Additive Manufacturing – A New Tool in the Manufacturing Toolbox Part 4

Blog Written by: Hutch Hutchison, Principal, Technology & Engineering, FuzeHub
This week we will explore 3-D Printing! Really! Yes, all of the techniques we have discussed so far have been variously tagged as 3-D Printing, and they are correct. It is just that now we are going to look at printers who perform much like the Inkjet printer we introduced in the first article, where we traced origins of this exciting technology.
POLYJET 3-D Printing
PolyJet 3D printing is similar to inkjet document printing. But instead of jetting drops of ink onto paper, PolyJet 3D printers jet layers of liquid photopolymer onto a build tray and cure them with UV light. The layers build up one at a time to create a 3D model or prototype. Fully cured models can be handled and used immediately, without additional post-curing, and in most cases, finishing. Along with the selected model materials, the 3D printer also jets a gel-like support material specially designed to uphold overhangs and complicated geometries. It is easily removed by hand and with water.

Objet, an Israeli company that recently merged with Stratasys, takes the inkjet printer analog to the extreme, with their Connex line of 3-D printers. All have the capability of printing up to 14 different materials, all jetted as shown in the above diagram. And Stratasys/Objet have a lot of materials to choose from! Over 100, including high temperature, transparent, rigid opaque, polypropylene-like, rubber-like, bio-compatible and dental. What’s even cooler about this printer line is that you can concoct digital materials, from among the offerings, mixing from a recipe specified by the company, or experiment!.
You can have a realistic prototype made, such as this car, with a plastic body, metal-like features, and rubber-like tires, all in the same build:

Not to go overboard on Stratasys/Objet, but they have brought 3-D printing to a great manufacturing level, in that they offer substantial build volumes, ranging from 250 mm to 1000mm (10 inches to nearly 40 inches.) All available with 16 micron resolution and 0.1mm accuracy.
Here is a video, from OBJET, showing the use of the Connex 500 printing a number of wrenches. This shows the beauty of the process, producing movable parts, and multiple sizes on the same build tray.
Objet prints giant wrenches
BINDER PRINTING
Yet another method, similar to inkjet printing, involves the deposition of powder, which can be metal, (which we saw last week from EXOne) plastic, sand, or ceramics into the build platform, and the CAD file guides the printing by one or more nozzles dispensing adhesive binder. Here is a diagram of the process:

Here’s a video of the binder printing process, showing EXOne’s sand printing capability:
EXOne Sand 3-D Print
EXOne has done a wonderful job of bringing 3-D Printing into industrial prominence. The sand-printing technology you saw above has application in making molds for sizeable industrial castings. This leads one to consider the use of 3-D Printing to fabricate homes, or stone-like sculptures, both on a large scale. It’s been done, and continues to grow. Here’s a video of the dream of Italian Enrico Dini, a robotic engineer, who has invented “D-Shape”, a simple, but giant 3-D Binder printer that has promise for architecture. (Caution – this is a 6 minute video!)
D-Shape – Building Buildings?
So, That’s it for this week! We’ve now covered most of the basic means of Additive Manufacturing, From SLA to 3-D Printing. Next week, we will explore some of the “Wow” features of this exciting manufacturing technology, looking at some medical applications, from printing bones to printing skin – all possible. Tune in!