Snapmaker down!

Tl/dr: If you are using a Snapmaker – I recommend re-tightening the screws frequently otherwise it will shake itself apart!

Picture the scene: It’s morning, I’m sat downstairs sipping a warm cup of yorkshire gold tea. The soft hum of my Snapmaker 3D printer is in the background as it works its way through the next print (Faujasite). It’s mechanical rhythm oddly soothing against the backdrop of bird song and the distant roar of an A road. Suddenly the song changes. The soothing mechanical purr is no more. Instead a deep, thumping, screech comes from up the stairs. I spring into action. Taking the steep, carpeted steps two at a time, yanking myself up using the wobbly banister I make it upstairs. I dash into what we call the ‘Student room’ and find the Snapmaker doing it’s best impression of a CNC machine with it’s hot end.

The print is ruined.

The beautiful print plate is scraped (brass is harder than aluminium). The heating block is dangling out of the bottom of the FDM (Fused Deposition Modelling) head.

My tea is cold.

This could happen to you!

So what happened?

I’ve noticed in the nearly a year I’ve been working with the Snapmaker that it slowly shakes itself apart, so am always tightening external screws. I didn’t think the internal ones would be as susceptible. I was wrong.

One of the grub screws holding the print head in place to the heat sink had come loose, dropping the heating block, causing a homing error which caused mass destruction.

Print head from Snapmaker with casing removed – hot end (blue arrow) with thermocouple (white cable) and heating element (red cable). The offending grub screw is identified by the green arrow recessed in the heat sink

Luckily I’ve discovered that the Snapmaker is pretty good for user repairs (I’d previously junked a old heating block due to filament being forced back inside) and after opening up the case (above) I quickly found the loose grub screw. It’s printed a couple of test prints beautifully now so is now re-printing the P2 space group example as I type.. Wish me luck!

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P1 failure

Half the fun in science, engineering or life in general really, is getting it wrong. The entire point of the maker movement is the ideal that ‘making is the process, not the end result’.

I believe in this fully. It is why problem based learning is the core of our internal offer at Winchester Science Centre. We need to show people it is OK to fail, and quite often more interesting!

So, soap-box moment over. My first print for this project? Failed:

The filament snapped about 4 hours into the print. Now I’ve noticed the prima value PLA I’m using is a bit more brittle than I’m used to, but it wasn’t the culprit..

The spool was a bit too big for the Snapmaker spool holder, and so after I left for work with the spool balancing on the end, the filament feeder tugged it closer, and closer and closer to the enclosure until it caught on a protruding screw and stuck.

Tug. Tug.

Snap.

Ah well, now I know and I’ve come up with an ingenious way to fix it:

Yup, a washie-tape washer. Here goes attempt number two!

Edit1:

Turns out attempt number two went a bit further but another problem, good old physics, rose its head:

When the model gets to about 60 mm in height the force of the print head moving around is enough to knock it off the raft – doh!

I’ll rotate the model in Snapmaker so there is more contact with the raft and try that next..

Edit2:

Damn, in my attempt to make the overall structure stronger, I forgot the lesson I learnt from printing tactile planets: ‘spheres do not like to stay on rafts’.. See if you can spot where it went wrong..