I lost a print last night. It pulled off the bed. I thought that was odd, but decided to try again in the morning. Nope! No heated bed today! A quick diagnostic with a volt meter found the problem! Broken wire. Has anyone seen this? I guess it is to be expected as the bed continuously moves.
Pretty common, if you don’t use some kind of strain relief.
Also, that wire looks ‘cooked’. Are those wires rated for the temperatures of the bed heater? I use silicone-insulated wires that have the additional benefit of being very flexible.
number one source of fire on a printer. You got lucky as hell.
This is why moving-Y-bed designs with HBPs are ridiculously dangerous.
Do you have a thermistor on your HBP? If so then is it normal for the print to start if the bed wasn’t at the expected temperature? I’d have thought that Heater On + No Temp Rise = Safety Cutoff, if only to guard against thermistor failure.
ive said it before , because you can think of it , doesnt mean that is how it is. Never assume safety measures are installed.
I absolutely agree. I don’t have a HBP or a moving Y printer, so the question was one of genuine curiosity. Shouldn’t be too difficult to add, as its similar to the same problem with Hotend thermistor failure.
@Nathan_Walkner Right, I’m personally opposed to moving-Y-bed designs for a variety of reasons, but if that’s what you’re stuck with, there are some big things to make it safer:
- Proper strain relief at the connectors
- Low-stress wire routing like a large U-loop or properly-designed cable chain (must be large enough radius for the wire gauge!)
- Flex-rated wiring good for the HBP temp
- Use a 24v power system and/or low-power heater so the wiring can be thinner and less prone to fatigue
The number one way to protect yourself, is to visual the connection and wires before and during each print. Replace it if it ever shows wear or gets flaky , as that flakyy operation means a break in the wire.
Mine actually has a break in the wire mid way. I havent been printing because of it . Watch the graphs as tyou heat, and during prints. This is dangerous to get complacent with.
What kind of printer? This is why I believe if you use a 3d printer then you should understand how it goes together and how to fix it. I build my own so I KNOW how safe it is. What probably happened is that the wire started breaking strands until it developed high resistance
And thus burnt. But as it was stated…strain relief is very important on any kind of flexing wires.
@Ryan_Carlyle I think you should do a little research before you put a biased statement out there like that.
Is there a matrix showing failure modes vs. failure mitigation support for the common firmwares anywhere? Similar to the reprap page that shows the various levels of G code support, I guess. If no then would it be worth while? I don’t mind having a go at it if people think it would be worth having.
@Jeff_Para what did I say that you think is biased?
Also you should be using stranded wire… bit more flexible.
@Carlton_Dodd Thanks for the constructive comment. The wire is not cooked, although it may look like it in the photo. It broke due to fatigue. When I built the printer, I did the calculations and current/voltage measurements. All should be fine in that regard. It was a simple fix. You are right about the strain relief. that was something I planned to do, but never got around to it. Thanks for the tip on the silicon wire. I will look into that. Getting tips like this is one of the reason I posted. Thanks again!
@Keith_Applegarth It is stranded.
@Nathan_Walkner you are correct! I didn’t see it. Probably because I’m in the middle of the Atlantic on a cruise and I’m sure my internet isn’t the fastest.
I’ve been printing for 5 years now and designed and built many printers using movable y platforms with no issues. Of course I use correct gauge multi stranded wire that’s strain relieved to the platform. Any design can be safe as long as forethought is used when building.
@Jeff_Para fair point. They CAN be safe. I personally think it’s a bad choice for a hobbyist’s first printer (which is what it typically is), due to the relatively larger electrical hazard risk compared to other architectures. Most people entering the field and most low-cost kit-sellers don’t have the knowledge or incentive to do everything necessary to make the flex-wiring safe.
@Jeff_Para Jeff, I built the printer and I know how safe it is, and how safe it isn’t. I can also fix anything on it. As to this issue, it was fatigue due to not having a strain relief. It didn’t have one because I was lazy, not because I didn’t think about it. I never did the cable management like i wanted to. I inspected the wire, there wasnt any burning of the wire. I have over 1000 Meters of filament through this printer now. It is definitely starting to show wear. Carlton made a good suggestion about the silicone insulated wire. I will probably take the printer down for some maintenance and update it properly. Thanks for the comment.