The Basics of Resin 3D Printing and How It Works

Vat photopolymerization, or resin 3D printing, is a type of 3D printing that uses a liquid resin as its building material along with light rays as a source for hardening the liquid resin.

There are many different kinds of resin 3D printing, such as stereolithography (SLA), digital light processing (DLP), and liquid crystal display (LCD). However, resin printing technologies are usually very flexible and can be used for a wide range of tasks that require fine details and high resolution.

This printing technique is used by professionals, both hobbyists and gamers, to make intricate miniatures, jewelry designers to create models and molds for casting, dentistry labs to make patient-specific molds, and more.

In this blog post, we will be covering the basics of resin 3D printing, including how it works and why it’s becoming so widely used today. 

Let’s get started!

What Is Resin 3D Printing 

“3D printing with resin” is a term for a group of techniques for making things by adding layers of solidified liquid photopolymers.

Although “resin printing” may not be the official name for the entire group, it is a more concise term for all machines because they use resin ingredients. Alternatively, you can run across words like polymerization by VAT or stereolithography.

Resin printers function using codes (or a computer generates a code directly based on an electronic model). It also uses the principle of polymerization in making items with the incorporation of  ultraviolet or light-sensitive resins (photopolymers) as a material, and the material is held in a basin or vat.

For resin 3D printing, a UV laser beam is shined on a liquid resin that reacts to light. The resin hardens in the right pattern, and the object is built up layer by layer until it is finished. This makes it possible to print models with incredibly tiny details.

Technologies for Resin 3D Printing 

Resin 3D printing is one of the most advanced and flexible ways to make models and prototypes in three dimensions. This technology are of three types, namely; 

Stereolithography (SLA) 

Perhaps the most popular and oldest 3D printing process utilized today is stereolithography (SLA). In the 1980s, Charles Hull, the creator of 3D Systems, created the first SLA 3D printer. A UV laser “draws” a portion of an object on a thin layer of liquid photopolymer resin during the SLA 3D printing process. 

Watch how stereolithography (SLA) 3D printing works: The Ultimate Guide to Stereolithography: How SLA Works

The ability of SLA 3D printing to produce excellent isotropic components with extremely smooth surfaces is one of the key factors contributing to its popularity. SLA pieces are also waterproof, unlike porous FDM prints. 

SLA can now work with several materials, such as regular resin, clear resin, strong resin (like ABS), flexible resin, biocompatible resin, and filled resin. This makes additive manufacturing (e.g., ceramic-filled resin) appealing to consumers.

These printers have outstanding quality and are frequently utilized in sophisticated 3D applications. SLA 3D printers like those made by Formlabs are excellent examples.

Digital Light Processing (DLP)

Digital Light Processing (DLP), which is often just called “DLP,” is one of the most common ways to print things out of resin. In many aspects, DLP and SLA are comparable. Both employ a light source to selectively cure layers of liquid resin photopolymer. 

DLP uses digital projection to transmit light to part of the printing material. SLA, on the other hand, prints designs on layers of resin using a single UV laser light. For each layer of liquid resin, the DLP projection system creates a 2D pattern (the small portion of the 3D object) before curing the whole layer.

One advantage of DLP 3D printing is its speed. Compared to SLA, which uses a laser to create the 3D model’s cross section, with DLP, objects are printed from an entire layer of resin at once due to its digital projector. 

Just as with many SLA 3D printers, DLPs are constructed from the ground up. In other words, the build plate digs itself into the resin while the projection system is positioned underneath the resin vat. Then, through the clear tank, the digital projector flashes and cures a pattern onto the layer of resin. The build platform advances one layer at a time as each layer is produced.

LCD/mSLA (Liquid Crystal Display)

Similar to DLP 3D printing, liquid crystal display (LCD) 3D printing, which is sometimes called masked stereolithography (mSLA), uses a light source to cure layers of resin material from the bottom up. 

DLP and LCD have very different types of light sources. LCD uses an LCD panel and LEDs, while DLP uses a digital projector and DMD. A 3D printer prints an LCD screen by shining light through it with an array of LEDs that are placed under the resin vat. 

The LED light pattern is effectively controlled by the LCD screen, which also lets the resin layers cure exactly. The LCD 3D printing method can cure a whole layer at once, just like the DLP method.

