Introduction:

What is Rapid Prototyping ?

Rapid prototyping is a group of techniques used to quickly

fabricate a scale model of a physical part or assembly using three-

dimensional computer aided design (CAD) data.

Fig-1 CAD Model Fig-2 Finished Part

History

The roots of Rapid Prototyping can be traced to Topography &

Photo sculpture

Topography was first proposed by Blanther in 1890.

Photo sculpture for 3D replicas of objects were proposed by Bogart

in 1969.

Fig-3: Topography Fig-4: Photo sculpture 3D

Fundamentals of Rapid Prototyping

RP techniques employ the some basic five-step process

1.Creating the 3D CAD model of the design

2.Converting the CAD model into STL format (stereo lithography)

3.Slicing the STL file into thin cross-sectional layers

4.Constructing the model one layer atop another

5.Cleaning and finishing the model

1. 2.

3. 4.

5.

Fig-5: Basic Steps in RP Technology

Classification of RP Systems

1. Liquid-Based

2. Solid-Based

3. Powder-Based

Direct Metal Laser Sintering (DMLS)

Direct metal laser sintering (DMLS) Is an additive

manufacturing technique that uses a laser as the power source to

sinter powdered material (typically metal), aiming the laser

automatically at points in space defined by a 3D model, binding

the material together to create a solid structure.

Working principle:

Fig-6: Step by step procedure of DMLS

Metal Powders used

Stainless steel 17-4

Aluminum

Titanium Ti-64

Nickel alloy IW 718

Advantages of DMLS

High speed: Because, no special tooling is required, parts can be

built in a matter of hours.

Complex geometries: Components can be designed with internal

features and passages that cannot be cast or otherwise machined.

High quality: DMLS creates parts with high accuracy and detailed

resolution.

Medical field

Application Aerospace Industries

Manufacturing Automotive

Limitations

Surfaces need to be polished.

Removing metal support structures and thermal post-processing is time

consuming (you can’t have the supports in a different material than the

part)

Case Study Titanium glasses using metal additive manufacturing

Fig-7: Titanium glasses

The eye venture decided to look into the possibility of using additive

manufacturing in titanium as this eliminated the need for tooling and also

allowed flexibility in future interchangeable designs of the frame can be made by

CAD data and the parts rebuilt quickly and cost effectively.

Conclusion

The DMLS uses high intensity laser source and imparts the energy over the metal powder as per the

required geometry pattern ,melts below it’s melting point and solidifies the metal powder to the

deposited layer without affecting the material properties.

DMLS process used for the actual material needed to make the part at one build time, there by

eliminates the secondary machining.

DMLS eliminates tool change & production line cost resulting in small batch & single part build cost

efficiency.

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