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anon4321

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Posts posted by anon4321

  1. There are some ingenious solutions for the probe.

    I was thinking of simply having the probe magnetically attached or manually clipped to the head only during measurement. Then the probe can't impact the head weight during printing very much.

    Someone came up with a way that through a series of moves of the build plate to the extreme Z causes the probe to lower and then a second series of x/y movements cause the probe to raise. Each position is maintained with magnets and springs.

    I mean c'mon.... someone had their head in the game with this solution:

     

    http://www.thingiverse.com/thing:89146

    Although, if it were me, I would just have the lever on the build plate controlled by a servo so you don't need to have the extreme Z movements and there wouldn't be the risk of the mechanism causing issues at the extreme Z if you are printing something near the volume limit.

    But still, that is some amazing out-of-the-box thinking and with the exception of a few pieces like the magnets and switch and springs, a 3D printable solution.

     

  2. Python code to generate circle gcode for UM1.

    NOTE: someone needs to check my calculations especially around the extrusion amount.

     


    #!/usr/bin/python
    filament_diameter = 2.89
    build_area_width = 205.0
    build_area_depth = 205.0
    rings = 10
    wide = 0.4
    thick = 0.2925 / 2
    temperature = 230
    bed_temperature = 60
    base_dia = 180
    pi=3.1415927
    center_x = build_area_width/2.0
    center_y = build_area_depth/2.0
    filament_area = (filament_diameter / 2) ** 2 * pi
    head = '''
    M107 ;start with the fan off
    G21 ;metric values
    G90 ;absolute positioning
    M82 ;set extruder to absolute mode
    M107 ;start with the fan off
    G28 X0 Y0 ;move X/Y to min endstops
    G28 Z0 ;move Z to min endstops
    G1 Z15.0 F9000 ;move the platform down 15mm
    M140 S{bed_temperature:.2f} ;set bed temp (no wait)
    M109 T0 S{temperature:.2f} ;set extruder temp (wait)
    M190 S{bed_temperature:.2f} ;set bed temp (wait)
    G92 E0 ;zero the extruded length
    G1 F200 E3 ;extrude 3mm of feed stock
    G92 E0 ;zero the extruded length again
    G1 F9000 ;set speed to 9000
    ;Put printing message on LCD screen
    M117 Printing...
    ;Layer count: 1
    ;LAYER:0
    '''
    loop = '''
    G0 F9000 X{x:.2f} Y{y:.2f} Z{z:.2f}
    G2 F1000 X{x:.2f} Y{y:.2f} I{r:.2f} E{total_mm3:.2f}'''
    tail = '''
    ;End GCode
    M104 S0 ;extruder heater off
    M140 S0 ;heated bed heater off (if you have it)
    G91 ;relative positioning
    G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure
    G1 Z+0.5 E-5 X-20 Y-20 F9000 ;move Z up a bit and retract filament even more
    G28 X0 Y0 ;move X/Y to min endstops, so the head is out of the way
    M84 ;steppers off
    G90 ;absolute positioning'''
    total_mm3 = 0
    body = ''
    cross_section = thick * wide
    z = thick
    for i in range(rings):
    dia = base_dia - ((wide * 2) * i)
    circumference = pi * dia
    r = dia/2.0;
    x = center_x - r
    y = center_y
    mm3 = (circumference * cross_section) / filament_area
    total_mm3 += mm3
    body += loop.format(**vars())
    print head.format(**vars())
    print body
    print tail.format(**vars())

     

  3. I've been thinking about this on and off.

    One problem with the electrical probing or even mechanical probing with the tip is anything stuck on the tip will lead to inaccurate measurement.

    Ideally, you would level the bed just before print with everything at temperature

    The problem for me is that the nozzle seems to weep plastic even if it is retracted. So it will almost always be difficult to use the nozzle in the measurement.

    BTW, Antiklesys , marlin has "mathematical" leveling if you can give it the distances to the nozzle at various points. It uses the measurements to adjust the platform through the Z axis to check the platform and nozzle in "virtual" level. It obviously needs good Z accuracy.

