Tuesday, 29 September 2009

Hairy Pea

I have had a few anonymous requests for a new post, so here is an object I made recently: -

It is a whistle downloaded from Thingiverse designed by Zaggo. It must be one of the most printed things on Thingiverse, and in a very short time after its posting. I think the reason it is so popular is that it is a functional item with a moving part (the pea) that is printed in situ. It is attached by one small point at its base and you detach it by pushing a scalpel through the slot.

It is very loud and annoys my wife every time I blow it!

The pea was initially very hairy because I get a lot of ooze with PLA. I had to pick the hairs off it through the slot, a bit tricky. I am currently working on a new extruder (when am I ever not?) with a much shorter melt zone to address this.

The reason I haven't posted for so long, apart from being on holiday in the Spanish Pyrenees, is that I have spent a long time thinking about the design of this one. It will also be super sturdy, so hopefully it will allow me to forget about extruders and move on to other things. I.e. new heads for HydraRaptor as it has spent too long having only two, so not living up to its name.


  1. Btw, on your picture there is a small brown colorization. Is it caused by the blobs, what you try to avoid in your new extruder design?

    Best regards,

  2. Not sure, it has been in my pocket for a few days. It is probably plastic that accumulates on the tip of the nozzle some times, burns, and then gets rubbed off onto the work piece.

    It is very hard to cure that completely. Covering the bulk of the nozzle with PTFE and wiping the nozzle frequently helps. It may well be a blob that got picked up onto the nozzle while building, i.e. after the nozzle wipe, in which case the next design should fix it.

    A complete cure would probably require a PTFE coating on the nozzle, including the tip, but I have no idea how to do that.

  3. Hey, I (resp. my object) made it on the HydraRaptor blog :D

    There's now a v2 of the whistle object, supposed to be (a little bit) quieter. Although, it should still be loud enough to annoy other people in the house...

  4. Which you intend to be the next head?

  5. SMT pick and place probably. I might add a big laser first though as more fun!

  6. I put a thin layer of silicone on the printhead. It makes the nozzle less sticky for thermoplasts, but only for a while. It does smoke for a while when you run it above 150 degrees. Not sure if its healthy smoke, so you should probably ventilate and stay out of the room for a while.

  7. Dude!!!
    Post stuff man!!! how are those heads comming along? what have you been printing lately?