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rimb05

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Posts posted by rimb05

  1. It is great to have the extruder start and end Gcode, but would it also be possible to have a layer change gcode ? This would enable to handle a robust purge tower process !

    Thanks in advance !

     

    I second this request. Please add layer change gcode customization.

  2.  

    I did some testing today and found that grounding ROSC actually made things a bit worse.  Possibly the back EMF is too strong in this mode, causing other issues...

     

    You were testing with UM2? What does worse mean, what happened?

     

    I tested on my UM3. Grounding all the ROSC pins made some wavy lines appear when printing a circular ring. On the other hand, when I did this hack on my UM2 last year, it really improved Z-banding.

    • Like 1
  3. I tested it with my UM3 and it works, but there's an issue when doing the active leveling, as the nozzles would dig into the bed and melt the BuildTak. But I found a solution:

    Flip the build plate around when doing the active leveling. Then, after it's done, flip it again. The thickness is the same either way, so it works great.

    • Like 2
  4. The decay fix is a fix for an electronics problem. The electrical motor drivers that we are using can be put into different modes of operation. The intention was to have it in a certain mode, which was done by putting a certain pin at 0V. However, this was done with a pull-down which is not strong enough. It causes an inaccuracy every 16 steps.

    This can be fixed with a simple solder bridge over this resistor.

     

    Daid, I think those unpopulated resistors were tied to VCC, not GND, which puts it into an "automatic" mode.

  5. I did some testing today and found that grounding ROSC actually made things a bit worse.  Possibly the back EMF is too strong in this mode, causing other issues...

    But... in my opinion, there's actually no need to change anything.  The UM3 has virtually no Z banding compared to the UM2.  I'm guessing this is because the Z axis now has 1/16 microstepping enabled, making the missed steps less troublesome?  I wonder if the stepper was also changed to a 400 step version...

    I'm very impressed by the quality I'm seeing out of this machine.  Z banding and the ubiquitous "stair stepping" ripple on circular objects is virtually gone.  dare I say it's finally surpassed the Zortrax in this regard ;)

  6. We did test with the decay fix, It seems like a straight forward fix but it does impact everything, things like the active leveling for instance.

     

    Do you mean the extra EMI generated is picked up by the capacitive sensor, or something else?  Mixed decay on the UM2 made such an improvement for Z banding, it would be great to be able to apply the hack on the UM3 as well.

  7. I use BuildTak on my UM2+ and love it.  Is it possible to use BuildTak on the UM3?  I wonder if it would interfere with the new capacitive leveling function.  It would seem like adding an extra couple of mm wouldn't make a difference with a capacitive sensor, but I wonder if Ultimaker can answer this officially.

  8. Daid,

    Have you guys looked into using Vespel as a material for the insulator, instead of PTFE? It's what Stratasys uses as an inlet for their FDM heads. It's got excellent insulating properties.

    Also, some of the issues you're having might be mitigated by software. What if you automatically cooled one head down before printing with the other one? It wouldn't need to cool down completely, just be at a "standby" temperature, until it needs to be used. This would slow things down when doing dual extrusion prints, but for certain use cases, it would be just fine (for example, printing support).

    Since no manufacturer has perfect dual-extrusion working, even this kind of interim solution would be much better than nothing I think.

    Rim

     

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