Binder Jetting vs. Material Jetting 3D Printing — What's the Difference?

Binder jetting and material jetting are two related 3D printing technologies that, on the surface, have similarities. On closer examination, the differences are much greater. Binder jetting is a material-adaptable, powder-bed process. Model slices are bonded and keyed to the slice below by jetting a wide range of adhesive compounds by bubble-jet or inkjet methods, to print/bond a picture of the slice.

Material jetting also uses bubble-jet technology, but prints model slices directly onto a build table. It generally uses modified acrylic resins or epoxies. Binder jetting provides cost-effective, rapid production of relatively low-resolution parts in a large range of materials, while material jetting offers higher resolution suitable for detailed plastic prototypes and models. The selection of applicable technology depends on the specific requirements of the project, including: resolution, materials, and production volume.

This article will discuss the differences between binder jetting vs. material jetting in terms of their processes, advantages and disadvantages, material selection, types, and more. 

What Is Binder Jetting?

Binder jetting involves powdered material metal, sand, plaster, or ceramics being deposited layer by layer. A liquid, generally a polymer binding agent, is selectively printed onto the powder bed. In this context, binder printing can be via inkjet or bubble-jet methods, though other approaches are possible. The binder solidifies on contact (or through a post-cure process) to couple the powder particles in a representation of the model slice both to itself and to the layer/slice below. The unbonded powder remains loose and supports the printed object during production. At the margin of the binder print, capillary action bleeds the binder into the surrounding powder to a limited degree. This is the largest contributor to the resolution issues in fine powder processes. In some variants of the process, an additional print stage allows layer-by-layer full-color printing to be used. This helps to create an extremely detailed color in the model that can endure any surface finish efforts that may follow. 

To learn more, see our guide on Binder Jetting.

Advantages and Disadvantages of Binder Jetting 3D Printing

The advantages of the approach are:

1. Faster than most other 3D printing technologies.
2. Can be cost-effective to produce parts in bulk, as materials are generally low cost. The process doesn't use support structures (other than the enclosing powder bed). Material wastage is minimal and cleanup is low effort.
3. Supports a surprisingly wide range of materials, from stainless steel, bronze, and aluminum, through ceramics to sand and plaster. 
4. It can produce complex, intricate geometries and internal structures, making it capable of delivering parts with very detailed features. 
5. Binder jetting can provide relatively large parts compared to many other 3D printing methods due to the relative simplicity of the equipment.

The disadvantages of binder jetting are:

1. Binder jetting parts are generally not smooth and have a surface made from bonded powder. The grades of powder were formerly quite large (100 µm) but more recent technology advances have reduced this to, at best, 10 µm. 
2. The mechanical properties of binder jetting parts are poorer than those of essentially all other 3D printing technologies. Parts are quite unsuitable for high-stress applications and generally serve as visual-only prints. This is considerably different in sintered metal binder jetting prints, which can have good mechanical properties. However, the sintering process is hard to control, so parts can suffer considerable loss of precision.
3. Generally has high porosity, which may require additional steps like infiltration or sintering to improve strength and density.
4. Offers moderate resolution. It generally does not come close to the high detail achievable with technologies like material-jetting or stereolithography. 
5. While binder jetting does support a wide range of materials, it cannot deliver such good material properties as most other 3D printing technologies.
6. Handling and disposing of metal or ceramic powders used in binder-jetting presents a significant risk to operator health and the waste chain.

Examples of How Binder Jetting 3D Printing is Used

One of the most common applications for binder jet printing is the making of photographic props such as product packaging and figurines that are required for zero-stress applications. Increasingly, binder jetting is reported as a practical means for rapidly producing metal components of relatively low precision and coarse surface finish. While such parts are somewhat restricted in their application, where the properties are appropriate they can serve very well and at relatively fast production and low cost.

What Is Material Jetting?

Material jetting is a 3D printing technology that uses inkjet or bubble-jet printing methods to deliver liquid polymer build and support materials directly onto a build table. The printed material is either partially or fully cured in the print process before the table lowers and the next slice of the model is applied.

The print process generally applies two (or more) related materials in the layer construction. Build materials are generally heat-cured or UV-light-cured polymers that can be rigid, semi-flexible, or pseudo-elastomers. Some variants of the process use wax as the build material, allowing direct production of investment casting masters of the highest quality without the need for skilled craftsmanship. Support material is co-printed by additional printer heads. Such support material will be either chemically soluble or a water-soluble version of the build material that couples fully to the model but can be later removed. In some cases, the build material can be printed from two different versions of the polymer using different printheads, which can be; merged in the print process to allow selective alteration and gradation of properties or alternated to allow changes in properties.

To learn more, see our guide on Material Jetting.

