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jakub.d
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Re: Pre-Print calibration destroys hot-end wires...

Feb 21, 2019 1:43 pm

Guys,
thanks for the feedback. There should be enough space between the wires and the screw. I will check with the devs, since all printers in my office are fine.
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marco.h6
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Re: Pre-Print calibration destroys hot-end wires...

Feb 22, 2019 9:29 pm

I used an 8mm screw from my stash of 3mm hardware. I did this not because of possible damage to wires, but because I've cut myself more times that I can remember on poorly sized hardware. I figured the stock set up was a recipe for drawing blood.

That said, after building my MK3S I moved the X- and Z-axis by hand to check out nothing was getting in the way at the extreme edges of travel. The hot end wires would have missed the larger screw on my machine. Perhaps I just got lucky.

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guy.k2
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Re: Pre-Print calibration destroys hot-end wires...

Feb 23, 2019 6:12 am

Well what do you know? Mine are scraped up like that as well. Never noticed it before you pointed it out.

martin.a22
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Re: Pre-Print calibration destroys hot-end wires...

Feb 23, 2019 6:18 am

Yeah, watch out for this when doing the mk3s upgrade. The hotend gets raised about 6-7mm, so there's a decent chance your cables will naturally try and sit lower than they should. Make sure they are seated up into the x-carriage.

george.e7
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Re: Pre-Print calibration destroys hot-end wires...

Feb 23, 2019 8:22 pm

I've added a comment to the online manual, but it could probably do with a picture.

EDIT:Looking the first post/first picture it looks as if the cable tie closest to the hotend is still attached, I had removed it on mine when I built the printer, but that looks as if when it is left on it would stop the wires sitting up into the channel at the bottom of the backplate.

frederick.r2
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Re: Pre-Print calibration destroys hot-end wires...

Mar 18, 2019 6:55 pm

I had the exact same issue. The wires don't sit well in the recess and so to hang down a bit. One of my cables got quite scraped up during the calibration.

I've loosend the screw to get it to sit flush and it no longer rubs, however now I'm wondering what to do with the damaged cable. The printer seems to run fine and I've been printing well for the first few hours but I'm a bit concerned about the damaged wire. What advice would people give? Would wrapping the damaged area with insulation tape do the trick or is a new hot end needed?

zoltan.f2
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Re: Pre-Print calibration destroys hot-end wires...

Mar 19, 2019 8:42 am

frederick.r2 wrote:
Mar 18, 2019 6:55 pm
I had the exact same issue. The wires don't sit well in the recess and so to hang down a bit. One of my cables got quite scraped up during the calibration.

I've loosend the screw to get it to sit flush and it no longer rubs, however now I'm wondering what to do with the damaged cable. The printer seems to run fine and I've been printing well for the first few hours but I'm a bit concerned about the damaged wire. What advice would people give? Would wrapping the damaged area with insulation tape do the trick or is a new hot end needed?
I wish I have seen this thread before doing the MK3S upgrade and running up against the same issue.
Regarding the wires, my had only a couple of surface scratches. However, since this is the outer heat-resistant shell that is most probably damaged in your case, you can use some el. tape if the internal 2 wires are not damaged. It's far enough from the hot-end that it should not matter. The cables and the hot-end wires can't be replaced without removing the whole thing from the block (or replacing the hot-end completely), so as long as it works I would not worry about it. Just make sure if you can see that the 2 internal wire insulations are not damaged.

How I addressed the problem in general:
- I did not have a shorter screw, so I used one regular nut from the spares bag and put that all the way to the screw head and then put the screw back to the connector, tighten it, now the other end of the screw sits flush but the screw is still dong it's job holding the connector together
- For cables, I removed the zip ties holding the cables together (hot-end and termistor) and re-tighten everything so it goes trough the "new" channel on the bottom of the carriage, as much as possible.

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