Thermocoupler, Cooked Nozzle, Copper Finish, YouTube

by Jason King on July 13, 2014

New Makerbot ThermocouplerIn my last few Beginner Series blog posts I may have mentioned once or twice that it looked like my thermocoupler was dying a slow death. Well, I was right.

After logging a support ticket with MakerBot I received a reply quite promptly.

The email was very detailed and explained a few things to try, basically checking the thermocoupler looked ok at both ends.

I checked the circuit board end and the connections were secure. When I checked the extruder end the wire was bent at 90 degrees which apparently isn’t good.

After gently straightening it my temperature readings from that moment on just showed ‘NA’. At least I’d found the problem, but I had finished off my dying thermocoupler in the process.

MakerBot told me I needed a new thermocoupler and that they would send me one immediately free of charge. So far so good and to my surprise it arrived within a few days. Bearing in mind I live in the UK and it was sent direct from the USA I thought that was pretty good.

Fitting a New Thermocoupler

MakerBot sent me more detailed instructions on how to replace the thermocoupler so I read them ahead of my receiving it so I knew in advance what to expect. It looked quite a simple process and when the new part arrived I set about following them.

To be honest I fitted the new thermocoupler in about 30 minutes and with no problems at all. One thing to note though is that the wire on the new thermocoupler was thicker and tougher looking than the old one (not a bad thing).

However, the nut at the end needs about 10 turns to screw it into the hot end of the extruder. With the wire being stiff it’s tricky to twist it this amount of times, but I had a solution…

I twisted the wire 10 times anticlockwise before screwing the nut into the hot end. What this meant was that the thing pretty much screwed itself in as the wire untwisted and it just required a little tightening with some pliers.

This method also meant that when the nut was screwed in fully the wire was no longer twisted as it had untwisted as I screwed it in. Made sense to me and I can highly recommend this method.

We don’t want overly twisted or sharply bent wires anywhere on our 3D printers because they’re bad news and end up in wires breaking over time, especially with all the moving parts putting pressure on the wires anyway.

With the new thermocoupler temperature readings were now back to normal. I’ve seen no more heating errors so far and I was back up and running again, or at least I thought I was…

Cooking the Nozzle

MakerBot in PiecesAfter a few small test prints, the usual comb and nut/bolt that comes preloaded on the MakerBot SD card, I had another attempt at the Emmets Gear Bearing. Click the link and you can see a picture of some of last weeks failed attempts.

This print has failed over and over for me and I really must be on my tenth attempt by now, but I cannot give up. Well, it failed again, twice, with extrusion stopping after anywhere between a few minutes and an hour, every time.

Incidentally while writing this it’s literally just failed AGAIN, with the stepper motor clicking implying a blockage. More on this in a second.

As you can imagine I’ve been getting pretty annoyed with this by now, especially after I’ve just had the thing apart and fitted a new thermocoupler.

If there was a partial blockage in the nozzle I needed to take drastic action, so long story short, I removed the nozzle and cooked it, heating it in a gas flame until the PLA plastic burned away.

I’d heard of people doing this quite successfully to clear a blocked nozzle and it worked quite well for me, as I could see though the 0.4mm nozzle hole and it was now perfectly clean.

Unfortunately this didn’t solve the problem and as I mentioned a minute ago my Nth attempt at the gear bearing has failed again. I’m almost out of ideas with this but I’m just going to try printing something else because it may have something to do with the nature of what I’m printing.

Watch this space because although I’m almost out of ideas I will solve it. I’ll keep you informed of how this issue unfolds.

Copper Plating Progress

Although I have bigger 3D printing issues to resolve right now, I have been looking into different ways of a producing better finish on my prints (the ones that work) and have been investigating copper plating.

RustOleum Copper SprayI have attempted to do a little brush plating on some coins I have. Using copper sulphate, a small power supply and some cotton buds I have managed to plate some coins.

What’s strange is that the plating looks ok, but occasionally a big black patch appears which isn’t so great.

This may be a number of things and I’ll continue to investigate this to achieve a better finish. The voltage might be too high because I’m using 12 volts, I will try lowering it and report back.

Many people seen to have great success with decent copper spray paint. Although this can’t be as good as copper plating it sure is easier and cheaper, so I’ve ordered some “Rust-Oleum Elegant Metallic Copper Spray Paint”. I’ll give this a try when it arrives. It might be great, or it might end up in the bin but again, I’ll report back on this with some pictures of items I’ve sprayed too.

New YouTube Channel

In my previous post in this series, I promised I’d put up a YouTube video of my first successful gear bearing 3D print. Well, as that hasn’t happened yet I decided to put on a video of my MakerBot in action, at least attempting to print one.

Here it is, my first ever video on our 3D Print HQ YouTube Channel. I’ve not uploaded anything to YouTube for years so I hope it looks ok?

Please let how it looks and I’ll use your feedback to post more videos on here, including the gear bearing in action (spinning freely) if and when I finally manage it.

Anyway, thanks for reading and as ever feel free to comment, like and share. It all helps me spread the word about the amazing (and sometimes frustrating) world of 3D printing.

Quickly before I go, I’m currently printing the LFS Elephant which I successfully printed a while ago. We’re 49 minutes in (59% complete) and it looks great. If it makes it to the end I’ll be celebrating 🙂

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{ 1 comment… read it below or add one }

Jason King July 13, 2014 at 11:48 am

By the way, the LFS Elephant printed really well so I’m convinced my MakerBot just doesn’t like printing the Gear Bearing with my current settings. The extrusion seems slow for this object which may mean that the plastic is being overheated.

Time to experiment a little with temperatures and different infill densities… if you have any ideas I’d love to hear them…

Thanks, Jason.


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