Stereo Lithography Presentation

A SEMINAR ON

GUIDED BY, PROF. PETER A R

PRESENTED BY, SOORAJ P N S7MB ROLL NO: 127

CONTENTS Prototyping Rapid prototyping process Stereo lithography

Machine Process Material used

Benefits Application Problems with RP Conclusion

PROTOTYPING

1. Subtractive (conventional process) Milling Grinding Turning

2. Compressive3. Additive

Photopolymer Thermoplastic Adhesives

Why Rapid Prototyping

Reduce product development time and cost

Get products to market sooner Enhance communications between

marketing, engineering, manufacturing, and purchasing

Present physical model at critical design reviews

Generate precise production tooling

Rapid Prototype Process You create a 3-D model of your object in a CAD program

Computer Aided Design (CAD)

Rapid Prototyping Device

3-D Object

BASIC PROCESS

Create CAD model of the design Conversion to STL format Slice the STL file Layer by layer construction Cleaning and finishing

Slices

Conversion of a solid model of an object into layers (only one layer is shown)

Software chops your CAD model up into thin layers -- typically five to 10 layers/millimeter

SLA Interface

Stereolithograpy was first commercial Solid Freeform Manufacturing process, released in 80’s by 3-D Systems

3-D Systems developed interface between CAD systems and their machine

STL files (*.stl) allow CAD systems to interface with 3-D system machines

Many CAD programs now can export the *.stl file for easy conversion from CAD to part

A typical Stereo lithography apparatus.

PARTS OF A SLA MACHINE Tank filled with several gallons of liquid

photopolymer. The photopolymer is a clear, liquid plastic. A perforated platform immersed in the tank. The platform can move up and down in the tank as the printing process proceeds. An ultraviolet laser A computer that drives the laser and the platform

INSIDE OF SLA MACHINE

SLA PLATFORM

MODELS ON PLATFORM

Polymer solidifies when struck by the laser’s intense UV light

Elevator lowers hardened cross section below liquid surface

Laser prints the next cross section directly on top of previous

After entire 3-d part is formed it is post-cured (UV light)

STEREO LIHOGRAPHY PROCESS

SLA MODEL BUILDS….

Stereolithography: (1) at the start of the process, in which the initial layer is added to the platform; and (2) after several layers have been added so that the part geometry gradually takes form

Stereo lithography Overview

LaserOpticsMirror Elevator

Laser is focused/shaped through optics. A computer controlledmirror directs laser to appropriatespot on photopolymer surface.Polymer solidifies wherever laserhits it.

When cross sectionis complete, elevatorindexes to prepare for next layer.

SLA MACHINE-OBJECT CURING PART

SLA Materials

Applications of SLA Technology

Aesthetic & conceptual models

Parts requiring detail & accuracy

Master patterns for castings

Benefits of SLA

Crisp, highly-detailed pieces

Speed of delivery (usually 2-3 days)

Tolerances within .005"/inch

Save Money Save Time

Test Product Catch Errors Improve Design Rapid

Manufacturing

Problems with Rapid Prototyping

Part accuracy: Staircase appearance for a sloping part

surface due to layering Shrinkage and distortion of RP parts

Limited variety of materials in RP Mechanical performance of the

fabricated parts is limited by the materials that is used in the RP process

Conclusions

Stereolithography is fast and effective. Stereolithography can be applied to

almost every industry, including oil refining, petrochemical, power and marine.

Stereolithography saves time, money, allows speed delivery, and improve designs

A MODEL..