Tech Talk / By Martha Knight

PAHS technology lab's MakerBot 3D printer, with a Gator on the platform  Martha Knight Photo

Michelangelo is said to have explained how to sculpt an elephant: “You take a block of marble and remove everything that doesn’t look like an elephant.”

Perhaps a similar approach is used by the members of the Allegheny Mountain Carvers and chain saw sculptors, but with wood as the medium. But 3D printing is based on just the opposite: You start with nothing and keep adding to it until it looks like what you are making. It’s an additive process.

If you are a regular at these TechTalk sessions you have “heard” me go on and on about 3D printing. It’s the next big thing. It will revolutionize manufacturing, and maybe medicine, and auto repair and…

Well, I tend to get carried away, just reading and imagining about it. So imagine my delight when Doug Dickerson, technology instructor right here in Port Allegany Junior-Senior High School, brings an actual 3D printer to a school board meeting, where he and it are introduced by our very own superintendent, Gary Buchsen, who is clearly enthusiastic about the latest, grant-funded addition to the technology lab.

Dickerson demonstrated the workings of the nifty device. He used a laptop to show some more information about the device, and handed around objects made by students using the 3D printer.

Meanwhile I have been watching for “consumer class” 3D printers to hit the market, and sure enough, some have. I notice that there are some that cost about what early laser printers did.

When you realize how recently this printer, about the size of a full-size microwave, arrived in the technology lab, and think how briefly the students have been learning to use it, you will be all the more impressed with the printer’s capabilities.

Just as conventional printers can print something original, such as a graphical image you created in a drawing program, or a photo, or a school report (of course those ARE original, right?) or a poem or a novel, so can a 3D printer print something original you have designed with a Computer Aided Design (CAD) program and saved to a file.

And just as a conventional printer, maybe a laser or an inkjet, can also function as a copier, so a 3D printer can copy existing objects.

A copier is a print engine combined with a scanner. Multi-function machines outnumber straight copiers now, most of them scanning and copying as readily as they print whatever you send them from your computer; and some also send and receive faxes if they are hooked to phone lines and have the ability to convert images to sound signals, which they warble to decoders at the other end.

Even straight printers can function as copiers in the 2D world, as long as there is some sort of scanner for image capture, or even a digital camera. Just input your image to the computer, and have the computer send it to the printer.

This applies just as nicely to 3D printers, which can copy. They have built-in scanning capabilities, but scan in 3D. They can also accept files that have been created in CAD programs.

Another technology we have become familiar with in recent years has to do with 3D diagnostic imaging. Remember when that was 2D? X-rays hanging on that lighted screen while the doctor showed you the fracture or the bulging disc?

Then there were CAT scans and PET and MRIs, some done with hand-held devices (analogous to the hand-held scanners that were tethered to our computers in the 1990s), others performed as we were sent through a tunnel very, very slowly.

Probably some health care professional told us that the scan was something like collecting many images of very thin slices of us. As if we were not unnerved enough already.

Some 3D printers produce objects by recreating all the slices of the object as conceived in the design, or as detected in the scan.

A 3D modeling program creates a file of the object—in the case of an original object, it is a hypothetical object so far. Then the file must be converted to one that represents the many 2D horizontal slices that must be layered one on top of another, hundreds of thousands of them, until the object is built.

The greater the accuracy or the detail desired, the more layers are needed, and the thinner they are. Holding some objects the technology lab’s 3D printer had produced, I could not detect any “pixilation” or lack of detail in any, although a couple of the links of one little chain did have some surface irregularities.

“Our” 3D printer uses a fused deposition modeling (FDM) system. A plastic filament is fed from a spool to an extrusion nozzle which controls the flow, turning it on and off as required for each layer. The nozzle is hot enough to melt the material, and is moved horizontally and vertically by the CAM (computer-aided manufacturing) software. The material hardens as soon as it is applied.

Another term for this approach to 3D printing is fused filament fabrication (FFF). The process can use metal filament (wire) in printers meant for production of metal objects.

All this makes me think wistfully of the wondermous machine from Germany that was going to do lean manufacturing for Pittsburgh Corning. At great cost it was acquired. At seemingly endless expense it was tweaked and tested and tweaked again. Various engineers tried to cajole it into accomplishing just-in-time manufacturing, however many or few glass blocks had been ordered. But it would not. My sources tell me it still sits in a storage area, probably habitat for spiders.

Well, let’s get a 3D printer that can do glass! Is there glass filament that could be put into spools? Or some nozzles that can extrude at that temperature? No? Well heck, use polycarbonate! (You’re right. They wouldn’t be the same. Forget I suggested that.)