Monday, April 9, 2012

Mean Time Between Failure?

For some time, I have been wondering what the meant-time-between-failure is for the J-head hot-end.  Today, I received an e-mail from a customer and he writes:

BTW: I've now done over 24 rolls of PLA through your head and NO ISSUES at all! (So thats like 2.5klms plus of plastic!)
An 6 month old early J-Head Mk III, that is regularly used to print ABS, is also reported to be still going strong.

Tonight, I was asked what the common reasons for failure were and I responded with 3.  Those are:

  1. Cheap filament with contaminants.
  2. Overheating to the point that the PEEK nozzle holder softens.
  3. If the PTFE liner gets "crimped" at the junction between the PTFE and the brass.
Does anybody have any experiences they would like to add?