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Dim3nsioneer

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Posts posted by Dim3nsioneer

  1. After having upgraded my Ultimaker with the Dual Extrusion Kit, I ran into my very first clog today after having run the Ultimaker for quite some time in a single extruder setup without any clogs.

    As gr5 pointed out in a previous post (http://umforum.ultimaker.com/index.php?/topic/3022-ultimaker-suddenly-stopped-working/?hl=clog&do=findComment&comment=22238), it can happen if the PLA stays inside the heated hotend for too long.

    With the dual extrusion this situation becomes more likely. For larger prints at small velocities, an idle time of up to 10 minutes becomes possible.

    Has anyone made a similar experience? What strategy for the retract length might be good?

    The second topic to be addressed is the underextrusion happening after a long idle time as the remaining filament in the hotend is slowly oozing out of the nozzle and missing at reactivation of the extruder.

     

  2. Hi there

    Today I wanted to switch from 50mm/s speed to 100mm/s, something I've done before w/o any problems. I was then very surprised finding my Ultimaker rush at nearly light speed on the first layer as the bottom layer speed was set to 20mm/s. After having tested around with old Cura settings, I found this configuration to work properly:

    Basic settings:

    20130926_Cura_Settings_Basic1.jpg

    Advanced settings:

    20130926_Cura_Settings_Advanced1.jpg

    Expert settings:

    20130926_Cura_Settings_Expert1.jpg

    There are no plugins activated, but present in the plugin folder.

    Then I tried to change the Minimal layer time in the Advanced settings from 5s to 7s. The result was, that the speed for the first layer G1 commands increased from 1200 (equal to 20mm/s) to insane 5940... Changing back to 5s and it became sane again.

    The same effect I got when changing the number of skirt lines from 3 to 1: the F-argument of the first layer G1 command increased to 5900.

    There is no such effect when the standard speed is set to 50mm/s.

    I already de-installed Cura and re-installed it: no change...

    Has someone ever experienced a similar effect? Any idea how I could cure Cura?

    thxs

     

  3. I agree on Blender's (non-)precision...

    And Cura is doing a fine job usually (no offense...), but I'm just thinking of those people who now buy the Ultimaker2 as they are told it's plug-n-play. I think the software is a major piece in this 'one-button-3D-printer' puzzle. And it has to be almost fail-save for those people...independet of the model's quality as non-experts will certainly deal with non-perfect models.

    It may be a very simpel idea, but what about giving the user a choice? Cura could for instance slice the STL three times, once the 'normal' way, once with an offset of +something and the third time with an offset of -something. Then the three results could be compared. Identical layers are then identified as 'stable'. For the 'unstable' layers, Cura could ask the user which version he wants. As any file-sync-software is doing it when both file locations have been changed... maybe there are even some criteria to decide which of the three versions is the best and Cura could do the job itself...

     

  4. Sometimes Cura 13.06.4 makes strange things when dealing with a horizontal surface created in Blender:

    Cura_Slicing_horizontal_nok.jpg

    The layer height was set to 0.1mm.

    To me it looks as if Cura interprets a z-position of e.g. 3.00001mm or similar as >3mm and adds a new layer. Depending on the program used to design a 3D model such artefacts may appear due to the numerical precision.

    To check this hypotesis, I moved the lowest z positions up by 0.05mm in Blender. This is what I got:

    Cura_Slicing_horizontal_ok.jpg

    Yes, this is what it should look like...

    To the Cura designers: Is there a possibility to make Cura a bit less sensitive to such minor precision fluctuations? At least when not sclicing with a layer thickness of 20um....

     

  5. [...] So I guess it is related to the tension of the short belts. I will follow AnthonyT's suggestion and file the screw holes for the motor a bit so I can push it further down to increase tension.

     

    You're right, I mixed it up with another issue... sorry! I was lucky the tension was just enough when I moved the x-motor as far as I could along the holes. Did you use threadlocker for the motor screws?

     

    [...]

    An adjustable mounting bracket helps a lot with fine-tuning the tension... http://www.thingiverse.com/thing:34785

     

    That looks very promising...! Thanks!

     

  6. Sounds familiar to me. It may come from the unevenness of the bed. Are you working with the standard Ultimaker bed?

    Ideally the cross-section of any line drawn would be a rectangle with the layer height and about the nozzle size (or a bit more) as width. If there is a valley in the bed, the cross section of the line becomes more like a half circle or similar. Consequently it becomes narrower and could detach from other lines. However, the effect should disappear after a few layers as the height difference between last layer and the nozzle balances out...

