Knowledge Base

SLA vs DLP vs LCD: How to Choose Between Three Resin Processes

2026-08-21

Short answer: large parts needing consistent accuracy across the whole area → SLA; small high-precision batches (dental, jewellery) → DLP; budget-driven, best build area per dollar → LCD. The key difference is not "which is most accurate" but whether accuracy varies with build area, plus the fact that DLP and LCD expose a whole layer at once, so filling the plate costs almost no extra time.

The chemistry is identical in all three: a photoinitiator absorbs light at a specific wavelength and triggers cross-linking. The only difference is how the light is delivered to the right place — and that single difference determines the entire character of the machine.

How the Light Source Shapes Everything

SLA steers a laser spot across the cross-section with galvanometers, curing point by point. Because a single spot covers the whole area, the build envelope can grow without losing accuracy — the spot diameter does not change with build size. The cost is that print time scales with scanned area: bigger parts take longer, and every extra part on the plate adds its own time.

DLP projects the entire layer image at once using a digital micromirror device. The whole layer cures simultaneously, so time per layer is essentially constant — one part on the plate or twenty takes about the same time. That is the decisive advantage for batches of small parts. The cost: resolution equals projector pixel count divided by projected area, so a larger build area means giving up XY resolution, or stitching multiple projectors.

LCD (also called MSLA) uses an LCD panel as a mask with a UV LED array behind it. It also exposes a full layer, so it enjoys the same "filling the plate is free" benefit, and panels are far cheaper than projectors — which is precisely why LCD offers the best build area per dollar. Two costs you must account for: resolution is locked to the panel's physical pixels, and the panel is a consumable — prolonged UV exposure degrades it, so it needs periodic replacement based on usage.

Dimension	SLA (laser)	DLP (projector)	LCD / MSLA (masked)
Light source	Laser spot + galvo scanning	Digital micromirror projector	UV LED array + LCD mask
Exposure	Point-by-point scanning	Whole layer at once	Whole layer at once
Time per layer	Grows with scanned area	Essentially constant	Essentially constant
Cost of filling the plate	Proportional time increase	Almost none	Almost none
Accuracy vs build area	Accuracy holds as area grows	XY resolution drops as area grows	XY resolution drops as area grows
Large-format capability	Strong — the mainstream large-part route	Limited by projected area	Limited by panel size
Consumable part	Laser (long life)	Projector lamp / light module	LCD panel (periodic replacement)
Machine cost at equal area	High	Medium	Low
Typical work	Large precise prototypes, casting patterns, automotive trim	Dental batches, aligner models, jewellery	Figures, education, cost-sensitive small-part batches

"Accuracy" here refers to XY-plane resolution. Z accuracy is mainly set by the lift mechanism and layer height, and differs little between the three.

Working Backwards From Your Work

Large parts (beyond what a projector or panel can cover) needing uniform accuracy → SLA
Small parts but dozens to hundreds per run (dental models, guides, ring settings) → DLP; the full-layer batch benefit is largest here
Same small batches but budget-first and accuracy needs are not extreme → LCD
Investment-casting patterns → SLA or DLP depending on part size and batch; choose a low-ash-residue resin
Running a service bureau with mixed work → usually one SLA plus one DLP, covering "large and precise" and "small and many"

One line item buyers routinely miss: when comparing total cost of ownership between LCD and DLP, fold in the panel replacement interval. A panel is not expensive individually, but at production duty cycles it becomes a recurring cost that can flip the conclusion. Asking a supplier for expected panel life and replacement cost tells you far more than comparing machine prices alone.

Frequently Asked Questions

Can the three processes share the same resin?

Not necessarily. Resin must match the light wavelength (commonly a 355 nm laser versus 385/405 nm LEDs) and the exposure intensity. A resin rated for 405 nm LCD/DLP generally cannot be dropped into a 355 nm laser SLA machine. Select by the wavelength your machine requires rather than by the generic label "UV resin".

How often does an LCD panel need replacing?

It depends on cumulative exposure time and intensity, not calendar age — a machine in continuous production needs replacement far more often than one used occasionally. Warning signs are incomplete curing at unchanged settings, defects that recur at a fixed position, or under-exposure at the edges. Ask for expected life and replacement cost at purchase and fold both into total cost.

If DLP exposes a whole layer, why is SLA faster on large parts?

DLP's speed advantage applies within a fixed build area. Covering a larger area means either lowering resolution or stitching multiple projectors, both with penalties. An SLA laser scanning a big part needs no optical change — time simply increases linearly. So once parts get large enough, SLA is often the only option that still holds up on accuracy.

What post-processing is required?

The same for all three: wash off uncured resin (typically IPA or a dedicated wash) and post-cure in a UV chamber. Supported parts also need support removal and sanding. The labour in this step is routinely underestimated — when sizing capacity, count "print + post-process" as one pipeline rather than print time alone.