Introduction
You hear the term "3D printing" everywhere. But 3D printing is not one technology. It is a family of technologies. Each works differently. Each uses different materials. Each serves different purposes.
The American Society for Testing and Materials (ASTM) defines seven categories of additive manufacturing. Understanding these categories helps you choose the right process for your project. Choose wrong, and your part may be weak, expensive, or impossible to make. Choose right, and you unlock design freedom and performance.
In this guide, we will explore all seven types. You will learn how each works, what materials they use, and where they excel. By the end, you will know which technology fits your needs.
What Are the Seven Types?
The seven categories are:
- Vat Photopolymerization
- Material Extrusion
- Powder Bed Fusion
- Material Jetting
- Binder Jetting
- Directed Energy Deposition
- Sheet Lamination
Let us explore each in detail.
Vat Photopolymerization
How It Works
Vat Photopolymerization uses light to cure liquid resin. A vat holds photosensitive resin. A light source—laser or projector—cures the resin layer by layer. The build platform moves up or down to expose fresh resin.
Key technologies:
- SLA (Stereolithography) – A laser traces each layer point by point.
- DLP (Digital Light Processing) – A projector cures an entire layer at once.
- CDLP (Continuous DLP) – A continuous process that prints faster by curing continuously.
Key specifications:
- Layer thickness: 0.025–0.15 mm
- Accuracy: ±0.05–0.1 mm
- Surface finish: Very smooth
Materials and Applications
| Materials | Applications |
|---|---|
| Standard resins | Visual prototypes, models |
| Tough resins | Functional prototypes |
| Castable resins | Jewelry patterns, investment casting |
| High-temperature resins | Heat-resistant parts |
| Dental resins | Crowns, bridges, surgical guides |
Real-world example: A dental lab prints surgical guides using SLA. The guides fit the patient's anatomy with ±0.05 mm accuracy. Surgeons use them to place implants precisely.
Material Extrusion
How It Works
Material Extrusion is the most common 3D printing technology. A nozzle heats and extrudes plastic filament. The printer moves the nozzle in X and Y directions, depositing material layer by layer. The build platform lowers after each layer.
Key technologies:
- FDM (Fused Deposition Modeling) – The trademarked term from Stratasys
- FFF (Fused Filament Fabrication) – The generic term for the same process
Key specifications:
- Layer thickness: 0.1–0.4 mm
- Accuracy: ±0.2–0.5 mm
- Build volume: From small desktop to over 1 meter
Materials and Applications
| Materials | Applications |
|---|---|
| PLA | Prototypes, educational models |
| ABS | Functional prototypes, automotive parts |
| PETG | Mechanical parts, containers |
| TPU | Flexible parts, seals, grips |
| Nylon | Gears, hinges, durable parts |
| PC | High-strength, heat-resistant parts |
Real-world example: A startup prints ergonomic handle prototypes in PLA. Each iteration costs under $10 and prints overnight. They test five designs in one week.
Powder Bed Fusion
How It Works
Powder Bed Fusion uses a heat source—laser or electron beam—to fuse powder particles. A layer of powder is spread across the build platform. The heat source fuses the powder where the part exists. The platform lowers, a new layer of powder is spread, and the process repeats. Unsintered powder acts as natural support.
Key technologies:
- SLS (Selective Laser Sintering) – Laser sinters plastic powder
- SLM (Selective Laser Melting) – Laser fully melts metal powder
- DMLS (Direct Metal Laser Sintering) – Similar to SLM for metal
- EBM (Electron Beam Melting) – Electron beam melts metal in vacuum
Key specifications:
- Layer thickness: 0.02–0.2 mm
- Accuracy: ±0.05–0.3 mm
- No support structures needed
Materials and Applications
| Materials | Applications |
|---|---|
| Nylon (PA12) | Functional plastic parts, housings, gears |
| Glass-filled nylon | Stiff, heat-resistant components |
| Titanium | Aerospace, medical implants |
| Aluminum | Lightweight structural parts |
| Stainless steel | Industrial parts, tools |
Real-world example: A drone manufacturer prints camera mounts in glass-filled nylon. The parts are 40 percent lighter than machined aluminum and survive crash tests.
