3D printing technology has advanced rapidly in recent years, with new processes and materials emerging all the time. Two of the most common technologies used in desktop resin 3D printers are Stereolithography (SLA) and Digital Light Processing (DLP). Both utilize photopolymer resins cured by light to build models layer-by-layer.
While SLA and DLP share some similarities in the printing process, DLP technology offers some distinct advantages that make it an appealing choice for many applications. In this guide, we’ll take an in-depth look at how DLP 3D printing works, compare it to SLA, highlight the benefits DLP provides, and discuss some of the top DLP printers on the market today.
What is Digital Light Processing (DLP)?
DLP is a type of stereolithography 3D printing that uses digital light processing technology to cure liquid resin into solid models. It was invented in 1987 by Larry Hornbeck of Texas Instruments and has since been adapted for 3D printing applications.
In DLP printing, a vat of photopolymer resin sits above an LED light source or projector. The projector displays sequential images of each layer, projecting light in ultraviolet wavelengths that cure the resin. As each layer is exposed, the build platform lifts slightly out of the vat, allowing fresh resin to flow beneath and prepare for the next layer.
This layer-by-layer process repeats until the full model is complete. DLP printing is similar to SLA, but offers faster print speeds, better accuracy, and higher detail in some cases.
How Does DLP 3D Printing Work?
The core components and printing process for DLP technology include:
- Vat of Photopolymer Resin: The resin is a liquid plastic that cures and hardens when exposed to UV light. Different resin types have varying properties when cured.
- Build Platform: This platform lowers into the resin vat and gradually lifts as layers are cured onto it.
- Light Source: DLP printers use a digital projector, LED array, or laser to project light and solidify each layer.
- Projection Screen: Light is projected onto this screen at the bottom of the resin vat. Screens have a transparent and UV-transparent window.
- Control System: Software slices the 3D model and controls the light source and build platform to expose and cure the resin layer-by-layer.
During printing, the build platform starts above the vat. It then lowers into the resin so a thin layer is submerged. The projector displays an image of the layer, projected onto the screen through the transparent window. The UV light cures the resin in this pattern.
After exposure, the platform lifts slightly to peel the cured layer away from the screen. Fresh resin flows beneath in preparation for the next layer. This process repeats until the full object is formed and can be removed for final curing and post-processing.
Key Benefits of DLP 3D Printing Technology
Compared to SLA, DLP offers some advantages that can benefit certain applications:
- Faster Print Speeds: Because an entire layer is exposed at once, DLP can solidify resin layers much faster than the scanning process used in SLA.
- Higher Accuracy: With no moving laser parts, DLP maintains a precise pixel-to-pixel accuracy throughout the build area. The projected light patterns have finer resolution than SLA lasers.
- Detailed Prints: DLP can produce crisp details down to 30-50 microns, making it ideal for printing miniatures, jewelry, dental models, and other small, complex designs.
- Simple Maintenance: DLP printers have fewer moving parts, making them relatively low-maintenance compared to SLA machines. There’s no laser or mirror system to calibrate.
- Affordable Machines: Basic DLP printers are available at lower price points than SLA, opening up the technology to more users. Higher-end DLPs still compete performance-wise with industrial SLA printers.
- Office-Friendly: DLP printers contain the resin vat, controlling odor and mess. They can work reliably in office settings.
For applications requiring fast turnaround, fine details, an affordable machine, or installation in shared workspaces, DLP offers clear advantages over SLA. The following sections go over these benefits in more detail.
DLP vs. SLA Print Speed
One of the biggest advantages of DLP over SLA is faster print times, making it ideal for rapid prototyping needs. DLP projects a single image of the full layer pattern, curing the resin in one quick flash.
SLA utilizes a scanning laser that needs to slowly trace out each layer. Most SLA machines have laser diameters around 140 microns, while DLP projectors can produce images down to 30 microns. This allows for faster movements across each layer.
Overall, DLP printers can produce models 2-3 times faster than SLA. Very complex and detailed designs may take longer due to the additional slicing computations, but DLP still maintains a speed advantage. For simple prints, speeds can be 5x faster or more.
If your application requires fast iteration and testing of designs, a DLP printer will provide much quicker overall workflow than SLA. The faster cycles can really expedite the product development process.
Superior Accuracy of DLP Printing
The DLP curing process also results in more consistent accuracy across the build area. With no moving laser system, the projection remains precisely aligned layer to layer. The pixel resolution stays consistent, eliminating distortions that can occur with SLA.
For example, an SLA laser has to accelerate and decelerate rapidly with changes in direction. This can slightly shift or stretch the laser positioning over time, reducing accuracy in certain build geometries. The optics also need periodic recalibration.
DLP avoids these issues entirely by using masked images projected from a fixed light source. The positioning remains exact throughout the build, producing crisp details and smooth surfaces.
Accuracy and repeatability are critical for applications like dental modeling, jewelry casting, and fitting pieces together in assemblies. DLP printing shines in these use cases and others requiring precision.
Unmatched Details from DLP Printers
The precision of DLP technology enables remarkably detailed 3D prints. While SLA typically operates at 70-200 micron resolutions, DLP can go as low as 30 microns.
By adjusting the projection optics, certain DLP printers can resolve details around the size of a red blood cell. This allows intricate designs like miniature figurines, microfluidics, and electronics housings to be reproduced clearly.
Jewelry makers take advantage of these fine-scale capabilities to produce one-off pieces directly in resin. The exceptional polish and crisp features rival quality casted pieces. Dental labs use DLP printers to make amazingly accurate crowns, aligners, and retainers fitted to the micron.
