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madoverlord

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Posts posted by madoverlord

  1. fns720 -- looks lovely!

    I've been lurking in this thread for a while because I've been hideously busy with a KickStarter project but it is of great interest to me. I'm glad to see this topic is heating up again :cool:

    Perhaps the solution to the issue of uneven cooling in the "lee" of the printhead where it blocks the airflow is a small fan on the printhead that blows directly downwards.

    So the setup would be that the fan is on the left side (the reverse of fns720's setup) and the fan is mounted to the printhead on the right side, blowing directly down, perhaps with a duct.

    My current setup has two fans on the printhead, one in the standard position and one blowing down vertically as described above, and seems to work well. You can see it here: http://www.thingiverse.com/thing:164499

    It is an accessory mount ring for the hot-end that makes it much easier to mount things to it, and it was designed with fans in mind.

     

  2. I'm going to get on the bandwagon and start experimenting with this. With regards to the side panels, probably the easiest construction method is going to be 4mm corrugated plastic sheet (basically plastic cardboard!) plus some small neodymium magnets located at the bolts; they should just pop on and off. I may play with some custom mounts so I can inset the panels.

     

  3. No matter how I adjust the tension spring/bolt in my Ultimaker extruder, the filament is getting ground up, and plastic dust is getting drawn up into the bowden tube, resulting in an eventual jam.

    I've backed off the bolt so that the distance between the blue plastic block and the washer at the other side of the spring is 12.39mm and it's still happening.

    When initially feeding the filament (before it gets to the hot end, so no resistance) I can see very small dimples in the filament caused by the knurled bolt.

    What should I try next?

     

  4. I am running OS X Mavericks.

    Cura 13.12 shows only Print speed under the Speed and Temperature part of Full Settings / Basic. I can't set the temperature. Also, I can't select objects once they are loaded.

    I went back to 13.10; it lets me set temperature but popups like Platform Adhesion type are stuck and don't work.

    I had to go all the way back to 13.06 in order to get a version where the UI worked for me.

    Bizarre! Any suggestions?

     

  5. Nick, I'd suggest that you remove some of the insulation higher up on the hot end, so that some of the cooling air can get in there and mitigate any thermal creep. You might even want to heat-sink that area.

    One of the issues I ran into with the thermal sock was that it was too effective and extended the hot zone, leading to clogs. I had to redesign the sock so that it left the area above the hot-block exposed, and that eliminated the clogs.

     

  6. You should just be able to print a passive duct/hood that modifies the airflow. It's won't have to get close to the hot-block to do the job.

    One trick I've used is to apply foil-tape (basically, aluminum foil with adhesive on one side) to the sides of the ductwork that face the hot-block. The foil reflects a lot of the IR, and conducts heat away from the parts closest to the hot-block (and into cooling airflow in this case). You can get within a few mm of the hot-block without issues.

    Not to mention my hot-end sock reduces heat-flow considerably. It will get up to full hot-block temperature eventually but it is so non-conductive that you can touch your finger to it for a second or two before it becomes uncomfortable.

     

  7. Given that the hot-block doesn't block that much and is in any case moving (and usually diagonally), I doubt this is a significant problem. There might be some marginal improvement to be had by putting a passive duct (perhaps with a small fan) on the hot-end that redirects some of the air from above the plane down behind the hot-block.

     

  8. I'm sorry I was not clear. I was not talking about retracting the hot end, but moving the feeder up, so that the path from it to the melt chamber was increased, and thus the filament was sucked up.

    In other words, one solenoid is a ratchet that does the normal feed, and one solenoid quickly retracts the filament -- not the hot end.

     

  9. Rereading this thread, a fairly insane idea occurred to me: how about a dual-solenoid system -- a solenoid-based feeder that pushes filament into the hot end, and a solenoid that retracts the entire feeder (!) to handle retraction.

    I'm thinking there may be mass issues, and also reaction forces when the retraction solenoid fires. But perhaps this will inspire someone.

     

  10. I tried the cornstarch method and found it reduced the surface quality a bit. I also did a lot of experimenting with injection ports (I actually made a threaded port that fit the silicone tube) but in the end found it wasn't worth the complication.

    I tried cooking the mold at about 110F to speed up the cure and while that does worth, the increased rate of acetic acid release during curing can cause delamination of the mold -- you get plastic flakes adhering to the silicone that are a pain in the ass to remove.

    If you find the part hasn't fully cured when you open the outer mold, just reassemble it and wait. You can fix any surface imperfections later by just adding some new silicone.

     

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