Si trabaja con piezas fotopolimerizables impresas en 3D, ya sea para prototipos, modelos medicos, o joyería: comprender la rugosidad de la superficie es fundamental para satisfacer las necesidades funcionales y de calidad.. Impresión 3D fotopolimerizable (como SLA y DLP) es conocido por su alto nivel de detalle, but its surface roughness can vary widely from Real academia de bellas artes 0.5 μm en Ra 5 µm depending on key factors. This guide breaks down typical roughness ranges, factores de influencia centrales, practical application standards, and actionable tips to improve surface quality.
1. Typical Roughness Ranges for 3D Printed Light-Cured Surfaces
Impresión 3D fotopolimerizable (SLA and DLP) produces smoother surfaces than many other technologies (p.ej., MDF), but the exact roughness depends on technology type, parámetros, y materiales. Below is a detailed breakdown of standard ranges:
| Technology Type | Typical Roughness (Real academia de bellas artes) | Optimal Roughness (With Optimization) | Key Advantages for Surface Quality |
| SLA (Stereolithic) | 1 μm ~ 3 µm | < 1 µm | High laser precision, minimal layer lines |
| DLP (Procesamiento de luz digital) | 1 μm ~ 5 µm | ~ 1 µm (High-Resolution DLP) | Fast printing; 4K projectors narrow roughness gaps with SLA |
| General-Purpose Resin (Any Tech) | 2 μm ~ 5 µm | 1 μm ~ 2 µm (With Post-Processing) | Rentable; suitable for non-critical prototypes |
| High-Precision Resin (p.ej., Dental) | < 1 µm | 0.5 μm ~ 1 µm (With Fine Tuning) | Low shrinkage; ideal for medical or jewelry parts |
Nota: Real academia de bellas artes (Average Surface Roughness) is the most common metric—lower values mean smoother surfaces. Para referencia, a polished metal surface has an Ra of ~0.02 μm, while a standard light-cured part (without post-processing) falls between 1 μm ~ 3 µm.
2. 4 Core Factors That Impact Light-Cured Surface Roughness
Surface roughness isn’t random—it’s shaped by controllable factors. Understanding these lets you adjust parameters to achieve your desired smoothness. Below is a breakdown with specific examples and data:
(1) Printing Technology & Equipment Precision
The type of light-curing technology and device resolution directly affect surface quality:
- SLA: Uses a focused UV laser to cure resin layer by layer. Industrial-grade SLA machines (p.ej., Stratasys) have laser spot sizes as small as 0.02 milímetros, producing surfaces with Ra < 1 µm. Consumer-grade SLA machines may have larger spots (0.05 mm ~ 0.1 milímetros), leading to Ra 2 μm ~ 3 µm.
- DLP: Uses a projector to cure entire layers at once. Resolution matters here—4K DLP projectors (with smaller pixel sizes) can reach Ra ~ 1 µm, while 1080p projectors may result in Ra 3 μm ~ 5 μm due to visible pixel edges.
(2) Parámetros de impresión
Even with the right equipment, poor parameter settings can ruin surface smoothness. The two most critical parameters are:
Espesor de capa
Thinner layers mean fewer visible layer lines, but overly thin layers can cause resin flow issues. Here’s how layer thickness impacts roughness:
| Espesor de capa | Typical Roughness (Real academia de bellas artes) | Notes |
| 0.025 milímetros | 0.5 μm ~ 1 µm | Ideal for high-detail parts (p.ej., joyas) |
| 0.05 milímetros | 1 μm ~ 2 µm | Balances smoothness and print speed |
| 0.1 milímetros | 2 μm ~ 3 µm | Fast printing; visible layer lines |
| > 0.1 milímetros | 3 μm ~ 5 µm | Only for rough prototypes |
Exposure Time
- Insufficient exposure: Resin doesn’t cure fully, leaving sticky, superficies irregulares (Ra can jump to 4 μm ~ 6 µm).
- Overexposure: Resin shrinks excessively, causing warping or surface cracks (Ra increases by 1 μm ~ 2 µm).
Best practice: Follow the resin manufacturer’s recommended exposure time (p.ej., 5 seconds per layer for standard resin).
(3) Resin Material Properties
Not all resins are equal—formulation affects shrinkage and surface finish:
- Contracción: Most resins shrink 2% ~ 8% durante el curado. High-shrinkage resins (p.ej., general-purpose resin) pull the surface unevenly, leading to Ra 2 μm ~ 5 µm. Low-shrinkage resins (p.ej., dental-specific resin) shrink < 2%, producing Ra < 1 µm.
- Resin Type:
- General-purpose resin: Real academia de bellas artes 2 μm ~ 5 µm; affordable but rough.
- High-precision resin (p.ej., for medical models): Real academia de bellas artes < 1 µm; formulated for minimal shrinkage.
- Flexible resin: Slightly higher roughness (Real academia de bellas artes 1.5 μm ~ 3 µm) due to elastic properties.
