Suggestions for wiring to be used inside heated enclosure.
I've been slowly working on making my printers' enclosure more capable of reaching higher temperatures. My long term goal is to reach ~90C. Does anyone have any suggestions on what kind of wiring I can get that is rated to work at that kind of temperature. I've been looking at this https://www.igus.com/product/14633?artNr=CF29-15-15-02-01-D and similar products from IGUS. I'm just reluctant to settle at 100C rating due to the temperature rise in the wiring once I start printing. Do I also need to be concerned about skewed temperature readings from my heater thermistor due to the change in resistance in my thermistor wiring? Thanks in advance!
You are probably limited to silicone, TPE, PTFE or polyalkane etc. if you need wires than exceed the ratings of PVC.
The Chainflex is suitable, but large. Other makers do smaller TPE types, eg.
Those look idea for making up multi-core connections for the moving parts as they are also extra flexible types that can stand repeated bending.
Fixed wiring could also be in such as fibreglass, which is relatively cheap.
@rjenkinsgb Thank you for the response, this will help my narrow down my search criteria for sure. I was primarily interested in the ChainFlex due to its shielding. However should I only be concerned with shielding cables that transmit data like thermistor and probe cables and just settle for twisting pairs for the steppers? I should have also mentioned that EMI management is also a priority for me as well.
I used a separate twisted pair (or triple or quad) for each signal or device on mine, with no screening anywhere.
Also try and separate noisy devices like motor cables from low power or sensor cables though; physical separation is a good way of restricting crosstalk.
Twisted pairs are near as good as screened cable for limiting interference, and can be improved further by adding ferrite sleeves to each separate pair or quad. They can be outside the heated section.
(Note the pairing & ferrites etc. only work if there are no cross connections between cables at the far end).
You could use eg. flexible sleeving then all-metal flexible conduit to add true screening to harnesses, like one for sensors and one for motors & heaters.
High temperature conduits are far easier to get than high temperature flexible cables, though still not cheap..
That's how I would do it if I were building an industrial machine with the same restrictions.
gwatson90 last edited by gwatson90
@rjenkinsgb Well, feeding a meter or so of cable through Electrical conduit would certainly be easier than using regular cable loom like I have in the past and it has a slightly better bend radius that the ChainFlex. So, if I'm understanding you correctly; Motor cables, signal cables, and heater cables all need to be channeled through their own conduit to obtain maximum avoidance of interference. Do the fans need to as well? Does the conduit then need to be grounded to a drain? Sorry for so many questions, but EMI suppression is a new avenue for me and I'm quite fixated on it at the moment. Are you aware of any good resources I can look to for more information? Thank you!
Also, I just ran across this: https://hollandshielding.com/Flexible-cable-shield
Is this a viable option as well?
@gwatson90 said in Suggestions for wiring to be used inside heated enclosure.:
So, if I'm understanding you correctly; Motor cables, signal cables, and heater cables all need to be channeled through their own conduit
Motor and heater cables can share a conduit, as long as they are similar voltage. If you are using a 110V or 240V bed heater, I'd keep that separate.
The metal conduits, grounded at one end, give you a reasonable screen; I'd not add anything else, as wrapping each cable bundle will reduce flexibility and decrease the life of the flexing cables.
Individual screening of each function cable is nice when it is practical, but I just do not see it as being realistic in a small 3D printer using high temperature cables. The twisting, grounded conduit and (if required) ferrite sleeves should take care of any possible crosstalk or EMI.
For the steppers, I'd suggest one, four wire cable each, (four wires spiralled together to give the twist effect) with each winding using diagonally opposite wires. That configuration minimises EMI and crosstalk.
For any cable with more than two wires, the "twist" spiral needs to be consistent, so the same order of wires all the way through.
[I'm working from experience with over 40 years designing and repairing industrial control systems; I've spent the last 15 mins trying to find something useful via google, but nothing practical so far beyond the basic twisted pair principle etc...]
@rjenkinsgb Thank you for helping me lay some ground work for all this! I'll keep an eye out for resources.