New Print: Cogsworth

I designed this in Sketchup, exported to STL, Skienforged to gcode, RepG’d to an S3G file, and printed. The feature I’m the most proud of is the pendulum inside his chest.

Digital Cogsworth

Digital Cogsworth

Cogsworth

Physical Cogsworth

The design needs to be tweaked a little since parts of him have too much plastic and a few parts have too little. But, overall I’m quite happy with the result.

How to unclog your extruder barrel and nozzle

Nozzle and barrel apart

Nozzle and barrel apart

Here’s the process I used to unclog my extruder barrel and nozzle without a lot of extra equipment.  Obviously you should take all reasonable safety precautions with goggles, gloves, tongs, with a fire extinguisher, etc.  Plan ahead and be safe.

1. Materials:

  • Clogged extruder
  • Yarn
  • Q-tips
  • Heavy iron hook
  • Wrench
  • A big rock
  • Ethernet cable
  • Wire strippers
  • Blow torch
  • Safety equipment
  • Drill bits
  • Thick rubber band
Cleaning the inside of the nozzle - kinda gross

Cleaning the inside of the nozzle - kinda gross

2. Process:

  1. Disassemble the extruder
    1. Since PLA had gotten into the threads I had to leave the extruder warm as I unscrewed the PTFE insulating barrier.
    2. Unwrap the heater – taking off the ceramic tape, thermistor, nichrome, and Kapton tape.
  2. Remove plastic from the extruder
    1. I wrapped the unsharp end of my smallest drill bit in a thick rubber band to give it a grip.
    2. I then rotated the drill bit into the barrel by hand.
    3. Extruder barrel and thick yarn

      Extruder barrel and thick yarn

    4. When I had gotten as much out as I could, I switched to a slightly larger drill bit (again wrapped in a rubber band for grip) and drilled out as much as I could.  I repeated this until I had gotten to my largest drill bit that would fit in the barrel.
    5. I used a precision flathead screwdriver to follow along the threads of the extruder barrel and chip out plastic.
    6. I used the same precision flathead screwdriver to follow the threads inside the PTFE and chip out plastic.
  3. Heat the barrel
    1. This prior post has pictures for the entire setup.
    2. I was unable to remove the nozzle from the barrel.  Don’t worry if you can’t either.
    3. Put the extruder nozzle and barrel inside the large washer so the barrel is hanging down through the washer with the nozzle keeping it in place.
    4. Place the washer on a big iron hook or some similar piece of large thick heavy metal.
    5. Weigh down one end of the hook with the rock.
    6. With all reasonable proper safety measures in place and with adult supervision, heat the barrel and nozzle with the blow torch until it emits black smoke (which you should NOT breathe) and then keep it hot until it stops emitting smoke.
    7. Flossing the nozzle with copper wire

      Flossing the nozzle with copper wire

    8. Use the wrench to pick up the assembly and check if you can see through the nozzle.
    9. If you can’t see through the nozzle, keep heating it.
    10. Once you can see through the nozzle, it’s time to clean the extruder again
  4. Clean the extruder
    1. Once the barrel and nozzle had been heated, I found the nozzle came off very easily.
    2. Clean out the large cavity of the nozzle with the Q tip.
    3. Clean out the barrel with the yarn by inserting the yarn and “flossing” it.
    4. I happened to have pieces of an ethernet cable lying around.  I cut open one of the wires inside and pulled out the thin copper strands.  I took two of them and fed them through the 0.5mm nozzle.  I “flossed” the nozzle until it felt reasonably clean.
  5. Reassemble!

Playing with fire

Well, not really playing.  But, I suppose not really “working” either.  Here’s how my experiments in unclogging a clogged extruder barrel went:

You can see where there is some minor plastic residue left over from the PLA in PTFE insulator which oozed into the threads.  I had used a precision screw driver to follow along the threads and chip out plastic.

PTFE insulator, mostly clean

PTFE insulator, mostly clean

Here’s the clogged barrel.  I had chipped out plastic from the threads using the same precision screwdriver.  You can see some of the scar marks from my brilliant idea to use a wrench on the smooth part of the barrel at one point.  (FYI, that was sarcasm – don’t use a wrench on the barrel.  It was, in fact, a bad idea).  I was totally unable to remove the nozzle from the barrel.

Extruder barrel, clogged

Extruder barrel, clogged

This was my idea for the setup so that the flame/heat would not discolor everything.  You can see where the nozzle has gotten a thin layer of black ABS fused to it.  Again, you can also see the marks on the nozzle where I tried to use a wrench.  And, again, not a good idea.  All I managed to do was just scar it up.

Extruder barrel with nut partway on

Extruder barrel with nut partway on

This is similar to the setup I settled on for trying to unclog the barrel.  I’m going to cut the suspense and let you know – this doesn’t work and you shouldn’t try it.  This setup did not work for two very important reasons you can learn from.  First, it was too low to the ground and the blow torch kept going out when I tilted it to get to the heater barrel.  Second, it relied on kitchen tiles – which is a terrible terrible idea.

Kitchen tiles - good intentions, bad idea

Kitchen tiles - good intentions, bad idea

Here’s the next part of the setup:  blow torch, flint, wrench for picking up hot things, and fire extinguisher.  Off camera right is a garden hose.  Again, this setup relies on kitchen tiles – which will actually shatter when this kind of heat is applied.  So don’t do it.  Oh, and it turned out I did have a blow torch – but it was empty.  :)

Setup - empty propane tank, bad kitchen tiles

Setup - empty propane tank, bad kitchen tiles

This is a better setup – with a brand new propane tank – but still a terrible idea with kitchen tiles.

