Dlp 3d printer wiki

Guide to Resin 3D Printers

There are many 3D printing processes on the market. Getting familiar with the nuances of each helps to clarify what you can expect from final prints to ultimately decide which technology is suitable for your particular application.

Stereolithography (SLA) and digital light processing (DLP) 3D printing are the two most common processes for resin 3D printing. Resin printers are popular for producing high-accuracy, isotropic, and watertight prototypes and parts in a range of advanced materials with fine features and smooth surface finish. 

While these technologies were once complex and cost-prohibitive, today’s small-format desktop SLA and DLP resin 3D printers produce industrial-quality parts at an affordable price point and with unmatched versatility thanks to a wide range of materials.

Both processes work by selectively exposing liquid resin to a light source—SLA a laser, DLP a projector—to form very thin solid layers of plastic that stack up to create a solid object. While very similar in principle, the two technologies can produce significantly varying outputs.

In this in-depth guide, we walk through the details of the two resin 3D printing processes and explore how they compare in terms of resolution, accuracy, build volume, speed, workflow, and more.

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Desktop SLA 3D printers contain a resin tank with a transparent base and non-stick surface, which serves as a substrate for the liquid resin to cure against, allowing for the gentle detachment of newly-formed layers. 

The printing process starts as the build platform descends into a resin tank, leaving space equal to the layer height in between the build platform, or the last completed layer, and the bottom of the tank. A laser points at two mirror galvanometers, which direct the light to the correct coordinates on a series of mirrors, focusing the light upward through the bottom of the tank and curing a layer of resin.  

The cured layer then gets separated from the bottom of the tank and the build platform moves up to let fresh resin flow beneath. The process repeats until the print is complete. 

Low Force Stereolithography (LFS) technology, used by the Form 3+ and Form 3L, is the next phase in SLA 3D printing. 

In LFS 3D printers, the optics are enclosed in a Light Processing Unit (LPU). Within the LPU, a galvanometer positions the high-density laser beam in the Y direction, passes it through a spatial filter, and directs it to a fold mirror and parabolic mirror to consistently deliver the beam perpendicular to the build plane and ensure accurate, repeatable prints. 

As the LPU moves in the X direction, the printed part is gently peeled away from the flexible bottom of the tank, which drastically reduces the forces exerted on parts during the print process.

LFS 3D printing drastically reduces the forces exerted on parts during the print process, using a flexible tank and linear illumination to deliver incredible surface quality and print accuracy.  

This advanced form of stereolithography delivers vastly improved surface quality and print accuracy. Lower print forces also allow for light-touch support structures that tear away with ease, and the process opens up a wide range of possibilities for future development of advanced, production-ready materials.

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Just like their SLA counterparts, desktop DLP 3D printers are built around a resin tank with transparent bottom and a build platform that descends into a resin tank to create parts upside down, layer by layer.

The difference is the light source. DLP 3D printers use a digital projector screen to flash an image of a layer across the entire platform, curing all points simultaneously.  

The light is reflected on a Digital Micromirror Device (DMD), a dynamic mask consisting of microscopic-size mirrors laid out in a matrix on a semiconductor chip. Rapidly toggling these tiny mirrors between lens(es) that direct the light towards the bottom of the tank or a heat sink defines the coordinates where the liquid resin cures within the given layer. 

Because the projector is a digital screen, the image of each layer is composed of square pixels, resulting in a three-dimensional layer formed from small rectangular cubes called voxels.

Resolution shows up more often than any other value in 3D printer spec sheets, but it’s also a common ground for confusion. The basic units of the SLA and DLP processes are different shapes, making it difficult to compare the different machines by numerical specifications alone.

In 3D printing, there are three dimensions to consider: the two planar 2D dimensions (X and Y) and the third vertical Z dimension that makes 3D printing.

Z resolution is defined by the layer thicknesses a 3D printer can produce. Resin 3D printers like SLA and DLP offer some of the finest Z resolutions—thinnest layers—of all 3D printing processes and users can normally choose from a range of layer height options between 25-300 microns, allowing designers to strike a balance between detail and speed. 

In DLP 3D printing, XY resolution is defined by the pixel size, the smallest feature the projector can reproduce within a single layer. This depends on the resolution of the projector, the most common being full HD (1080p), and its distance from the optical window. As a result, most desktop DLP 3D printers have a fixed XY resolution, generally between 35 to 100 microns.

