General Build Questions / Build Procedures / Common Pitfalls

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

  1. sandman

    sandman Member

    I am an early bird kit and only 4 of my shoulder bolts fit, I sanded the rest and they worked just fine.
  2. Rick Gordon

    Rick Gordon Member

    I wired to the picture, and did a smoke test. Power supply came up successfully.
  3. KDog

    KDog Member

    Terence, you really should post a wiring diagram for the psu or at least point out which photo, paragraph, etc. is correct. Lots of newbies building right now and this is one place where a screwup could be a liability issue.
    Terence Tam likes this.
  4. KDog

    KDog Member

    Finished my build of KS053 tonight. One thing that helped with space in the base was moving the power button to the other side of the brainwave closer to the psu connecters. I also moved the brainwave over a bit. I can still reach all the connectors from the hole in the bottom but now have plenty of room to disconnect servos if I need to. Will wait until tomorrow to power on and start messing with printing. I'll be up all night if I start messing with it tonight :p
  5. Rick Gordon

    Rick Gordon Member

    I'm mostly finished with KS023 tonight - got a late start on it.
    Yeah, I know what you mean - the one on the left is pretty tight that close to the PSU. I may try sliding the board over a bit to make that easier to access in the future. Can't say the wire routing in the base is the prettiest but it all seems to fit.
  6. Rick Gordon

    Rick Gordon Member

    I'm (mostly) finished with KS023 tonight - got a late start. Still need to wire PSU and heater to the board - wanted to run a voltage check first and took me awhile to find my meter. (voltage check fine - drifting between 23.99V and 24.0V)

    I'm going to run a motor test tomorrow - before connecting the end-effector up - just to make sure I don't crash it into anything! I've learned to be incremental.

    One thing I've noticed - the belts seem to be awfully close to the end-stop switch screws.
    A lower profile screw would help, but they look to be fairly long - 14mm maybe - and I don't have any suitable replacements.
    I'm not really sure if they're touching - but on two of the towers they look to be barely brushing them. Not sure if its a problem yet - but it is a moving part and they will wear...
  7. Paul Tan

    Paul Tan New Member

    Ok. Got it. These are the hot end mount studs!136&v=3.

    That is good to hear. But that is not reassuring because some of the slide doesn't have any picture and I feel that some might be wrong and I'm already in the wiring part just when I thought I can finish everything tomorrow. I might postpone the build when I encounter something strange with the instructions again.

    Thank you for the advice guys.
    Last edited: Jan 3, 2015
  8. Terence Tam

    Terence Tam Mr. OpenBeam Staff Member Vendor

    I'm wrapping up my tour of Asia (just left Singapore this morning, currently in Macau, leaving tomorrow for Hong Kong. Actually on Monday I am visiting our injection molder, picking up some tools from my usual Hong Kong maker / hardware supply haunts, hopefully meeting up with the Reprap Discount guys about potentially sourcing a hot end from them (cost reduction + gain the ability to print in Nylon). I'm also taking this opportunity to patch a big hole in my photography arsenal and getting stuff for better photos (and eventually, video) for the documentation. Lots of good stuff.

    Once I am back to the US, we'll be fixing up the documentation. I've not been active in the last week (family time), but I have been keeping an eye on the forum, and it's been really useful to see where questions come up and where people seem to have the most confusion. I'll also ping MatterHackers to see where they are with the software.

    I've sent all my firmware and slicer settings over to @Matthew Wilson and I know him and @Chris will be testing things out before publishing more here.

    If there are questions, and if you can wait, please give me about a week after I get back to get some more documentation churned out. As someone pointed out, there's more updated pictures on my OneDrive account, but we don't intend to leave the documentation in its unfinished state for long. (It feels ... almost naked to travel for this long without CAD capabilities, but my laptop kicking the bucket a few months earlier didn't help things... and frankly, it's *NICE* to be able to unplug for a little bit).

