What is Digital Light Processing (DLP) 3D Printing: Benefits, Applications, Materials and Costs

In additive manufacturing, Digital Light Processing (DLP) 3D printing stands out for its precision and efficiency. Derived from digital light projector technology, DLP 3D printing has revolutionized model creation and prototyping.

This guide explores the essence of DLP technology, its benefits, applications, and more. Discover how DLP 3D printers can enhance your projects and bring your ideas to life.

What Is DLP 3D Printing?

DLP is a vat polymerization process in which a conventional light source cures a photopolymer resin vat. This process utilizes a digital micromirror device (DMD) with countless tiny mirrors that pivot to direct UV light precisely onto the resin. DLP printers excel at creating highly detailed parts with exceptional accuracy and a smooth surface finish, surpassing many other 3D printing technologies.

How Does DLP 3D Printing Work?

DLP printing begins by creating a digital model and then slicing it into thin horizontal layers. Each layer represents a cross-sectional area of the model. The DLP projector displays these layers on the liquid resin’s surface. Exposing the resin to light causes the liquid polymer to harden and form a solid layer. The build platform moves, allowing fresh resin to cover the previous layer, and this process repeats.

Before we delve into the various stages of the DLP printing process, there are five key printing terms and components to understand.

What is a Voxel?

A voxel, also known as a volumetric pixel, is the smallest unit of a 3D print, similar to how a pixel is the smallest unit of a digital image. In DLP 3D printing, each voxel corresponds to a specific point in the printed object, with its position defined in three-dimensional space.

This concept is crucial as it creates objects with intricate internal structures and detailed exteriors. Manipulating individual voxels using the DLP printer’s light source enables high resolution and precision, setting DLP printing apart from other additive manufacturing techniques.

Digital Light Projector Screen

The digital light projector is the main component responsible for the DLP 3D printing process. It uses a digital micromirror device (DMD) with thousands of tiny mirrors to project an image onto the resin surface. By directing UV light onto the resin, specific areas are hardened layer by layer to create the final object.

Vat

The vat, or resin tank, stores the liquid photopolymer resin during printing. It has a transparent bottom to allow the light from the digital projector to pass through and cure the resin. The vat’s design is crucial for DLP printer operation, exposing a thin and even resin layer to light for each print. Proper maintenance or replacement of the vat’s bottom is necessary to maintain consistent print quality.

Build Platform

The build platform, or build plate, is the surface where the resin cures and the printed object forms. It starts close to the vat’s bottom, allowing printing of the first layer. After each layer cures, the build platform moves up incrementally to accommodate the next layer. Precise control of the build platform’s movement ensures it achieves the desired layer height.

Elevator

The elevator mechanism controls the vertical movement of the build platform on the z-axis. This precise adjustment allows each layer to be accurately positioned and exposed to UV light for curing. It ensures the creation of detailed and dimensionally accurate parts layer by layer.

What are the stages of a typical DLP 3D printing project?

1. Design Creation and Preparation: 3D modeling software creates a digital model and slices it into thin, horizontal layers for printing. The slicing software converts the model into a series of images. Each represents a layer of the object.
2. Resin Tank Preparation: To begin the printing process, the resin tank, which holds the liquid photopolymer resin, is prepared. This tank contains the material that will form the final printed object.
3. Build Platform Calibration: Calibration of the build platform, or build plate, is vital to ensure proper adhesion of the first layer and precise alignment of subsequent layers.
4. Layer-by-Layer Printing: The DLP projector displays an image of the first layer on the liquid resin’s surface. The UV light exposure solidifies the resin where it strikes, forming the first layer of the printed object.
5. Build Plate Movement: After each layer cures, the build plate moves, typically in the z-axis direction, to allow the flow of a new resin layer over the previously solidified layer. The distance moved corresponds to the layer height, usually between 25 and 100 microns.
6. Repeating the Exposure Process: Steps 5 and 6 are repeated, with the DLP projector displaying each subsequent layer and the build plate moving accordingly until the printing of the entire object finishes.
7. Washing After removal from the build plate, the object is subjected to a washing process. This crucial step involves immersing the object in a solvent or using a specialized washing machine to remove any uncured resin. Effective washing ensures that the surface is clean and prepared for the next stage of post-processing.
8. Curing: Following the washing, the object undergoes curing under UV light. This process solidifies the resin, enhancing the mechanical properties and stability of the final product. Curing is essential for achieving the desired durability and structural integrity of the 3D printed object.
9. Support Removal and Finishing: Removing any supports used during printing the object happens once the exposed liquid polymer hardens. The object may then undergo sanding or finishing to enhance its surface quality.
10. Quality Inspection and Testing: The final step involves inspecting the printed object for any defects and conducting mechanical tests, if necessary, to ensure it meets the required specifications.

