Digital Light Processing (DLP)

Digital Light Processing (DLP) 3D printing cures liquid photopolymer resin with projected light, producing high-detail plastic parts with smooth surfaces and fast layer exposure.

Overview

Digital Light Processing (DLP) is a resin 3D printing process that projects patterned light to cure an entire layer at once. It produces sharp features, smooth surfaces, and consistent XY resolution across the build area, making it strong for small-to-medium parts with fine detail. Parts require post-processing (washing, support removal, UV post-cure) and typically benefit from light finishing where supports touch.

Choose DLP for appearance models, detailed prototypes, small batch end-use parts, and elastomeric/clear resin components where feature fidelity matters more than bulk mechanical performance. Tradeoffs: photopolymer parts can be more brittle and UV/heat sensitive than thermoplastics, support placement affects cosmetics, and long unsupported spans can warp during cure. Tolerances are good for resin printing, but tight fits still need controlled orientation, cure process control, and often a secondary ream/tap.

Common Materials

  • Standard rigid resin
  • Tough resin
  • Flexible (shore) resin
  • High-temp resin
  • Castable resin
  • Clear resin

Tolerances

±0.003" to ±0.008"

Applications

  • Dental models and surgical guides
  • Hearing aid shells and small housings
  • High-detail appearance prototypes
  • Microfluidic and small manifold prototypes
  • Investment casting patterns (castable resin)
  • Small-batch enclosures with fine text/logos

When to Choose Digital Light Processing (DLP)

Pick DLP when you need fine features, smooth surfaces, and repeatable small-part quality in low volumes (one-offs through short runs). It fits parts that can be oriented with manageable supports and don’t require high continuous-temperature or long-term UV stability. Expect best results when critical dimensions are designed with post-cure shrink and finishing in mind.

vs Fused Deposition Modeling (FDM)

Choose DLP when surface finish, small features, and cosmetic detail matter and you can accept resin post-processing. DLP typically beats FDM on fine text, thin walls, and fit/finish, especially on small parts where layer lines are unacceptable.

vs Stereolithography (SLA)

Choose DLP when you want fast layer times and consistent in-plane resolution for small-to-medium parts with crisp edges. DLP often delivers similar surface quality to SLA, but can be more predictable for arrays of small parts where full-layer exposure improves throughput.

vs Selective Laser Sintering (SLS)

Choose DLP when you need smoother surfaces, finer detail, or transparent/elastic resin options and the part can tolerate supports. SLS is better for support-free builds and tougher thermoplastic behavior, but DLP wins on aesthetics and micro-features.

vs Multi Jet Fusion (MJF)

Choose DLP for higher detail and smoother cosmetics on small parts, especially where logos, textures, or sharp edges matter. MJF generally targets stronger thermoplastic performance and higher-volume nesting, while DLP favors precision-looking parts and specialty resin properties.

vs PolyJet

Choose DLP when you want strong detail and smooth surfaces without paying for multi-material jetting capability. PolyJet is better for true multi-material/color and very soft overmolds, while DLP is a simpler path for single-material high-detail parts.

Design Considerations

  • Orient critical surfaces to minimize supports and keep support touchpoints off cosmetic faces
  • Add small chamfers/fillets to reduce edge chipping and improve support removal on sharp corners
  • Use escape/drain holes and access for washing if printing hollow sections to avoid trapped resin
  • Oversize and post-machine precision bores, press fits, and threaded features; plan for inserts where needed
  • Control wall thickness and avoid large flat panels without ribs to reduce warp during post-cure
  • Call out finish expectations (as-printed vs sanded/painted) and identify critical dimensions tied to print orientation