General Build Questions / Build Procedures / Common Pitfalls

Discussion in 'OpenBeam Kossel Reprap and OpenBeam Kossel Pro' started by Terence Tam, Dec 24, 2014.

  1. Frank

    Frank New Member

    I resolved the extruder problem on an radical way: shorten the ptfe-tube and change the extruder place. So I did not longer here thet snap over while printing perimeters with 30mm/s. The second step was to reduce the speed of filling from 60mm/s@210° to 50mm/s@210° for PLA. Now it works better, but not perfekt. I ordered an geared stepper. lets see if that will help.
  2. Def

    Def Member

    I got a similar reading to this. The thermistor (not plugged into anything) at about 70 deg F/21 deg C was 116.8-117 kohms. The heated bed was around 3.3-3.5 ohms with my cheap meter probes that can sometimes add a little bit of resistance(half an ohm or so).
  3. shchua

    shchua Member

    That makes sense. The discrepancy is probably due to mis-reading the multimeter display (k ohms instead of ohms). AFAIK the heated bed uses a 100k NTC thermistor so both our readings are in line with expectations (85k for 29C, 116k for 21C)
  4. shchua

    shchua Member

    @Mike - can you verify that your multimeter is showing k ohm range when it shows the value 116.5 ? AndyG measured his at 116.8k at 21C. This is about right for a 100k NTC thermistor.

    In any case, if MatterControl shows a reasonable heat bed temp of around room temp when the heater is off, then your heat bed thermistor should be fine.
  5. Mike Francies

    Mike Francies Member

    Yes, my mistake - the multimeter was in the 200k range so my reading was in fact 118 kohms. Really should get my eyes tested!

    My next question is about MatterControl - someone on this forum wrote that they had managed to load a version that had the Kossel Pro as a default printer. I downloaded the latest version but it does not include the KP. Is there a list of default settings for the KP anywhere that can be copied?
  6. shchua

    shchua Member

    Check out post #78 from AndyG here:
    These worked very well for me after I changed the temperature to 220C and Z offset to 0.2mm
  7. Corin Lawson

    Corin Lawson New Member

    The Y endstop cable was the definitely most difficult to route, but I managed to take it around the back of the PS and it still has a little slack at the PCB. I did something a little different with the other two endstop cables by threading them through the lower vertices and all the way out of the extrusions. This means that I'm unable to cap off the bottoms (not that that's noticeable). There's also plenty on room for the cables to run underneath, after you put on the little feet. The feet (six sets of a little plastic square and the clear rubber stick-on thingies) were the last step in my build --- I had no idea what they were until the penny dropped :)

    I think the end result is quite tidy, I didn't feel the need to use any zip ties (except on the end effector).
  8. kwmachine

    kwmachine New Member

    Where do the little clear self-adhesive feet go? We're done building except for figuring out where those go.
  9. David Boyd

    David Boyd Active Member

    Please share a picture of how you ran the Y endstop cable!!!
    Right now I have it running over top the PSU and closer to the heated bed than I would like.
    I am making good progress (pictures attached) but I am not sure I have the bed probe built correctly.
    It was extremely tough some times matching pictures to text and when I could not find pictures to match to text.

    Any updates or words on the linear slides being very sticky and not sliding smoothly? Mine are so tight they will stay in place on the vertical rail where ever I put them.

    2015-01-05 07.54.50.jpg 2015-01-05 07.54.39.jpg
  10. Mike Francies

    Mike Francies Member

    The adhesive pads/feet go into the recess, above the screws that secure the six black, plastic feet.
    kwmachine likes this.
  11. Mike Francies

    Mike Francies Member

  12. jpcardier

    jpcardier New Member

  13. Def

    Def Member

    Use the vertex length to space down the endstop as shown in the pic. Use lockwashers on the M3 SHCS. Space the nuts in the openbeam with paper spacers.
  14. protoserge

    protoserge Member

    @Terence Tam wrote somewhere to run it in a similar manner, but run it inside the OpenBeam side between the power supply cardboard and then out. I don't think there is enough slack for this, so I just did the same as you (I also didn't read the routing for the Y before I installed the power supply.
  15. Corin Lawson

    Corin Lawson New Member

    Yes, sorry, a picture tells a 1000 words... But I think there might be something wrong with the camera on my phone, I couldn't get the focus right.

    Also, like others, I have found the vertical rails quite stiff and clunky at first but once everything is together they seem ok. I just need to figure out the driver software.
    image.jpg image.jpg image.jpg image.jpg
  16. TimothyT

    TimothyT New Member

    As shown in the pictures by @Corin Lawson, the key for me on the Y axis was to I run my end-stop cable in the right channel (as KP seen from outside) - same side adjoining power supply. Initially I was doing the outside channel, but this ended up with a just barely reaching cable.

    Route the cable along power supply side and then over to BWP. Since I already had my PS in, I had to take out the 4 bolts on the bottom, slide the PS back a bit, then sneak the Y cable up into the bottom of the top extrusion, again - as illustrated by Corin.

  17. hojalot

    hojalot Member

    One thing I wish I had done when I started pulling plastic bags out of kit boxes was to label each bag. I now have several bags with parts and I can't remember which kit they came from. I'm sure I'll figure it out, but it would have been nice to just put the kit name in magic marker of each bag.
  18. Don Williams

    Don Williams New Member

    Is there an easy way to isolate the heated surface from the electronics, like the material that covers the power supply?
  19. Dantzler

    Dantzler Member

    I don't think that is necessary. The duct over the power supply keeps the PSU fan from blowing on and cooling the heated bed.

    Make sure you route cables away from the underside of the heated bed and you'll be fine.
  20. Paul Tan

    Paul Tan New Member

    I need help with my printer.

    I was trying to print this Managed to print one stand. But when I started printing the less tight 150mm bar. I started experiencing a lot of errors like printer was disconnected or lost connection.
    Tried 7 times. Here is the picture The 1st try is on the left and the last is the right most one.

    On my 7th try the printer went haywire the "y" motor suddenly dropped. Making the hot end hit the brackets on the xz plane.

    And here is the aftermath

    Can this still be fixed? The wires including the material holding it was ripped off the j-head.

    Can I just splice the wire and just glue it back with heat resistant epoxy?

    I should have saved the terminal output so I can maybe report a bug but I was panicking and end up immediately turning the printer and the software off.

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