bigseb
Alibre Super User
For the last 3 months or so I struggled getting a decent quality print from my CR-X. Missed layers and clogged nozzle. But why? In the beginning the printer worked flawlessly and those of you that read my Creality CR-X review saw the excellent quality of the prints I posted there. So what went wrong? Its turns I went wrong but in a way I would never have guessed.
So what was the problem? The short answer is insulation. Some months back I thought I'd try a steel nozzle. Didn't get great results so I removed it, cleaned it and attached it to the hotend again. No change. Removed it and cleaned it again, still no change. Put the old brass nozzle back on and that didn't work either. Thinking the nozzle was accidentally flatnosed I changed it for a new one. My mistake here is that all the nozzles changes were done without removing the hotend from the carriage. Basically I was working upside down with the hotblock covered in insulation (because I was too lazy to disassemble the hotend) and due to the resultant upside-down working condition trying remove/attach fiddly little bits I must loosened the hotblock insulation (the cotton and kapton wrap) and this caused heat to dissapate too quickly. Not enough to be noticable but enough to cause a momentary blockage that had a knock-on effect. Essentially I was putting on a new nozzle very often which ran fine for half a print, then came a tempoerature fluctuation that last for 2-3 layers and the print was ruined. Subsequent reheating of the nozzle with material in it (during troubleshooting) caused the nozzle to become completely charred up and unusable. For many many weeks I have checked parts over and over and replaced a shedload of parts but it never occurred to me to reinsulate the hotblock. So the problem cycled. Its was only when the insulation came off completely and I replaced it that I saw a massive difference in performance.
I went through a lot of parts. Not expensive but just a lot of extra work. These thing do wear out with constant reassembly, not to mention the damage done when molten plastic leaks out between incorrectly fastened throat pipe and nozzle:
3 new hot blocks (2 from Amazon, 1 I made at work)
3 new throat pipes (2 from Amazon, 1 I made at work)
About 8 nozzles in total
Replaces heater cartridge and thermistor (broke due to constant handling)
Several strips of cotton insulation
Several Bowden tubes
I struggled to find single spares for the CR-X. You can get an entire replacement hotend for about 50 quid on Banggood but takes 20 days for delivery so in the end I bought a set of 10 0.4mm nozzles, a set of 5 24V heater cartridges and thermistors, cotton strips and kapton, ptfe tubing, 2 hotblocks and 2 throat pipes and it still cost less the a new pre-assembled unit. I made a custom hotblock and throatpipe at work because nothing the same as the original.
The printer is running now and running like new. This wasn't a particularly difficult repair, just incredibly tedious since it took a while to find the problem.
So what was the problem? The short answer is insulation. Some months back I thought I'd try a steel nozzle. Didn't get great results so I removed it, cleaned it and attached it to the hotend again. No change. Removed it and cleaned it again, still no change. Put the old brass nozzle back on and that didn't work either. Thinking the nozzle was accidentally flatnosed I changed it for a new one. My mistake here is that all the nozzles changes were done without removing the hotend from the carriage. Basically I was working upside down with the hotblock covered in insulation (because I was too lazy to disassemble the hotend) and due to the resultant upside-down working condition trying remove/attach fiddly little bits I must loosened the hotblock insulation (the cotton and kapton wrap) and this caused heat to dissapate too quickly. Not enough to be noticable but enough to cause a momentary blockage that had a knock-on effect. Essentially I was putting on a new nozzle very often which ran fine for half a print, then came a tempoerature fluctuation that last for 2-3 layers and the print was ruined. Subsequent reheating of the nozzle with material in it (during troubleshooting) caused the nozzle to become completely charred up and unusable. For many many weeks I have checked parts over and over and replaced a shedload of parts but it never occurred to me to reinsulate the hotblock. So the problem cycled. Its was only when the insulation came off completely and I replaced it that I saw a massive difference in performance.
I went through a lot of parts. Not expensive but just a lot of extra work. These thing do wear out with constant reassembly, not to mention the damage done when molten plastic leaks out between incorrectly fastened throat pipe and nozzle:
3 new hot blocks (2 from Amazon, 1 I made at work)
3 new throat pipes (2 from Amazon, 1 I made at work)
About 8 nozzles in total
Replaces heater cartridge and thermistor (broke due to constant handling)
Several strips of cotton insulation
Several Bowden tubes
I struggled to find single spares for the CR-X. You can get an entire replacement hotend for about 50 quid on Banggood but takes 20 days for delivery so in the end I bought a set of 10 0.4mm nozzles, a set of 5 24V heater cartridges and thermistors, cotton strips and kapton, ptfe tubing, 2 hotblocks and 2 throat pipes and it still cost less the a new pre-assembled unit. I made a custom hotblock and throatpipe at work because nothing the same as the original.
The printer is running now and running like new. This wasn't a particularly difficult repair, just incredibly tedious since it took a while to find the problem.