Here’s a little tip about tech blogs, and journalism in general: absolutely everything you read is one hundred percent true, except in the cases where you – the reader – know anything about the story being discussed. Th...
Here’s a little tip about tech blogs, and journalism in general: absolutely everything you read is one hundred percent true, except in the cases where you – the reader – know anything about the story being discussed. Those stores on Wired and CNet where a device using an ARM Cortex-M3 is described as having, “the same CPU as a modern-day smart phone?” Totally legit, unless you know that running Android on such a chip is a virtual impossibility.
Such is the case with ‘key 3D printing patents set to expire in 2014′ – a phrase bandied about tech blogs with the fervency of news the seventh seal has been broken. If you believe everything you read on the Internet, we’re looking at a world of 3D printed lollipops, unicorns, and rainbows in just a few short months. Following the logic of journalistic veracity above, this obviously isn’t the case. What does the expiration of these patents actually mean, then?
Let’s Back Up A Bit Here
The current crop of 3D printers use fused deposition modelling, FDM, or the ‘squirting melted plastic’ method. This technique was patented in 1989 by [Scott Crump], co-founder of Stratasys, one of the largest manufacturers of 3D printers. This patent expired in 2009, and there’s no coincidence 3D printing really started to pick up around that time with the development of the Reprap Mendel and the founding of what was previously the Open Hardware community’s golden child, Makerbot.
If past results are any indication of future performance, the expiration of these key 3D printing patents will result in yet another boom in the field of one-off manufacturing, rapid prototyping, and some really cool projects coming out of hackerspaces in the next year or two.
And Here Are The Patents
The ‘key patents‘ (just search for [Carl R. Deckard] as the inventor if you want more) referenced by hundreds of articles spread out all over the Internet involve selective laser sintering. What is SLS, you ask? It’s actually pretty simple: take some powder, shoot it with a laser, let the powder melt, and put a dusting of new powder over the mess you just created. You can use a wide range of plastics with SLS compared to the FDM Repraps and Makerbots we have today; you can even print in metal and make yourself a rocket engine. If NASA is doing it, it has to be awesome, right?
So What Makes SLS So Great?
Even though the current lineup of ‘squirting plastic’ printers is fairly capable and can do a lot in the right hands, there’s some stuff an FDM machine such as a RepRap or Makerbot can’t do. Overhangs are possible, but for very intricate shapes – a one foot tall scale model of the Eiffel Tower, perhaps – you’re looking at a world of hurt. The only way an FDM machine could print something like that is with two filaments, using one material as a support and later dissolving it away.
The same goes with printing parts inside parts like the popular ‘ball in a cage’ carving project. No squirting plastic 3D printer can do this without supports, but an SLS machine makes it very, very easy.
SLS also allows for many, many different materials. While most FDM machines will not see a filament besides ABS and PLA, laser sintering machines can print in just about any powder that melts. Everything from nylon to polycarbonate to metals are possible with laser sintering.
Finally. lasers allow for much higher accuracy than the most common 3D printers. While very accurate FDM machines can print with an accuracy equal to that of a human hair, this isn’t the case for the majority of RepRappers out there. SLS simply doesn’t have the problems of oozing and misaligned layers so common in home-built printers.
Why You Won’t Have an SLS Printer in Your Garage
Oversimplifying everything a great deal, these printers are basically made of two parts: a laser cutter on top, and a plunger