If you work with 3D printed light-cured parts—whether for prototypes, медицинские модели, or jewelry—understanding surface roughness is critical to meeting quality and functional needs. Light-cured 3D printing (like SLA and DLP) is known for high detail, but its surface roughness can vary widely from Раствор 0.5 мкм до РА 5 мкм depending on key factors. This guide breaks down typical roughness ranges, core influencing factors, practical application standards, and actionable tips to improve surface quality.
1. Typical Roughness Ranges for 3D Printed Light-Cured Surfaces
Light-cured 3D printing (SLA and DLP) produces smoother surfaces than many other technologies (НАПРИМЕР., ФДМ), but the exact roughness depends on technology type, параметры, и материалы. Below is a detailed breakdown of standard ranges:
| Технологический тип | Typical Roughness (Раствор) | Optimal Roughness (With Optimization) | Key Advantages for Surface Quality |
| СЛА (Stereolithic) | 1 μm ~ 3 мкм | < 1 мкм | High laser precision, Минимальные линии слоя |
| DLP (Цифровая обработка света) | 1 μm ~ 5 мкм | ~ 1 мкм (High-Resolution DLP) | Быстрая печать; 4K projectors narrow roughness gaps with SLA |
| General-Purpose Resin (Any Tech) | 2 μm ~ 5 мкм | 1 μm ~ 2 мкм (With Post-Processing) | Рентабельный; suitable for non-critical prototypes |
| High-Precision Resin (НАПРИМЕР., Стоматологический) | < 1 мкм | 0.5 μm ~ 1 мкм (With Fine Tuning) | Низкая усадка; ideal for medical or jewelry parts |
Примечание: Раствор (Average Surface Roughness) is the most common metric—lower values mean smoother surfaces. Для справки, a polished metal surface has an Ra of ~0.02 μm, while a standard light-cured part (без постобработки) falls between 1 μm ~ 3 мкм.
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) Технология печати & Equipment Precision
The type of light-curing technology and device resolution directly affect surface quality:
- СЛА: Uses a focused UV laser to cure resin layer by layer. Industrial-grade SLA machines (НАПРИМЕР., Страты) have laser spot sizes as small as 0.02 мм, producing surfaces with Ra < 1 мкм. Consumer-grade SLA machines may have larger spots (0.05 mm ~ 0.1 мм), leading to Ra 2 μm ~ 3 мкм.
- DLP: Uses a projector to cure entire layers at once. Resolution matters here—4K DLP projectors (with smaller pixel sizes) can reach Ra ~ 1 мкм, while 1080p projectors may result in Ra 3 μm ~ 5 μm due to visible pixel edges.
(2) Параметры печати
Even with the right equipment, poor parameter settings can ruin surface smoothness. The two most critical parameters are:
Толщина слоя
Thinner layers mean fewer visible layer lines, but overly thin layers can cause resin flow issues. Here’s how layer thickness impacts roughness:
| Толщина слоя | Typical Roughness (Раствор) | Примечания |
| 0.025 мм | 0.5 μm ~ 1 мкм | Ideal for high-detail parts (НАПРИМЕР., ювелирные изделия) |
| 0.05 мм | 1 μm ~ 2 мкм | Balances smoothness and print speed |
| 0.1 мм | 2 μm ~ 3 мкм | Быстрая печать; Видимые линии слоя |
| > 0.1 мм | 3 μm ~ 5 мкм | Only for rough prototypes |
Время контакта
- Insufficient exposure: Resin doesn’t cure fully, leaving sticky, неровные поверхности (Ra can jump to 4 μm ~ 6 мкм).
- Overexposure: Resin shrinks excessively, causing warping or surface cracks (Ra increases by 1 μm ~ 2 мкм).
Лучшая практика: Follow the resin manufacturer’s recommended exposure time (НАПРИМЕР., 5 seconds per layer for standard resin).