LCD technology is used in most hobby 3D resin printers, like the Anycubic Photon and the Elegoo Mars series, because it is cheap.

How Does It Work

Either by hand or mechanically, resin material is added to the resin tank. Manual filling of the resin by a professional should be done with caution to prevent skin contact with some resins, which might be harmful.

To generate a thin film of resin contacting the build platform, the machine lowers the build platform into a resin vat. The resin is liquid until it is subjected to a UV laser. Each design layer is drawn onto the print bed by the laser, which serves as the print head. 

The resin solidifies into the finished object as soon as the laser touches it. This process is done over and over again until the print is done and the final product is ready to be taken off the print bed. 

In order for the uncured resin to pass through and create a new slim covering over the plate, the platform must move. And in the case that the unit has a roller, it would roll across the construction site to ensure that the resin was correctly laid out. This is repeated over and over till the model id printed

Watch for more details on resin 3d printing workflow: https://youtu.be/Qha7N28sM2g

The Benefits of Resin 3D Printing Over Other Types of 3D Printing

Resin 3D printing has the potential to revolutionize the 3D printing industry with its unique capability of printing complex, intricate details with very high resolution and accuracy. 

• It is a layer-by-layer method that melts photosensitive polymer before it solidifies upon hardening. 
• This technology is mainly utilized in the medical, automotive, dentistry, and jewelry fields due to its ability to precisely document even the tiniest details consistent with no degradation in quality. 
• The end product from resin 3d printing is reproducible, highly accurate parts and prototypes at a much faster rate than other types of 3D printing technology. But what sets resin 3D printing apart from other technologies is that it doesn’t require laser lenses or complicated maintenance. 
• No extra materials are needed since all the melted plastic gets reused multiple times throughout a project. 
• Resin 3d printing allows for complete control over critical factors like light intensity, exposure time, and focus depth, allowing flawless results every time.

Materials Used in Resin 3D Printing 

To get started with resin printing, all you need is a reliable 3D printer with a very precise LCD monitor. There is a significant probability that a resin printer you buy from a well-known company will come with a basic set of supplies and equipment. 

These probably aren’t enough, though. Before beginning your first resin printing job, you should pick up a few extra accessories, which include;

 

Resin

You should use the resin container that came with your 3D printer before purchasing additional bottles. Resins may appear similar but can differ in functionality or appearance. Before you can determine which brand is best for you, you must get some experience.

As an entry-level resin, the ELEGOO Plant-Based 3D Printer Resin is a fantastic choice. It is simple and one of the market’s most affordable 3D printing resins. 

It might not be the most excellent option for small action figures because it needs to be more accurate in detail. The ANYCUBIC 3D Printer Resin costs twice as much but significantly improves print quality.

 IPA Washing Station

When resin printing is complete, you will end up with a solid object with a lot of uncured resin. It is necessary to rinse this resin with 99% isopropyl alcohol (IPA). You can purchase a commercial IPA washing unit or shake the print within a sizable IPA container.

If you build your own DIY IPA washing station, get containers big enough for your prints to submerge. Additionally, we advise doing IPA rinsing in two stages: the first is to remove the resin in bulk, and the second is to make sure there is no longer any residue.

UV Curing Box 

A resin print is still technically in its “green” condition, even though it may feel quite firm after printing. More UV curing will be required for the plastic to be solid and durable. 

A UV curing box is the ideal setting for this. If money is tight, you may make your UV curing box with a clean paint can and an $8 UV light bulb.

Nitrile Gloves and Safety Goggles

Toxic photopolymer resin is utilized in 3D printing. There is a need to wear safety goggles and nitrile gloves whenever you touch resin, including when you pour it into the resin tank and when you clean your final 3D prints. 

Regular latex gloves should not be used since they quickly degrade when in touch with resin.

Paper Towels

Despite your best efforts, resin spills and drops will inevitably land on your work surface. To clean up the mess, you will most likely need a lot of paper towels. Paper towels can also clean the resin vat in your printer and remove extra resin or alcohol from your prints.

Plastic Funnel with Paper Filters

After finishing a print, you’ll still have a sizable amount of resin in your 3D printer’s tank or vat. You can recover the resin and put it inside a brand-new bottle, but leaving it in the vat till your next job is OK too.