    So maybe a re-check of the bed leveling might help you?

     

  7. M221 sets the flow rate I beleive so this would be trivial. There already is a plugin that lets you insert gcodes at a particular layer - just add the M221 command. Although most of the plugins broke when cura changed the move commands to G1 and G0 instead of ... just G1 maybe? Or you can insert the M221 command by hand with a text editor:

    M221 S90 ;set flow to 90%

    http://reprap.org/wiki/G-code#M221:_set_extrude_factor_override_percentage

    Regarding antenna - it's not clear to me that flow rate needs to be changed here. If your antennae's look "melted" or overextruded it's actually common - it's caused because it's printing them too fast and not letting the layer below cool. In Cura make sure:

    advanced/cool/minimal layer time: 7 (at least 5 seconds here)

    expert/cool/minimum speed: 0 (this is probably your problem - this defaults to a bad value and should be zero)

     

    Thanks!

     

  8. Hi there

    Has anybody thought of or even tried to write a Cura plugin which changes the flow rate at a certain z?

    Changing (reducing) flow rate seems to be a good thing when printing small details like the tops of the Ultimaker robot. However, the same flow rate might lead to holes in larger parts of the same body...

     

  9. There are scientific publications saying that below 100nm it doesn't really matter what materials the particles are made of (that's why you should e.g. not use ordinary tap water with ultrasonic humidifiers, at least in regions with large lime content...). They are physically dangerous, not chemically... as a physicist, I think one has to keep an eye on it...

    Laser printer made significant prograss within the last few years. In many (European) countries restrictions on particle densities are tough...

    And I agree with the cigarette... ;-)

     

  10. I just switched from the Ultimaker silver metallic filament to a different PLA filament. I found the quality of the prints significantly better with the new filament. Especially the thickness of the printed lines seems to have less variation.

    As the orignial filament is named 'metallic' I think there are metallic particles included in the PLA. This means it is an emulsion which shows a different flow behavior than the pure stuff.

    The quality of silver metallic prints is therefore not an issue of poor filament quality but caused by the mixture of the material.

     

  11. Thanks a lot for your help. I checked they pulleys; they show a very slight wobble which seems to origin from the natural play they have on the axis. But when checking I found the x-motor not fixed very vell to the back plane and the front x-belt being not as tight as the back belt and as it should be. After having fixed these two issues, I get quite accurate prints (9.8mm when 10mm in the model, 100.0mm when 100mm in the model, 30.5mm when 30.6mm in the model, etc...) even when printing with 150mm/s!

     

  12. I read the publication too, two days ago...

    Nanoparticles are a serious issue. The size the particles from 3D printers have is sufficiently small to allow the particles not only to penetrate the lung but also to transfer into the blood (<100nm). And they seem not to origin from condensation as then they would be approx. 10-15nm in size.

    I think the proper way to deal with that issue in closed rooms is to enclose the printer and install a controlled ventilation to that enclosure with a HEPA filter. I think closed 3D desktop printers will become standard within a few years (especially the commercial ones).

     

  13. Hi there

    In order to test the x-y-accuracy of my new Ultimaker (no modifications so far) I printed a cube with 1cm length at 0.1mm z-resolution (using Cura) in PLA. The results I got were x=9.4mm, y=9.9mm and z=10.2mm. I'm fine with the y-scale, also with the z-scale as I printed a 0.3mm first layer. However, the x-scale seems to be out of range.

    I then checked the distances for certain head movements. When driving 150mm in x-direction I got 151.5mm; the same for the y-direction. I adjusted the x- and y-step values and saved them in the EPROM. Checking the driving showed it was ok then. But the cube-print stayed the same, I still got 9.4mm instead of 10mm.

    When checking the Ultimaker forum I found a post about shrinking, arguing the shrink in x-direction might be significantly higher due to the fan blowing in that direction. I tested this theory by setting the fan to 25% PWM; it didn't change anything.

    I would like to ask the experts among you I they had any idea what might be wrong.

    I'm aware I could change the x-scale in Cura for compensation but I'm not looking for a work-around but for a serious solution.

    I'm looking forward to your inputs...

    Stefan

     

  14. Hi together

    On Monday evening I got my Ultimaker kit, just one week after ordering! Just one minute after starting, I ran into the first problem (original holes in the back plane too big for the bearings). Well, that's DIY. I could have ordered the Ultimaker preassembled, but then I would have missed all the fun... :wink:

    I'm curious what my learning curve will be... :smile:

    see you

    Stefan

     

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