additive manufacturing, 3D printed building, clean energy

7 Additive Manufacturing Categories You Need to Know

Read Time: 4 minutes

Whether you’re a hobbyist tinkerer or you build must-have products in a business setting, sometimes creating something amazing means learning about new tools.

You might already be familiar with some of these different additive manufacturing processes, but even if you are, you might find something here that better suits one of your intended projects or opens up new opportunities altogether. Read on for a quick guide on the seven different types of additive manufacturing.

VAT Photopolymerization

Photopolymerization is probably one of the more visually interesting additive manufacturing methods.

VAT polymerization begins with a build platform being lowered into liquefied photopolymer resin. A powerful UV light, controlled by computer, is applied where needed and cures the liquefied material into a solid shape. Your material choices include plastics, polymers and resins.

Unlike several of the other processes listed here, the VAT polymerization process itself does not provide support for the in-progress object being created — additional support may be required. However, it does result in high accuracy and lends itself well to larger build areas. Plus, the final product usually features a pleasing finish without the need for post-processing.

Powder Bed Fusion

Powder bed fusion refers to several similar manufacturing methods that cover a variety of build materials. The process works by first applying a very thin — less than .1 mm — layer of material onto a build platform. Then, using a laser, the powdered material is fused into place and shape. Electron beam melting is similar, but may use a vacuum. Direct metal laser sintering is the better choice for building with metals.

Because each cross-section of your intended product is fused one at a time, there is no inherent support structure, and the process is relatively slow. Powder bed fusion also uses somewhat more energy than other methods listed in this article. However, the process is relatively inexpensive and is a good choice for prototyping. The technology required also has a small footprint, meaning production of this kind doesn’t require a massive bespoke facility.

Binder Jetting (3D Printing)

3D printing, also called binder jetting, is taking the world by storm, and for good reason — it’s increasingly cost-effective, and new technologies make it more versatile all the time.

During this process, you’ll get to watch your product take shape as liquid bonding agents are applied alternatively with layers of powered plastics, ceramics and metals. The binders themselves may be organic or inorganic. Parts derived from metal or ceramic must be furnace-fired after the printing is complete.

An advantage of 3D printing is that it allows you to create full-color “prints” and parts. It also allows you to choose from a variety of materials and is a relatively high-turnover manufacturing method.

Material Jetting

Material jetting is similar to binder jetting. In this process, liquid material — including waxes, photopolymers and polymers — are dropped down onto a work surface. Of the manufacturing methods described in this piece, material jetting is most like the traditional inkjet printer you might have in your home office.

Ultraviolet light cures the finished object. Choose this method if cost is of concern to you — little material goes to waste in material jetting. A downside is that while material jetting is highly accurate, the limited material selection results in a product that might require additional materials for support.

Sheet Lamination

The term “sheet lamination” may refer to either ultrasonic additive manufacturing or laminated object manufacturing. Both processes are similar in that they involve ribbons, or sheets, of solid material. During the manufacturing process, ultrasonic welding fuses together ribbons of metal in ultrasonic additive manufacturing or joins sheets of paper with adhesive in laminated object manufacturing. Either way, the product takes shape layer by layer.

This process does result in some waste and requires additional computer numerical control machining to remove excess material not joined with the finished product. It is inexpensive and relatively fast, however. The finish on your product may vary, depending on the material you choose, and you may have to invest in additional finishing or post-processing.

Material Extrusion

Material extrusion is a branch of 3D printing — you’ll find it employed by hobbyist printers turning out basic builds and components in home and perhaps office settings.

In this manufacturing process, material is drawn through a nozzle and deposited on a build surface layer by layer. If the image in your head resembles a baker applying frosting with a frosting gun, you are not too far off.

Unlike other forms of 3D printing, the material passing through the nozzle must be applied consistently and under uniform pressure. An accurate and visually pleasing result depends on it. The variables involved in material extrusion make it one of the fussier methods here, and the physical limitations of the nozzle itself put an upper limit on the fit-and-finish of your final product. It’s also a somewhat slower process than some of the others seen here.

Directed Energy Deposition

You’ll also hear directed energy deposition referred to as laser-engineered net shaping or 3D laser cladding, among other terms. It’s a different type of additive manufacturing — one that’s generally employed to add new material to an existing object.

That also makes it a more complex process than some of the others. The process itself resembles material extrusion, except the nozzle arm can move more freely and along four or five axes. The arm deposits melted material onto the work object, where it then cools and solidifies. The base material may arrive spooled or powdered.

You cannot use this method with ceramics or polymers — only cobalt-chromium and titanium. This method is also not currently considered a mainstream additive manufacturing method. In addition, note that while this process gives you superior control over the grain structure of your product, you might desire post-processing for final fit-and-finish.

Creativity Comes Next

By now, you should have a good foundational knowledge of the different types of additive manufacturing. From here, it’s a matter of consulting your imagination, coming up with a can’t-miss product and matching it with a suitable additive manufacturing technique. And as each of these processes gets refined even further by new technologies, your imagination will feel even more unfettered.

Featured Image By: The U.S. Department of Energy via Flickr

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Article by: Megan Ray Nichols

Megan Ray Nichols is a freelance science writer and science enthusiast. Her favorite subjects include astronomy and the environment. She encourages discussions in these fields. Megan is also a regular contributor to Datafloq, The Energy Collective, and David Renke’s World of Space. When she isn’t writing, Megan loves watching movies, hiking and stargazing.

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