What Are the Technical Characteristics and Specifications of DLP 3D Printing?

DLP 3D printers offer unique characteristics and outperform other 3D printing methods. Fast printing speed, precise layer height, exceptional surface finish, high resolution, and versatile support material make them an ideal choice for various applications.

Printing Speed

With a typical printing speed of 25 mm/hour, DLP printers can produce parts much faster than other methods. The DLP projector’s ability to cure an entire resin layer in a single exposure significantly reduces printing time.

Layer Height

The UV light from the printer’s light source can cure resin to a depth of up to 100 microns, allowing layer heights between 25 and 100 microns. This precision is crucial for creating complex parts with tight tolerances.

DLP-printed parts boast a superior surface finish. Precise control over resin curing gives a smoother finish than using other methods. This quality makes DLP printing ideal for visual prototypes and parts that require minimal post-processing.

Resolution

Using digital micromirror devices (DMD) within the digital light projector means DLP printers can achieve extremely high resolutions. They can create intricate designs, finely detailed features, and smooth surfaces, which makes them perfect for detailed visual prototypes.

Support Material

Support structures uphold overhanging designs, maintain dimensional accuracy, and prevent deformation during the printing process. Careful design and planning ensure that supports fulfill their role without compromising the final part’s aesthetics or integrity.

Post-Processing Requirements

DLP-printed parts undergo post-processing. Typically, this involves washing to remove uncured resin, UV curing for maximum strength, and removing support structures. Additional processes like sanding, polishing, or painting can enhance appearance and surface finish.

Washing

For washing DLP 3D printed parts, the goal is to remove any excess or uncured resin from the surface and cavities of the print. The most commonly used solutions are:

• Isopropyl Alcohol (IPA): A popular choice due to its effectiveness in dissolving uncured resin. Parts are usually submerged in an IPA bath and gently agitated to remove the resin. However, IPA is flammable and requires handling and disposal in accordance with safety regulations.
• Ethyl Alcohol (Ethanol): Similar to IPA, ethanol can also be used to clean 3D printed parts, though its availability and cost might vary.
• Commercial Cleaning Solutions: There are also specialized cleaning solutions designed specifically for 3D printed parts. These solutions are formulated to be effective at resin removal while being less harsh on the parts and potentially safer for users compared to IPA or ethanol.
• Water Washable Resins: Some DLP printers use resins that can be cleaned with water, eliminating the need for chemical solvents. These resins are designed to be easily washed away with water, simplifying the cleaning process.

Curing

After washing, the parts need to be cured to achieve full strength and stability. This step typically involves exposing the part to UV light. UV radiation (UVR) spans from 100 to 400 nm in wavelength and is categorized into UVA (315–400 nm), UVB (280–315 nm), and UVC (100–280 nm). The material used in this step is primarily UV light, but the setup can vary:

• Sunlight: Direct exposure to sunlight is a cost-effective method for curing, as natural sunlight emits UV light. However, this method offers less control over exposure time and intensity.
• UV Nail Lamps: For smaller parts or hobbyists, UV nail lamps used for curing gel nail polish can be repurposed for curing 3D prints.

Strength and Accuracy

The choice of resin determines its mechanical properties, making it suitable for many applications. Precise dimensions, perfect fit, and conformity to original models are essential for custom medical implants and tightly fitted components.

What are the types of materials used in DLP 3D printing?

DLP 3D printing relies on liquid resin for creating solid structures layer by layer. These photopolymer resins react to specific light wavelengths, like UV, to harden. The choice of resin is crucial for determining mechanical properties, resolution, and application of printed parts.