Advantages and Disadvantages of Material Jetting

The advantages of material jetting are:

1. Offers exceptional print resolution, the highest in commercially available equipment. It is ideal for printing intricate models with fine detail and thin sections.
2. Some machines in this class can simultaneously print with two materials in variable proportions from 0–100%. This allows for the creation of variable and custom material properties and, to a very limited degree, some color variation options. 
3. Offers high dimensional accuracy and repeatability. Printed parts closely match their digital designs, when machine calibration is thorough and correctly performed. 
4. The machine type for this process is relatively fast compared with other good-resolution technologies like stereolithography (SLA).
5. The photopolymer materials available include: rigid (various colors), flexible (rubber-like from 30 to 90 Shore A), transparent (lens/window quality), and biocompatible options. The material family is continuously expanding and material properties are slowly improving to approach those of molded plastics. 
6. Support materials, co-printed with the build, are easily removable and maintain the integrity of complex overhangs and geometries, without excessive cost or cleanup difficulties.
7. Unlike SLA, material jetting doesn't require post-curing in UV chambers, simplifying the post-processing steps. The resins are cured immediately after being printed, as powerful UV lamps pass over in the same process.

Some disadvantages include:

1. The photopolymer materials used are high to very high cost, and they are generally single source. 
2. Is limited to proprietary photopolymer resins, lacking the wide range of options that are available in some other technologies.
3. Often has smaller build volumes compared to some 3D printing technologies.
4. Removing certain, complex supports can be a delicate and skilled manual process. Additional post-processing steps are commonly needed to achieve a cosmetic finish.
5. Equipment maintenance and basic, everyday OPEX are skilled tasks and require high-cost, single-source components. This adds considerably to per-print costs and cost-savings in this regard can have disastrous consequences.

Examples of Material Jetting is Used

Some examples of material jetting 3D-printed parts are:

1. Precise models for crowns, bridges, and dentures.
2. Detailed prototypes and intricate wax patterns for casting precious metals.
3. Engineering evaluation models of aircraft components for testing and design validation.
4. Consumer electronics, particularly for creating prototypes of small electronic components, casings, and customized device enclosures.
5. Microfluidic devices with precise channel geometries for applications in life sciences, diagnostics, and as research tools. Devices such as micro dispense nozzles, and Tesla flow microvalves are extremely expensive to make by other methods.

Which Is Better, Binder Jetting 3D Printing or Material Jetting 3D Printing?

Better is a term that must refer to the detailed specific needs that the printed part is to fulfill since both methods have great advantages but specific weaknesses. For example, material jetting is the best choice for high-precision printing for virtually any application that requires or can accept plastic printed parts and has low-cost sensitivity. It is essentially the only option for wax parts directly printed to enable precise investment casting. Until recently, material jetting was the only practical option for directly printed and high-accuracy functional rubber-like parts. While binder jetting can produce flexible parts, they are very low in strength and suffer the intrinsic resolution/accuracy issues of the process.

Binder jetting is capable of direct printing of metal parts, whereas material jetting is not. Binder jetting is the best option for full-color printed parts for non-demanding applications such as photography props, as limited additional finishing is required to make these models. It can serve directly and is the only practical option for sand-casting cavities and inserts.

Difference in Terms of Process

Binder jetting is a branch of powder bed fusion in that the build volume is constructed from layered powders or a range of materials and grain sizes. Material jetting directly prints the build and support materials with no additional matrix component. Binder jetting parts are “finished” by shaking off the unbonded powder. Material jetting parts require a chemical and/or water jet wash to remove supports.

Difference in Terms of Types

There are several classifications of binder jetting 3D printing: single-material binder jetting, multi-material binder jetting, color binder jetting, sand binder jetting, metal or ceramic binder jetting, polymer binder jetting, and hybrid binder jetting. 

In single-material binder jetting, a single powder is used, and the binding agent is deposited to create the object layers and bind them to the layer below. Multi-material binder jetting employs multiple powder materials, generally in alternating layers of metals, ceramics, and polymers. The selection of binding agents to suit each powder material enables the printing of multi-material, composite, or property-graduated parts. Color binder jetting includes full-color 3D printing. It generally combines gypsum build materials and printable binding agents with full-color inkjet printing on each layer, for full-color prints. Sand binder jetting uses fine sand as the build material to create sand molds and cores for metal casting. Metal or ceramic binder jetting uses metal or ceramic powder as the build material. After printing, the green part is sintered to shrink/fuse the metal particles to full density and burn out the binding agent. Polymer binder jetting is specific to the layering of polymer powders, often using a solvent-binding agent that welds the particles. In some cases, the binder jetting device can operate in more than one of the listed modes, and can also be integrated with other 3D printing technologies to allow regional selectivity in appropriate processes applied to a build. This is known as hybrid binder jetting.

There are also several classifications of material jetting technologies, differentiated by method and by materials. Polymer material jetting is the most common and earliest form of material jetting, depositing polymer inks in liquid or gel form. These polymers are generally UV-cured in place, for rapid and finished printing with limited post-processing. Multi-material jetting uses the simultaneous deposition of multiple materials (usually two) such as rigid and elastomer types to build graduated properties, graduated colors, and sudden material changes in parts. Full-color jetting is a specialized category that delivers full-color and high-resolution components, for the production of figurines, architectural models, and artworks. Ceramic or metal material jetting deposits ceramic-based or metal materials in a polymer suspension, to create intricate ceramic parts that can be sintered to achieve the final ceramic density. Microfluidic material jetting is used to create microfluidic devices with precise channel geometries for applications in research, diagnostics, and fluid-logic devices. Wax material jetting is used in jewelry for pattern making in lost-wax casting. Wax patterns are directly printed as sacrificial masters for metal part production.

