Platform heater repeated failures

[pleppik]

Since getting my printer at the end of December, I am on my fourth platform heater. Each time, it fails with a break in the cable in one of the wires leading to the heater cartridge, and in about the same place (about 75mm from the plug end).

I'm guessing from the failure mode and the consistent place where it breaks that there's some mechanical issue, with the repeated flexing of the cable. I'm careful about installing the cables to make sure they don't get pinched or hit the belt, but maybe I'm installing them wrong somehow. I do use my printer very heavily (it's running almost 24/7), so that's almost certainly a factor in the repeated failures.

Anyone else had this problem? Any ideas? Two of the heaters have been replaced under warranty and I bought the third, and I'd really like to find a permanent fix. Cost aside, it's a nuisance to have to replace the part every six weeks.

[wilsonj]

Damn, sorry to hear. Could you not make your own cable as an alternative? Perhaps a nice soft silicone jacket wire might fair better.

Something like this http://www.hobbyking.com/hobbyking/stor ... duct=10938

The OEM cable does seem quite stiff.

Incidentally, I'm intrigued. Can I ask what you are printing 24/7 ?

Cheers
Jamie

[pleppik]

Incidentally, I'm intrigued. Can I ask what you are printing 24/7 ?

What am I not printing? Toys for the kids, clever little boxes for my wife, desk knickknacks, everyone seems to have a request.

The other day my brother asked if I had actually made anything useful. I had a hard time coming up with a good answer when he said printer parts didn't count.

Lately I've been doing some lampshades in glow-in-the-dark plastic (I bought a wholesale reel for 2.4 cents/gram). It's a reading light AND a nightlight!

[pleppik]

I think I've found the root cause (knock on wood).

I took apart the arm under the platform for the nth time carefully inspected the cable path for the platform heater.

I discovered that the cable clamp--the printed plastic piece which holds the cable in place--was warped upwards towards the front of the printer. It was warped enough to pinch the cable just a bit at the tip of the cable clamp as the cable moved over the clamp.

Repeat this slight pinch a few thousand times and eventually the cable fails.

I put a drop of crazy glue under the foot of the cable clamp to try to correct the upward warp. We will see if that fixes my problem with a failing platform heater.

Posted here in case someone else has the same problem in the future.

[art103]

I was hit by this one today.
The problems are always worse when you've committed to an order

Just as pleppik found, the repeated flexing of the platform heater cable caused one of the wires to break completely. I'm assuming by the blackened insulation that it has been intermittent for some time and sparking due to the heater current.
A second wire is broken, but held close enough to be only occasionally intermittent, which explains my "platform too hot" errors...

Note to anyone who hasn't checked their cable yet, it is a simple check:
- Remove two bolts holding the platform on.
- Remove 4 bolts on the X-Axis cover.
- Gently lift off cover.

The cable is easily visible, and the break happened to me where the cable bends as you move the platform all the way forwards.
It has obviously been rubbing too judging by the abrasion marks on the outer insulation.

As an interim fix to get me up and running, I stripped back ~15mm of outer insulation, then ~1mm of the inner wire insulation.
Solder back together with a some heat shrink tubing and suddenly my platform heats in half the time!
Not worth the effort of a return IMHO, but not sure where I'll stand on warranty

My printer is 6 months old and has had approx. 5kg of plastic go through it - mostly 90mmx90mm prints, so the cable is being flexed a lot.

Longer term I will replace all 4 wires with flexible silicon wire as suggested by wilsonj.

[APA]

Anyone else had "Platform too hot" errors? It halts a print and just sits there until I reset the system.

I have tried a number of prints now and keep getting stopped by this error. I checked the heater cable as suggested above and it appears to be intact. I also tried unplugging the USB cable, but had the same thing happen.

The platform heats to 103C fine and the print kicks off with no issues. Not sure of other things to try so any suggestions would be welcome.

[josejuako]

Clean all contacts , look , clean the sensor and resistance contacts whit wire . APA

[pleppik]

Anyone else had "Platform too hot" errors? It halts a print and just sits there until I reset the system.

I have tried a number of prints now and keep getting stopped by this error. I checked the heater cable as suggested above and it appears to be intact. I also tried unplugging the USB cable, but had the same thing happen.

The platform heats to 103C fine and the print kicks off with no issues. Not sure of other things to try so any suggestions would be welcome.

If one of the wires to the temperature sensor is intermittently broken you will see these symptoms. The wire can be almost-broken inside the insulation, and usually makes good enough electrical contact. But occasionally the flexing of the cable will cause the break to lose contact completely, causing the "too hot" error and shutting down the print.

The printer is designed such that an open circuit in the temperature sensor trips the fail-safe condition. This is appropriate (otherwise you could get runaway platform heating), but frustrating.

[APA]

Thanks for the replies.

I unplugged, examined, and then reconnected the platform heater cable after it appeared intact. I then heated the platform to 103-104C, jogged the axis back and forth, up and down, while gently tugging on the cable to test for broken connections. I couldn't seem to make it break connection or act incorrectly in any other way, so I decided to try another print.

I did a 4 hr print successfully and tonight a shorter 1.5hr print. I can only guess that reconnecting/re-seating the cable fixed a loose connection at the connectors that are at the base of the x axis arm.