New MakerBot upgrade!

This most recent Z-Woggle arrester/eliminator is one of the most interesting.  Unlike the super-fantastic Z axis crank, this part does more than just make the MakerBot easier to use – it will almost certainly improve the quality of your prints.  Also, unlike it’s predecessors it does not require the installation of a second set of Z axis rods.

It’s pretty amazing how quickly upgrade parts can evolve.  The first version of this upgrade was posted on April 7, 2010 and this pretty nifty version was posted on May 10, 2010.

Another thing I like about this part is it easily made with a 3D printer, but much more difficult to manage with just a laser cutter.

One possible issue I could see with this part is that it may cost you a slight bit of Z axis resolution.  Since the part doesn’t appear to fit snugly in the Z stage, the Z axis rod will have to rotate a little before it will “catch.”  (Or, so I suspect).

Open Source Monopolies, Unicorns, and Perpetual Motion Machines

Want a hint?  They’re all imaginary.

There’s no such thing as a monopoly on a truly open source hardware project.  So what if someone cornered the market on some critical widget?  The plans are open source and your options are infinite:

  • Build your own widget.
  • Hire someone to make it for you.
  • Design an alternate part.
  • Design a new assembly using more available part.
  • Hack a work around until you can get the part.

Or, my personal favorite:

  • Start your own business producing and selling that very same critical widget.

These are not problems.  These are opportunities for creativity and innovation.

Optimal RepRap sizes

To my thinking there’s basically two optimal RepRap sizes (in terms of build area):

  • A small RepRap with a build area just large enough to replicate it’s largest part, one at a time
  • A large RepRap with a build area large enough to print all of it’s own parts in a single print job

Random tangent:  wouldn’t it be cool if all RepRaps came with the designs for their own printed parts already on board?  Just fire it up for the first time, calibrate, and start printing replacement parts.  (I realize this isn’t quite feasible – in order to be ready-printable the files would need to be in S3G format and the machine would have to run the STL’s through it’s own Skeinforge settings).

Blender help?

Ball joint thing

Ball joint thing

I’ve designed a new part for printing on Bender1 .  Here’s a picture of the part.  I’m trying to see if I can print a working ball joint.  Obviously, it needs to consist of  breakaway multi-parts.

If this works I’d like to try using it as a component of a larger more complicated object.  However, Skeinforge throws a fit every time I try to skein it.  I’m uploading it here in case anyone can help me fix it.

Printable ball joint v5

  1. If you’re just tuning in, that’s the name of my MakerBot []

First part prototyped!

I’ve just prototyped my first part for a client!  What fun!

He sent over some design files, we discussed some of the constraints of the MakerBot Cupcake CNC (overhang limits, printing resolution, ABS warpage, build sizes), went back and forth over several iterations of the design, and today I printed it up!

In getting ready to print his part I had tuned my ‘bot over the weekend.  The part has the absolute smoothest sides I’ve been able to print on anything to date with minimal stringing.  I’m really really proud of that print.  The resolution came out so well I want to reprint several prior prints – such as the TARDIS and dalek.

Anyone want a second hand TARDIS?

PLA versus ABS, initial thoughts

I’ve yet to print something big as I am still working out some of the black ABS specks from the extruder.  Of the things I have printed so far, it looks like the PLA feels more brittle than the ABS.  ABS will flex slightly when pressure is applied, whereas PLA seems to resist until it snaps.  I like that I’m not wasting PLA by building rafts any more, now that the raft option is turned off in Skeinforge.

PLA takes a little longer to cool which has a few effects on a build.  If the layer underneath is still molten and saggy, the layer on top will sag too.  When an ABS part is done printing you’re basically ready to remove it.  I find that a PLA object can still be a little soft for as much as 15-30 seconds after a build.

I’m loosing finer details on prints.  I just reprinted the toy fire truck swivel.  It turned out really nice except for the actual swivel part.  Unlike the ABS model where the swivel snapped off immediately, the PLA model’s swivel was pretty solid (once it cooled and hardened).  However, it came out too thin!  As I watched it print, the PLA was so warm that it just stretched back during parts of the print – meaning the extruder nozzle made the full circuit, but the plastic stretched a little and pulled back closer to it’s last position.  Uh, that may not sound like the clearest example.

