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Anders Olsson

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Everything posted by Anders Olsson

  1. May I ask if the quality issues are mainly related to alignment of the nozzles or to oozing?
  2. Don't worry, I don't mind other people working at this. In fact I could just have given away the step-file by now if it wasn't for the scientific paper we are writing where my heater block is featured. And just as both of us concluded, a heater block for the Ultimaker 2 more or less has to look this way if you are not going to modify other components. The pictures in this thread shows version 1.2 of my heater block by the way. Since then there has been version 1.3, 1.4, a few more poorly documented iterations and then version 2.0 which is being manufactured right now. It was not necessary
  3. I haven´t really thought about that, but it is worth investigating. If you go for stainless steel you more or less end up with something that looks like the E3D-V6 hotend: http://e3d-online.com/E3D-v6-Documentation In my design the bits would have been too tiny and the threads too short, so I abandoned the idea of a two piece heater block at some early stage of the design. In theory this would help, but I have not thought about doing something like that yet. Mainly because it requires custom tools and custom nozzles. My design was based on what I could get made in my local works
  4. I think another property of brass that is important is that it does not corrode easily. Few other materials has that combination of price, thermal conductivity, hardness, easy machining and corrosion resistance (in air). Pure copper for example would corrode heavily if you got finger prints on it and kept it heated to 260 C in atmosphere for an extended period of time. For alternative heater block designs, I have some comments on gixxers design. Don't read this as criticism. I am just using your drawing to explain the design challenges with this part of the printer a bit more in detail: -
  5. I did some further tests on the properties of the heating. My custom heater block, which has about 40% more mass than the original block, gets from 50 to 150 C in 41 seconds. To investigate if thermal conductivity between sensor/heater and heater block affects the heating speed I greased both sensor and heater with copper grease. After heating the nozzle to dry the grease, I repeated the experiment. I get exactly the same heating speed with copper grease applied. However, without copper grease, 10 degrees of temperature increase (18-28 C) takes 10 seconds. With copper grease the first te
  6. Strange, it should not differ that much, I will do some more tests on my machine this evening. I am pretty sure I have never seen 100 C increase in 20 seconds on my machine, not even when it was brand new. My machine probably does like 40-50 degrees in 20 seconds at low temperatures. However, the issue is mostly the delay when the temperature is dropping and you start heating again. If doing that at 200 C, the triggering function starts counting from 200 C. The temperature then drops to 195 C before it starts increasing again. On my machine that means it now has to do 25 degrees in about
  7. I am using a slightly modified version of the 15.01-RC1 firmware now. This time I reduced the triggering criteria from 20 degrees to 8 degrees in 20 seconds. That seems to be fool-proof. I can not trigger the monitoring even if I try my best now. I don´t know if Daid would be open to a similar change in coming firmware, or if there is a very good reason to keep it at 20 degrees? It is clever to use this kind of monitoring function, even if the main reason to have it seems to be to reduce the risk of disasters caused by the non optimal design of the sensor locking screw. If the monitoring
  8. We have two Stratasys printers at work, one uPrint SE and one Dimension Elite. I have compared prints, and even printed the same object, with my Ultimaker 2. The Stratasys machines has the advantage of a heated chamber, which makes large components easier to print. For the Ultimaker, large ABS things are always a bit tricky to print (they want to bend and come off the platform). With some experience you can mostly get it to work, but some designs are almost "unprintable" in ABS without a heated chamber. For the print quality, the Stratasys machines seems as accurate as the Ultimaker in t
  9. Check if the heater block is in contact with the fan cap. That can potentially drain a lot of heat and trigger the monitoring. I have this issue too by the way. Eventually I modified the firmware to only require 10 degrees in 20 seconds and this more or less fixed it. I am of course using my custom heater block, which has slightly larger mass and therefore heats slower, but I still think the monitoring function is a bit too sensitive. As I understood it, it is changes in PID parameters made after 14.09 rather than changes in the monitoring parameters that has increased the sensitivity? I
  10. I was worried about that too, but it has worked fine so far. The thread inside the heater block is very short which means the nozzle can tilt quite a lot before it is tightened. I think this helps it align with the seat inside the heater block. Both sealing surfaces are machined in a proper way too and the sealing surface on the nozzle is not very wide, so I would say the design is not that bad as a metal to metal seal. Here is a picture of how the nozzles look after some use. The right one has been printing about 200 hours I think, using all sorts of strange plastic. Inte
  11. The nozzles are standard nozzles from E3D: http://e3d-online.com/E3D-v6/Extra-Nozzles So I can not take any credit for that design :smile: As you can see they are not that expensive, which was one of the reasons why I selected E3D. That also means one heater block and three nozzles would be more like 80 Euro. (depending on how expensive nozzles you select) The internal shape of the E3D nozzle is, even though it looks complex, a bit primitive in the way that it seems optimized for manufacturing with standard tools. That is why it has that two step shape as I understand it. The flat ar
  12. Your enemy is basically temperature gradients in the printed object. Professional printers solve that problem with a heated chamber. I have like 95% success rate printing ABS on the UM2, but I generally print small things and/or things which are suitably designed for printing in ABS. I just wrote a rather long reply about that in another thread: http://umforum.ultimaker.com/index.php?/topic/8157-percentage-of-prints-completed/?p=81116 If you insist on printing difficult objects, like large thin walled cubes, in ABS, you should try to mimic the heated chamber concept. That means: - Hot bu
