Resin 3D Printing for Beginners: SLA vs DLP Explained

When I pulled my first resin print off the build plate, a 28 mm tabletop miniature with individually visible chainmail links and facial expression, I understood immediately why people call resin printing "the detail printer." My best FDM prints at 0.08 mm layer height looked hand-carved compared to the precision coming off a $200 resin machine. The detail resolution is genuinely a different league.

But resin printing is not just "FDM but better." It is an entirely different process with different materials, different safety requirements, different post-processing, and different failure modes. I got into resin printing 18 months ago after years of FDM experience and still had a significant learning curve. This guide covers everything I wish someone had explained before I bought my first resin printer, so you can skip the expensive mistakes and get straight to printing incredible parts.

How Resin Printing Works

All resin 3D printers use the same fundamental principle: a light source selectively cures (hardens) liquid photopolymer resin, building an object layer by layer. The print hangs upside down from a build plate that lowers into a vat of liquid resin. For each layer, the light source exposes the bottom of the resin vat, hardening a thin layer against the build plate (or the previous layer). The plate lifts, fresh resin flows underneath, and the process repeats.

This bottom-up approach means the print grows downward from the build plate, which is the opposite mental model from FDM where prints grow upward from the bed. It also means the build volume is limited by the screen size (XY resolution) and the vertical travel of the Z-axis (build height), not by the size of a print bed.

SLA vs DLP vs MSLA: The Technology Breakdown

The three main resin printing technologies differ in how they project light onto the resin. Each approach has distinct trade-offs in resolution, speed, and cost.

SLA (Stereolithography)

SLA uses a focused laser beam that traces each layer point by point, similar to how a laser engraver works. The laser moves on galvanometer mirrors that steer the beam across the build area with extreme precision. SLA was the original resin printing technology (invented in the 1980s) and is still used in professional and industrial machines.

Advantages: Excellent detail resolution (the laser spot size can be as small as 25–85 microns), uniform quality across the entire build area (the laser delivers consistent energy regardless of position), and the ability to produce very large parts by scaling the build area without losing resolution.

Disadvantages: Slow. Because the laser traces each layer point by point, print time scales directly with the surface area of each layer. A full build plate takes significantly longer than a single small object. SLA machines are also more expensive due to the precision laser and galvanometer system. The Formlabs Form 4 ($3,500) is the most popular desktop SLA printer.

DLP (Digital Light Processing)

DLP uses a projector (similar to a presentation projector) to flash each entire layer as a single image. A digital micromirror device (DMD) inside the projector contains millions of tiny mirrors that individually tilt to create the projected pattern. Because the entire layer is exposed simultaneously, DLP is faster than SLA for full build plates.

Advantages: Faster than SLA for dense build plates, good resolution, and mature technology. DLP projectors can achieve very fine pixel pitch (25–50 microns) for high-detail applications.

Disadvantages: The projected image has a fixed resolution determined by the DMD chip. This means there is a trade-off between build area and XY resolution, a larger build area means each pixel covers more area, reducing detail. DLP machines also suffer from slight brightness falloff at the edges of the projected image (vignetting), which can cause inconsistent curing near the build plate edges.

MSLA (Masked Stereolithography / LCD)

MSLA is the technology that made resin printing affordable for consumers. Instead of a laser or projector, MSLA uses an LED array shining through an LCD screen (the "mask") that selectively blocks light. Each pixel on the LCD either passes light (curing resin) or blocks it (leaving resin liquid). Like DLP, the entire layer is exposed simultaneously.

Advantages: Dramatically cheaper than SLA or DLP. Consumer MSLA printers start at $150–$200. Modern monochrome LCD screens offer excellent resolution (35–50 micron pixel pitch), fast exposure times (1–3 seconds per layer), and uniform light distribution. The Elegoo Saturn 4 Ultra and Anycubic Photon Mono M7 represent the current state of the art for consumer MSLA.

Disadvantages: The LCD screen is a consumable component that degrades over time (typically 500–2000 hours of UV exposure before replacement needed). Like DLP, resolution is fixed by screen pixel count, so larger build areas mean lower XY resolution per pixel.

Safety: This Is Not Optional

This section is first in my setup checklist for a reason. Liquid resin is a skin sensitizer, respiratory irritant, and environmental hazard. Unlike FDM filament (which is inert plastic you can handle bare-handed), uncured resin requires real protective equipment every time you interact with it.

Nitrile gloves: Wear them every single time you handle resin, the build plate, the vat, or anything that has contacted uncured resin. Latex gloves are not sufficient, many resins dissolve or permeate latex. Use nitrile, and change gloves if you get resin on them. Repeated skin contact causes sensitization (allergic reaction) that is cumulative and potentially permanent. I know two people who developed resin allergies from casual handling and can no longer work with the material without severe skin reactions.

