Jump to content

Weird structure in outer shell...


Recommended Posts

Posted · Weird structure in outer shell...

Hey guys,

Today I noticed a weird finish of my outer shell. As you can see in the picture, there are some layers that seem to be shifted... The axles are calibrated just fine. I think that this is caused by the Bang Bang bed heating technique, due to that the temperature always is 1 or to 2 degrees too high, before it cools down and so on... I will change that to PID later... Do you have any other ideas what could cause that?

51D5181C-30EC-471F-8A0C-5C9E865995D7.jpeg

  • Link to post
    Share on other sites

    Posted · Weird structure in outer shell...

    It could be a Z-screw issue too, but then it should always be at the same height in all prints.

     

    One of my UM2 has this too a little bit, the other has not. Both have a different board: the affected one has a newer board with controlled nozzle fan (switches off below 40°C), the unaffected one has an older board with nozzle fan always on. But there doesn't seem to be any Z-issue.

     

    So I have been thinking in the direction of the bed heater too, although from a different viewpoint: if the heated bed (or the nozzle heater) draws a lot of current through the board, this might shift the ground level a few millivolts. And this ground-shift might influence the temperature measurements, which are probably in millivolt too. So the temperature regulator would adjust the temperature incorrectly because of this ground-shift, although it would still display the correct temperature value.

     

    This is a very wild guess as I don't know the board layout, but it does not seem impossible? Are the ground-lines of measurement circuits (temp sensors) totally separated from the grounds of power-circuits (heaters and steppers)? Or do they use the same printed circuit traces? And are these circuit traces really thick for lowest resistance (e.g. 5...10mm), or are they rather thin?

     

    If this would be the cause - if - then soldering thick wires parallel to the ground circuits involved might reduce the ground resistance and thus this effect. However, that could lead to the wires acting like an antenna and picking up or radiating HF-noise. Like a simple transistor-amplifier with long open input wire sometimes acts like a radio, playing all stations together (had that long ago when trying amplifier circuits on a breadboard for the first time).

     

    If this would be the cause - always *if* because I don't know - then another option would be to never heat or move steppers and measure temp at the same time: switch off all heaters and steppers, let transient currents settle down, measure temperature, and then resume heaters and steppers.

     

  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
    • Our picks

      • S-Line Firmware 8.3.0 was released Nov. 20th on the "Latest" firmware branch.
        (Sorry, was out of office when this released)

        This update is for...
        All UltiMaker S series  
        New features
         
        Temperature status. During print preparation, the temperatures of the print cores and build plate will be shown on the display. This gives a better indication of the progress and remaining wait time. Save log files in paused state. It is now possible to save the printer's log files to USB if the currently active print job is paused. Previously, the Dump logs to USB option was only enabled if the printer was in idle state. Confirm print removal via Digital Factory. If the printer is connected to the Digital Factory, it is now possible to confirm the removal of a previous print job via the Digital Factory interface. This is useful in situations where the build plate is clear, but the operator forgot to select Confirm removal on the printer’s display. Visit this page for more information about this feature.
          • Like
        • 0 replies
      • Ultimaker Cura 5.6 stable released
        Cura now supports Method series printers!
         
        A year after the merger of Ultimaker and MakerBotQQ, we have unlocked the ability for users of our Method series printers to slice files using UltiMaker Cura. As of this release, users can find profiles for our Method and Method XL printers, as well as material profiles for ABS-R, ABS-CF, and RapidRinse. Meaning it’s now possible to use either Cura or the existing cloud-slicing software CloudPrint when printing with these printers or materials
        • 48 replies
    ×
    ×
    • Create New...