For SLA 3D printers, XY resolution is a combination of the laser’s spot size and the increments by which the laser beam can be controlled. For example, the Form 3 LFS 3D printer features a laser with an 85 micron spot size, but because of the constant line scanning process, the laser can move in smaller increments and the printer can consistently deliver parts with 25 micron XY resolution.

However, resolution in itself is often just a vanity metric. It offers some indication, but it doesn’t necessarily correlate directly with accuracy, precision, and print quality.

Learn more about resolution in 3D printing in our in-depth guide.

Because 3D printing is an additive process, each layer introduces an opportunity for inaccuracy, and the process by which layers are formed affects the level of precision, defined as the repeatability of the accuracy of each layer. Accuracy and precision depend on many different factors: 3D printing process, materials, software settings, post-processing, and more. 

In general, both SLA and DLP resin 3D printers are among the most accurate and precise 3D printing processes. Differences in accuracy and precision are often better explained by the differences between machines by various manufacturers than differences between the technologies themselves.

For example, entry-level SLA or DLP printers might use off-the-shelf projectors, lasers, or galvanometers, and their manufacturers will try to get the best performance possible out of these parts. Professional SLA and DLP 3D printers, like the Formlabs Form 3, feature a custom optical system adapted to the specifications required by professional customer applications.

Accuracy and precision are crucial for parts like dental splints (left) and surgical guides (right). 

Calibration is also crucial. With DLP projectors, manufacturers need to deal with the non-uniform light distribution on the build plane and optical distortion of the lenses—meaning that pixels in the middle are not the same size or shape as pixels on the edges. SLA 3D printers use the same light source for every part of the print, which means it’s uniform by definition, but they still require extensive calibration to account for distortions.

Even a 3D printer with the highest quality components and degree of calibration can produce widely varying results depending on the material. Different resins require optimized material settings to perform as intended, which might not be available for off-the-shelf materials or resins that are not thoroughly tested with a specific 3D printer model.

The takeaway? Accuracy and precision are almost impossible to understand from the technical specifications alone. Ultimately, the best way to evaluate a 3D printer is to inspect real parts or ask the manufacturer to create a test print of one of your own designs.

With DLP 3D printers, there’s a direct trade-off between resolution and build volume. The resolution depends on the projector, which defines the number of pixels/voxels available. If one moves the projector closer to the optical window, the pixels get smaller, which increases the resolution, but limits the available build area. 

Some manufacturers stack multiple projectors next to each other or use a high-definition 4K projector to increase the build volume, but this leads to substantially higher costs that often price these machines out of the desktop market.

As a result, DLP 3D printers are generally optimized for specific use cases. Some have a smaller build volume and offer high resolution to produce small, detailed pieces like jewelry, while others can produce bigger parts but at a lower resolution.  

The stereolithography process is inherently more scalable, since an SLA 3D printer’s build volume is completely independent of the resolution of the print. A single print can be any size and any resolution at any location within the build area. This makes it possible to 3D print large parts at high resolution or a large batch of detailed small parts to increase throughput with the same machine.

The other main barrier to increasing build volume in both SLA and DLP 3D printers is the peel force. When printing larger parts, the forces exerted on the parts increase exponentially as a cured layer separates from the tank. 

In LFS 3D printing, the flexible film at the base of the resin tank gently peels away as the build platform pulls the part up, significantly reducing the stress on the part. This unique feature has made it possible to substantially increase the build volume for the first accessible large format SLA 3D printer, the Form 3L.

The Form 3L is the first affordable large format SLA 3D printer with a build volume of 30 cm x 33. 5 cm x 20 cm.

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SLA and DLP resin 3D printers both known for creating parts with the smoothest surface finish of all 3D printing processes. When we describe the differences, in most cases these are only visible on tiny parts or highly detailed models.

Because objects are made of layers in 3D printing, 3D prints often have visible, horizontal layer lines. However, because DLP renders images using rectangular voxels, there is also an effect of vertical voxel lines.

DLP 3D printers render images using rectangular voxels, which causes an effect of vertical voxel lines. In this image, see the vertical voxel lines as they appear naturally on the left, and then outlined to more easily identify on the right.

Because the unit is rectangular, voxels also have an effect on curved edges. Think of building a round shape out of LEGO bricks—the edges will appear stepped on both the Z axis and the X-Y plane.

The rectangular shape of voxels makes curved edges appear stepped. Removing the appearance of voxel and layer lines requires post-processing, such as sanding.

