OVERVIEW

Stereolithography (SLA) is the most accurate and versatile rapid prototyping technology available. SLA prototypes are constructed from a liquid photopolymer that is selectively cured using an ultraviolet laser.

Due to their accuracy and ability to reproduce fine details, SLA models are perfect for use as concept models, form-and-fit studies, functional testing, and as master patterns for a variety of molding techniques.

 

PROCESS

Step 1 : The Preparation

SLA begins with a 3D CAD file that is oriented in the appropriate orientation for building the part. The data is then mathematically sliced into 2D cross-sections (layers) along the Z-axis. The layer data is then transferred to the SLA machine.

Step 2 : The Build

The SLA build begins with the build platform lowered into the resin of the SLA machine so that the surface of the platform is a layer-thickness below the surface of the resin.

Computer-controlled mirrors direct an ultraviolet laser beam across the surface of a vat of photo-curable liquid polymer. The laser traces boundaries and fills in a two-dimensional cross-section of the model. The resin hardens only where touched by the laser beam until the complete layer is formed.

When the layer is complete, the platform is lowered into the vat by one layer thickness and a mechanical blade deposits material over the solidified area. Successive layers are drawn or built layer by layer, one on top of another, each adhering to the last, until a three dimensional part is formed. This step of the process can take anywhere from a few hours to several days, depending on the size and complexity of the part.

Step 3 : The Completion

Once all the layers are drawn and the model is complete, the platform rises out of the vat and the excess resin is drained. The model is then removed from the platform, washed of excess resin, and then placed in a UV oven for a final curing. The part is then hand finished to the customer requirement.

 

APPLICATIONS

• Limited number of prototypes needed (1-10)
• Form and fit testing
• Functional testing (ex. snap-fit)
• Plastic part rapid tooling patterns
• Metal part rapid tooling patterns
• Focus group and presentation models

 

QUICKCAST™

QUICKCAST™ is a SLA build style that allows for the creation of direct shell investment castings patterns. The QuickCast™ method allows you to rapidly build highly accurate investment castings patterns, eliminating the expensive and time-consuming step of tooling when a limited number of castings is required.

Instead of the SLA part being completely solid, QuickCast™ eliminates 95% of the internal mass of the part. This is achieved by curing only external surfaces and an internal lattice structure. Holes in the bottom of the part allow uncured resin to drain from the part. The result is a 65-80% hollow part with an internal lattice structure that gives the part structural integrity.

QuickCast™ replaces traditional wax patterns for investment casting with patterns created in SLA material. During burnout, the QuickCast™ pattern collapses before the ceramic shell can crack. The QuickCast™ pattern will burn out in the investment casting process leaving little residue in the cavity that can easily be evacuated.