Let’s explore the commonly used resins in DLP 3D printing, their properties, and why they are well-suited for this technology:

• Standard Resin: Highly versatile, standard resin is perfect for many applications, offering an optimal balance between strength and detail. It’s ideal for prototypes, art objects, and functional parts that require high accuracy.
• Tough Resin: Designed to mimic the strength and stiffness of ABS plastic, tough resin is ideal for parts that will undergo significant stress or strain. It is popular in functional prototyping, snap-fit assemblies, and durable casings.
• Flexible Resin: This resin provides excellent flexibility and bendability, making it suitable for applications like hinges, wearable prototypes, and items that require rubber-like properties.
• High-Temperature Resin: With a high heat deflection temperature, this resin is perfect for applications that require parts to withstand elevated temperatures, such as molds, heat-resistant fixtures, and automotive components.
• Durable Resin: Its outstanding impact resistance and smooth glossy finish make durable resin popular for parts created to withstand repeated stress cycles without fracturing.
• Castable Resin: A popular choice in the jewelry industry, castable resin burns out cleanly without leaving ash or residue, making it perfect for investment casting of intricate designs.
• Water Washable Resin: This resin simplifies the post-processing stage as it can undergo cleaning with water instead of alcohol. It also reduces handling time and exposure to chemicals.
• Dental Resin: Specifically formulated for dental applications, dental resins are biocompatible and designed for producing crowns, bridges, and orthodontic models with exceptional detail and accuracy.
• Ceramic-Filled Resin: This resin combines the properties of ceramics and polymers. Ceramic-filled resins are ideal for parts requiring high-temperature resistance, stiffness, and a smooth finish.
• Clear Resin: Ideal for applications that demand transparency, such as lenses, fluidics, and light guides, clear resin can be polished to achieve a glass-like transparency.

What are The Advantages of DLP 3D Printing?

Digital Light Processing (DLP) 3D printing stands out in the additive manufacturing industry for its ability to create highly detailed and precise parts.

Digital light processing brings some notable benefits over other types of 3D printing. It’s a preferred choice for professionals across various fields.

Below, we explore some of the main advantages that DLP 3D printing offers:

• High Resolution and Detail: DLP printers have ultra-high resolution thanks to digital micromirror devices (DMD). The tiny mirrors in the DMD allow precise control over the UV light exposure, enabling the creation of parts with intricate details and smooth surface finishes.
• Speed: DLP printing is known for its speed. The ability to cure an entire resin layer simultaneously, rather than tracing the layer’s outline with a laser or extruding filament, significantly reduces the time needed to print objects.
• Efficiency: The process is highly efficient in material use and energy consumption. DLP printers use the precise amount of resin needed for each layer, minimizing waste.
• Versatility in Materials: DLP technology supports a wide range of resins, each with unique properties that cater to different applications. DLP printers can produce parts for diverse applications using standard resins or tough, flexible, high-temperature, and castable options.
• Dimensional Accuracy: The precision of DLP printing results in parts with exceptional dimensional accuracy, making it suitable for applications where tight tolerances are critical, such as in the dental and jewelry industries.

Does Digital Light Processing Printing Have Any Disadvantages?

While Digital Light Processing (DLP) 3D printing offers numerous advantages, including high speed, precision, and efficient use of materials, DLP technology has limitations.

Understanding the potential drawbacks of DLP 3D printing can help you make informed decisions about the best printing methods for your specific needs.

Here are some of the disadvantages of digital light processing when compared to other 3D printing processes:

