Ceramics and Metals: Direct or Indirect Additive Manufacturing? Pros & Cons

Additive manufacturing of ceramic and metal parts enables the production of complex geometries that are difficult or impossible to achieve with conventional manufacturing. However, when producing functional ceramic and metal components, it is essential to distinguish between different additive manufacturing routes, as they differ significantly in process robustness, material performance, scalability and risk.

Ceramic and metal additive manufacturing can be broadly classified into direct and indirect approaches. In addition, alternative direct additive manufacturing technologies, such as Selective Laser Sintering (SLS) using binder powders, provide further possibilities.

This page presents a technical comparison of direct, indirect and alternative direct additive manufacturing routes, highlighting advantages, limitations and trade-offs to support informed process selection.

1. Direct Additive Manufacturing Using Photopolymer-Based Technologies (SLA / DLP / LCD)

In direct additive manufacturing using photopolymer-based technologies, ceramic or metal powders are directly dispersed into a photocurable resin and printed using SLA, DLP or LCD processes. The printed part represents the near-final geometry of the ceramic or metal component.

After printing, parts must undergo debinding and sintering to remove the organic binder and densify the material.

This route enables a fully additive, mold-free workflow, but introduces significant formulation, printing and thermal post-processing challenges.

Technical Characteristics

  • Highly filled photocurable suspensions containing ceramic or metal powders

  • Strong coupling between formulation, geometry and thermal behavior

  • Debinding and sintering are critical, failure-prone steps

  • Dimensional accuracy and defect formation depend strongly on geometry

Advantages

  • Mold-free production

  • High geometric freedom and fine feature resolution

  • Suitable for small, intricate components

  • Fully digital manufacturing workflow

Limitations

  • Complex formulation tuning required for each ceramic or metal system

  • Limited printable wall thickness (typically ~1–2 mm)

  • High risk of micro-cracks during debinding and sintering

  • Long and delicate thermal cycles

  • Shrinkage, warping and anisotropy must be carefully controlled

  • Often lower final density and inferior mechanical properties compared to conventional ceramic and metal routes

Due to these constraints, direct photopolymer-based additive manufacturing is generally limited to prototyping, R&D activities or very small technical parts, where geometric complexity outweighs material performance requirements.

2. Indirect Additive Manufacturing of Ceramics and Metals

In indirect additive manufacturing, 3D printing is used to fabricate patterns, molds or tooling, while the final ceramic or metal part is produced using established industrial processes, such as Ceramic Injection Molding (CIM) and Metal Injection Molding (MIM).

In this approach, the printed component is not the final part, but a temporary element within the manufacturing chain.

By decoupling shape generation from material densification, indirect additive manufacturing significantly reduces process risk while maintaining the benefits of additive design.

Typical Indirect Manufacturing Routes

  • Printed sacrificial patterns for casting

  • Printed molds for ceramic injection molding (CIM)

  • Printed molds for metal injection molding (MIM)

  • Hybrid workflows combining additive manufacturing with conventional ceramic and metal processing

Advantages

  • Compatibility with traditional ceramic and metal feedstocks

  • Higher achievable density and improved mechanical properties

  • Better isotropy and reduced micro-porosity

  • Lower risk during debinding and sintering

  • Use of affordable SLA, DLP and LCD printers

  • Scalable to industrial production volumes

Limitations

  • Multi-step manufacturing workflow

  • Requires expertise across printing, molding and thermal processing

  • Sacrificial molds or patterns are typically single-use

Despite these limitations, indirect additive manufacturing is often the most robust and industrially mature route for producing functional ceramic and metal components.

3. Alternative Direct Additive Manufacturing

Direct AM by SLS Using Binder Powders

In addition to photopolymer-based technologies, direct additive manufacturing of ceramic, metal and polymer parts can also be achieved using Selective Laser Sintering (SLS) with binder-based powder systems.

In this approach, layers of ceramic, metal, polymer or exotic powders mixed with binder powders are selectively sintered to form three-dimensional objects. The printed parts retain their original shape and do not require molds, which qualifies this technology as direct additive manufacturing.

As with other direct AM routes, debinding and sintering are required after printing, using water, solvents or thermal treatment, before final use.

3Dresyns Bio-Based Binder Powders for Cold SLS Printing

3Dresyns has developed universal, bio-based, non-photoreactive binder powders designed for easy physical mixing with ceramic, metal, polymer/plastic and exotic powders or fibers.

These materials enable cold SLS printing, also referred to as:

  • Cold Metal Fusion (CMF)

  • Cold Ceramic Fusion (CCF)

  • Cold Polymer Fusion (CPF)

  • Cold Exotic Powder Fusion (CEPF)

This technology supports direct, mold-free additive manufacturing of a wide range of materials while maintaining high geometric fidelity.

Benefits of 3Dresyns SLS Binder Powders

  • Universal, water- or solvent-soluble eco bio-based binder powders

  • Over 90 % bio-based content

  • Easy dry powder mixing with low-cost equipment

  • Excellent dispersion and stability without gravitational separation

  • Powder loading up to 60 vol % (lower for nanoparticles, nanowires and microfibers)

  • Printable on most polymer / plastic powder SLS printers

  • Water or eco-solvent debinding using EDS1 Bio at 90 °C

  • Controlled and reproducible shrinkage

  • Low expansion coefficient to prevent micro-fractures

  • Final resolution down to ~50 microns (depending on powder particle size)

4. How to Choose the Right Manufacturing Route

Selecting the appropriate additive manufacturing route depends on material requirements, part geometry, wall thickness, production volume and acceptable risk level.

  • Direct AM (photopolymers) prioritizes geometric freedom but involves higher process risk

  • Indirect AM prioritizes robustness, scalability and material performance

  • SLS with binder powders offers an alternative mold-free route with broad material compatibility

There is no universal solution, and each application must be evaluated individually.

5. More In-Depth Technical Analysis

Applications, Materials & Properties

Typical Applications

  • Medical devices and instrumentation

  • Dentistry: crowns, implants, copings and bridges

  • Jewelry and watches

  • Industrial end-use parts, tools, fixtures, molds and micro-reactors

  • Biomedical implants, prostheses and surgical guides

Typical Properties of Technical Ceramics and Metals

Ceramics

  • Flexural strength: 300–1200 MPa

  • Fracture toughness: 4–10 MPa√m

  • Vickers hardness: 10–20 GPa

  • Tensile strength: 1000–1500 MPa

  • Compression strength: 2000–3000 MPa

Metals

  • Flexural strength: 200–1200 MPa

  • Fracture toughness: 10–300 MPa√m

  • Vickers hardness: 200–400 HV

  • Tensile strength: 300–1000 MPa

  • Compression strength: 300–1000 MPa

Final properties depend on the selected ceramic or metal material and processing route.

6. How 3Dresyns Supports Ceramic and Metal Manufacturing

3Dresyns supports direct, indirect and alternative direct additive manufacturing routes through:

  • Photopolymer resin and binder formulation

  • Bio-based SLS binder powder development

  • Sacrificial and durable mold systems

  • Water-soluble and eco-friendly debinding solutions

  • Process optimization and technology transfer from lab to industry

Final Note

Choosing the optimal ceramic or metal additive manufacturing route is highly application-dependent.

If you have a specific application or process in mind, our technical team can help you identify the most efficient and reliable manufacturing strategy.

Contact us to discuss your application.