Pouring the resin into a funnel lined with paper filters is the simplest way to accomplish this. The filter will strain out any solid particles that may have developed during the curing process. Reusing 3D-printed resin is possible if UV light sources are avoided.

Spare FEP sheets

Your 3D printer’s FEP sheet is a definite barrier between the light source and the photopolymer resin. The sheet with your printer should work well for various tasks. 

However, any scuff, hole, or hazy area will require replacing the FEP sheet. Having a few FEP sheets on hand at all times is a smart idea because they are not pricey.

Other post-processing tools include an X-acto knife, a pair of pliers, and a putty knife set for removing prints.

Materials Made With Resin 3D Printers

Recently, resin 3D printers have become more affordable and found more consumers. This has created an opportunity for a wide variety of products to be made with resin. 

These products include prostheses, jewelry, art, costume accessories, full-color resin sculptures, everyday items such as cups and phone cases, and even complex parts for machines or vehicles. 

The precision and accuracy of resin 3D prints make them preferable for medical industry manufacturers who need to manufacture accurate parts for joint replacements or medical devices. This includes detailed objects, especially in dental applications. 

Also, resin 3D printing can make complex structures that would be hard or impossible to make with other printing methods. For example, it can make specific net shapes or lattice structures that would take a long time to make by hand. 

With resin 3D prints taking on all sorts of ideas, we will continue to see the widespread use of resin 3D printers for various purposes.

Pros and Cons of Resin Printing’s 

Different resin 3D printing techniques exist, and each technology has distinct characteristics. It also depends on the technical details of the machine, such as the brightness of the light source, the build volume, the firmware, and the properties of the photopolymers that are used.

Pros

Great Specifics

Photopolymers are easier to mold into complex shapes than melted plastics since they are introduced in liquid form into the printer.

A Uniform Surface

Layer lines are still used in resin printing, but they are much smaller and on some colors of resin, they are almost impossible to see.

Several Types of Materials

The resins on the market are able to meet all common needs and applications, which are growing steadily. Essentially, a photopolymer resin is made up of the parts of the reaction that make it work, as well as colors, visual aids, and functional additives.

Supports Don’t Significantly Degrade the Surface

In the event of any light overhangs on molds, they may simply be joined to the major parts of a component during curing because the resin tank is completely filled with resin around the outside.

High Tempo

Resin printing is much faster than other ways to make prototypes, and most modern machines are also fast.

Lower Prices

Resin printing lowers the cost of making jewelry master models, dental equipment, and prototypes, among other things.

It Is Waterproof to Print

In comparison to plastics or powders, photopolymers are strong and water-resistant. They are resistant to wet air or any form of water, and the majority are used in watertight applications.

Cons

There is a Tiny Build Volume for Many Devices.

Manufacturing large things would be fairly costly due to the need for an industrial upgrade. For tall prints made with pricey photopolymers as well,  it will be necessary to fill up the entire tank, which will raise the cost of the project.

Design Constraints and Specifications

Resin printing has a number of requirements that must be met before a project can go into production. For instance, the width and thickness of etched features must measure  a minimum of 0.2 mm. For a model to be built properly, considerable expertise and experience are needed. The orientation of the part and the quality of the mesh have an impact on the printing process as well.

Too Many Supports Involved

According to experts, an item should be positioned for the highest level of quality so that it “flies” at a 45-degree angle without touching the plate. As a result, there are several structures used as supports that, once they have dried and solidified, cannot be recycled to create new resin.

Following the Completion of Printing, Curing Continues

Polymerization is a complicated process because reactions within the parts are a continuous process, even after prints have been molded from resin. This is why postprocessing in the form of curing is so important. This could result in breakage and deformation with regards to the component and material.

Difficult Resolution

A number of variables that influence the resolution level (precision/quality) of resin printing is dependent on a number of variables, including the kind of resin used, the orientation of the object, firmware, etc.

Conclusion

Resin 3D printing has revolutionized the way we think about prototyping and manufacturing with its ability to produce intricate, accurate parts quickly and cost-effectively. 

With a variety of resins available, it is now possible to create objects with high detail, strength, and flexibility. Whether you are looking for a one-off prototypes

If you’re thinking about adding a 3D printer to your home or office, resin is a great option. It’s versatile and can be used for a variety of projects. And, once you understand the basics of how it works, it’s easy to get started. 

FAQ On How Resin 3D Printing Works