Rapid Prototyping ManufacturingMECH 311

JOYSHAN THANGARAJAH

MEHDI AIT BEN LAARBI

What is a prototype?

A prototype is an early sample of a product• Used as a proof of concept• Allows manufacturers to examine a design more closely• Can be used to test new designs

Development of manufacturing over the last two centuries

• The aim is to use additive manufacturing of material instead of subtractive ones or formative ones.

• Examples of subtractive manufacturing include: Turning, Boring, Milling, Drilling• Subtractive technologies may be used but only as a secondary, finishing process to

improve precision and accuracy.• Can be also referred to as free-form fabrication, computer automated manufacturing

or layered manufacturing

What is Rapid Prototyping?

What is Rapid Prototyping?

Applications of RPM

Liquid-based SystemsMaterial that is to be process exists in liquid form, ex. Polymers and wax. Contains 4 main technologies:

• Stereolithography• Solid-Based Curing• Fused Deposition Modeling (FDM)• Ballistic particle manufacturing (BPM)

Stereolithography• Process is based on photosensitive liquid resin which solidifies in the presence of UV light.

• After one layer is formed by laser, the build platform on which the layer rests will move one thickness layer down and then a new layer is formed on top of the previously existing layer.

• This process is repeated until the part is obtained

Solid-Based Curing

• Very similar to Stereolithography with the addition of milling operations after each layer is formed.

Fused Deposition Modeling (FDM)• Material exists in solid form that is spooled

• Material is heated to temperatures slightly above its melting temperatures and then deposited by a moving nozzle to form the layer.

• Support materials are also used for complex part shapes which are later removed.

Ballistic Particle Manufacturing (BPM)• Micro-droplets of molten wax are fired onto the platform. Droplets will solidify when they make

contact with the previous layer.• Nozzle moves while platform is stationary

Powder-Based Systems

This method uses powder material as an input. Contains 2 main technologies:

• 3D Printing• Selective Laser Sintering (SLS)

3D Printing

Selective Laser Sintering (SLS)

• Laser beam is used to cure a slice of powder that is in direct contact with the beam.

• Once a layer is formed, the elevator moves one thickness level down and a new layer of power is rolled on to be sintered again.

Solid-Based Systems

Laminated Object Manufacturing (LOM)

• Slices are cut in required contour from sheet material before using a laser beam.

• A hot roller binds the slice to the previous one, which activates an adhesive.

Advantages and Disadvantages of using RPM in Manufacturing

ADVANTAGES

Can easily make very complex parts

Cost efficient for both low and high volume production

Can produce multiple parts that are functional without the requirement for assembly

Minimizes material waste

Design errors can be quickly fixed with the modification of computer CAD models

DISADVANTAGES

Very poor precision and surface roughness for final products

High precision RPM systems are very expensive.

Mechanical properties such as elasticity and hardness are also lower. For this reason RPM parts cannot be used as final products but only prototypes.