In LFS 3D printing, layer lines are close to invisible. As a result, surface roughness is reduced, which ultimately leads to smooth surfaces, and for clear materials, more translucent parts.

When thinking about speed in 3D printing, it’s important to consider not just raw print speed, but also throughput.

Raw print speed for SLA and DLP resin 3D printers is comparable in general. As the projector exposes each entire layer all at once, print speed in DLP 3D printing is uniform and depends only on the height of the build, whereas, SLA 3D printers draw out each part with a laser. As a rule of thumb, this results in SLA 3D printers being comparable or faster when printing small or medium-size single parts, while DLP 3D printers are faster to print large, fully dense prints, or builds with multiple parts that fill up much of the platform.  

But once again, it’s worth considering the trade-off between resolution and build volume for DLP printers. A small DLP 3D printer can print a small part or a (small) batch of smaller parts fast, at high resolution, but the build volume limits the part size and the throughput. A different machine with a larger build volume can print larger parts or a batch of smaller parts faster, but at a lower resolution than SLA.

SLA 3D printers can produce all of these options in one machine and offer the user the freedom to decide whether she wants to optimize for resolution, speed, or throughput.

SLA 3D printers offer a larger build volume, allowing users to batch parts and print overnight to increase throughput. 

Speed can also depend on the material choice. Printing four times faster than Formlabs standard materials, Draft Resin fast-printing resin that is ideal for initial prototypes, rapid iterations, as well as dental and orthodontic models. From fast print initiation speeds to minimal support removal, wash, and cure times, Draft Resin has an optimized workflow to truly maximize efficiency.

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Just like with accuracy and precision, the workflow and available materials differ more from machine to machine than technology to technology.  

Most SLA and DLP 3D printers are “plug and play,” with easily swappable build platforms and resin tanks. Some more advanced models also come with a cartridge system to automatically refill the tank with liquid resin, which requires less attention and facilitates printing overnight. 

Some printers come with proprietary software to prepare 3D models for printing, such as PreForm for Formlabs SLA 3D printers, while other manufacturers offer off-the-shelf solutions. Features differ by software tool, for example, PreForm offers one-click print setup, powerful manual controls to optimize support density and size, adaptive layer thickness, or functions to save material and time. Luckily, the software can be easy to download and test before purchasing a 3D printer.

Resin 3D printers offer a variety of materials for a wide range of applications.

One of the most significant benefits of resin 3D printing is the variety of materials that make it possible to create parts for diverse applications. Resins can feature a wide range of formulation configurations: materials can be soft or hard, heavily filled with secondary materials like glass and ceramic, or imbued with mechanical properties like high heat deflection temperature or impact resistance. 

However, the range of supported material options depend on the 3D printer model, so we recommend inquiring with the manufacturer before purchase. 

Parts printed with both SLA and DLP technologies require post-processing after printing. First, the parts need to be washed in a solvent to remove excess resin. Some functional materials like engineering or biocompatible parts also require post-curing. For SLA 3D printers, Formlabs offers solutions to automate these steps, saving time and effort.

At last, 3D printed parts printed on supports require these structures to be removed, a manual process that is similar for both SLA and DLP 3D printers. LFS 3D printing simplifies this step by offering light-touch support structures that use very small touchpoints to enable easy removal with minimal support marks left behind.

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After sorting out the differences in technology and outcomes, we hope it’s much easier to select a resin 3D printer that best matches your workflow and output needs.

To explore the next generation of SLA 3D printing, learn more about the Form 3 and Form 3L LFS 3D printers. 

Curious to see the quality firsthand? Order a sample part shipped to your office.

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What is Digital Light Processing (DLP)?

What is Digital Light Processing (DLP)?

DLP (Digital Light Processing) is a 3D printing technology used to rapidly produce photopolymer parts. It’s very similar to SLA with one significant difference -- where SLA machines use a laser that traces a layer, a DLP machine uses a projected light source to cure the entire layer at once. The part is formed layer by layer.

DLP printing can be used to print extremely intricate resin design items like toys, jewelry molds, dental molds, figurines and other items with fine details. Due to it curing the entire layer at once, it’s much faster than SLA

DLP printers are popular for their ability to quickly produce objects and parts with intricate designs with a high degree of accuracy. They are relatively affordable, so they are often found in offices. Limitations of DLP printing include strong odors produced by melting photopolymers in the printing process, and the risk of warping in larger items.