Ventilation: Resin emits volatile organic compounds (VOCs) that irritate the respiratory system. At minimum, operate your resin printer in a well-ventilated room with a window open. Better: use the printer in a garage, workshop, or dedicated space with an exhaust fan. Best: build or buy an enclosure with an activated carbon filter. The Elegoo Mini Air Purifier ($35) fits inside most printer enclosures and noticeably reduces odor and VOC exposure.

Eye protection: Safety glasses prevent splashes during pouring, handling, or cleaning. Some resins are mildly corrosive to eye tissue. This is basic lab safety.

UV protection: Uncured resin hardens when exposed to UV light (including sunlight). Keep resin bottles and the printer vat covered or in an opaque enclosure when not actively printing. Resin that cures inside the vat forms a solid sheet that can damage the LCD screen.

Essential Equipment Beyond the Printer

A resin printer by itself is not enough to produce finished parts. You need a post-processing workflow that adds cost and space requirements beyond what FDM demands.

Wash station: After printing, parts are coated in uncured liquid resin that must be removed. The standard approach is washing in isopropyl alcohol (IPA, 90%+) or a proprietary wash solution like Elegoo cleaning fluid. A magnetic stirrer wash station ($40–70) automates this. Elegoo Mercury Plus and Anycubic Wash & Cure machines combine washing and curing in one unit ($50–80). Budget option: two containers of IPA, dunk the part in the first for 2 minutes (dirty wash), then the second for 2 minutes (clean wash).

Cure station: After washing, parts need UV exposure to fully harden (post-cure). Under-cured parts are soft, tacky, and will yellow or degrade over time. A cure station with 405 nm UV LEDs and a turntable ($30–50) provides even curing in 5–15 minutes depending on resin type. DIY alternative: a cardboard box lined with aluminum foil and a 405 nm UV LED strip ($10) works surprisingly well.

FEP film: The transparent film at the bottom of the resin vat (FEP or nFEP) is a consumable. It stretches, clouds, and eventually punctures with use. Stock FEP typically lasts 20–50 prints before replacement is needed. nFEP (newer variant) lasts longer and improves print separation. Keep 2–3 spare sheets ($5–10 each) on hand so a punctured FEP does not halt your printing.

Supplies: Nitrile gloves (buy in bulk), 90%+ IPA (or Elegoo cleaning solution if you prefer less flammable options), paper towels, plastic scrapers (metal scrapers can scratch the build plate and LCD), plastic funnels with paint filters for pouring unused resin back into the bottle, and UV-blocking containers for resin storage.

Choosing Your First Resin Printer (2026)

The consumer MSLA market has matured significantly. Here are my picks for beginners in 2026:

Best entry-level: Elegoo Mars 5 ($170–$200). 6.6-inch 4K mono LCD, 35-micron XY resolution, and a build volume large enough for miniatures, jewelry, and small functional parts. This is where I tell everyone to start, cheap enough that you are not devastated if resin printing is not for you, good enough that you will not feel limited as a beginner.

Best mid-range: Elegoo Saturn 4 Ultra ($350–$450). 10-inch 12K mono LCD with 19-micron XY resolution and tilting/peeling release mechanism that reduces peel forces and improves success rates for large prints. The build volume accommodates full-size helmets, large terrain pieces, and multi-part assemblies. This is what I use for 80% of my resin printing.

Best large-format: Anycubic Photon Mono M7 ($400–$500). 14-inch screen with 14K resolution and an enormous build volume. If you are printing cosplay armor, large-scale models, or production batches of parts, the M7's build area means fewer print sessions.

Resin Types: What to Print With

Standard resin is where you start. It produces detailed, rigid parts with a smooth surface finish. Standard resins cost $20–35 per kg, come in dozens of colors, and are the easiest to dial in. Cured parts are relatively brittle (comparable to hard candy, they snap rather than flex). Use standard resin for miniatures, display models, prototypes, and anything that will not experience mechanical stress.

ABS-like resin adds toughness and impact resistance. Parts flex slightly before breaking instead of shattering. This is the go-to for functional parts, enclosures, clips, and anything that needs to survive handling. ABS-like resins cost $25–40 per kg and require slightly longer exposure times than standard resin.

Water-washable resin replaces IPA with water for the cleaning step, which is cheaper and less flammable. Modern water-washable resins (2025–2026 formulations) have closed the quality gap with standard resins significantly. The downside: water-washable resin waste water cannot be dumped down the drain, it still contains toxic resin particles that must be cured and filtered out.

Flexible/elastic resin produces parts with rubber-like properties. Think gaskets, phone case inserts, and vibration mounts. Flexible resins are harder to print (they tend to deform during the peel step) and require slower lift speeds. For most flexible applications, I recommend TPU on an FDM printer instead, it is easier to work with and produces stronger flexible parts.

Slicing for Resin: Key Differences from FDM

Resin slicing uses different software and different parameters than FDM slicing. The most popular resin slicers are Lychee Slicer (my recommendation for beginners) and ChiTuBox. UVtools is essential for validating and repairing sliced files.

