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jeremy

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  1. Daid - Have you guys closely examined this? If you are referring to US patent 6,722,872 it only patents methods of getting the extrusion head and xyz gantry out of the heated envelope so that higher temp materials such as Ultem and PC can be used (at chamber temperatures well over 100C). Lower temperatures (~80C) do not infringe on this patent AFAIK. Most Stratasys machines - the ones that only print ABS - are not covered under this patent. Again - this is this only my understanding of it.
  2. I'm glad someone has done some work on this! I've noticed a lot of underextrusion as well - moreso with some material than others. Some material obviously has higher viscosity at a given temperature than other material. Also, though, it seems that the hobbed bolt can apply more force to some filament - I'd guess that this is a function of the material hardness. It would be interesting to see what could be done with a more elaborate filament drive mechanism... say with 2 or more larger diameter wheels simultaneously pushing the filament. Do you mind saying where you got the material from and what grade/name it was sold as? -Jeremy
  3. For what it's worth, I've extruded the taulman3d nylon at 255 degrees and it works great. Layer-to-layer bonding strength at that temperature is far beyond any other material I've printed with - so unless you need to print a particular grade of high-temp nylon, or some other material like PEEK, I don't see why anything higher than 300 is necessary. I've also tested some polycarbonate from ProtoParadigm using an all-metal actively cooled hot end I made and found that it flows well at 265~270. The problems I had with it were more with the temperature of the build environment than the extruder. I had my platform set at 130C to get it to stick, but anything built more than ~1cm above the bed was crap (layers separated before the print was even finished). So what I concluded was that if I want to be serious about printing PC, I need an enclosed, heated build environment... not just a high temp extruder. Could be wrong though...
  4. Regarding ventilation: I was thinking of closing off my ultimaker to get a heated chamber as well. However, I think the ideal setup would be to have some sort of fan that recirculates the hot air inside the enclosed chamber. When the build is finished, you'd flip a valve or something to vent all the air outside (I was thinking of using my dryer vent). This would prevent wasted wasted energy from constantly heating air and blowing it outside, and at the same time the airflow would prevent heat from building up in the stepper motors.
  5. Yes - from a quick search it looks like that would start happening around 300 C. Anything else? PEEK is listed as having a melting temp of 343 C but I assume bad things would start happening well before that. Would there be any issues with the temperature controller or thermocouple handling higher temps? I'm wondering if a ceramic piece could be made to replace the PEEK component as well as insulate the brass barrel from the bowden tube. Just wondering if anybody can think of reasons why this wouldn't work before I go any further...
  6. For a stock Ultimaker, setting the hot end temp to anything above 260C will generate a warning message. What exactly is the risk if this temperature is exceeded i.e. which components would need to be replaced to safely extrude, say, PC or nylon 6/6? -Jeremy
  7. I am also interested in getting a wider variety of materials to work on the Ultimaker - but I can't see how such as soft material would be possible without a complete redesign of the extrusion mechanism. The Ultimaker uses a Bowden tube through which it pushes a plastic filament. If the filament compresses, it will expand radially and jam itself in the tube. I don't doubt that you could get something a bit softer than PLA to work, but I can't see 55 shore A as doable. :?
  8. I designed something to mount a dial indicator on my extrusion head a little while ago. It works quite well! I've been meaning to put it on thingiverse but haven't gotten around to it yet. My design uses 2 clips that clamp the 10 mm rod that came with the dial indicator parallel to one of the m3 threaded rods on the extrusion head and use the corners of top and bottom wooden plates to prevent it from rotating. I will post here once I have uploaded it.
  9. I appreciate your taking the time to explain this. I'm sure you saved me at least a few hours of head-scratching. So if I understand correctly, your program does the volumetric calculation that SF40+ would do, and then spits out an old-school calibration based on that for Netfabb...
  10. Thanks for the responses guys. owen - didn't work for me. I actually had better luck when I dropped the temperature. go figure. ddurant - I tried your utility and it recommended an extruder rpm of 1.06 for my settings (20 mm/s). That seemed high to me because it was almost as high as my successful 1.21 rpm @ 75 mm/s setting. However, I tried it and it worked - leaving me very puzzled. Then I re-tried the 1.21 rpm @ 75 mm/s setting and it also worked - however as I watched it, I realized that the extruder motor was actually turning way faster than 1.21 rpm. So this explains why it prints successfully in both cases, but it leaves me wondering what the "rpm" value in Netfabb means if it is not the actual extruder rpm. Is there some hidden multiplier? I looked through the gcode (specifically the last line of each file) and found: "F4500 E3311.1677" in the 75 mm/s / 1.21rpm file and "F1200 E2900.7219" in the 20 mm/s / 1.06rpm file. ...so this makes sense in a way because 4500 / 1200 = 75 / 20 and 3311.1677 / 2900.7219 = 1.21 / 1.06. So it seems to be correcting the rpm for the additional speed... but what is the assumed uncorrected speed? I seem to have some misunderstanding about how Netfabb is calculating things here... maybe I should contact their tech support?
  11. Hi all, I've had my Ultimaker for about a month now and have managed to make some pretty good looking prints with skeinforge at larger layer heights (.2 mm). However, with Netfabb, I can't seem to successfully print at the low extruder speeds that are required for high quality prints. When I try the calibration cylinder on .4 width, 20 mm/s speed and .075 mm layer thickness, all I get is tiny blobs strung together. It looks as if the extruder speed is way too low. When I try the same cylinder at the same settings except for 75 mm/s speed, it prints successfully and is .4 mm thick as it's supposed to be. My extruder rpm for the successful 75 mm/s speed is 1.21 rpm, so it would seem reasonable to set the extruder rpm to 1.21 x 20/75 = .32 for the 20 mm/s speed, right? I've tried that setting and all I get is the mesh of tiny blobs and strings (I can upload a pic if its helpful). Even if I increase it to .6, I get the same result. At first I thought the nozzle might be jamming, but if I stop the print, I can push the filament through by hand fairly easily. Any thoughts? My firmware is Marlin build 2 if that is relevant. -Jeremy
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