SLA or Carbon DLS? How to Choose a Prototype Process

Short answer: choose SLA when you need the finest detail, a surface that takes paint or plating, or a clear part. Choose Carbon DLS when the part has to behave like an injection-moulded one: strong in every direction, repeatable and ready for use.

By David Kent. Complete Fabrication runs both processes in Whittlesford, near Cambridge.

What each process does

SLA (stereolithography) cures liquid resin with a laser. It produces very accurate parts with fine detail, and the surface is non-porous, so it accepts primer, paint, clear coat and plating with little preparation. That makes it a good fit for presentation models, form-and-fit testing, casting patterns for vacuum casting, and clear parts such as light pipes and fluidics.

Carbon DLS (Digital Light Synthesis) uses projected light and oxygen-permeable optics with programmable resins. Because of the way it builds, parts have consistent mechanical properties in every direction, closer to an injection-moulded part than a conventional layer-by-layer print. Carbon lets you go from prototype assemblies to volume without tooling, from one part to one thousand.

How to choose

• The finest detail and a show surface: SLA
• A part painted, plated or polished to a high finish: SLA
• A clear or water-clear part: SLA
• A master pattern for vacuum casting: SLA
• Strength that does not depend on print direction: Carbon DLS
• Functional or end-use parts in repeatable batches: Carbon DLS
• Medical-grade, sterilisable material: Carbon DLS or SLA, depending on the resin
• Parts tomorrow: SLA, 24 hours as standard

A common route

Many projects use both. SLA models test the design early, then Carbon DLS or vacuum casting produces the functional batch. If the volume grows, the same CAD data can move to tooling.

Ask us

Send the CAD file and what the part has to do. We will recommend the process and quote it. We quote fast, and if you need a quote quickly, let us know and we will do our best to match your timings: Info@compfab.co.uk, +44 1223 836837.

Frequently asked questions

Is Carbon DLS stronger than SLA?

Carbon DLS parts have consistent mechanical properties in every direction and behave more like injection-moulded parts. SLA parts are accurate and detailed, and some resins are tough, but strength can vary with print direction.

Which is faster, SLA or Carbon DLS?

SLA at Complete Fabrication is ready in 24 hours as standard. Carbon DLS lead time varies with part size, quantity and finish.

Which gives the better surface for painting?

SLA. Its non-porous surface takes primer, paint, clear coat and plating with little preparation.