Thursday, 27 October 2016

How I Repair Broken 3D Printed Support Structures On The Fly (and Salvage Big Prints)

I do 3D printing, and sometimes I do large or complex 3D prints.  In these, there are sometimes large support structures as part of the print.  These are breakaway pieces that support parts of the model. They are intentionally fairly fragile - they are only as stiff and as thick as they need to be.  They are made to be strong enough to do the job, but also fragile enough to be easily broken away.

Unfortunately, sometimes they break accidentally during the printing process.  Maybe the print head pushed in the wrong spot - unwanted things can happen over 24 or 50+ hour print jobs.  It's bad news, because at worst it means the job is ruined.  All that time and plastic so far might be down the drain.

On the left is a support column.  It looks solid, but it's really just a very thin zigzag ribbon, and the taller it is, the easier it tends to be to snap.

I discovered a tool that is really useful to salvage some broken support pieces. On a longer print, all you really need to do is put some support and anchoring back where there is none.  If you provide some structure and stability, and the printer has enough printing left to do, then the support should slowly be able to pick up where it left off.  If you can anchor things, or at least provide some foundation without interfering with the new layers the head wants to lay down, then you can probably salvage the print.

At first I tried to use various glues - but they never really worked.  Either they are too hard to do a get-in-get-out application (because you need to dodge the print head), or they are too messy, or they are too hard to apply where you need, or they don't set quickly enough.

I eventually settled on a product called Bondic. It's a small dispenser of UV-curable resin.  The resin is a clear syrupy fluid that sets hard when it's hit by UV.  It hits all the bases for an emergency fix. 

Monday, 26 September 2016

3D Printed Laser Cutter Bed Clips

A short while ago I needed to laser cut a large number of 1/8" plywood panels.  Normally this would be no problem, but many of the panels were warped in various ways and would not lay completely flat.  This is a problem for laser cutting because it makes the cuts a little off, and sometimes the focus would be off enough to not quite cut through the material.

At the time I solved this by taping the edges of the panels down to the knife edge table, but that was really inconvenient so I came up with a solution for next time.  (A knife-edge table is a row of triangles - points up - that you lay a material onto when laser cutting it.)

I designed and 3D printed some clips that would snap down and grip a section of the table, and a little tab that would keep the edge of material held down tight.  It's specifically sized to work with 1/8" thick material, but they are low-profile and re-usable.

Printing on my Raise3D N2.
The top of the "V" has a tab to hold material down, the mouth of the "V" snaps over the table support.

Thursday, 16 June 2016

Evaluating the Perf+ Prototyping Board (or How to Build a Laziness Defender)

The Perf+ is part perfboard, part busboard, part something else entirely.  I recently tested it out to see how it measured up and whether it had a place in my toolbox.  Short version, yes it does but it has some quirks.

I built a fun project I called the Laziness Defender to test it out.  Read my writeup on Hackaday.com for the details.

Wednesday, 27 April 2016

Accidentally "Smuggled" Batteries from China

Well this was unexpected. I ordered some small batteries from China several weeks ago.  The other day, a package arrived.

I opened the padded envelope to find two cheap plastic cars.  "What the hell?  I didn't order any plastic cars from China via Swiss Post," I thought.  But the address is correct ... the supplier must have messed up my order.  (That would be a first - I've had a couple things not show up, but never be flat out wrong.)

"Huh, there's something rattling inside here," was my next thought.

I broke open the cheap, hollow plastic car to discover a battery inside each.


Well, I haven't seen that before.

I suspect shipping in this way is due to recent changes the USA has made to shipping regulations.  The USA says lithium-polymer cells can no longer be shipped by air, except as part of a device (i.e. installed as part of something else.)  Perhaps this is an effort to obey that regulation in letter, if not in spirit.




Friday, 19 February 2016

Tiny Dinosaur Hunting Parties


I updated my Tiny Dinosaurs With Rifles a short while ago to include display cases complete with little grass flats.  Something was still missing, so I added Velociraptors to accompany the rifle-toting T-Rex and form a complete hunting party.

Click the Read More link for pictures.

And of if you like laser-cut stuff, check out my Aliens Facehugger Popper!


Monday, 15 February 2016

Making the Star Wars Droid Translator Helmets: Droid Sounds Are Hard

When it came time to figure out a way to have my Star Wars Droid Translator Helmets speak "Droid" language, I didn't realize what a big job it was going to be.

The good news is that I've done the hard parts so you can reap the rewards!  Click read more to learn and download.

This is a followup to my original post about the details behind designing and building the Star Wars Droid Translator helmets.