Keeping tracks of failures

Here I want to keep a track of every little fail that I experience or that someone report back to me. Even if they are a lone case, it's alway something we can improve on.

As a first post :

#000 : My first failure was due to heat (summer+day of printing) and the x-carriage got deformed (that's now resolved with the real heatsink and a different way to hold the belt).

#002 : the machine was shipped in the heavy suitcase with foam, but the foot-rear-left and the z-motor-bracket-left broke

#007 : the peltier stopped working after a few print

#008 : the filament was fed with some difficulties in the extruder-idler (making a chamfer at the pneumatic fitting entrance could help a little)

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another lesson learned, from the #004 : don't put the big acrylic plate at the bottom of the package under the aluminium extrusions, as I should expected it arrived shattered (another was sent for replacement of course ^^')

Hopefully it was the first machine shipped and I'm taking care to avoid that with the others

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Hi,

Here is a list of failures I have had:
- Peltier stop working:
I burned 2 Peltiers. I suspect my temperature setting was too high and the Peltiers burned (65°C). I also think that there should be an (electrical) energy limit on the heat bed, whatever the technology used (Peltier, resistors, ...). This because the sensor senses temperature a few seconds after the heating element gets its temperature. Also, the heating element will be much hotter than the plate and the temperature sensors. So it would make sense to pause (for instance 10s) every time the heater is at 100% (for 30s for example). Thus the temperature overshoot would be much smaller and it would protect the heated bed. I just have to find the time to implement that in the firmware.
Also NEVER use PWM (i.e. not bang-bang) temperature control for beds with Peltiers, Peltiers hate PWM! They need constant mean current.
- Gap between perimeter and filling on X-axis:
I have had two problems with the same symptoms. What happens is that when there are strong accelerations, the axis slides and the final distance is smaller than expected, whereas when acceleration (and possibly velocity) are small, there is no sliding and distance is as expected. For example infill versus perimeter or if the head is traveling from left to right and printing from right to left, final distance is different.
+ X-pulley loose (pulley screw not tight enough)
+ X-belt loose (solved by loosening X-motor, pulling out the motor and tightening the 3 screws agains).
Picture of space between infill and perimeter.

That's that for now,
Jérôme.

Thanks for the information

I seen someone (CDNreprap on a thread about peltier, who used them without temp control just leaving it self-regulating) using ABS, in my case I only use PLA. Tried once to print ABS but indeed it's hard to go higher than 80°C : /
(theoretically the delta between the two face is 60°C max, so if the "hot face" is around 80°C the "cold face" is probably at 20°C, with some insulation to keep the warmth of the bed recirculating it's may be possible to go a little higher)
I didn't knew for PWM, I'll change that to try (that's not why I'm moving toward cold-bed + blue-tape but it's not a problem with them fortunately ^^')

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Hi,

Here is another failure:
- Laptop computer got unplugged (and I didn't notice) and I left after a few minutes. Some time later the battery ran low and the computer shut down automatically, but the hot end stayed on, at the same spot, for many hours. Consequences: a large black spot on the printed part where the head stayed, and a completely clogged hot-end. I could still retract the plastic (thank you hot-end fan), but I still had to disassemble the hot end. I could remove the nozzle, but broke the barrel inside the hot alu block, so I don't know if I'm gonna be able to fix that. Thankfully, I was extruding ABS, so now my nozzle is sunk in an acetone bath, we'll see if it dissolves and the nozzle becomes usable again.
OK, from now on I think I'll always print from SDCard.

Till next catastrophic failure (not too soon I hope).

Outch ! The laptop going in sleep mode, I had it few times too ^^' if you react quickly you can resume the print where it stopped, but as you seen if the mainboard is not disconnected properly it can freeze on what it's doing

Some weeks ago I started to had extrusion problems : a wire of the hotend's fan broke



Must be changed otherwise the filament will soften to early in the hotend,
at least a 40mm generic fan is a cheap replacement...

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Emmanuel Wrote:
-------------------------------------------------------
> (that's not why I'm moving toward cold-bed +
> blue-tape but it's not a problem with them
> fortunately ^^')


Why are you moving to cold-bed + blue-tape ? If that question is not indiscreet ^^.

In fact I like the both, but on my personnal prototypes I tend to prefer blue tape, it is just simpler

But a little harder to fine tune... so I'm still sending kits with heated-bed for the moment, and later let people choose it or not as an option, probably

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