Although the first description of a 3D printer was published in 1964 by the sci-fi author, Arthur C. Clarke, it wasn’t until 1987 that the stereolithography, or SLA, process was developed. DLP printing followed soon after, and is frequently compared to SLA printing. Direct Light Processing was originally developed in 1987.

DLP is popular because of high print speeds, though accuracy is sacrificed in the process. It is limited to photopolymers that often emit odors that can be problematic in an office environment.

FAQ

What is the difference between DLP vs SLA? Both are 3D printing processes that work with photopolymers, but DLP uses a more conventional light source, such as an arc lamp, rather than a UV light as in SLA. DLP cures an entire layer at once; SLA printers trace out a path with the laser, curing along that path.

How is DLP cheaper than other methods of 3D printing? DLP uses a shallow vat of resin, and uses everything within the vat for each printing. This can result in lower costs and less waste.

How do DLP printers compare to other 3D printers? Since DLP printers house a projector to project an image to be formed, they tend to be larger than other 3D printers.

What kinds of materials can be used in DLP printing? Usually, DLP uses photopolymers to create objects, but some companies make DLP printers that can use other materials, like rubber and thermoplastics.
Can DLP printers be used to print large, intricate pieces? Because the size of the object printed is dependent upon a projector and resolution of the image it projects, DLP printing is not suitable for very large items.

Digital LED Projection (DLP)

• 1 DLP Technology
• 2 Technology
• 3 Application
• 4 Advantages and disadvantages
• 5 Other additive manufacturing technologies

DLP technology

Digital LED projection (DLP) is an additive manufacturing method, a variant of stereolithographic 3D printing.

Technology

One of the most popular methods for additive manufacturing of high-precision prototypes is laser stereolithography (SLA). The method is based on the use of photopolymer resins that harden when irradiated with ultraviolet light. While SLA technology is widely used in a professional environment, its distribution is limited by the rather high cost of devices due to the use of expensive laser emitters.

An alternative method uses digital LED projectors (DLP) to reduce the cost of the devices. Unlike laser systems that scan the surface of a material with one or more laser heads, DLP printers project an image of an entire layer until the polymer resin hardens, after which a new layer of material is applied and an image of a new layer of a digital model is projected.

It is difficult to judge the advantages of one method or another. DLP printing is relatively new, but is already showing excellent results, comparable in precision and performance to the original laser stereolithography (SLA) technology patented by Charles Hull in 1986 and gave the first significant impetus to the development of 3D printing. The main advantage of DLP over SLA may be the lower cost of the projectors used compared to laser emitters.

Applications

Since their inception, DLP printers have been in direct competition with SLA devices. DLP printers are used in dentistry, jewelry, freelance design and souvenir production.

Advantages and disadvantages

Like standard stereolithographic devices, DLP printers have high printing accuracy - the minimum layer thickness can be up to 15 microns using existing installations. The minimum layer thickness applied by more affordable FDM printers is usually at least 50 microns. In practice, the resolution is inversely related to the layering speed - the technology allows you to achieve even higher accuracy at the cost of lowering the print speed. Consumables, namely photopolymer resins, have a high range of mechanical characteristics: imitators are possible in the range from hard plastics to rubber. As a rule, printing is carried out with a material of one color, but there are no restrictions on the palette. The main disadvantage of the DLP method, as well as SLA, is the relatively high cost of consumables - about $ 80-160 per liter of liquid polymer. In comparison, a kilogram of FDM printing filament can be purchased for $35. Ultimately, the user must find the right balance between print quality and cost.

Other AM technologies

• Mask stereolithography (SGC)
• Multi-Jet Simulation (MJM) Technology
• Color Inkjet (CJP)
• 3D Inkjet Printing (3DP)
• Selective Laser Sintering (SLS)
• Selective laser melting (SLM)
• Stereolithography (SLA)
• Selective heat sintering (SHS)
• Lamination of objects (LOM)
• Electron Beam Melting (EBM)
• Direct Metal Laser Sintering (DMLS)
• Electron Beam Fusion Manufacturing (EBFȝ)
• Fused Deposition Modeling (FDM)

Go to the main page of Encyclopedia of 3D printing

Encyclopedia of 3D printing

Welcome to the help section of our portal!