(4) Post-Processing Processes
Post-processing is the final step to refine surface roughness—even a rough printed part can become smooth with the right treatments:
| Post-Processing Step | Roughness Reduction (Real academia de bellas artes) | Rango de costos (RMB/Piece) | Mejor para |
| Simple Cleaning (Isopropyl Alcohol) | 0.5 μm ~ 1 µm | 5 ~ 10 | Removes uncured resin; basic smoothness |
| Lijado (1200 ~ 2000 Grit Sandpaper) | 2 μm ~ 4 µm | 20 ~ 50 | Eliminates layer lines; Ra drops from 5 μm en < 1 µm |
| Pulido (Polishing Paste) | 0.3 μm ~ 0.5 µm | 30 ~ 80 | Acabado tipo espejo; ideal for jewelry |
| Secondary UV Curing | 0.2 μm ~ 0.5 µm | 10 ~ 30 | Reduces stickiness; improves surface uniformity |
| Pulverización (Clear Coat) | 0.5 μm ~ 1 µm | 40 ~ 100 | Fills micropores; adds protection |
3. Surface Roughness Standards for Practical Applications
Different use cases require different levels of smoothness. Below are common applications and their recommended roughness:
| Application Type | Required Roughness (Real academia de bellas artes) | Post-Processing Needed? | Key Reasoning |
| Basic Prototypes (p.ej., part fit checks) | 2 μm ~ 5 µm | No | Smoothness isn’t critical; saves time/cost |
| Aesthetic Parts (p.ej., custom figurines) | 1 μm ~ 2 µm | Sí (Lijado + Pulido) | Visible surface quality matters |
| Medical Models (p.ej., coronas dentales) | 0.5 μm ~ 1 µm | Sí (High-Precision Polishing) | Prevents bacterial growth; ensures biocompatibility |
| Joyas (p.ej., pendants) | < 1 µm | Sí (Pulido + Clear Coat) | Mirror finish enhances appearance |
| Partes funcionales (p.ej., engranajes pequeños) | 1 μm ~ 2 µm | Sí (Lijado) | Reduce la fricción; improves part longevity |
4. 5 Step-by-Step Tips to Improve Light-Cured Surface Roughness
If your parts are too rough, follow these actionable steps to optimize smoothness:
- Choose the right technology: Use industrial-grade SLA or 4K DLP for Ra < 1 µm; avoid low-resolution DLP machines for high-detail parts.
- Set thin, but not too thin, layers: Start with 0.05 mm layers (balances smoothness and speed); usar 0.025 mm for critical parts.
- Select low-shrinkage resin: Opt for dental or high-precision resin instead of general-purpose resin to reduce surface warping.
- Master exposure time: Test 3–5 exposure times (p.ej., 4s, 5s, 6s) to find the sweet spot—avoid under/overexposure.
- Invest in post-processing: For Ra < 1 µm, sand with 1200 grit sandpaper, then polish with a microfiber cloth and polishing paste.
Yigu Technology’s Perspective on Light-Cured Surface Roughness
En Yigu Tecnología, we believe balance between precision, costo, y necesidades de aplicación is key to managing light-cured surface roughness. Many clients overspend on ultra-thin layers or expensive post-processing when their parts don’t require it—for example, usando 0.025 mm layers for basic prototypes (unnecessary for Ra 2 μm ~ 5 µm). Our team helps clients match parameters to their use case: for dental models, we recommend industrial SLA + low-shrinkage resin + high-precision polishing (achieves Ra 0.5 μm ~ 1 µm); para prototipos, we suggest 0.1 mm layers + sin posprocesamiento (guarda 30% ~ 50% of time/cost). We also provide resin testing kits to let clients compare shrinkage and roughness before full-scale production—ensuring they get the right smoothness without overpaying.
Preguntas frecuentes
- Can DLP ever be smoother than SLA for light-cured parts?
Yes—high-resolution 4K DLP machines (with pixel sizes < 0.01 milímetros) can reach Ra ~ 1 µm, matching mid-grade SLA machines. Sin embargo, industrial-grade SLA (with smaller laser spots) still outperforms DLP for ultra-smooth surfaces (Real academia de bellas artes < 1 µm).
- Why does overly thin layer thickness (p.ej., < 0.02 milímetros) increase roughness?
Thinner layers require more frequent resin refilling, which can cause uneven resin levels across the build plate. This leads to inconsistent curing and visible surface defects, pushing Ra up by 1 μm ~ 2 μm compared to 0.025 mm layers.
- How much does post-processing (lijado + pulido) reduce roughness?
For a part with initial Ra 5 µm (de 0.1 mm layers + general resin), sanding with 1200 grit sandpaper can drop Ra to 1 μm ~ 2 µm. Adding polishing paste further reduces it to < 1 μm—total roughness reduction of 80% ~ 90%.