The most problematic part of my 3D Printing experience has been the hot end assembly. I have had it jam, the fan stop working and the Bowden tube pop out of more than one occasion. Today I am trying to find the fault in the hot end again. I have been trying to print some items for a company (my first commission!) and there is one part of it that starts to print and about half way through the hot end appears to jam and then the Bowden tube pops off. At first I thought it was the connector – I have had problems with that before. So I replaced it. Started the print up again and the same thing happens.
Could it be that something is blocking the nozzle – I ask myself. To find out if have removed the nozzle, rigged up a simple aluminium foil holder and baked it at 210C for 20 minutes. Unfortunately that didn’t work. I resorted to a combination of heating with the gas stove, using a 1.7mm drill bit to push the remaining PLA through and then a 0.5mm bit to clean out the nozzle. I also used the larger drill bit to clean out the connector as well.
Another thought occurred to me, what if it wasn’t the nozzle at all, what if it was the print it had been doing? I had been using Slic3r to produce the gcode, something I noticed was the large number of retracts it was doing as it infilled. In this image you can see the infill but the greenish colour is where it moves without extruding – you can see there are loads of them – and every time it doesn’t extrude while moving is another retraction. So I switched back to Skeinforge. It had done a better infill without the retraction and also I didn’t have the jamming either. I have reported my findings into the Github for Slic3r, I hope it is something that can be fixed.
And no sooner had I reported the problem then it had been sorted! Just have to wait for the next pre-compiled build to be released.