    And that wiring diagram is definitely very, very high on our priority list, along with a visual BOM and part identification, such as the photo attached below (but with actual numbers and annotation, etc)


    -=- Terence
    Don Williams, hojalot and Bruce Segal like this.
  9. Mike Francies

    Mike Francies Member

    Well, it took some time but all the shoulder bolts now fit perfectly. Some of them needed quite drastic action and I had to use a fine, diamond needle file on them, whilst in a drill, before polishing them with fine wet & dry paper. So, Terence, no need for replacement parts.:)

    I now have everything finished but I did have a problem with a solder short on the heated bed - much the same as others have commented on. I think I have fixed it but would like to know what the resistance should be - mine measures 118 ohms. Does this sound about right?
  10. Paul Tan

    Paul Tan New Member

    @Terence Tam now worries. I'm not in a hurry even if I manage to finish it today. The test I can do will be limited because I don't have filaments. Some filaments sold here in Philippines are expensive and the materials are limited. I might end up buying from matter hackers and wait for it to arrive.
  11. shchua

    shchua Member

    118 ohms at room temp sounds a bit low. I think mine was aa few kilo ohms at room temp. I'll measure it after the print job is done.
  12. Don Williams

    Don Williams New Member

    I just measured mine right out of the box it is 116.5 ohms. So I would guess that you have pretty good wiring.
  13. TimothyT

    TimothyT New Member

    I'm nearing completion of my mostly "3rd shift" build.

    * I'm curious to see some images of cable management/routing if anyone has some good examples.
    * Is it just me, or does the Y-end stop cable run just barely reach... so it fits, but perhaps I should route direct underneath the KP?
    * I see the BWP board has a bed probe connector. I'm not missing this am I? The bed probe connector should go through the 10 pin cable harness, right?

    2 cents:
    - The ring terminals for the AC power to power supply were a bit large. I took snips and cut the edges off to make a better fit/flush fit. Don't know if a poor connection here could be the cause of some of the print issues in combination with printer vibration? I'd think not, but though I'd suggest it.
    - As related to above, for 24 VDC from PS to BWP, I used the narrow end lug of the cable jumper at the PS, at the BWP I ended up cutting down the ring connector to prevent possible/accidental short. Theoretically you should be able to tighten the lug down and know there is no short, however with vibration perhaps something unexpected could happen. In retrospect I would have flipped the cable and cut down the ring lug connector and use that at the PS.

    I also had a comment/concern on the linear rails, I'll put that in the other thread.

  14. shchua

    shchua Member

    That's strange. I just measured my heat bed thermistor at 84.7 k ohms at 29C. The heat bed itself is about 3 ohms.
  15. Paul Tan

    Paul Tan New Member

    Done. Well sort of. Here is the picture

    I didn't install the swing arm to the drive block. Just to avoid crashes once I test it next week.

    I noticed that every time a stepper motor is moved a green light turns on from the brainwave pro and the led light in the effector. Is that normal? The printer is not plugged in yet.
  16. Mike Francies

    Mike Francies Member

    Shchua; It was the heated bed thermistor I was measuring at 118 ohms, not the heated bed. I just measured the heating element of the bed and it was indeed about 3 ohms as you say.
  17. shchua

    shchua Member

    Still, 118 ohms seems very low. I measured 84700 ohms with the thermistor cable disconnected from the BWP. It reads 5042 ohms if the cable is connected.
  18. shchua

    shchua Member

    That's normal. The back EMF generated by the moving stepper motors seems enough to light the green LED. Not sure if doing this too often will cause any damage to the unpowered BWP.
  19. Mike Francies

    Mike Francies Member

    Shchua; It sounds like we need to do a bit more work - Don Williams measured 116 ohms across the thermistor and mine was 118 ohms, disconnected from the BWP. I think we need one or two others to measure their heated bed thermistors to know if there is a problem or not. I have not, and dare not, fire this thing up till I know a bit more about what I should be doing.
  20. Wacky

    Wacky Member

    I got readings from 114 to 116 ohms. (There better be some variance because of differing temperatures). But it sounds to me as if Don and you have "good" readings.

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