Rapid Prototyping & 3D Modeling in the Chicago area - Exact Proto

Rapid Prototyping & 3D Models



StereoLithogrAphy: Is an additive fabrication process utilizing a vat of liquid UV-curable photo-polymer "resin" and a UV laser to build parts a layer at a time. On each layer, the laser beam traces a part cross-section pattern on the surface of the liquid resin. Exposure to the UV laser light cures, or, solidifies the pattern traced on the resin and adheres it to the layer below.

After a pattern has been traced, the SLA's elevator platform descends by a single layer thickness, typically 0.05 mm to 0.15 mm (0.002" to 0.006"). Then, a resin-filled blade sweeps across the part cross section, re-coating it with fresh material. On this new liquid surface the subsequent layer pattern is traced, adhering to the previous layer. A complete 3-D part is formed by this process. After building, parts are cleaned of excess resin by immersion in a chemical bath and then cured in a UV oven.


Selective Laser Sintering: Is an additive rapid manufacturing technique that uses a high power laser to fuse small particles of plastic, metal, ceramic, or glass powders into a mass representing a desired 3-dimensional object. The laser selectively fuses powdered material by scanning cross-sections generated from a 3-D digital description of the part (for example from a CAD file or scan data) on the surface of a powder bed. After each cross-section is scanned, the powder bed is lowered by one layer thickness, a new layer of material is applied on top, and the process is repeated until the part is completed.

SLS can produce parts from a relatively wide range of commercially available powder materials, including polymers (nylon, also glass-filled or with other fillers, and polystyrene), metals (steel, titanium, alloy mixtures, and composites) and green sand.


Fused Deposition Modeling: Like most other additive fabrication processes (such as 3D printing and stereolithography) FDM works on an "additive" principle by laying down material in layers. A plastic filament or metal wire is unwound from a coil and supplies material to an extrusion nozzle which can turn on and off the flow. The nozzle is heated to melt the material and can be moved in both horizontal and vertical directions by a numerically controlled mechanism, directly controlled by a computer-aided design software package. The model or part is produced by extruding small beads of thermoplastic material to from layers as the material hardens immediately after extrusion from the nozzle.

Several materials are available with different trade-offs between strength and temperature properties. As well as acrylonitrile butadiene styrene (ABS) polymer, the FDM technology can also be used with polycarbonates, polycaprolactone, polyphenylsulfones and waxes.


Objet: The PolyJet process provides fine detail and surface finish in prototypes and manufactured parts. In a process similar to ink jetting, liquid photo polymer resin is jetted out in fine layers to build a model. The layers measure only 16 microns (0.0006 in.) which results in a superior surface finish smoothness.

The materials are jetted in ultra-thin layers onto a build tray, layer by layer, until the part is completed. Each photopolymer layer is cured by UV light immediately after it is jetted, producing fully cured models that can be handled and used immediately, without post-curing.

It offers the completely unique ability to print parts and assemblies made of multiple model materials, with different mechanical or physical properties, all in a single build. Taking the revolution even further!

Printing with Digital Materials allows you to print parts with specific Shore A values to match the values of the intended production materials. This capability opens up new opportunities, bringing you much closer to realizing the final product at an early stage, including feasibility testing and over-molding process simulation.


Z-Corp: Is a process where a plaster or starch based powder is spread out in layers from .0035" to .005" in thickness and the layers are bonded by cyanoacrolyte and ink for color. These models can be printed in monochromatic or in multiple colors at one time to produce a like-finished look for marketing models in just a few hours. The colors can be chosen in most CAD software and are exported with the model when saved as a VRML file. This process is very fast, and relatively inexpensive compared to the other processes, but may not provide the strength or flexibility of the others.

Urethane Castings

Urethane Castings: To start the mold making process, a master pattern is needed; it can be a part you supply, or a stereolithography prototype that has been finished. The master pattern is coated in a silicone-based liquid rubber. Once the liquid hardens, the master pattern is removed, and the void left behind is injected with a urethane casting material that best fits your material requirements. Using this process, several copies, or urethane castings, can be made of the initial prototype.