Difference in Terms of Materials Used

Material jetting builds directly in polymer models of rigid, elastomeric, and wax materials. Binder jetting, on the other hand, generally uses polymer bonding agents to adhere to a variety of powder materials ranging from metals to ceramics and sand. 

Difference in Terms of Applications

Material jetting is suited to functional and design evaluation prototypes that can be used to assess assemblies, test mechanism performance, and when required substitute for molded parts. Wax prototypes can be directly used to produce investment castings, being printed with all sprue and channel parts pre-attached and integral in a single stage.

On the other hand, binder jetting provides visual test components of relatively low precision and poor mechanical properties. These are suited to visual evaluation of shape and aesthetics, and can directly produce examples of packaging and color-critical prototypes for photographic props, etc.

Difference in Terms of Machine Characteristics

Binder jetting machines handle powders, laid down in layers that are wiped and, in some cases, roller packed to height. These machines have a difficult material handling task in this aspect of the process which makes them relatively complex and can create reliability issues if powders are abrasive and the machine hygiene is poor. Additionally, the jetting component of the machine that delivers the bonding agent is a relatively simple single printhead that requires little customization to the task and offers simplicity and reliability.

Material jetting uses a similar-in-principle jetting system to deliver the build polymers directly to the build platform. These heads are highly customized and create some significant setup and maintenance issues that result in ongoing high effort in OPEX. Binder jetting machines are essentially reliable and low maintenance. Material jetting machines are delicate precision instruments that require regular and skilled daily, weekly, and intrusive maintenance and setup.

Difference in Terms of CAD Software

Both machine types use the typical CAD file formats as input, slicing either with proprietary or generic software to make .STL files that can be directly machine-interpreted. The .STL resolution should be set fine and the build height should be appropriate for the machine to utilize the precision of material jetting technology. 

Binder jetting in full color requires the color information to be applied to the .STL file, as this format does not generally contain such information. Proprietary means are used to apply the color data, whenever this function is included.

Difference in Terms of Cost

Binder jetting machines are simple and typically lie in the price range from$30k - 200k, increasing as superior capability and build volume are required. Material jetting machines, on the other hand, range from around $20k for a desktop-size machine with moderate resolution and limited build speed. Prices rise to $750k for the more advanced and precise machines capable of multi-material printing. These require highly skilled operational and maintenance labor, plus some limited ancillary equipment.

Difference in Terms of Quality

Quality is a term that is open to interpretation. Quality differentials between the technologies can be mapped according to function.

Material jetting offers higher-resolution builds than binder jetting. If precision and accuracy are quality references, the differential can be a factor of 3–5 in favor of material jetting. If metal or sand printing is required, material jetting cannot serve and binder jetting is the clear quality choice. If full-color printing is required in the prototype, material jetting cannot provide this, whereas some types of binder jetting equipment can. If functional parts and material qualities are required in non-metal parts, material jetting offers significantly higher quality than binder jetting.

Difference in Terms of Accuracy

Accuracy can be measured in a variety of ways. It’s critical to consider the real needs of the project before selecting these criteria.

Both processes offer good repeatability, so multiple-part consistency is good for the two types. Binder jetting delivers lower resolution than material jetting, so the fineness of models is considerably different. The imprecise nature of binder jetting delivers a less accurate representation of small features that can be achieved in material jetting.

Difference in Terms of Manufacturer

With lower operational and capital costs and a considerably lower cost of setup and ongoing overheads, binder jetting is somewhat suited to in-house use. However, there is a strong tendency to centralize services in contract printing companies, as few companies have the volume of need that justifies the in-house setup investment.

Surprisingly, material jetting is commonly the in-house choice for larger companies that have sufficient demand to justify the investment and operational costs. However, few companies can show ROI on this cost, so there is the same tendency towards centralized service providers who can support a wide range of capabilities and attract enough demand to justify ongoing investment. 

Is a Material Jetting 3D Printer Fast?

No. The build-layer thickness or Z-axis resolution of binder jetting machines is generally greater than that of material jetting equipment, making overall printing times shorter for binder jetting. In addition, the post-print cleanup of binder jetting is minimal, increasing the overall process speed differential.

Can a Material Jetting 3D Printer Print Metals?

No, material jetting offers no direct metal printing process.

Does Binder Jetting 3D Printer Require Supports?

Binder jetting is built within a stable and full machine volume powder mass, so no separate support structures are required for this printing type, reducing the post-work required for print jobs.

Summary

This article presented binder jetting vs. material jetting, explained each of them, and discussed their key differences. To learn more about binder jetting and material jetting, contact a Xometry representative.

Xometry provides a wide range of manufacturing capabilities, including 3D printing and other value-added services for all of your prototyping and production needs. Visit our website to learn more or to request a free, no-obligation quote.

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