Resin 3D printer

How a resin 3D printer works

Resin 3D printers represent a significant advance in the field of object manufacturing. Unlike FDM (Fused Deposition Modeling) 3D printers, which use plastic filaments, resin printers employ light-sensitive liquid resins to create three-dimensional objects. This technology, also known as stereolithography (SLA), produces prints of remarkable precision and surface quality.

Components and general principle

Key components of a resin 3D printer

Light source (UV laser or LED) and precision optical system

The light source, whether UV laser or LED, is essential for curing the photosensitive resin. The UV laser offers high precision by focusing a beam of light on specific points, while LEDs project patterns of light through an LCD screen acting as a shadow generator to cure entire layers at a time.

The optical system, meanwhile, directs the light with great precision. This system is responsible for the resolution and precision of prints, controlling exactly where and how the light hardens the resin.

The resin tank

Also known as the tank or reservoir, this contains the photosensitive liquid resin. It is fitted with a transparent bottom or FEP (Fluorinated Ethylene Propylene) film to allow light to pass through and harden the resin. This tray must be kept clean and in good condition to guarantee high-quality prints.

The mobile printing plate mounted on a linear axis

This is the surface on which the 3D object is built. It moves vertically in the resin tray, layer by layer, as printing progresses. The precision of this movement is crucial to print quality, as it determines layer thickness and detail alignment.

Control screen and dedicated software

These enable the user to manage print parameters, launch jobs and monitor the process. The user interface must be intuitive and offer precise control over the various aspects of printing, such as speed, light exposure and plate movement. The software also interprets the 3D files and converts them into instructions for the printer.

Stereolithography technology (SLA)

The heart of SLA technology lies in the polymerization of light-sensitive liquid resins. The UV laser or LED light source projects a precise pattern onto the bottom of the resin tray, selectively solidifying certain areas. This process is repeated layer by layer, gradually building up the 3D object.

The layer-by-layer printing process

The printing process begins by immersing the printing plate in a tray filled with liquid resin. Once in position, the light source, be it a UV laser or LED, projects a precise pattern corresponding to the first slice of the object to be created between the bottom of the tray and the surface of the platen. In this way, the first layer is bonded to the tray and can be lifted by it.

The light hardens a thin layer of resin, solidifying the desired shape. After this stage, the tray is raised slightly, allowing the liquid resin to cover the already-hardened layer.

This cycle is repeated for each successive layer, with the platen rising progressively, until the object is fully formed. This layer-by-layer process enables three-dimensional objects to be produced with great precision and fine detail.

The advantages of resin 3D printers

High precision and detail

Resin 3D printers can achieve exceptional print resolutions, often below 50 microns. This precision makes it possible to reproduce minute details and complex geometries impossible with other consumer 3D printing technologies.

Finer finishing of printed objects

Unlike FDM prints, which often feature visible lines between layers, resin-printed objects have a smoother surface. This greatly reduces the need for post-processing to achieve a high-quality finish.

Variety of materials available

There is a wide range of resins with different properties: transparent, flexible, heat-resistant, biocompatible, ceramic, and so on. This variety makes it possible to adapt the material to the specific requirements of each project.

Applications and fields of use

Industry (prototyping, moldmaking)

The precision of resin printers makes them ideal for rapid prototyping in industry. They are also used to create high-quality molds for very small series production.

In medicine and dentistry

The biocompatibility of certain resins enables the manufacture of dental prostheses, surgical guides and even precise anatomical models for the planning of complex operations.

In jewelry, watches and jewelry

The ability to reproduce fine details is particularly appreciated in jewelry design, enabling the creation of complex, detailed models.

In watchmaking, these printers can be used to create prototypes of watches and watch components with exceptional precision and finesse. Watchmakers can thus test and refine their designs before moving on to final production. What’s more, the use of calcinable resins facilitates the creation of lost-wax molds, an essential process for the manufacture of precise, detailed metal parts.

In model making and miniatures

Model-making enthusiasts and miniature designers appreciate the quality of resin 3D prints for their projects, achieving results close to professional quality.

But what does this mean in practice?

Safety and precautions for use

Liquid resins can be irritating and potentially dangerous. It is essential to follow safety instructions:

  • Wear protective gloves and goggles
  • Work in a well-ventilated area
  • Avoid direct skin contact
  • Dispose of resin waste properly
  • Work with resin in an area protected from UV light. It’s not ideal if the resin solidifies while you’re trying to handle it!

Choosing the right resin for the project

It’s crucial to select the right resin for the job: mechanical strength, flexibility, transparency and so on. Each type of resin has its own characteristics and optimum fields of application:

  • Standard resins: versatile for prototypes and decorative objects.
  • Transparent resins: translucent, ideal for glass effects.
  • Water-washable resins: easy to clean, odor-reducing.
  • Flexible resins: rubber-like, for malleable parts.
  • Heat-resistant resins: stable at high temperatures, for electronic components.
  • Burnable resins: used to create foundry molds, burn without residue.
  • Biocompatible resins: safe for medical applications.
  • Dental resins: biocompatible, for dental prostheses and models.
  • Technical resins: formulated for specific properties such as impact resistance.
  • Colored resins: available in various shades, for decorative applications.

After printing, objects require post-processing to guarantee their quality and performance. First, it’s essential to clean the parts with isopropyl alcohol to remove any excess resin. Next, final curing under UV light is necessary to achieve optimum mechanical properties. Finally, to achieve a neat finish, light sanding or painting may be considered.

Resin 3D printers represent a fascinating technology that pushes back the boundaries of object manufacturing. Their ability to produce parts of exceptional precision and surface quality opens up new possibilities in many fields, from industry and medicine to art and design.

With constant advances in materials and printing processes, the future of resin 3D printers looks bright, pointing the way to ever more innovative and diverse applications.
Whether you’re a professional looking to improve your prototyping processes, a designer in search of new artistic possibilities, or simply curious and fascinated by cutting-edge technologies, resin 3D printers offer a world of possibilities to explore. As such, 3D ETPLUS can advise you on the acquisition, configuration and maintenance of these machines.