Material Jetting
How It Works
Material Jetting ejects tiny droplets of liquid material onto a build platform. The droplets solidify immediately. The process is similar to inkjet printing but with 3D layers.
Key technologies:
- NPJ (Nano Particle Jetting) – Deposits nano-scale particles for high precision
- DOD (Drop-on-Demand) – Ejects droplets only when needed
Key specifications:
- Layer thickness: 0.01–0.05 mm
- Accuracy: ±0.05 mm
- High surface finish
Materials and Applications
| Materials | Applications |
|---|---|
| Photopolymers | High-detail prototypes |
| Wax | Investment casting patterns |
| Biocompatible resins | Medical models, surgical guides |
Real-world example: A jewelry designer prints wax patterns using material jetting. The patterns have smooth surfaces and capture fine details. They are used directly in lost-wax casting.
Binder Jetting
How It Works
Binder Jetting deposits a liquid binder onto a bed of powder. The binder bonds the powder particles together. After printing, the "green" part is sintered in a furnace to fuse the particles and remove the binder.
Key technologies:
- Metal Binder Jetting – For metal parts
- Sand Binder Jetting – For sand casting molds and cores
Key specifications:
- Layer thickness: 0.05–0.1 mm
- Shrinkage during sintering: 15–20 percent
- Large build volumes available
Materials and Applications
| Materials | Applications |
|---|---|
| Stainless steel | Industrial parts, tools |
| Sand | Casting molds, cores |
| Copper | Electrical components |
| Ceramics | High-temperature parts |
Real-world example: A foundry prints sand cores for engine blocks using binder jetting. Traditional core-making required multiple assemblies. The printed cores are one piece, reducing assembly time and improving casting quality.
Directed Energy Deposition
How It Works
Directed Energy Deposition (DED) uses a high-energy source—laser or electron beam—to melt material as it is deposited. Material is fed as powder or wire into the energy beam. The process is often used for repair or adding features to existing parts.
Key technologies:
- LENS (Laser Engineered Net Shaping) – Laser with powder feed
- EBAM (Electron Beam Additive Manufacturing) – Electron beam with wire feed
Key specifications:
- Layer thickness: 0.1–1.0 mm
- Accuracy: Moderate
- Large build volumes possible
Materials and Applications
| Materials | Applications |
|---|---|
| Titanium | Repair of aerospace components |
| Stainless steel | Adding features to existing parts |
| Inconel | Repair of turbine blades |
Real-world example: An aerospace company repairs a damaged turbine blade using DED. The blade is mounted in the machine. The laser deposits new material onto the worn area. After machining, the blade returns to service.
Sheet Lamination
How It Works
Sheet Lamination bonds thin sheets of material together. Each sheet is cut to shape using a laser or knife. The sheets are stacked and bonded using adhesive, heat, or ultrasonic welding.
Key technologies:
- LOM (Laminated Object Manufacturing) – Paper or plastic sheets with adhesive
- Ultrasonic Additive Manufacturing – Metal sheets bonded with ultrasonic welding
Key specifications:
- Layer thickness: 0.05–0.5 mm
- Accuracy: Moderate
- Low equipment cost
Materials and Applications
| Materials | Applications |
|---|---|
| Paper | Architectural models, prototypes |
| Plastic | Large-scale prototypes |
| Metal | Metal parts with embedded electronics |
Real-world example: An architectural firm prints large-scale building models using sheet lamination. The models are lightweight and can be scaled to any size. The process is faster than other methods for very large parts.
How Do the Seven Types Compare?