Suffice it to say that small round details such as the swivel didn’t turn out very well.  Which is pretty odd since similar small round detailed parts on the teapot did turn out well.  I suppose part of the reason is the swivel was one small round part where the next hot layer was set down on the prior still hot layer, unlike on the teapot where the thin round spout would be drawn, then the body, then the thin round part for the handle and back over the body – so that by the time the next thin layer was set down the prior layer had cooled.

Dragging my feet on PLA

I’ve been a total slacker about getting started printing in PLA.  Part of the reason is I’ve seen others have a lot of problems printing with it – ruining extruders, oozing out of barriers, too hot, too cold, too just right, the heat is uneven, the barrel jams, etc, etc.  However, since I’ve been printing larger and larger objects I’m finding that warpage is become more of an issue.  This means I need to either buy/make a heated platform for the ABS or I need to switch to PLA.

There’s a few things I’d like to build that are big and flat.  I’d like to print up a modular chess board (already have it designed in my head, I just need to export it to Sketchup) and crank out a few Mendel or Mini Mendel pieces.

MakerBot Is The New Duct Tape

Google Sketchup Model of Broken Window Latch

Google Sketchup Model of Broken Window Latch

This summer I discovered that one of the window latches in my home was broken.  Since the windows are so old, I didn’t even bother checking for replacement parts at the hardware store.  My repair consisted of wrapping duct tape over the broken part and fitting back inside the latch mechanism.

It worked, but was a less than ideal fix.  The part had snapped in two places, making the entire part slightly unstable even when reinforced with duct tape.   Additionally, the extra thickness of the duct tape prevented the latch from sliding smoothly and eventually started to bunch up the duct tape.

Several months ago, figuring that it was only a matter of time before I bought a MakerBot CupCake CNC, I modeled the part in Google Sketchup.

After getting my MakerBot operational yesterday, this was my second print.  It was also my fourth print – another window was missing a latch entirely.  A little light sanding and a slight use of a hacksaw blade to separate the small divide underneath the part, and it was ready for installation.  Both latches installed without fuss and work far better than the duct tape version.

Window latches, top view

Window latches, top view

Window latches, underside

Window latches, underside

Unlike the duct tape fix, this repair permanently replaces the broken part with a functionally identical part that is also far more cosmetically appealing.  Best of all, I now live in a house that is partially built by a robot I made.  :)

Print 5: Replacement toy fire engine part

Here’s another part I printed.  The original piece was from a toy fire truck.  It served as a rotating platform, hinge, and guide for the fire ladder.  The toy broke when the part was pushed laterally, shearing the axle off.  Overall, I’d say it was a poorly designed piece.  The entire toy would have been much sturdier if the axle stuck out from the body of the truck in the form of a low round stub the rotating platform fit around.  However, I’m rarely consulted in the engineering of toy fire trucks.  :)

As with the window latch, I had taken the measurements and modeled the piece in Google Sketchup several months before ever purchasing my MakerBot.  I had to make several small changes to the design of the part to reduce overhangs.

Replacement toy fire truck part, for comparison

Replacement toy fire truck part, for comparison

Replacement toy fire truck part

Replacement toy fire truck part

This wasn’t the cleanest piece I’ve printed, but it’s fine for a part that is destined to be broken all over again.  If I were printing it again I’d widen the two walls which serve as the hinge to the ladder.  The piece I printed had the same kind of unevenness in the tall thin axle that I had on the handle of the Z-axis crank. The part became so blobby that I tried to sand it down to be more even – and accidentally snapped the axle off.  Hence, the piece of round chop stick glued into the part.  I’m still fiddling with the Skeinforge settings to deal with this issue.

The process was really pretty easy:  Measure broken piece -> model in Sketchup -> export to STL file using a plugin -> Skeinforge -> ReplicatorG -> FIRE THE MAKERBOT!

First and second test prints

Well, I’m trying the traditional mini-mug!

Mini-Mug test!

Mini-Mug test!

Something tells me they’re not watertight.  The first one (left) snapped off the foam-core raft part way through the build.  The second one (right) got all gloppy and then snapped off the foam core raft part way through the build.

Except for the fact they’re not even close to done, the adhesion between the layers seems pretty good.  The raft on the second one was a little gloppy which caused me to be a little apprehensive throughout the build.  After a few layers the gloppiness evened out.  However, it cropped up again, accumulated, got super gloppy, and ruined the build.