  13. I have been printing almost exclusively ABS and my success rate lately is probably 95% The biggest improvement in reliability was the firmware upgrades last summer which fixed leveling bugs and improved the priming cycle. Lately I have been using Roberts feeder, but it worked just as good with the original feeder and ABS. Apart from that the only modification I have done is to add a small pulley below the feeder to get a more straight path for the filament into the feeder. I can not recall that I have had a single clog with ABS (my home made filament with particles in not counted :smile: )
  14. Are there any specification of what kind of polymer MPflex45 is? If it is the same kind of flexible polyester as "flexible FPE 45D" from 3DVerkstan I have the following advice: - The only way i could make it stick was by cleaning the platform properly and heating it as much as possible. Glue made it less likely to stick (!) - You need Robert's feeder (the one Didier linked to) and you need to use the filament guide designed for it. - Printing relatively slow makes feeding issues less likely. Printing thick layers (0.2mm) makes it less likely that the part it is pushed loose from the platfo
  15. I had a reply from a workshop now. If I sell them one by one, I probably have to charge 60 Euro each, one 0.4 mm nozzle included, delivery costs not included. (If I can send many at once, I can reduce the price a bit, so don't hesitate to order several and distribute them in your area) Anyone who wants one, can you please send me a PM so I can estimate if there is a market. (I have to get about 50 pieces manufactured get down to a reasonable price) Please note: I can not guarantee that this thing will work as good as the original nozzle with for example dual extrusion, or that it will be c
  16. Interesting development, a video would be nice! I am also happy to read Daid's post, now I just need to get the remaining parts for the second extruder :smile: My quite extensive tests with full metal hotends really confirms what Daid wrote, PLA and a full metal hotend is not a reliable combination. When it comes to polycarbonate (PC), I have been printing it with my modified UM2 and I also did extensive destructive testing on the prints. PC is not completely trivial to work with. I had to dry the filament in an oven at 130C for a few hours to get reasonable transparency and adhesion. I d
  17. Okay, thank you for your reply, I kind of suspected that. I might have to go for another slicer for objects with this walls then.
  18. Well, if you suggest modifying the original heater block there are space constraints both towards the sensor/heater and in the opposite direction, towards the front of the printer: The red lines are the outlines of the original UM2 nozzle and the blue/greenish lines are the outlines of the E3D-V6 nozzle.
  19. Did you try to power cycle the printer? I had this error numerous times with my custom heater block and the latest firmware before i modified the firmware. The error message appears when you are heating up the nozzle and the temperature increases less than 20 degrees in 20 seconds. As I said I have managed to trigger this monitoring function several times even though it was nothing wrong with my temperature sensor. If it is consistent after power cycling though, there is most likely something wrong with your temperature sensor. Did you check the temperature reading in the "heat nozzle" men
  20. That is exactly how I wanted it to be designed. (Don't ask me why UM did not design it that way from the start) Just drilling and threading the original UM2 heater block was not an option though. There is simply not enough material in the original heater block to fit a standard M6 threaded nozzle in it. If there were M5 threaded nozzles it could just about work, but those seems rare and I wanted a off-shelf drop in replacement nozzle that is available in different diameters. This was the main reason why I had to make a new heater block. While redesigning it, I also tried to address the he
  21. Yes, I made some slight improvements to the design in order to make it easier to remove the sensor and the heater. I have had hundreds of hours of printing with it on my printer, so I am quite confident it will work now. Regarding print quality and oozing properties, the E3D-nozzle might differ slightly from the original nozzle. This is something that I can or will not do anything about though. In my opinion it seems to work as good as the original nozzle, but I have not done extensive comparisons yet. One of my heater blocks has been living at Ultimakers HQ for some time now, but I have ha
  22. This inability of Cura to print single line objects is something which has caused me quite a lot of trouble and I am surprised that I don't read more complaints about this. As far as I understand some other slicers like Makerware can slice single line structures. See this one for example: http://www.thingiverse.com/thing:289650 (Using Cura you will have to print such object twice the size to get the physical properties right :shock: ) Another situation where Curas double walls are really limiting is when printing text on surfaces. You have to go for a rather large bold font to make Cura p
  23. Wow! That looks very interesting! Was it difficult to machine? (Our workshop did not like what they read about machining it as I mentioned before) Did you try printing anything with lots of retraction yet? I am very curious how Duratron handles hot plastic since one of it's recommended uses is for components for injection molding machines. That means it could be the perfect material for the thermal insulator, if the friction with molten PLA is reasonably low. If Duraton seems to work, I would switch focus back to that since Kalrez seems very difficult to get and since Duratron is no more
  24. If heat-related deformation of the PTFE insulator is the main problem with dual extruders I think a short Vespel spacer might work. I though another major heat problem with dual extruders was that PLA will melt further up the PTFE insulator when both extruders are heated, causing retraction issues? Personally, I would really like to get a sheet or a suitable diameter o-ring made from FFKM (Kalrez). I think that material has a combination of properties which makes it even more promising than Vespel, even though Vespel is not bad at all. It seems even more difficult to get FFKM than Vespel t
  25. You can probably get it back in working condition by drilling the inner diameter to 3.2mm. You have to use a drill which is about 3.3-3.5mm, because teflon deforms quite a bit before when you try to machine it.
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