The table below summarizes key differences.
| Type | Materials | Accuracy | Speed | Equipment Cost | Best For |
|---|---|---|---|---|---|
| Vat Photopolymerization | Resins | High | Slow | Moderate | High-detail parts, jewelry, dental |
| Material Extrusion | Thermoplastics | Moderate | Slow | Low | Prototyping, education, low-cost |
| Powder Bed Fusion | Metals, plastics | High | Slow | High | Functional parts, aerospace, medical |
| Material Jetting | Resins, wax | Very high | Slow | High | High-detail, investment casting |
| Binder Jetting | Metals, sand | Moderate | Fast | Moderate | Medium-volume metal, casting molds |
| Directed Energy Deposition | Metals | Moderate | Slow | Very high | Repair, large-scale metal |
| Sheet Lamination | Paper, plastic, metal | Moderate | Moderate | Low | Large-scale models, prototypes |
Which Technology Should You Choose?
Decision Factors
What material do you need?
- Plastic functional part → Powder Bed Fusion (SLS) or Material Extrusion
- Metal functional part → Powder Bed Fusion (SLM/DMLS) or Binder Jetting
- High-detail plastic → Vat Photopolymerization or Material Jetting
What quantity do you need?
- 1–10 parts → Any technology works
- 10–100 parts → Powder Bed Fusion, Binder Jetting
- 100+ parts → Binder Jetting or traditional manufacturing
What is your budget?
- Low → Material Extrusion
- Moderate → Vat Photopolymerization, Binder Jetting
- High → Powder Bed Fusion (metal), Directed Energy Deposition
What surface finish do you need?
- Smooth → Vat Photopolymerization, Material Jetting
- Textured → Powder Bed Fusion
- Rough → Material Extrusion (requires post-processing)
Yigu Technology’s View
At Yigu Technology, we work with multiple additive manufacturing technologies. Our experience has taught us that no single technology is best for everything.
Case Study: Choosing for Prototypes
A client needed functional prototypes for a new consumer product. They wanted low cost and fast turnaround. We used Material Extrusion for initial form testing. Once the design stabilized, we switched to Vat Photopolymerization for high-detail presentation models. The combination saved time and money.
Case Study: Choosing for Production
A client needed 500 metal brackets with complex geometry. Traditional machining was too expensive. We evaluated Powder Bed Fusion and Binder Jetting. Binder jetting offered lower per-part cost for the quantity. We printed the brackets in stainless steel. The parts met all specifications at 40 percent lower cost than machining.
Our Approach
We match the technology to the need. We ask:
- What is the part’s function?
- What material properties are required?
- What quantity is needed?
- What is the budget?
- What is the timeline?
The answer guides our technology selection.
Conclusion
Additive manufacturing is not one technology. It is seven families of technologies, each with unique strengths.
Vat Photopolymerization delivers high detail. Material Extrusion offers low-cost accessibility. Powder Bed Fusion produces strong functional parts. Material Jetting achieves the highest precision. Binder Jetting scales to medium volumes. Directed Energy Deposition repairs and adds features. Sheet Lamination creates large, low-cost models.
The right choice depends on your material, geometry, quantity, and budget. By understanding the differences, you can select the technology that delivers the best results for your project.
FAQ
What is the difference between SLA, DLP, and CDLP in vat photopolymerization?
SLA uses a laser to trace each layer point by point. DLP uses a projector to cure an entire layer at once, which is faster. CDLP is a continuous process that cures material continuously as the build platform moves, making it the fastest of the three.
What is the difference between SLS, SLM, and DMLS in powder bed fusion?
SLS sinters plastic powder—the particles fuse without fully melting. SLM fully melts metal powder to create dense parts. DMLS is similar to SLM but often refers to the process for metal alloys. EBM uses an electron beam instead of a laser and operates in a vacuum.
Can I use multiple additive manufacturing technologies for one project?
Yes. Many projects use a combination. For example, use Material Extrusion for initial form testing, Vat Photopolymerization for high-detail presentation models, and Powder Bed Fusion for final functional parts. Each technology serves a different stage of development.
Contact Yigu Technology for Custom Manufacturing
Need help choosing the right additive manufacturing technology? Yigu Technology offers services across all seven categories. Our engineers help you select the best approach for your project.
Contact us today to discuss your needs. From prototypes to production, we deliver quality and expertise.
