A Sick 3D Printer

Yes, the printer was sick. But it was my fault.

When I was done with PETG testing I pulled the filament and pushed through some PLA to clear it out – only I couldn’t push the PLA through. The PETG had broken off and there was now a clog in the hot end (the nozzle, heater, and the other associated stuff). No problem – I’ve seen the video on how to disassemble it and put it back together. I did that, got rid of the clog, and put it back together.

I should have watched the video again – I reassembled it incorrectly and didn’t get things properly seated together. As a result I had plastic oozing out all over the hot end making a mess and dripping plastic chunks on my prints during the printing process. It took me a couple of days to realize what the problem was and since I discovered it late in the day I put off fixing it until the following day.

I started tearing it down again and found that I was going to have to order a part. There is an insulation wrap that goes around the hot end block (a chunk of aluminum with the heater in it) and it was gunked up with plastic. It would be hard when cool and then a dripping mess when things got hot. I know where to order it so I place my order (minimum order is 2 of course) and wait about a week to get the part. In the meantime I start cleaning up the rest of the mess.

The nozzle threads were gunked up with plastic. The heat brake threads (screws into the other side of the heater block) are gunked up. These cleaned up pretty easily with my Dremel with a wire brush.

The threads inside the heater block are gunked up. The obvious way to clean this out is to run a tap down it. Do I have one? Of course not – it’s metric M6-1.0. I start hunting for one locally and find several possibilities. Menard’s listed one (and only one) in the store so I went there. Nope. It’s slot is empty. I knew I could go to Lowes but I thought that Oriley’s across the street just might have one. They did but it came with a drill bit (just like Lowes) – and a higher cost. Oh well, gotta have it so I bought it. The threads inside cleaned up nicely.

I had to remove the thermocouple temporarily so I could get the insulation wrap off. It’s held in by a silicone sealer. Not your normal silicone of course – high temperature stuff. Some research found the right stuff – the kind used to make gaskets on auto exhaust pipes. Of course it’s an auto parts store item and the tube would be able to do about a thousand of these things. I only need one drop. Probably one more tube of stuff that will be hard as a rock the next time I want to use it for something. Of course I have to wait 24 hours (maybe a little less) for it to set up properly before I can move on to the next step.

Now to clean off the block itself. Heat it up to 100C (that’s 212 Fahrenheit) so the plastic would get soft. Of course it’s now HOT and I have to hold the block with pliers and scrape off the gunk.

Time to rewrap the new insulation around the block and start putting this thing back together. The PROPER way to put the nozzle and heat brake together is to heat things up to 240C (464F) and screw in the nozzle, with my trusty 7 mm nut driver, snug and then back it out about 1/4 turn. Then you screw in the heat brake snugly (quickly before it gets too hot). Then TIGHTEN the nozzle firmly up against the heat brake. Then it’s time to let it all cool down so I can put everything back together.

Want to see what I’m talking about? Click on this YouTube video link for an explanation. It’s actually a different printer than mine but the hot end is identical to what I have.

I printed a test cube and it came out fine. I’m printing a stamp dispenser as I type this and when I left it about an hour ago it was doing fine. It’s a 2-1/2 hour print so it’s about time to check it again.

That’s all for now.


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