Printing goes 3D
A new generation of printers can bring your imagination to life.
WITH a loud whoosh of the cooling fan and a whir of the printhead, the bright orange machine slowly builds up a three-dimensional physical model of an object by melting plastic filament and depositing it, layer by layer.
Welcome to the world of 3D printing, where instead of simply printing on a flat piece of paper, machines with cute names like the MakerBot, Cube and the Up! Plus can produce real, three-dimensional models of almost any kind of product you can model in CAD (computer aided design) software, from toys to product prototypes.
Bytz met up with Jason Tay, the director of Pasosmas Sdn Bhd, a local IT consulting company located in Solaris Dutamas who bought a 3D printer to produce custom cases for tiny embedded computer systems. Tay is one of a small group of Malaysians who owns such a printer.
Right now, though, 3D printers are very much for the serious hobbyist or for companies interested in prototyping products, largely because of the cost of the hardware and the user-unfriendliness of most software available for such printers.
A small 3D printer like the Up! Plus that Tay uses, costs upwards of RM5,000, while the model most popular with hobbyists, the MakerBot, costs upwards of RM8,000 — certainly not a small investment for anyone just casually interested in printing out toys for their kids.
However, the ability to produce small, high-quality plastic components at a reasonable cost is a real benefit for small businesses.
“All those who shied away from more traditional means of fabrication — carpentry, CNC milling and such, will appreciate the clean, tidy and safe desktop manufacturing power of a 3D printer,” said Tay.
“Small businesses benefit by being able to produce their own plastic components and cases in-house, and can even begin lowvolume, on-demand production immediately, switching to injection moulded parts once volume is high enough to justify it.”
The technology
Like home photo printers, there are actually a number of different types of 3D printers on the market, utilising a number of different technologies to produce a 3D object, although the principle of building objects up layer by layer is essentially the same.
Expensive industrial 3D printers utilise a technology known as Selective Laser Sintering (SLS) which uses a high-powered laser to melt and fuse together plastic (or even glass)
particles to form a 3D object.
There are also 3D printers which spray a binding agent onto a powder to build up the object.
These printers can produce very fine, highquality objects, but are very expensive and have to go through an extra step to harden the final product.
However, the most common type of 3D printer for the home market is currently one which uses Fused Filament Fabrication — utilising a printhead which heats up a filament of ABS (acrylonitrile butadiene styrene) plastic or (polyactic acid, a kind of polyester derived from cornstarch) to melting point and depositing the material layer by layer to build up the object.
“These printers can accept either ABS or PLA, but while some prefer PLA because it’s made from environmentally friendly materials, ABS is actually recyclable and can be sent to a factory to be broken up and remanufactured back as more ABS plastic filament or other products,” said Tay.
Like a regular printer, a 3D printer’s quality is dependant on the resolution — the thinner the printed layer, the more detailed and smooth the final product can be.
The Up! Plus that Tay uses has a 150 micron resolution which is only a little thicker than human hair (which can be as thick as 120 microns).
The original (and popular) MakerBot Replicator only had a resolution of 200 microns although the latest model, the Replicator 2, has improved the resolution to 100 microns.
Modern 3D printers are capable of printing not just knobs and objects, but also fully articulated, moving parts in one single print job. For example, some people have printed fully-working toys with internal moving parts, or even a working model of a piston and driveshaft assembly in a single print job.
Printing process
The printer usually starts by printing a “raft,” which is a simple base on which the printer will then print the actual object.
For complex parts with moving parts, support structures are also printed to hold up those parts during the printing process.
Both the raft and the support structures can easily be broken or cut off once printing is done.
Again, like photo printers, the maximum size that can be printed largely depends on base size of the printer — the larger the base, the larger the maximum size of the object that can be printed.
Of course, larger objects can also be printed
if you split them into separate print jobs and then join the pieces together later.
Generally, objects printed using most 3D printers will come out with a characteristic “layered” or “terraced” pattern which requires some finishing if you want to make it smooth.
Objects made using ABS plastic filament (which is incidentally what Lego blocks are made of) can be sanded smooth or put in an acetone bath for a few seconds tomelt the surface layer smooth.
The products produced using most consumer grade 3D printers have only one tone — the colour of the plastic filament used.
However, some professional products are capable of printing in full colour as well, although it’s going to take awhile to see such printers available to home users and small businesses.
Challenges of software
Currently the biggest challenge in 3Dprinting is that the software is very much a hobbyist thing where many disparate pieces of software need to be utilised to produce the final product. t.
To start with, one needs to have a 3D CAD (computer-aided design) model of the object, which can be made in a variety of applications from professional to more user-friendly ones like Google Sketchup.
The file is then exported into a standard format called STL and then on some printers, a separate piece of software is used to “slice” the model into layers and turn them into instructions known as GCode, a simple text based instruction that can be understood by the printer.
“This is where more professional products like the Up! Plus have an advantage — the slicing is all handled by the supplied printer software and all I have to do is adjust the parameters, the scaling, positioning and rotation,” said Tay.
According to him, the software supplied with the Up! Plus is also better in that it’s more consistent and tuned to work well with the printer itself. Using open-source software will usually require one to tweak a lot of settings to get a good final productproduct.
Designing a 3D model in CAD software isn’t the only way to get a 3D model, however — Tay also uses a Microsoft Xbox Kinect module to scan and create 3D models of products and even humans.
Utilising the Kinect’s object tracking technology, it’s actually possible to build up a 3D model by pointing the device at it and walking around it.
However, since the Kinect was not originally designed to do this, it requires using a few different applications to capture
and then reconstruct the data received from the Kinect using
a computer. “There are still limitations and errors when scanning objects using Kinect. Some objects just scan better than others and sometimes you get a bumpy surface when scanning very flat surfaces,” he said.
Tay is currently looking into more accurate scanning methods by using other off the shelf parts like webcams in combination with a laser.
“Interestingly, a high resolution webcam isn’t required — even relatively low-resolution 640 x 480-pixel webcams are capable of producing a pretty high-quality 3D model,” he said.
As an early adopter, Tay admits that it’s going to take a while before 3D printing really hits the mainstream where any consumer can simply buy a 3D printer, then purchase a design online and print toys and other products at home.
“I can’t say if and when that will happen, but my experience with the 3D printer has made me a strong believer that many will find one indispensable,” Tay said.