• Limited Material Options: Although DLP technology supports a wide range of resins, it’s generally more restricted compared to technologies like Fused Filament Fabrication (FFF), which can use a variety of thermoplastics and composites.
• Size Constraints: The build volume of DLP printers, especially desktop models, can be smaller than that of some 3D printers, limiting the maximum size of the objects they can create.
• Dependency on Resin Properties: The mechanical properties and durability of printed parts produced by DLP are highly dependent on the resin used. Some resins may not match the strength or thermal stability of materials used in other 3D printing methods.
• Cost of Materials: High-quality DLP resins can be more expensive than the materials used in other forms of 3D printing. The added expense potentially increases the cost per part, especially for large-volume production.
• Sensitivity to Light and Oxygen: Photopolymer resins used in DLP printing can be sensitive to ambient light and oxygen. Incorrectly storing and handling materials can affect the longevity of printed parts.
• Messy: Post-processing of DLP prints like washing the printed parts in solvents like isopropyl alcohol to remove any uncured resin can be messy. Additionally, spills of resin or solvents need to be cleaned up immediately to prevent damage or staining. here are some extra points:
• Spills and Splashes: Liquid resins can easily spill or splash during handling, leading to a messy workspace. Cleaning up resin spills requires immediate attention, as uncured resin can be sticky and difficult to remove once it hardens.
• Resin Containers: Pouring resin into the printer’s vat, or returning unused resin to its container, can be tricky without spilling so you will have to be extra careful.

What are the Applications of DLP Printers in Various Industries?

Many industries use Digital Light Processing 3D printing.

Here’s how DLP 3D printing is making an impact across various sectors:

• Jewelry Making: DLP printing is widely used in the jewelry industry to create intricate patterns for molding. Its exceptional quality and resolution make DLP printing ideal for producing complex jewelry pieces. Designing jewelry with CAD software and printing it with a DLP printer can create plaster or silicone molds. Mold-making resins can fully decompose in a furnace, leaving no residue. These molds are filled with molten metal, resulting in jewelry showcasing intricate designs while minimizing the use of raw materials.
• Dental Industry: DLP printers play a crucial role in the dental field by producing highly accurate dental models, crowns, bridges, and clear aligners for orthodontic treatments. The precision of DLP technology ensures a perfect fit for patients, enhancing the effectiveness and comfort of dental appliances.
• Medical Sector: DLP technology is instrumental in manufacturing customized prosthetics and implants tailored to each patient’s anatomy. Additionally, it is used for creating detailed anatomical models for surgical planning, training, and patient education, leading to improved medical procedures and outcomes.
• Prototype Development: DLP printers are invaluable in engineering and design for rapid prototyping of product designs. The ability to rapidly transform concepts into high-fidelity prototypes accelerates the development process, enabling faster iterations and improvements.
• Education and Research: DLP printing is a powerful tool in academic settings, empowering students and researchers to bring their theoretical designs to life for experimental and educational purposes. Hands-on experience drives innovation and learning, particularly in STEM fields.
• Entertainment and Art: DLP printing fuels creativity in art and entertainment, allowing artists and designers to transform their visions into reality. Create detailed figurines and props for movies or craft bespoke pieces for art installations. DLP printing’s attention to detail supports pushing the boundaries of creativity.

How Much Does DLP Printing Cost?

Like any technology, digital light processing comes with costs, which can vary widely depending on several factors, including the printer model, the type of resin used, the scale of production, and operational expenses such as maintenance and post-processing supplies. Here’s a closer look:

Here are some of the most popular resins and their average costs:

• Standard Resin: Typically costs between $50 to $100 per liter. Suitable for general prototyping.
• Tough Resin: Priced around $80 to $150 per liter. Perfect for parts requiring higher strength.
• Flexible Resin: Ranges from $100 to $200 per liter. Ideal for objects needing flexibility.
• Dental and Castable Resins: These specialized resins cost between $100 to $300 per liter, reflecting their use in precise dental work and jewelry making.

How much does a DLP 3D Printer Cost?

For those interested in purchasing a DLP 3D printer, the market offers a wide selection ranging from entry-level to high-end models. Desktop printers, ideal for hobbyists and small businesses, can be found in the $1,000 to $5,000 range. However, professional-grade and industrial DLP printers, which offer larger build volumes and higher precision, can cost anywhere from $5,000 to over $10,000.

Raise3D DLP Printer

A notable example of a high-performance DLP 3D printer is the Raise3D DF2. The DF2, designed for small-batch production, delivers high precision, repeatability, and reliability. At a starting price of $4,999.00, the Raise3D DF2 is optimal for engineering prototyping, manufacturing aids, and low-volume production. It supports a diverse selection of high-performance engineering resins, making it versatile for various applications. The investment in a machine like the Raise3D DF2 underscores the commitment to quality and efficiency in 3D printing. It gives users a tool capable of meeting the demands of professional-grade projects.

