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Everything posted by kris

  1. I am afraid I did not take any pictures of the process, so I will try to explain in words. First I removed the four long bolts at the top that hold the extrude together. That can be done without tools. Then you remove the side fans and the little screws that hold together the bottom aluminium part to which the nozzle is attached. Then you need to heat up the nozzle to >200°C. With the hexagon key you can now unscrew the ring that holds the nozzle in place (the one with the holes in the side). You can also do that with a hexagon key. Be careful not to touch the hot parts. I used a pair of flat nose pliers to hold the brass part. The nozzle can now gently be pulled free from the aluminium frame. Regards, Kris
  2. Hi everyone, I would quickly like to share with you how I managed to get rid of underextrusion on my UM2. This first happened to me in the middle of a print. I then tried standard prints that used to work fine, so I could rule out Cura as a possible failure source. Then I tried every method I could find on the forum; the 'atomic' cleaning, readjusting the material flow, taking apart the extruder wheel. It seemed as if material was supplied to the nozzle just fine, but in retrospect the material that left the nozzle looked very rough. Nothing would help. I finally took the entire extruder apart and soaked relevant parts in acetone for a few minutes, cleaned everything with a q-tip, soaked, cleaning etc. After 20min or so the parts were completely clean again. Now the prints look exactly the way they did when I first received the machine. Sounds easy, but I would not have though that the performance of the extruder would deteriorate over time to the point where it needed to be cleaned. This is probably the regular maintenance the machine requires in order to function properly. Another theory is of course the contaminated filament. This happened while using white ABS from UM. A few days prior to the incident I found a huge piece of something very hard in the filament. If you miss something like that, it ends up in the nozzle. Anyway, next time I experience underextrusion, I will again give the extruder a good acetone bath :-P . Regards, Kris
  3. Hi all, @ Wallan: Maybe with your approach you basically achieve the same effect: You control the temperature to get an even temp distribution by simply turning off the heated bed. I did read about the ABS 'slurry' but was hoping to find a way to set may process parameters to get the print under control. @Jonny: I hope I understand stringing correctly, but I think I had that from the start. But by reducing the material flow (tried 91%-86%) I managed to completely get rid of that. Attaching an image, hope it is visible. The image shows the printed surface.
  4. Hi everyone, I have been struggling with warping over large and thin ABS structures for some time. I did try out many possible countermeasures that I found on the internet or that I came up with by myself. But nothing really worked. Although I managed to reduce the effect somewhat, I started to loose hope that the problem can be totally overcome. But yesterday I managed to make a first print that is totally warp- free. Here are my findings: The main problem of warping is the non uniform cooling of a part that will result in internal stresses and thus deformation. I am using the UM2 with a heated bed. I found that warping will reduce with increased bed temperature, but 100°C is a maximum for the bed. A brim will help to stick the component to the bed, but will not do anything against the cause of warping. At some point even a brim will fail and stress concentrations at corners will make them peel of. With increasing height of the component temperature will decrease and stresses will arise. So I covered the top of my UM2 will a simple cardboard box with a cut out for the filament hose. I also covered the front with cardboard. Increased the temperature of the bed to 100°C and turned of the two cooling fans in Cura. I also used Cura 14.03 TEST2. That didn't help initially, I just found that the gcode size reduced by 50% in size compared to 14.03. I was a bit worried that the temperature could be too much for the internals of UM2, but the bottom section keeps pretty cool. After the print I am letting it cool down for a while. For the adhesion to the glass plate I am using the glue stick supplied with UM2. I think key is the uniform temperature (low gradient) inside the build volume. The structure I printed is a 0.8mm thick shell and minimum 40mm high and about 200x30mm at the base. I used the black ABS from Ultimaker. Anyway, the result: No warping at all. I am now planning on building a plexiglas door and roof to better control the internal temperature. I think I will also install a few temperature sensors for monitoring. I addition I reduced material flow to 86%, there was a little overextrusion. Now with 0.1mm layer height I can hardly make out the layers. Regards, Kris
  5. Here are the results. I noticed that sometimes the extruder stays so low for the first layer, that it is unable to extrude any material. The filament transporter starts to grind the filament then. This happens even without me changing the z-level.
  6. Yes I have used the glue. But I will have a go with the advanced settings tomorrow. Thanks for the tips. I'll post the results.
  7. Hi, I have been printing with PLA using the Cura settings 'normal quality print'. Without any problems. Now I tried the settings 'high quality print' and experience underextrusion. I did not change any other settings. The filament is from Ultimaker. What did I do wrong? The first couple of centimetres turn out good, then it get's totally messy. I also readjusted the platform 3 times, without effect. Also cleaned the nozzle; raised the temperature and extruded a couple of centimetres. Didn't help. Glad if you could help. Regards, Kris
  8. Many thanks for the quick reply. You saved my day! The file apparently got corrupted when saving. Used another SD- card reader and voila...it works. Again, thanks alot! Kris
  9. Hi, I tried doing my first print today. So I loaded a model into Cura and wrote the Gcode with standard settings. But when loading the file into the Ultimaker 2 it says: 'This file will override machine setting with setting from the slices'. If I confirm, nothing else happens. It dosnt' warm up or print. Gcode in the beginning looks like this: ;FLAVOR:UltiGCode ;TIME:9758 ;MATERIAL:13280 ;MATERIAL2:0 ;Layer count: 79 ;LAYER:0 M107 G0 F9000 X61.51 Y75.91 Z0.30 G0 X61.51 Y75.91 ;TYPE:SKIRT G11 G1 F1200 X62.06 Y78.89 E0.36405 G1 X62.06 Y78.89 E0.36417 G1 X62.16 Y79.44 E0.43129 G1 X62.50 Y80.06 E0.51583 G1 X62.57 Y80.20 E0.53553 G1 X62.97 Y80.93 E0.63462 What did I do wrong? Regards, Kris
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