WHAT YOU NEED TO KNOW ABOUT RAPID PROTOTYPING

WHAT YOU NEED TO KNOW ABOUT RAPID PROTOTYPING

1 - What is Rapid Prototyping?

Rapid Prototyping (RP) is the process of physically manufacturing parts from digitally modeled component files created using Computer-Aided Design (CAD) programs. In this method, the parts to be manufactured are first modeled in 3D within CAD programs. Then, the modeled parts are produced as physical objects using rapid prototyping machines. These models can be single parts or assemblies consisting of multiple components.

Rapid prototyping refers to the technology of devices that produce tangible models from 3D model files. The first examples of this technology emerged in the late 1980s. The company "3D Systems," founded by Charles Hull, made the first commercial production of this technique in 1988.

The working principle of rapid prototyping involves dividing each 3D model into layers of approximately 0.1 mm thickness and sequentially stacking these layers to form the desired product. Materials such as plastic-based powder, metal, or paper can be used in the layer formation process.

Some prototypes may require pre-production testing. Based on the test results, modifications can be made to the part model to refine its final form and properties. This ensures that the final version of the CAD model is determined before mass production.

2 - Purpose of Rapid Prototyping

When a new product idea is developed, rapid prototyping is essential for quickly identifying potential design flaws and bringing the product to market in the shortest possible time. The produced prototypes can also be used as master parts for mold production.

While early rapid prototyping methods had certain limitations, today, there are virtually no constraints regarding part complexity or industrial applications. Additionally, fully functional and moving prototypes can now be manufactured.

3 - Stages of Rapid Prototyping

• Digital design and CAD modeling
• Preparing the 3D printer
• Prototype production
• Post-processing and cleaning
• Testing and evaluation
• Refinement and optimization

4 - Reasons to Choose Rapid Prototyping

Compared to traditional physical model manufacturing, rapid prototyping enables part design and production within 1-2 business days. This significantly benefits companies, giving them a competitive edge.

Prototypes are highly beneficial for testing designs. They allow engineers to make informed decisions regarding product development and performance expectations.

Repeated testing of a product can be easily conducted using rapid prototyping, allowing design modifications based on test results.

This process enhances flexibility, whereas traditional prototyping methods can be time-consuming, costly, and challenging. Therefore, rapid prototyping is a fast and cost-effective solution.

While rapid prototyping is ideal for special, low-volume parts, mass production of frequently used components is still more efficient and cost-effective using traditional methods.

Despite its advantages, investing in a rapid prototyping system comes with high initial costs and requires maintenance, material cleaning, and expensive consumables, which may be considered disadvantages.

5 - Types of Rapid Prototyping

Rapid prototyping devices can be categorized based on their layering technique:

• Stereolithography (SLA)
• Laminated Object Manufacturing (LOM)
• Selective Laser Sintering (SLS)
• Fused Deposition Modeling (FDM)
• Solid Ground Curing (SGC)
• 3D Ink Jet Printing

5.1 Stereolithography (SLA)

SLA is based on the solidification of a liquid resin layer using ultraviolet (UV) laser beams. A computer-controlled laser system moves according to the geometry of the part, exposing specific areas of the resin. The workpiece platform is then lowered by one layer thickness, and a new photopolymer layer is spread on top. This process continues until the final 3D part is completed. The supporting structures are then removed, and the product is ready for use.

5.2 Laminated Object Manufacturing (LOM)

LOM involves spreading a polymer or metal sheet over a platform, followed by cutting the layer according to the part’s cross-sectional geometry. The platform then lowers by the thickness of the layer, and the process repeats until the complete model is built.

5.3 Selective Laser Sintering (SLS)

SLS (Selective Laser Sintering) and Selective Laser Melting (SLM) involve spreading metal or alloy powders over a base surface. A high-power laser selectively melts the powder, forming the cross-section of the part. After melting, the build platform lowers, and a new powder layer is applied. This cycle repeats until the entire 3D model is completed.

5.4 Fused Deposition Modeling (FDM)

FDM (Fused Deposition Modeling) is a widely used additive manufacturing method that utilizes thermoplastic materials. A filament material is fed through a heated extruder, which moves according to the part's geometry. As the layer is completed, the material solidifies, and the platform adjusts to form the next layer. Today, FDM is one of the most popular 3D printing techniques.

5.5 Solid Ground Curing (SGC)

SGC (Solid Ground Curing) involves creating layers using two separate systems. In the first system, a photopolymer is sprayed according to the part's geometry. The second system creates an electrophotographic mask on a glass plate. This mask is aligned with the photopolymer layer and solidified using UV light. Uncured sections are removed via vacuum, and melted wax is injected into the empty spaces. To harden the wax, the part is cooled on a metal plate. Finally, finishing tools remove surface irregularities, producing a smooth final product.

5.6 3D Ink Jet Printing

This process functions similarly to other additive manufacturing techniques. The heated material is extruded through a nozzle, forming 3D objects layer by layer. Although marketed under different names like PolyJet or MultiJet, their working principles are fundamentally the same. The photopolymer resin is cured using UV light, forming a solid 3D part.

A key advantage of this technology is its ability to create parts with different properties simultaneously—such as varying hardness and structural characteristics within a single component.

Article by: Hamit Arslan (Senior Mechanical Engineer)
Tezmaksan Academy – Training Coordinator