What are Key Factors to Consider When Selecting a DLP Printer?

When embarking on the journey of selecting a DLP printer, there are several pivotal factors you should take into account.

These considerations will guide you in making an informed decision, ensuring that the DLP printer you choose aligns with your requirements and objectives.

• Resolution and Precision: The resolution of a DLP printer is paramount, especially for applications requiring fine details, such as jewelry and dental models. Higher-resolution printers can produce parts with intricate details and smooth surfaces. For example, the Raise3D E2 is renowned for its exceptional resolution, making it a favored choice among professionals requiring high-detail prints.
• Build Volume: The build volume determines the maximum size of the objects you can print. If your projects typically involve large parts or you prefer to print multiple small items in one go, a printer with a larger build volume.
• Material Compatibility: DLP printers use photopolymer resins that vary in properties and applications. Some printers are compatible with various materials, offering versatility for different projects. For example, the Raise3d E2 is compatible with multiple resins, allowing users to print objects ranging from flexible to high-strength parts.
• Print Speed: DLP printers are generally faster than SLA printers because they cure an entire resin layer at once. Print speed can significantly impact productivity, especially in a commercial setting. Raise3D printers are known for their rapid print speeds without compromising output quality.
• Post-Processing Requirements: DLP-printed parts often require cleaning and curing. Consider the ease of post-processing and whether the printer manufacturer provides compatible cleaning and curing solutions.
• Cost and Budget Considerations: The initial cost of the printer and the ongoing expenses for resins and replacement parts should fit within your budget. While some printers, like the Raise3D DF2, might have a higher upfront cost, they offer precision and reliability that can prove cost-effective in the long run for small-batch production and prototyping.

Consider the case of a small jewelry design studio that opted for the Raise3D DF2. The studio required a printer capable of producing intricate designs with precision and reliability. Despite the higher initial investment, the DF2 was compatible with high-performance engineering resins, and its optimized features for prototyping provided the studio with the ability to create detailed molds for their unique jewelry pieces efficiently.

This decision not only enhanced the studio’s design capabilities but also streamlined its manufacturing process and saved costs in the long term, demonstrating the importance of selecting a DLP printer that aligns with specific needs and industry requirements.

What are the Differences between DLP and SLA 3D Printers?

DLP and SLA utilize UV light to cure photosensitive polymers, but how they achieve this is fundamentally different.

As already discussed, DLP uses a digital micromirror device (DMD) composed of hundreds of thousands of tiny mirrors, each capable of pivoting to direct UV light onto the surface of the resin.

To provide a better understanding, let’s compare DLP and SLA across several critical factors:

• Resolution and Precision: SLA printers generally have a higher resolution and precision than DLP because the laser can draw fine details more accurately.
• Speed of Printing: DLP printers are often faster than SLA printers because the digital light projector screen can cure an entire layer of resin in one go, whereas SLA printers have to trace the pattern of each layer with a laser point.
• Suitability for Large Prints: DLP technology, with its array of mirrors on the DMD, can be less effective for larger prints, as the light can lose uniformity across a wide area. In contrast, SLA can maintain high detail for large objects, though it might be slower.
• Durability of Prints: Since SLA can achieve higher precision, the prints are finely detailed and structurally strong. DLP prints are still quite durable but might lack intricacies on minute features.
• Ease of Use: DLP printers typically come calibrated and ready to print, making them more user-friendly for beginners. SLA printers might require more fine-tuning and calibration efforts.
• Cost of Equipment: Entry-level DLP printers are more affordable than SLA printers. Price can be a determining factor for hobbyists or small businesses choosing between the two technologies.
• Maintenance: DLP printers have fewer moving parts, which can lead to lower maintenance costs and effort over time, whereas the laser and complex mechanics of SLA printers might need more regular servicing.

Conclusion

DLP 3D printing is an incredible tool that changes how we turn ideas into real-life objects. It’s super versatile and handles all sorts of materials; whether durable parts for machines or fine details for jewelry, it handles it. If you work in medicine, jewelry, or car manufacturing, learn how DLP 3D printers can make items more precise, faster, and better quality. And DLP 3D printer technology keeps getting better and better. Just imagine how DLP 3D printers could help you with your projects.