    Here is an extreme demo:

     

  4. BUT I AM EMOTIONAL !!!! j/k no problem. I was largely wrong anyway as others pointed out that the remaining instructions correctly cause a 0 distance to be used.

    I stole the gcode from the leveling wizard and print the big square. Then measure it with calibers and adjust so that it is like .25mm (for first layer squish for bed adherence and a tiny amount of shrinkage) and adjust a necessary.

    Then I know when the gcode calls for .3mm first layer, it is very near .3mm regardless of the actual tip to bed plus all the thermal expansion and whatnot.

     

  5. The nearest measurement is 2cm and the resolution is 0.3cm.

    The real question is the repeatability. You could overcome the above by mounting the sensor at say 2cm and then do something like when the measurement goes from 2.1 to 2.4 assume it is at 2.4cm and use that value,

    The problem is will it repeatedly and reliably go from 2.1 to 2.4 at the same distance? There is always slop in repeated measurements. If the slop is +-0.005 cm, it would work. If the slop is 0.1 cm (1mm), probably won't work.

    resolution and repeatability are usually related with repeatability being defined in the minimum resolution or half of it If that is the case for this sensor, 0.3cm or +-3 mm or even +-1.5mm isn't going to be good enough when your first layer is on the order of 0.3mm

    So it is a good idea but I doubt that sensor has the resolution and repeatability required.

     

  6. Hmmmm, I have seen some behavior similar to this.

    If I turn off the power, like in an attempt to abort a print but don't disconnect the USB then reestablish the 19V power, I get the MINTEMP error. Nothing seems to clear it except removing ALL power including the USB power. Even unplugging the USB with the 19V on won't reset it so it appears locked into this state. I believe that without the 19V power, the 5V power "sags" and puts either the Arduino or the TC amp into a weird state.

    I think the MINTEMP error really causes a fit in the firmware. I've seen really weird behavior if the machine is started in the MINTEMP state. Like the controller display filling with blocks (try disconnecting the TC from the amp and turning on the machine).

    So given all this, is it possible that you are intermittently losing 19V power? Could the jack be "iffy" becoming temporarily disconnected due to vibration? How about the power brick? Is the line side solidly connected?

    If it isn't that, you might get the same behavior if the 12V regulator is going bad.

     

  7. Save Tool Path is the same as save gcode and requires that the model be sliced before it is enabled.

    I believe slicing requires a lot of floating point calculations and that is something the Celerons are not particularly good at..

     

  8. Unlike other motors, steppers use current for holding torque when not moving so will also generate heat when not moving. You should be able to test this. Without filament in the second extruder, try turning the gear during a print then with the power off. During the print, you will probably feel a lot resistance because even though it isn't in use, the driver is enabled and the stepper is powered.

    Steppers can take a lot of heat so you might want to just leave it alone.

    If it really bothers you, you can dial back the current.

    NOTE: Others including myself have damaged drivers while adjusting them !!!!!!!!!!

    DO THIS AT YOUR OWN RISK.

    See http://wiki.ultimaker.com/Electronics_build_guide

    You don't need to use a multimeter, Just use the information above to determine how to reduce the current and then

    just reduce in small increments WHEN THE POWER IS OFF.

    Be careful and note that the drivers get HOT. Make sure you replace the fan/electronics cover after adjusting.

    I would unload all filament and try to match the force required to get the second motor to skip against the first and then adjust a little HIGHER so you don't skip steps on the second extruder causing bad prints.

    GOOD LUCK! HEED THE WARNINGS!

     

  9. Awesome stuff Joerg. Meshmixer support definitely seems like the key to cleanly printing this.

    Thank you for the extra pics.

    Don't worry about sharing the stl. This is more of a "try it yourself, learn by doing" type contest so I'll give meshmixer another shot.

     

  10. Cool. that is what this idea is all about! I like seeing people try different ways, tools and materials.

    Please clean off the supports and take a picture if you have time.. I'd like to see the underside. How much and in what direction did you rotate it?

    I tried to install meshmixer but unfortunately it doesn't like running as a non-admin user under windows.

    How do you like the XT? I was thinking about using it to print a new head and sliding blocks and was wondering if it would standard up to a heated chamber.

     

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