Setup - FULL propane tank, bad kitchen tiles

Setup - FULL propane tank, bad kitchen tiles

This was a good setup.  Friend nearby with a garden hose and fire extinguisher, no nut on the barrel so it sits in the washer and is easier for me to heat the entire barrel, suspended in air by a metal hook, held down by a big rock, high enough that I didn’t have to tilt the blow torch.  Here you can see the scorched and shattered kitchen tile in the pile on the right.

GOOD setup with extruder barrel suspended in air by metal

GOOD setup with extruder barrel suspended in air by metal

Since I was in charge of the blow torch and my friend had the fire safety equipment I really only pictures of stuff as it was in a relatively cool state.  This means I did not get a picture of the barrel as I was heating it – I had gotten it glowing red hot which was pretty nifty.  I also missed out on getting a picture of flame spewing from the nozzle as the ABS inside ignited.  It was like a mini flame thrower tossing out a thick black smoke.

I was expecting some of the ABS to leak out of the bottom – but the barrel was essentially clean.  I could see all the way through the nozzle with no problem.

Burn with me

Doctor Who - "42"

Doctor Who - "42"

I’m really looking forward to my blow torch/clogged extruder barrel adventures.  Obviously, it will take place (1) outside (2) on a wide patch of cement (the non-flamable variety) (3) with a friend, hose, and fire extinguisher handy. 1  Since I haven’t had any time to do unclog it this week, I’ve been thinking about it all week.  And every time I do I remember this episode of Doctor Who and the phrase, “burn with me.”

A MakerBot, a blow torch, Doctor Who, and Hitchhiker’s Guide to the Galaxy.  Pinch me!

  1. Photo courtesy of BBC. []

MakerBot extruder clog experiment

DO NOT USE THIS extruder unclogger setup

DO NOT USE THIS extruder unclogger setup

UPDATE: DO NOT USE TILES!!!  THEY WILL SHATTER!  READ LATEST POST!

The bad news is this is my first clogged extruder.  The good news is I have all the spare parts to whip up a new extruder, no problem.  That means I can experiment with wild abandon!  My backup plan is to slice and dice the PTFE insulator into washers.

Having drilled out most of the plastic clog from the barrel, it’s mostly empty.  The PTFE is in pretty good shape with the threads intact, if a little worse for wear.  My plan to get the remaining plastic out of the nozzle is to put the nozzle/barrel assembly into the large washer upside down and prop it up on some ceramic tiles.

My hope is that by applying a heat source to the nozzle the plastic will just drip/fall out.  The suggestion for using a blow torch to clear out the barrel and nozzle comes from Rick Pollack / MakerGear.  Thanks again Rick!

By the way, wicked Google Sketchup skillz, no?

Leonardo Robot

Leonardo Robot

Leonardo Robot

Freaking cool. This robot was designed by jrombosky by taking the measurements/proportions/ratios from Leonardo DaVinci’s Virtuvian Man. Even if these proportions were all messed up, this would still be super awesome. It’s a little printable robot!!!

Lego Robot Set

Lego Robot Set

It reminds me of a lego set from a few years ago:

Noise reduction via rubber bands

A common question from some of my friends is “How noisy is the robot?”  Since getting the belts tensioned pretty well and getting the stepper motors tuned up, it’s a little noisier.  But, it is quieter than our dishwasher or central heating unit.

Rubber band for MakerBot noise reduction

Rubber band for MakerBot noise reduction

Besides making sure the rods are oiled and bolts tightened (they get loose with all the shaking) I noticed that compressing the two sides of the Y stage helped with noise reduction.  By taking a thick rubber band, stretching it, and tying a big knot in either end I can put it in the slots for the opto-endstop triggers.  This has helped a little.  You’ll notice I stretched them over the two bolts.  This seems to also have helped just a little bit.

Blue platform

Foam core build platform, covered in blue painters tape

Foam core build platform, covered in blue painters tape

As the caption suggests, this is just the foam core build platform placed on top of the wooden platform and taped down with blue painter’s tape.  The tape has worked very well for my first PLA print, the teapot.  I’ll try this new platform setup in a little bit.

Ball bearings

A standard MakerBot Cupcake CNC requires:

  • 8x 608 bearings for the four X axis threaded rods
  • 2x 608 bearings for the two Z axis pulleys
  • 1x 608 bearing for the X axis pulley
  • 1x 606 bearing for the Y axis pulley

With all the cool things that could be built with the addition of bearings to a MakerBot toolkit I wanted to pick up some additional bearings.  I figure I could print an improved version of my retractable spring loaded tape measure, the microlathe, and other cool things.

But, where to find these things?  My local hardware store didn’t carry them.  I went to a hobby shop nearby which had exactly two bearings for $5.  It sounded expensive, but I’d never priced bearings before and I really just wanted the two at the time.

A few weeks later I had a brainstorm.  Where could I find cheap skate ball bearings?  Well, why not a place that sells cheap skates!  I called my local used sporting goods store and they had a 16 pack of bearings for $5.  Right on.

Ball bearings

Ball bearings

Microlathe thoughts

Cathal Garvey’s Mircolathe is a printable mini lathe made from MakerBot printable parts, ball bearings, a dremmel and other minor parts.

Microlathe by Cathal Garvey

Microlathe by Cathal Garvey

Now, I don’t have a dremmel… but from problems are born solutions.  Everyone has an electric drill, right?  What if the back of the left printable piece had a flathead screwdriver shaped hollow?  You could pop a flathead screwdriver bit into the drill, slide the drill up to the microlathe, put the screwdriver bit into the hollow and turn it on.