As you can see, the world of 3D printing deserves the title of "mysterious". The rapid development of technology gives rise to a lot of all kinds of terms, concepts and designs, whose essence is far from obvious to a simple layman. The main task of our site is to acquaint you with the latest news from the world of 3D printing, tell you about technological innovations and help you with the purchase of the necessary equipment.
The task is complicated by the fact that currently in Russia there is no official standard for terms related to 3D printing. As a result, many of them are differing translations of the originals, somewhat confusing to the reader. In addition, 3D printer manufacturers themselves often try to monopolize parts of the market by making fairly minor changes to existing technologies in order to obtain a patent, and supplying “new” products with new names, thereby only exacerbating the confusion.
But don't despair. In this section, we will try to explain all the nuances of the world of 3D printing: the technologies used, how they work, terminology options, and so on. Keep in mind that the world of 3D printing does not stand still, and therefore we will constantly update and supplement our help section with new information.

Reference sections:

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• 1 3D printing
• 2 3D printing technologies
• 3 Consumables for 3D printers
• 4 3D equipment
• 5 slisers
• 6 Articles about 3D printing
• 7 Our reviews about 3D printers and about 3D printing
• 8 Technica
• 9 Literature
• 10 Work with a 3DTODAY portal. Reference book

3D printing

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• What is a 3D printer.
• All about 3D printing. additive manufacturing. Basic concepts.
• 3D printing for dummies or "what is a 3D printer?"
• How to build a 3D printer with your own hands"
• Frequently Asked Questions for 3D Printers and 3D Printing"

3D Printing Technologies

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• Mask Stereolithography (SGC)
• Multi-Jet Simulation (MJM) Technology
• Color Inkjet (CJP)
• Digital LED Projection (DLP)
• 3D Inkjet Printing (3DP)
• Selective Laser Sintering (SLS)
• Selective laser melting (SLM)
• Stereolithography (SLA)
• Selective heat sintering (SHS)
• Lamination of objects (LOM)
• Electron beam melting (EBM)
• Direct Metal Laser Sintering (DMLS)
• Electron Beam Fusion Manufacturing (EBFȝ)
• Fused Deposition Modeling (FDM)
• Technology Selective Deposition Lamination (SDL)

3D Printer Consumables

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• FDM/FFF Consumables
• 3D printing consumables table. Melting points and extrusion rates
• Photopolymer consumables
• PLA for 3D printing
• ABS plastic for 3D printing
• Printable PVA plastic
• PET plastic for printing
• 3D Printable Nylon
• Laywoo-D3 for 3D printing
• NinjaFlex for 3D printing
• Laybrick for 3D printing
• Stratasys
Photopolymer Resins
• 3D Ink Photopolymer Resins
• Photopolymer resins Asiga
• Photopolymer resins Digital Wax Systems
• RapidShape 9 Photopolymer Resins0004
• MadeSolid Photopolymer Resins
• 3D Systems Photopolymer Resins
• Fun To Do Photopolymer Resins
• Polystyrene for 3D printing
• 3D printed polycarbonate
• Portable bar extruders. Filament manufacturing. How to make your own 3D printing consumables

3D equipment

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• 3D pen
• 3D printer FDM
• Catalog of DIY and OpenSource 3D printers
• Photopolymer 3D printer
• Metal 3D printing

Slicers

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• All versions of CURA - download

3D printing articles

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• How to avoid deformation of models when 3D printing
• How to choose high quality filament
• Processing of 3D printed models
• How to clear a clogged extruder nozzle
• "Rescue" of the product using the Repetier-Host program when 3D printing is stopped
• 3 Commandments to make 3D printed products cheaper
• Photoshop CS6 modeling and 3D printing tutorial

Our reviews about 3D printers and about 3D printing

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• We bought a 3D printer and decided to earn some money. What's next?
• Cheap 3D printers for every taste
• Household 3D printers for your home
• Jewelry 3D printers or what to give your beloved man
• Metal 3D printing on a home 3D printer. Technology Today and Immediate Prospects
• 3D printer and metal - the present and future of metal 3D printing‏
• ChefJet confectionery 3D printers – the end of the sugar cube era‏
• MBot Home 3D Printer Review‏
• 3D printing with chocolate or how to organize your sweet business
• 3D printers for jewelers - unrivaled print quality‏

Technical

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• Set up the Marlin firmware and upload it to the 3D printer
• We print with ABS plastic without cracks and heat chambers

Literature

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• Book: 3D printing - short and clear

Working with the 3Dtoday portal.

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