AM 101: Continuous Liquid Interface Production (CLIP)

Continuous Liquid Interface Production (CLIP) is the key to Carbon's Digital Light Synthesis. Here's a look at how it works and how it differs from stereolithography.

What Is CLIP?

Continuous Liquid Interface Production (CLIP) is a proprietary process developed by Carbon. The process enables Digital Light Synthesis (DLS), the name for the company’s 3D printing system.

How Does CLIP Work?

The Continuous Liquid Interface Production (CLIP) process is based on stereolithography. Both processes use UV light to cure resin. Unlike stereolithography, however, the CLIP process doesn’t pause after each layer. Instead, the resin continuously flows through a “dead zone” just above the oxygen-permeable window, as shown below. UV images representing the cross-section of the part are projected onto an oxygen-permeable window to solidify the resin. Parts are built upside-down, as the build platform rises from the vat of resin.

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What Materials Can Be Used?

CLIP resins available from Carbon include elastomeric, flexible, rigid and medical-grade polyurethanes; silicone; cyanate ester; epoxy; urethane methacrylate; and dental materials.

What Postprocessing Is Required?

After printing, the parts are cleaned of resin and freed from the build plate. Any supports are removed. UV-curable resin parts are complete at this stage. Many materials, however, require a thermal post-cure in an oven; this can take from 4 to 13 hours to complete. The heat sets off a secondary chemical reaction that strengthens the parts. Typically no further postprocessing is required after cleaning and curing.

Why Use CLIP?

The continuous nature of the CLIP 3D printing process avoids the creation of layer lines in the part, offering a surface finish comparable to injection-molded parts. According to Carbon, CLIP parts are also watertight and isotropic, having the same strength in all directions. In addition to providing a means of making prototypes, CLIP can be used as an alternative for making production parts that would otherwise be injection-molded.

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