Image: HP Inc.
Creating multi-color plastic parts is a complex process. In conventional manufacturing, colored parts are created either by a multi-step molding process (e.g., overmolding) or via the post-processing of unicolor parts (e.g., screen printing or manual coloring).
Additive manufacturing has long been limited to unicolor parts. With the introduction of new technologies, such as Multi Jet Fusion or full-color Polyjet, multi-color or full-color parts (i.e., parts with texture and color gradients) became possible.
Very recently, color 3D printing became a hot topic in 3D printing when multiple new technologies hit the market, increasing both quality and efficiency.
In this article, we will introduce multiple aspects of full-color 3D printing:
- Technologies and machines: Industrial & Entry Level
- The creation of (virtual) full-color 3D models
- Full-color 3D printing options available through 3Faktur
Apart from the ‘traditional’ applications of multi-color plastic parts, most famously in toys, additive manufacturing enables new applications that would have been too complex to produce with conventional manufacturing methods. For example, jigs with color information can help production workers by indicating part directions or providing visual assembly instructions.
Other applications include:
Prototypes for multi-color parts used to be very complex to produce with conventional manufacturing methods and often involved complex post-processing technologies and intensive manual labor. With full-color 3D printing, multi-colored or textured prototypes can be 3D-printed directly, which decreases the cost of production and shortens the turn-around time.
Jigs / Fixtures
Color codes or visual information can help the production worker position or assemble parts correctly. Jigs and fixtures are often required in small quantities, which makes additive manufacturing a very cost-efficient production option.
The 3D printing of full-color functional or end-use parts is a revolutionary new option. In conventional manufacturing, parts undergo complex production or post-process steps to add colors and textures. Industrial full-color 3D printing solutions, such as the HP Jet Fusion, can create fully-colored parts in manufacturing-grade material (polyamide).
Scale models of machines or architectural models often require textures or colors. With state-of-the-art 3D printing technologies, such as full-color Polyjet or Jet Fusion, even fragile details can be printed, making it possible to create very realistic models.
Conventional physical scientific models (e.g., molecular, organ, astronomical, geographical or geological models) are often simplified due to the high level of complexity of the structures being modeled. 3D printing enables a more accurate representation of reality since highly complex structures can be produced.
Color or textures are essential for most toys. Since price sensitivity is high in the industry, 3D printing is applied mainly to prototypes and small-batch toys.
The applications of full-color 3D printing for hobbyists are diverse and include scale models (e.g., train models), fantasy figures, gadgets (e.g., fidget spinners) and decorative items. For cost reasons, privateers often use simpler technologies, such as FDM printing.
Technologies I: Industrial solutions
Industrial-grade 3D printers are used for professional applications, such as prototyping, professional models and batch production. While the Colorjet uses the first full-color technology, the recently introduced full-color polyjet / UV-curable inkjet and HP’s Multi-Jet Fusion have made this technology outdated for most applications.
Full-color HP Jet Fusion
So far, the Multi-Jet Fusion is the only technology which can print engineering-grade plastics (Polyamide) in full-color. The parts generated by this technology, when compared to other full-color solutions, are stronger and less costly. The technology is fairly new and just hit the market in mid-2019.
- Mechanically strong—can be used for end-use parts
- High productivity—can be used for batch production
- No transparencies possible
- The white is not pure white but rather greyish
- Not suitable for very small, fragile parts
Full-color Multi-Jet Fusion parts can be ordered at 3Faktur. More about the Multi-Jet Fusion in the full-color PA12.
Polyjet / UV-curable inkjet
The manufacturers Mimaki (model 3DUJ-553, ‘UV-curable inkjet’ technology) and Stratasys (model Objet J735 & J500, ‘Polyjet’ technology) have introduced their machines within the last few years. The technologies work in a similar fashion.
While the materials used are acrylic and, in many cases, not suitable for end-use parts, these technologies offer the advantage of being able to mix materials with different mechanical properties, e.g., rigid and soft materials.
- Multi-material options (rigid and soft materials)
- Transparent material can be used and combined with opaque material
- Highest resolution among industrial full-color 3D printers
- Materials not suitable for end-use or functional parts
- High cost per part
- Productivity is limited
3Faktur does not offer full-color Polyjet printing. Rather, we offer multi-material polyjet printing. Our service includes combinations of soft, rigid, transparent, and opaque (white and black) materials. More about multi-material Polyjet printing.
This technology has been around for some 20 years and is based on a simple principle: plaster powder is selectively bound by colored glue. The resulting material is heavy but very brittle and mechanically weak.
- Heavy material—popular for architectural models due to its concrete-like look and feel
- Material breaks very easily and can only be used for very compact objects
3Faktur offers Colorjet printing. More about Colorjet 3D printing.
Technologies II: Entry-level solutions
Low-cost solutions are mostly FDM/FFF 3D printers. Many FDM printers print only one material at a time. However, there are machines that are capable of multi- or full-color 3D printing:
- Single-printhead FDM printers: For one-printhead 3D printers, additional devices, such as Mosaic’s “Palette 2,” are required. Four different filaments are combined by the device into one with a defined sequence of colors.
- Multiple-printhead FDM printers: FDM printers with multiple printheads use different materials per printhead. However, the printing time is significantly longer than it is for regular 3D printing with one printhead.
- Indirect full-color FDM 3D printing: This technology was developed by the Taiwanese manufacturer XYZ Printing (New Kingpo Group). It is considered to be indirect color printing because a unicolor (white/translucent) material is printed and subsequently colored with a ‘regular’ printhead (comparable to a desktop 2D inkjet printer).
Creating colored 3D-models
Full-colored models can be scanned or created with CAD or modeling software.
- 3D Scan: Many 3D scanners are capable of creating full-color scans of objects or persons. However, depending on the complexity of the scanned object, the resulting files are often unsuitable for 3D printing. Raw color-scan files often require a skilled 3D designer to fix and improve the scanned data. Popular color 3D scanners are, amongst others, Artec 3D Scanners.
- Designing with CAD programs: Most CAD programs (e.g., Autodesk Inventor or Fusion360, SolidWorks, Creo) allow for the addition of color or texture to parts. The files can be exported as full-color STEP files or, in some cases, as full-color mesh files, such as 3MF or VRML. CAD programs have the advantage of creating parametric models which can be modified easily.
- Designing with 3D modeling programs: 3D modeling with software such as ZBrush or Rhino 3D is more art than engineering. The process is sometimes referred to as 3D sculpting. Free forms are created based on basic geometric shapes such as spheres or cubes. 3D modeling allows for the creation of organic shapes (e.g., sculptures) but is not suitable for technical objects.
Full-color 3D printing at 3Faktur
3Faktur offers two full-color 3D-printing technologies and one multi-material option.
- HP Jet Fusion Full-Color: We offer a 3D printing service for full-color and robust polyamide parts. This technology is currently the best choice for creating fully functional colored parts.
- Colorjet: With HP’s launch of the Multi-Jet Fusion Color technology, Colorjet has lost its importance. While the parts look quite comparable, Colorjet uses a rather brittle, mineral-based material which breaks easily. Nevertheless, Colorjet printed parts can still be ordered. These parts are popular with architects due to the material’s heavy weight and concrete-like look and feel.
- Polyjet: While we do not offer full-color polyjet 3D printing services, we operate a Polyjet machine with multiple printheads for combining two different colors and material properties (e.g., soft and rigid and/or opaque and transparent).
Please contact customer support with any questions concerning our services.