The critical settings that determine print success:

Layer height: 0.05 mm (50 microns) is the standard for detailed prints. 0.03 mm for maximum detail on small objects. 0.1 mm for faster prints where detail is less critical. Unlike FDM where layer height affects both detail and layer adhesion, resin layer height primarily affects Z-axis resolution and print time.

Exposure time: This is the resin equivalent of print speed. Each layer is exposed to UV light for a set duration (typically 1–3 seconds for mono LCD screens). Too short: under-curing causes soft, delaminating layers. Too long: over-curing causes loss of detail (light bleeds beyond pixel boundaries) and makes supports harder to remove. The correct exposure time depends on your specific resin, LCD screen, and ambient temperature.

Bottom exposure: The first 4–8 layers (bottom layers) are exposed for much longer (15–45 seconds) to ensure strong adhesion to the build plate. These layers are intentionally over-cured because the build plate adhesion force must exceed the peel force for every subsequent layer. If prints detach from the build plate mid-print (the most common resin print failure), increase bottom exposure or bottom layer count.

Lift speed and height: After each layer cures, the build plate lifts to peel the print from the FEP film. Lift speed (how fast it pulls away) and lift height (how far it rises) affect print success and speed. Too fast: the suction force rips the print off the supports. Too slow: each layer takes unnecessarily long. Start with the printer's default settings and adjust if you see layer separation or build plate adhesion failures.

Supports: The Make-or-Break Skill

Support generation is the most important skill in resin printing. Unlike FDM where supports are optional for many geometries, resin prints almost always need supports because the print hangs upside down from the build plate and each layer must resist the peel force from the FEP film.

The key principles: orient the model at 15–45 degrees to minimize large cross-sectional areas on any single layer (reducing peel force), place supports on surfaces that will be hidden or sanded, use light supports where possible (they are easier to remove and leave smaller marks), and ensure every island (disconnected section on any layer) has support.

Lychee Slicer's automatic support generation handles 70–80% of cases well. For the remaining 20–30%, you will need to add manual supports in areas the algorithm missed. Check each layer in the slicer's layer preview to verify there are no unsupported islands, a single unsupported island creates a loose cured piece that floats in the resin vat and can scratch your LCD screen.

Post-Processing Workflow

The complete workflow from print completion to finished part:

1. Remove from build plate (wear gloves). Use a plastic scraper at a low angle. Metal scrapers work but risk scratching the build plate surface, which can cause adhesion issues on future prints. Some build plates have a spring-steel flex plate system that lets you pop prints off by flexing the plate, a worthy upgrade if your printer supports it.

2. Wash in IPA or cleaning solution. Two-stage washing produces cleaner results: a dirty bath first (2 minutes), then a clean bath (2 minutes). Agitate the parts or use a magnetic stirrer. Do not leave parts in IPA for more than 10 minutes, prolonged soaking can soften the cured resin and degrade surface detail.

3. Remove supports after washing while the resin is slightly softened. Supports snap off cleanly with flush cutters. Remove them before post-curing, as fully cured supports are significantly harder to remove and leave larger marks.

4. Post-cure under 405 nm UV light. 5–15 minutes in a cure station, rotating for even exposure. Under-cured parts remain tacky and will yellow or become brittle over months. Properly cured parts are hard, dry to the touch, and stable long-term.

5. Sand and finish (optional). Resin sands beautifully, starting at 400 grit and progressing through 800, 1500, and 2000 grit for a smooth finish. Spray primer reveals surface imperfections for additional sanding. The final surface quality achievable with resin far exceeds FDM, making resin ideal for display pieces, prop replicas, and anything that will be painted.

FDM vs Resin: When to Use Which

Having both an FDM and a resin printer gives you the best of both worlds. Here is how I decide which technology to use for each project:

Use FDM for: Large parts (anything bigger than a fist), functional parts that need impact resistance or flexibility, multi-material prints, rapid prototyping where speed matters more than surface finish, and anything you want to print in engineering-grade materials (PETG, ASA, nylon, carbon fiber).

Use resin for: Miniatures and figurines, jewelry and fine art, dental and medical models, parts requiring sub-0.1 mm features, batch production of small identical parts (leveraging the "time equals height" advantage), and anything that will be painted or displayed where surface quality matters.

The two technologies are complementary, not competitive. My FDM printers handle about 70% of my projects (functional parts, enclosures, brackets, large prints) while my resin printer handles the remaining 30% (miniatures for D&D, fine-detail prototypes, and display pieces). Understanding when to reach for each tool is the real skill.

Resin printing has a steeper learning curve than FDM, mainly because of the safety requirements and post-processing workflow. But the results speak for themselves. Once you see what 35-micron XY resolution looks like on a finished print, you will understand why so many FDM users eventually add a resin machine to their workshop.