Engineers rely on the detail to visualize tiny components and confirm fit in assemblies. The process opens up applications in aerospace, medical devices, microelectronics, and more. Parts integrating multiple materials can also benefit from DLP’s resolutions.
If your application requires replicating small features, you’ll benefit greatly from partnering with a DLP printer. SLA machines simply can’t match the fidelity in many cases.
Low Maintenance DLP Printers
With fewer components and moving parts, DLP printers are designed to be relatively hassle-free compared to SLA machines. There are no optics, mirrors, or galvanometers that need periodic recalibration and alignment.
The light projector does all the work in precisely curing each layer. As long as the build platform is level and the projector works reliably, you can achieve great prints without much intervention. Just keep the resin tank clean and filters changed as needed.
This low maintenance makes DLP a great choice for non-experts and offices that can’t be constantly monitoring and tweaking the printer. Once dialed in, it should run consistently without much hands-on care.
Of course, higher-end DLP printers may require closer attention to resin changeouts, build plate leveling, and projector calibration. But in general, the technology lends itself to steady, reliable operation over long periods. Less downtime results in higher productivity.
Affordable Desktop DLP Printers
Driven by progress in projection technology, affordable DLP printers have hit the desktop market in recent years. Machines from Anycubic, Phrozen and others provide the benefits of DLP starting under $300.
While industrial DLP machines still cost many thousands, amateur users can now explore the technology on a budget. The affordable machines are surprisingly capable too, able to produce jewelry, miniatures, scale models, and other detailed prints.
Flexible resins allow prototypes with precise mechanical properties to be tested. Different material formulations also enable dental, medical, casting, and engineering use cases.
For schools, small businesses, and independent creators, desktop DLPs open up a world of detailed printing possibilities. More users can take advantage of faster speeds and finer resolutions that were once only available on high-end printers.
DLP 3D Printers for Offices
DLP printers contain the photopolymer resin in vats, controlling odor and mess. This allows them to operate reliably in office, classroom, and studio environments alongside personnel.
SLA printers involve more handling of resins, alcohol washes, and post-curing protocols that can irritate eyes and skin. DLP keeps the liquids enclosed and used resin contained for proper disposal.
Maintenance is also cleaner. Changing filters and emptying the resin tank can be performed quickly without major spills or contamination. This makes DLP an ideal option for print farms serving multiple users.
The fast operation and office-friendly nature of DLP printers let product design teams efficiently iterate and test new concepts without leaving the lab or workshop. Faster turnarounds support agile development workflows.
Leading DLP Printer Manufacturers
Now that we’ve covered the core benefits of DLP technology, let’s take a look at some of the top printers on the market utilizing it:
Formlabs Form 3 & 3L
The Form 3 series from Formlabs leverages high-precision DLP technology to achieve incredible print resolutions and details. With a 25 or 50 micron (0.001/0.002 inch) XY resolution, it can produce super smooth surfaces and tiny complex structures.
The Form 3 L model has a larger build volume of 11.5 x 7.6 x 18 cm, allowing longer parts and higher production runs. Both printers use Formlabs’ proprietary resin formulations to deliver excellent mechanical properties. The Form Wash and Cure units streamline post-processing.
Anycubic Photon Mono/Mono X
Anycubic offers very affordable DLP options like the Photon Mono starting under $200. The LCD matrix projects light from below with a pixel size around 50 microns. While not as advanced as the Formlabs printers, the Mono provides an entry point for new users to get acquainted with DLP capabilities.
The Mono X has a larger 18 x 11 x 6 cm build area with mostly similar specs. Anycubic has also developed its own resins from basic prototyping up to castable, elastic, and dental materials. Open material options are also available.
Prusa SL1
Prusa is well known for their FDM printers, but they recently developed the SL1 DLP printer as a precise, affordable option for resin printing. It offers 25-50 micron XY resolution for crisp details. At $1299, it hits a nice sweet spot for features and performance.
A 5.5″ 2K LCD panel projects light from below the resin with fast layer exposure times down to just 1.5 seconds. The printing process is very streamlined, and the printer includes PTFE-lined tanks and other smart design elements. It produces excellent prints for the price.
Peopoly Phenom Noir
At the high end, Peopoly’s Phenom Noir DLP machine boasts printing speeds up to 155mm/hour. A 1080p DMD projector cures layers at 35 microns, while a 1440p mode achieves 25 microns. The large build volume of 276 x 155 x 200 mm enables production-scale runs.
It’s an industrial machine designed for relentless operation. Reliable, consistent performance makes it ideal for design studios, manufacturers, dental labs, and engineers needing extreme precision on large parts. The Phenom line exemplifies the capabilities possible with cutting-edge DLP printing.
Leveraging DLP For Your Applications
From rapid prototyping through mass production, DLP 3D printing offers unique advantages over other technologies:
- Speed for fast iterations and turnaround
- Precision and repeatability for detailed prints
- Reliable operation with less maintenance
- Affordable desktop machines
- Resin containment for cleaner office printing
With these benefits, DLP helps drive innovation across jewelry, dental, medical, engineering, and manufacturing. As projector resolutions and resin materials advance, DLP will continue opening new possibilities in 3D printing.
Understanding the technology and processes behind DLP printing enables you to produce higher quality prints faster. Our guide covered how DLP works, key benefits compared to SLA, and leading printer models on the market today. Before investing in your own machine, consider your business needs and where DLP can provide the most impact.
