Is this a bad joint or not? - Page 1
Forum section: electronics / general

author: fx991ex
author_rank: Contributor
timestamp: October 16, 2018, 08:30:04 pm
content: So my 3D printer broke down and it was because of what I think is a bad electrical joint. The specific joint connects a steel braiding and a solid metal wire.A solid metal wire twisted three times around the steel braiding and a heat shrink tubing put over it.I notified the manufacturer of the printer to make them aware of the problem and here is the message I got back from them:QuoteSo is that a bad joint or not?In the attachments you can see the joint I described above.

author: wraper
author_rank: Unknown
timestamp: October 16, 2018, 08:32:24 pm
content: It's a crap solution, however it has nothing to do with any faults. It's just a little bit of shielding.

author: fx991ex
author_rank: Contributor
timestamp: October 16, 2018, 08:37:01 pm
content: Quote from: wraper on October 16, 2018, 08:32:24 pmThe electrical connection for printer calibration is done through thermocouple's braiding. If there is a bad connection then the printer won't calibrate properly.

author: metrologist
author_rank: Super Contributor
timestamp: October 16, 2018, 08:45:29 pm
content: If you cannot solder it, I would re-fit the wrap properly and back that up with many more turns of thin bare copper wire wrapping around the braid and around the existing wrap so there is more contact area, and then heatshrink.

author: wraper
author_rank: Unknown
timestamp: October 16, 2018, 08:45:43 pm
content: Quote from: fx991ex on October 16, 2018, 08:37:01 pmNonsense. Thermocouples usually don't have any shielding at all. And it certainly is not connected to thermocouple itself. If this shield is used for electrical connection of anything else besides shielding thermocouple itself, then it's completely ridiculous design.

author: fx991ex
author_rank: Contributor
timestamp: October 16, 2018, 08:51:17 pm
content: Quote from: wraper on October 16, 2018, 08:45:43 pmWatch the video. The printer calibrates itself by touching a metal plated part of the platform with the nozzle. The nozzle is connected to the controller through the thermocouple's shielding.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: October 16, 2018, 09:15:07 pm
content: So, what you're saying is that the only reason for this ground is for the touch-sense?If this is true, I have other questions. The braided covering on the wires, is it stainless steel or nickel or silver plated copper? If it is nickel or silver plated copper, then solder would be fine to secure it further, as I am of the opinion that wrapping it is inadequate. However, if it is stainless steel, I am not sure how easy it is to solder, although I have been successful at soldering stainless steel, it is difficult. You could be more successful if you wrap the single wire in a longer spiral and then use ty-wraps (multiple) to further secure it and then use the heat shrink over the ty-wraps.Is the single wire copper with nickel or silver plating or is it aluminum? If it is aluminum, then I recommend the ty-wrap/heat shrink method as opposed to soldering.Hope this helps...

author: hiddensoul
author_rank: Regular Contributor
timestamp: October 17, 2018, 11:14:28 am
content: Just open up the braid at the end using a small screwdriver or scribe until you have about 1.5 cm of loose ends, fold around to one side of the wire and then just crimp to it off the side using a standard auto butt crimp, I have used this method before to attach to braid