Empty

Total: 0,00 €

h:D

Planet openmoko

  • Sunday, April 20, 2014 - 18:14
    Talpadk: Measuring printbed tempeartures on a RepRapPro Huxley

    I have finally gotten around to measuring the surface temperature of my Huxley.

    Temperature as function of set-point

    Temperature as function of set-point

    Method and instruments used

    For measuring the temperature a Agilent U1233A with a U11186A (k type thermocouple) has used.

    The ambient temperature has measured by waiting for the display to settle and the taking a readout.

    The heat bed temperatures has measured on top of the aluminium print surface with the polyarmide tape left in place.
    The thermocouple was held in place by another piece of polyarmide tape.

    The thermocouple was left on the print bed for 1 minute for the temperature to stabilize, the temperature was then measured on  the multimeter using the “avg” function after a 2 minute sampling period.

    Measurements

    The temperatures were measured at the centre and approximately 1cm from the edge.
    The center temperature was measured an additional time at the end of the measurement cycle.
    The print bed was in its forward position with the print head to the left at the end stop (cooling fan running)

    The ambient temperature was measured as 22.1C at start of the surface scan, and 24.4C at the end.
    The heat bed has maintained at 85C using the 3d printer firmware.

    NA 71.2C 75.8C
    77.6C 71.1C
    76.1C
    75.2C
     75.6C  77.1C  72.8C

    After this the thermocouple was reapplied using a fresh piece of polyarmide tape at the centre of the print bed and left there.
    The print bed set point was then reduced and the surface temperature measured.

    Set point [C] Measured [C] Percentage
    85 76.2 90
    70 63.1 90
    55 50.2 91
    40 37.8 95

    Notes

    Some of the variances in the measurements across the bed might be related probe mounting relative to the surface and cooling to ambient.
    Using a piece of foam or another insulator might improve this.
    The lower measurement points may simply be caused by a bad thermal contact to the print bed.
    Heat sink compound could perhaps have alliviated some of this as well (and made a lot of mess).

    Also even though the measurements was taken as a 2 minute average, the temperature swings of the heat bed regulation may have contributed with some noise.

    Also a thermal camera would have made this much easier and quicker, too bad they are so expensive.
    (And that Fluke VT02/VT04 visual thermometers has such a bad resolution)

    Conclusion

    I would consider the bed temperature constant across the print bed within the uncertainty of my measurements.

    At “higher” temperatures the surface temperature seems to be roughly 90% of the set point.

  • Sunday, March 23, 2014 - 19:01
    Talpadk: A fast and beautiful terminal

    xrvt-unicode/uxrvt has long been my favourite terminal, it is fast and it supports faked transparency.

    rxvt terminal with transparencyOne problem with using a darkened background was however that some terminal colour simply were bit too dark.

    After a quick googling and short man page reading it was however clear that this can actually easily be resolved.
    Additionally I can store some extra settings making my keyboard short cur for launching the terminal nice and simple.

    Requirements:

    sudo apt-get install xrvt-unicode 
    sudo apt-get install tango-icon-theme

    The last line is only for getting the terminal icon, and is optional if you comment out the iconFile resource

    Configuring rxvt-unicode

    In the file ~/.Xdefaults add the following lines:

    !===== rxvt-unicode resource definitions =====!
    !The number of scrollback lines
    URxvt*saveLine: 5000
    
    !Add fading for unfocused windows
    URxvt*fading: 33
    
    !Specify the icon for the terminal window, requieres the "tango-icon-theme" package
    URxvt*iconFile: /usr/share/icons/Tango/16x16/apps/terminal.png
    
    !Transparency setting
    URxvt*transparent: true
    URxvt*shading: 25
    URxvt*background: Black
    URxvt*foreground: White
    
    !Colour setup for the darker background
    URxvt*color0:  Black
    URxvt*color1:  #ffa2a2
    URxvt*color2:  #afffa2
    URxvt*color3:  #feffa2
    URxvt*color4:  #a2d0ff
    URxvt*color5:  #a2a2ff
    URxvt*color6:  #a2f5ff
    URxvt*color7:  #ffffff
    URxvt*color8:  #000000
    URxvt*color9:  #ffa2a2
    URxvt*color10: #afffa2
    URxvt*color11: #feffa2
    URxvt*color12: #a2d0ff
    URxvt*color13: #a2a2ff
    URxvt*color14: #a2f5ff
    URxvt*color15: White
    
    !Colour notes from the man page
    !color0       (black)            = Black
    !color1       (red)              = Red3
    !color2       (green)            = Green3
    !color3       (yellow)           = Yellow3
    !color4       (blue)             = Blue3
    !color5       (magenta)          = Magenta3
    !color6       (cyan)             = Cyan3
    !color7       (white)            = AntiqueWhite
    !color8       (bright black)     = Grey25
    !color9       (bright red)       = Red
    !color10      (bright green)     = Green
    !color11      (bright yellow)    = Yellow
    !color12      (bright blue)      = Blue
    !color13      (bright magenta)   = Magenta
    !color14      (bright cyan)      = Cyan
    !color15      (bright white)     = White

    The last comments can of course be left out but is handy if you need to find a particular colour that you want to change.

    Also adjust the shading resource to your liking.

    After saving the file you may start the terminal using urxvt or rxvt-unicode and enjoy it fast and good looks.