thinks you have the wrong material loaded.) I also have no extrusion problems with the Polybox, you should just place the box in a way, that the filament goes in a "natural" way into the Bowden tube to avoid too much friction. I have mine on the floor beside the printer, without any problems.

     

    Option 3 is not good. Without good ventilation, the air will get too hot inside and can cause problems with the material and stepper motors get too hot.

     

    The Polybox is also nice to store the filament, so normally I don't put the spool back in an airtight container after printing, I just rewind the filament back and that's it.

     

    But your drybox is also ok, so just use it, it fits perfectly behind the printer and you can use the NFC reader too.

    • Thanks 2

    Diagnosing Ultimaker 2 - Wrong Nozzle Size?

    in Improve your 3D prints

    Posted

    1 hour ago, Perchik said:

    Can a mismatch between nozzle size in cura and on the machine lead to under (or over) extrusion?

    Could be yes, but only when 0.25 is configured, all other nozzle sizes would produce over extrusion. (or a clogged nozzle)

     

    A clean nozzle is a good start point, then make a new test print. Look for the calibration cube, which prints faster than the benchy and should give us a good view of what happened. Use the default Cura profile 0.2 layer height and check the line width if it is 0.4.

    Diagnosing Ultimaker 2 - Wrong Nozzle Size?

    in Improve your 3D prints

    Posted

    The UM2 without an Olsson block has a 0.4 nozzle which cannot be changed. Some users have upgraded the UM2 with Olsson block, and then you are able to change the nozzle. On the changeable nozzles, you find the number 40 and points which indicates the nozzle size.

     

    I guess your nozzle is clogged or you have to replace the PTFE coupler (the white part between Bowden tube and nozzle). Check the UM website how to do hot/cold pulls to clean the nozzle and try it again with Cura default settings.

     

    But under extrusion (this is your problem) can be caused by several other things too. (Temperature, printing too fast, feeder problem)

    UM3+ Druckt nicht Maßgenau

    in Deutsch

    Posted

    Hallo

    Du brauchst keine Schritte pro mm einstellen, das ist am UM3 nur über Umwege die nicht empfehlenswert sind, möglich.

     

    Generell sind deine Werte die du erreicht hast nicht so schlecht - 100% wirst du mit einem FDM Drucker nie schaffen, aber du hast Möglichkeiten besser zu werden. Zum einen ist es wichtig, langsam (ca. 30mm/sec oder noch langsamer) zu drucken und dabei alle Geschwindigkeiten auf den gleichen Wert zu setzen. (sollten 6 sein). Weiters ist es wichtig so kühl wie möglich zu drucken, da muss man sich herantasten. Reduziere solange die Temperatur bis du Underextrusion bekommst und dann gehst du wieder um 5-10° höher. Zusätzlich kannst du noch Jerk und Acceleration Control ausschalten. Dann besteht zwar die Gefahr, dass du "Ringing" an den Seitenflächen bekommst, aber das ist nur optischer Natur, aber deine Ecken werden dadurch maßhaltiger.

     

    4 hours ago, ToPi said:

    Ich möchte aber nur das Modell in Cura laden und auf drucken drücken müssen. Und das zu druckende Teil kommt Massgenau aus dem Drucker heraus. 

    Ganz so einfach wird es nicht werden. Jedes Modell und jedes Material ist geringfügig anders. Gerade bei Materialwechsel (Hersteller oder oft auch schon die Farbe) musst du ein paar Anpassungen machen (Temperatur) und wirklich das Optimum aus dem Drucker herauszuholen.

    Supports for tall thin objects

    in UltiMaker Cura

    Posted

    It is possible, then you have to set both the model and the support to Extruder 1, so everything will be printed with Extruder 1. Additionally, configure the "Support Roof" option and set the Support Roof to Extruder 2. So your support will be printed with PLA for example and just the roof of the support (1 mm) will be printed with PVA.

     

    But, you should test if this is really a practical solution, because PVA sticks well to the glass, but not so well to PLA. So it can happen, that your "roof" doesn't stick well to the underlying PLA support structure.

     

     

    Supports for tall thin objects

    in UltiMaker Cura

    Posted

    Of course, you can. You only have to design it in different bodies or spilt your body afterward. Then export both to Cura, assign the extruders to it, select both parts and click on merge objects. All parts will get in the orientation as you have it designed and exported and your print will use both extruders.

    Custom Supports (3/4 normal filament, 1/4 PVA)

    in UltiMaker Cura

    Posted

    It is possible, you have to enable the Support Roof. The Support Roof option makes a more intense structure below the surface of your model and results in a nicer flatter surface, but harder to remove.

     

    But, you can set the Extruder which should print the Support Roof, so when you print your model with extruder 1 and support also with extruder 1, then set the extruder for the support roof to extruder 2 and you get exactly what you want.

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