IMR Materials Testing Technical Blog

Additive manufacturing (AM), commonly known as 3D printing, has evolved from a niche prototyping tool into a versatile technology capable of producing a wide range of functional parts and products. While the image of a laser melting metal powder is a well-known example, it’s just one of many methods. The best approach depends on the final application, including material requirements, desired complexity, and cost. Today’s AM platforms are more affordable and efficient, allowing manufacturers to use them for large-scale production, not just prototyping.

Common Additive Manufacturing Methods

There are numerous AM methods, each with its own advantages and suitable applications. They generally fall into categories based on the material and the process used.

Powder Bed Fusion

These methods use a heat source to fuse powdered material, layer by layer.

• Selective Laser Sintering (SLS): This process partially melts powder with a laser. The unfused powder acts as a support structure during the build, eliminating the need for designed supports. It’s fast and ideal for functional prototypes and end-use parts.
• Selective Laser Melting (SLM): Similar to SLS, but it fully melts metallic powders with a high-powered laser. This produces stronger components with fewer voids, making it suitable for complex metal parts with thin walls.
• Electron Beam Melting (EBM): This method uses an electron beam to melt and fuse metallic powders. It’s often used for demanding applications like aerospace components due to its ability to characterize material properties under various conditions.

Directed Energy Deposition (DED)

These methods use a focused energy source, such as a laser or electron beam, to melt material as it’s deposited.

• Wire Arc Additive Manufacturing (WAAM): Unlike powder-based methods, WAAM melts metal wire with an electric arc. A robotic arm extrudes the melted wire onto a substrate, building the part layer by layer. It’s one of the fastest metal AM methods and is also popular for repairing parts.

Vat Photopolymerization

These methods use a liquid photopolymer resin in a vat, which is solidified by a light source.

• Stereolithography (SLA): The oldest 3D printing technology, SLA uses a UV light to cure and harden liquid photopolymers into detailed shapes.
• Digital Light Processing (DLP): Similar to SLA, but it uses arc lamps instead of UV light, resulting in faster print times while still providing high-resolution models. It’s a very economical choice and widely used for prototyping.

Material Extrusion

This category involves pushing a material through a nozzle to build an object.

• Fused Deposition Modeling (FDM): A popular technology for creating functional prototypes and manufacturing jigs. It provides accurate detailing and has an exceptional strength-to-weight ratio.

Binder Jetting (BJ)

This process uses a liquid binding agent to bond a powdered material, layer by layer.

• Binder Jetting: The printer nozzles extrude a liquid binder onto a powder bed. A new layer of powder is then swept over the fixture, and the process repeats. This method can use a wide array of materials, including metals.

Other Additive Manufacturing Methods

• Material Jetting (MJ): Also known as wax casting, this method is similar to an inkjet printer. It deposits droplets of material, like polymers or waxes, onto a build platform and cures each layer with UV light. It’s used to produce high-resolution parts for industries like dental and jewelry.
• Laminated Object Manufacturing (LOM): This rapid prototyping system uses heat and pressure to cut and fuse laminated layers of plastic or paper. It is one of the fastest and most affordable prototyping systems available.
• Sheet Lamination: This method uses ultrasonic welding to connect thin sheets of material. Parts created with this process often require additional CNC machining to be finalized.
• Direct Metal Laser Sintering (DMLS): This is a highly accurate form of metal 3D printing that uses a laser to heat and form metal powders. Parts made with DMLS are durable and often used in industries like aerospace and medical devices.

Benefits of Metal Additive Manufacturing

The advancements in metal AM technology have brought significant benefits to the manufacturing industry.

• Innovation: Designers can now rapidly prototype and test new ideas, accelerating the innovation process from weeks or months to just minutes.
• Cost-Effectiveness: Modern AM equipment is more affordable and efficient than traditional fabrication techniques, offering a significant return on investment.
• Eco-Friendly Efficiency: AM is often more energy-efficient and produces less waste compared to large-scale CNC machining.

Materials Testing and Quality Control

The success of additive manufacturing depends heavily on the quality of the materials used. IMR Test Labs offers a range of services to ensure the quality of both raw materials and finished parts.

Finished Part Testing: Once a part is complete, testing methods such as density tests, tensile, compression, and impact tests are used to measure the cohesiveness of the bonds and the durability of the final product. Fatigue testing also helps determine a component’s expected lifespan.

Powder Analysis: Since many 3D printers use powdered materials, testing services like chemical analysis and particle size testing are crucial to verify the quality of raw materials before production begins.

For more information on IMR’s Additive Manufacturing Testing & Analysis capabilities, click here.