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Stringing and bumps

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  • Stringing and bumps

    How do i fix the stringing and bumps you see here?
    Ender 3 V2, Cura 4.7

  • #2
    What hotend temp are you using? If it's 180C or higher, you could try lowering the temperature 5C at a time, to see if it helps. You might also look into calibrating the extruder feed rate.


    • #3
      Right now im printing PLA+ on a Microswiss all metal hot end at 235C. I have some calipers on the way from amazon. Once i get those i can calibrate.


      • #4
        PLA+ at 235C sounds pretty high. I would try a print at 200C. You don't need calipers to calibrate the extruder: a millimeter ruler is good enough. Just make sure that, at printing temperature, the extruder pushes 100mm of filament through when told to. If you get within 1mm you should be good.
        Last edited by Ender5r; 09-14-2020, 03:04 PM.


        • #5
          Ender5r is right. Your temperature is way to high for PLA. The plastic is ether just oozing out or burning to ash inside your hotend.

          Usually PLA is rated 190°C till 220°C. Check the spool or the package for the specifications of your filament.

          This range is given for a reason. The lower value is for slow prints, while the higher value is for - you guessed it - higher speeds.

          When printing with a new filament brand it is always a good idea to use the middle of that, so in my example 205°C should give good results.

          About the calibration of the e-steps. For the extruder you don´t need calipers. Just get a water prove marker and a ruler. Mark the filament next to the extruder, now measure 100mm from that mark towards the spool and mark again. Make sure the nozzle is at least 20mm in the air and heated up. Push the filament into the extruder until the first mark is just in. Use the metal of the extruder inlet as a fix point.

          You can perform the procedure even without extruding filament. This is just about the speed of the extruder gears. Just unload the filament and load it manually into the extruder gears. So you can try the extruding process several times using the same markings. Just keep in mind that the extruder needs to be hot during the process, or the extrude function will be blocked (cold extrusion prevention).

          Now extrude 100mm of filament and watch the second mark. Once the filament moving is done, check where the mark is. If it is outside, subtract that distance from 100mm (under extrusion). If it is to far in, add that distance to the 100mm (over extrusion). Now calculate the new e-steps. The formula is (100mm*current_e-steps)/distance_measured)

          If your printer allows e-step setup via menu, enter the new value, store settings and repeat the process. You should see the difference as the markings should now be spot on after the 100mm extrusion.

          Please note that 100mm is just a "random" value. You can use 50mm or even 10mm, but the higher the value the more precise is the result.

          If you want to measure and calibrate the X,Y and Z movement do not use a calibration cube. You basically do the same as you did before. Hold the caliper against the frame and move the head until it bumps into the calipers. Now reset the calipers and move 100mm. Note the value and calculate using the formula above. Same for the Y and Z axis. This is a little harder and best done, with an additional pair of hands to control the printer, while you hold the calipers.

          Setup settings and measure again. Repeat if needed. Your printer is now calibrated.

          Now is the time to print a calibration cube and see if the measurements are right or not. BUT if the measurements are wrong use your slicer to fix the sizing problem. Do not touch the e-steps again.

          Calculating the e-steps by using a calibration cube is simply wrong. In that case you calibrate your printer to a specific filament and specific slicer settings, which not only sounds wrong. Your measurement is also even harder, as there are overshooting corners and elephant foots to deal with just to get a messed up set-up.

          It is funny that people build mounts for dials in all variations to check their print surface, but try to find a caliper mount for X,Y and Z measurements. That would be a really nice thing to have.
          Last edited by Geit; 09-14-2020, 03:49 PM. Reason: typos--


          • #6
            Let's not get too excited. Some PLA+ filaments DO print as high as 235C. But, yah, lowering the temperature will help with stringing and 'zits.'


            P.S. -- Also, upgrade to Cura 4.7.1. I'm pretty sure I read that 4.7 was causing zits for some people.


            • #7
              Originally posted by Alan View Post
              Let's not get too excited. Some PLA+ filaments DO print as high as 235C. But, yah, lowering the temperature will help with stringing and 'zits.'
              I have normal PLA, too that is rated for 190-220 and prints at 235°C quite well.

              I guess at some point it is cheaper to just sell filament under different names with different temperature ranges and special features than creating different materials.
              Last edited by Geit; 09-14-2020, 07:22 PM.


              • #8
                Originally posted by Geit View Post

                I have normal PLA, too that is rated for 190-220 and prints at 235°C quite well.
                I suspect some filament formulas are just more temperature tolerant than others but, given the results the OP is getting, dropping the temp is the 1st thing I would do.