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HPB power wire keeps breaking

Posted: Mon Dec 08, 2014 10:46 pm
by SDSMT3DPC
Well, definitely not a new problem but i'm hoping to find a permanent solution.
So far, the heated bed power wire has broken twice. After the wire broke the first time I lengthened the amount of cable between the cable tie on the motor and the HPB in hopes some more length to flex would solve the problem. It didn't and it just broke again. I've got about 1/2'' of usable wire coming out of my HPB now and i'm determined to find a solution while not having to purchase a new HPB. I'm thinking a cable track would be the best solution.

I see this cable track for the Y-axis on the M2 on thingiverse, but i'm not thrilled about drilling a hole in my aluminum HPB.
http://www.thingiverse.com/thing:154841

I also found this, but it's not very professional looking:
http://softsolder.com/2013/07/05/makerg ... ilization/
I've been unable to find another Y-axis track online.

I've uploaded photos. You'll notice i've placed a thin layer of fiberglass insulation under the HPB to decrease warm up times.
Does anyone have suggestions or solutions that doesn't require drilling more holes and looks professional?

Kind regards.

Re: HPB power wire keeps breaking

Posted: Mon Dec 08, 2014 11:05 pm
by jimc
if properly secured there should be zero movement of the wires from the red plug to the bed. everything there should be strapped up so the only thing flexing at all is the black harness out the back. forward of that first tywrap nothing moves. its completely stationary. dont take your wires straight off the back of the platform. goto the corner of the spider like i have. the harness move nice big gentle sweeps with no kinking or actual flexing. it just rolls back and forth.

IMG_3760.JPG
IMG_3760.JPG (57.81 KiB) Viewed 15718 times

Re: HPB power wire keeps breaking

Posted: Tue Dec 09, 2014 1:00 am
by benavery
Interesting. The kit build instructions don't include anything about securing the wiring like that, but it is a good idea. I should try and do that on mine.
Do the pre-assembled M2's come like that ?

Re: HPB power wire keeps breaking

Posted: Tue Dec 09, 2014 1:12 am
by jimc
i bought mine as a kit and i dont know how the instructions say to run the wire but there arent many other ways to make it go that wont strain things over time. when i assembled it i left the wires out the back, moved the bed back and forth and right away knoew that wasnt really going to work :lol: . i added the black plastic strap. i just took one of the longer screws from the left over hardware and used it in the corner of the bed corner rubber to let it stick through then just put a lock nut on it. it still moves there. thats just a support. the tywraps keep all the joints stable.

Re: HPB power wire keeps breaking

Posted: Tue Dec 09, 2014 5:20 pm
by insta
jimc wrote:if properly secured there should be zero movement of the wires from the red plug to the bed. everything there should be strapped up so the only thing flexing at all is the black harness out the back. forward of that first tywrap nothing moves. its completely stationary. dont take your wires straight off the back of the platform. goto the corner of the spider like i have. the harness move nice big gentle sweeps with no kinking or actual flexing. it just rolls back and forth.

IMG_3760.JPG
Doing this tonight. Thanks.

Re: HPB power wire keeps breaking

Posted: Wed Dec 10, 2014 2:23 am
by Dale Reed
jimc,

Nooice!

BTW, how is it that you are able to anticipate and solve problems BEFORE they occur? I'm great at not repeating stupid stuff, but I guess I just don't have that extra insight to avoid having experience teach me that such-and-such will give me curly, smoking hair, burnt fingertips, a painful limp or a new negative impression of some hard object in the middle of my forehead... :-(

Maybe Rick should have hired you for that mech. engr. position at MG HQ. I can just imagine the fit, finish and usability of the Mosaic M3 as a result. As a bonus, it would be nice to have you here in the Cleveland area to show me how to get a great finish if I ever decide to restore my grandmother's 1962 Chevy Corvair Monza 4-door.

Happy (impending) holidays to all! And to all, good prints!
Dale

Re: HPB power wire keeps breaking

Posted: Wed Dec 10, 2014 2:34 am
by jimc
haha i guess its from spending my whole life fixing stuff thats broke, poorly repaired or designed. i really get tired of that so it gets me in the habit of thinking 10 steps ahead i guess.when i worked for viking yacht co. that was actually my full time job. reengineer and repair.....needless to say now i work for myself! lol

Re: HPB power wire keeps breaking

Posted: Sat Dec 13, 2014 3:40 am
by pyronaught
jimc wrote:if properly secured there should be zero movement of the wires from the red plug to the bed. everything there should be strapped up so the only thing flexing at all is the black harness out the back. forward of that first tywrap nothing moves. its completely stationary. dont take your wires straight off the back of the platform. goto the corner of the spider like i have. the harness move nice big gentle sweeps with no kinking or actual flexing. it just rolls back and forth.

IMG_3760.JPG

I notice the mat for the bed heater does not run all the way out to the edge on your platform. Did you have to trim that back or did it come that way? Mine runs all the way out to the edge, which kind of bugs me because the rubber is resting on the mounts and I just don't like the idea of flexible material being between the plate and the mounting brackets.

Re: HPB power wire keeps breaking

Posted: Sat Dec 13, 2014 7:34 am
by jimc
It came that way because mine is a 12/19v machine so the heater is different

Re: HPB power wire keeps breaking

Posted: Wed Sep 02, 2015 6:50 pm
by SouthSideofdaSky
jimc wrote:if properly secured there should be zero movement of the wires from the red plug to the bed. everything there should be strapped up so the only thing flexing at all is the black harness out the back. forward of that first tywrap nothing moves. its completely stationary. dont take your wires straight off the back of the platform. goto the corner of the spider like i have. the harness move nice big gentle sweeps with no kinking or actual flexing. it just rolls back and forth.


IMG_3760.JPG
I know this is a really old thread but my HBP wire just snapped this morning, almost exactly like in the OP. I purchased my M2 assembled and the wire layout was as shown in the OP pic. It never occurred to me that it might strain and fail over time. Fortunately my colleague was able to solder the wire back together but I came here to look for a more long-term solution. Securing the wire to the spider piece is a great idea! Thanks jimc.