(3) Resin Material Properties
Not all resins are equal—formulation affects shrinkage and surface finish:
- Усадка: Most resins shrink 2% ~ 8% во время отверждения. High-shrinkage resins (НАПРИМЕР., general-purpose resin) pull the surface unevenly, leading to Ra 2 μm ~ 5 мкм. Low-shrinkage resins (НАПРИМЕР., dental-specific resin) shrink < 2%, producing Ra < 1 мкм.
- Тип смолы:
- General-purpose resin: Раствор 2 μm ~ 5 мкм; affordable but rough.
- High-precision resin (НАПРИМЕР., for medical models): Раствор < 1 мкм; formulated for minimal shrinkage.
- Flexible resin: Slightly higher roughness (Раствор 1.5 μm ~ 3 мкм) 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:
| Поступ-обработка шага | Roughness Reduction (Раствор) | Диапазон затрат (RMB/Piece) | Лучше всего для |
| Simple Cleaning (Isopropyl Alcohol) | 0.5 μm ~ 1 мкм | 5 ~ 10 | Removes uncured resin; Основная плавность |
| Шлифование (1200 ~ 2000 Grit Sandpaper) | 2 μm ~ 4 мкм | 20 ~ 50 | Eliminates layer lines; Ra drops from 5 мкм до < 1 мкм |
| Полировка (Полировка паста) | 0.3 μm ~ 0.5 мкм | 30 ~ 80 | Mirror-like finish; ideal for jewelry |
| Secondary UV Curing | 0.2 μm ~ 0.5 мкм | 10 ~ 30 | Reduces stickiness; improves surface uniformity |
| Распыление (Clear Coat) | 0.5 μm ~ 1 мкм | 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 (Раствор) | Post-Processing Needed? | Key Reasoning |
| Basic Prototypes (НАПРИМЕР., part fit checks) | 2 μm ~ 5 мкм | Нет | Smoothness isn’t critical; saves time/cost |
| Aesthetic Parts (НАПРИМЕР., custom figurines) | 1 μm ~ 2 мкм | Да (Шлифование + Полировка) | Visible surface quality matters |
| Медицинские модели (НАПРИМЕР., зубные короны) | 0.5 μm ~ 1 мкм | Да (High-Precision Polishing) | Prevents bacterial growth; ensures biocompatibility |
| Ювелирные изделия (НАПРИМЕР., подвески) | < 1 мкм | Да (Полировка + Clear Coat) | Mirror finish enhances appearance |
| Функциональные части (НАПРИМЕР., Небольшие шестерни) | 1 μm ~ 2 мкм | Да (Шлифование) | Уменьшает трение; 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 мкм; avoid low-resolution DLP machines for high-detail parts.
- Set thin, but not too thin, слои: Начните с 0.05 ММ слои (balances smoothness and speed); использовать 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 (НАПРИМЕР., 4с, 5с, 6с) to find the sweet spot—avoid under/overexposure.
- Invest in post-processing: For Ra < 1 мкм, sand with 1200 Грит наждачная бумага, then polish with a microfiber cloth and polishing paste.
Yigu Technology’s Perspective on Light-Cured Surface Roughness
В Yigu Technology, Мы верим balance between precision, расходы, and application needs 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, с использованием 0.025 mm layers for basic prototypes (unnecessary for Ra 2 μm ~ 5 мкм). 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 мкм); для прототипов, we suggest 0.1 ММ слои + no post-processing (спасение 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.
Часто задаваемые вопросы
- Can DLP ever be smoother than SLA for light-cured parts?
Yes—high-resolution 4K DLP machines (with pixel sizes < 0.01 мм) can reach Ra ~ 1 мкм, matching mid-grade SLA machines. Однако, industrial-grade SLA (with smaller laser spots) still outperforms DLP for ultra-smooth surfaces (Раствор < 1 мкм).
- Why does overly thin layer thickness (НАПРИМЕР., < 0.02 мм) 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 ММ слои.
- How much does post-processing (шлифование + полировка) reduce roughness?
For a part with initial Ra 5 мкм (от 0.1 ММ слои + general resin), sanding with 1200 grit sandpaper can drop Ra to 1 μm ~ 2 мкм. Adding polishing paste further reduces it to < 1 μm—total roughness reduction of 80% ~ 90%.