Technology: SLS, FDM and SLA

3D Prototype Design strives to be an industry leader by keeping current with technology and new materials as they become available. This allows us to provide our customers with the most current solutions, processes and parts.

While each method may have its own advantages, 3D Prototype Design still has a preference for the SLS process, as it offers the closest to final product characteristics available to date. The benefits of incorporating FDM and SLA 3D prototype design technology into our products often far outweigh the use of any other process and their strongest selling points, making it a better rapid prototyping solution.

Selective Laser Sintering (SLS)

Selective laser sintering uses a co2 laser to fuse powdered materials. As the laser contacts the powder bed, it raises the material to its sintering temperature to create a layer of solid part geometry.

The Process*

1. STL file is sliced to create layers
2. Laser draws the bottom-most layer
3. Powder is spread over completed layer
4. The process is repeated for subsequent layers
5. Upon completion, the powder cake is removed
6. Part is extracted from the loose powder
As the co2 laser scans across the powder bed, it brings the material to the melting point. At this temperature, individual particles bond at their contact points to solidify a layer of the prototype. The depth to which the powder solidifies is a function of laser power and material sintering temperature. Solidifying a single layer is controlled by passing the laser over the powder bed at a speed that imparts the necessary level of energy.

*3D Prototype Design builds only at 0.004" to offer the best resolution available to our customers. The typical layer thickness for the Selective Laser Sintering process is between 0.004" and 0.006".

Fused Deposition Modeling (FDM)

The FDM process forms three-dimensional plastic models and objects from CAD generated 3D solid or 3D surface models.

The 3D drawing is then ‘sliced’ by custom software into horizontal layers .010" thick. Support is automatically or custom generated based on the position and geometry of the part. Tool-paths are then created; path data is reviewed, changed if necessary and then downloaded to the FDM machine.

A temperature-controlled head extrudes abs or polycarbonate plastic material, layer by layer. It draws the prototype one layer at a time, similar to how a hot glue gun extrudes melted beads of glue. The designed object emerges as a solid three-dimensional part without the need for tooling.

Stereolithography (SLA)

The SLA process creates prototypes layer by layer using an ultra-violet laser, a vat of photo-curable liquid resin and a controlling system. After a layer is solidified, the building platform drops down by one more layer thickness into the vat of liquid resin, just below the surface and the laser touches down again, solidifying (or curing) the next layer.

At the same time each layer is created, a secondary support structure is also solidified. Layer thickness settings can vary depending on the type of machine use and the budget. (often the higher the resolution the higher the cost as more time in building is required)

Upon completion of all layers, the excess resin is drained. The model is taken from platform where the supports are removed and washed of excess resin and then placed in a UV oven for final curing.

At 3D Prototype, we use the most up-to-date FDM and SLA 3D prototype design technology to create the products that you can rely on for performance and functionality.

Note: Due to the nature of the process, SLA prototypes continue to cure even after the process is complete. In time, part brittleness will increase.