Stereolithography

A. Process

Stereolithography is a 3D printing process which produces 3D prototype parts layer by layer directly from 3D CAD data under computer control. The first step involves designing the 3D prototype by using a suitable CAD software or 3D scanning. This 3D CAD file is then prepared for building the 3D prototype by having the computer software slice it into hundreds of horizontal layers depending on its size. The 3D printer reads each sliced pattern produced by the CAD software and prints the object one layer at a time. This 3D printing technology uses a vat of ultraviolet curable photopolymer resin and an ultraviolet laser to build these 3D prototypes.

The first layer is printed as soon as the laser traces the first cross section of the part pattern on the surface of the liquid resin. The machine’s elevator platform then descends by a distance that is equal to one layer. After the machine descends to where it needs to be, a blade sweeps across the cross section of the first cured layer, re-coating it with fresh material. This creates a new liquid surface and the subsequent layer pattern is traced, joining the previous layer. This process is repeated until the entire prototype is printed.


B. Materials

1. ABS-like
This prototype material is an opaque white, low viscosity resin that produces accurate and durable prototypes with ABS-like performance and appearance.
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2. Flex
This prototype material is a clear amber resin that produces very high durability polypropylene-like parts.
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3. WC (Water Clear)
This prototype material is a clear, low viscosity resin with excellent accuracy.
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C. Design guidelines

1. Maximum build size
Maximum size for prototype parts that can be built using this technology is 25.6 in. x 29.5 in. x 19.6 in.

2. Tolerances
Tolerances of ±0.002 in. to ±0.004 in. can be typically achieved on prototype parts that are well designed.

3. Minimum feature size
Minimum feature size that can be achieved is 0.020 in. for prototypes that are well designed.

Sharp edges or pointsCurrent 3D printers cannot produce prototypes with sharp edges or points as minimum feature size is limited to 0.020 in.

ThreadsCurrent 3D printers cannot produce prototype parts with threads unless they are rough and on large diameters. Taps and dies are often used to create threads after the prototype is built.

Living hingesCurrent prototype materials do not work well with living hinges. Urethane casting process can be used instead if this feature is crucial.

Text or logosCurrent printers cannot produce prototype parts with text or logos which are less than the minimum recommended feature size of 0.020 in.

Hollow prototypes – Hollow prototypes are great because reduction in volume reduces cost and build time.


D. Surface finishes

There are eight surface finish levels available for this 3D printing technology. Please contact our knowledgeable technical team for more information.


E. Applications

Parts made using stereolithography 3D printing technology are typically used as master patterns for silicon molding, concept models or functional prototypes.

Created by RedOrum