Should You Make Your Resin Prints Hollow? How to Decide

When creating a 3D printed model, it will be somewhat hollow on the inside in most cases. Although there is usually infill of some level (to keep it stable), it’s rare to see them 100% solid. But what about 3D printing with resin?

Resin prints should be hollow because they’re cheaper to make and take far less time to print than solid designs. That said, it depends on the purpose of the finished product. For example, solid prints are often used in medical and jewelry-making professions where the print needs to be more durable. 

Read on to learn more about why hollow resin prints are more affordable and convenient for the average printer. Then, we’ll discuss the kinds of factors and costs you need to take into consideration when deciding to print with resin. 

Why Hollow Printing With Resin Makes Sense

Resin printing, also known as vat polymerization, is a process that relies on photopolymerization. 

This refers to chemical reactions that take place when a liquid is exposed to UV light (or other forms of light) that cause the fluid to change shape. In this case, from a liquid to a solid print. 

Resin printers are specialized pieces of equipment that consist of several elements that ensure they function effectively. These include:

• The material, in this case, resin. Resin comes in a range of types, such as daylight-sensitive, castable, and UV resins.
• The resin vat. This contains the liquid resin to be cured before printing can take place.
• A light source and mirrors cure the resin once it’s been printed into the desired shape. These can vary from a DLP projector, LCD, or SLA UV light source.
• The build platform where the model is formed out of the liquid resin. Regular 3D printers have a similar platform.
• Some resin printers have rollers. They sweep across the build platform to ensure the resin is smoothed out in even layers.

Resin Printing Takes a Lot of Time

Understanding the actual resin printing process is integral to understanding whether you should print solid or hollow resin, as it’ll put into perspective the cost of materials and the time it takes to produce a final product. 

The process happens as follows:

1. The resin tank is filled with resin material, either automatically or manually. 
2. The build platform is lowered into the resin to create a layer of liquid resin on the platform.
3. The light source will then draw a pattern in the resin, causing it to solidify.
4. If the machine is equipped with a roller, the roller will run across the resin film to ensure it is perfectly level. 
5. This process will continue in a cycle until the entire object is formed layer by layer.
6. The object, once complete, is removed from the machine for post-processing, which includes the cleaning of the item.

Resin Printing Can Be Expensive

Vat polymerization can produce excellent quality prints; however, everything comes with a proportionate price. 

That said, the standard lies at approximately $40 per liter, and depending on the size of your prints and how much you’re printing, it can last for a month. 

A solid print will cost more time and money than a hollow one. 

The same can be said for hobbyist printing, say, chess pieces. If you opt for solid prints, it will take far longer and cost a lot more in materials than it would for hollow pieces. 

Hollow Designs Are Ideal for Faster Prints

To print a miniature can take between half an hour and 10 hours. This, of course, varies according to layer height, the complexity of design, and other settings on the printer. 

You can drastically speed this up by adjusting the infill. However, if you have a solid piece, which would have 100% infill, it will take more time and material to create. 

By adjusting the infill percentage, you can significantly reduce the print time. That is to say, if you make a hollow print, your waiting time for the result will be far less. 

For context, a solid resin print that uses around 250 mL of resin could take as long as 15 hours. In contrast, the same design may only use about 77 mL if it were hollow. Not only that, it would likely take less than half the time to print.

Key Takeaways

After evaluating all that goes into resin printing, it becomes clear that hollow makes more sense than solid. 

The printing process is long and uses a lot of material – these factors are cut in half when your print is hollow. 

Also, hollow prints will also be far easier on your equipment. Therefore you run less risk of damaging your equipment in the long term. 

Why Solid Printing Can Be Useful

An advantage of making solid resin prints is, of course, the strength of the finished product. In addition, a solid print will last longer and is more resistant to wear and tear, so some specialists might choose to use this method. 

For example, in dentistry, it’s more desirable to use solid resin for fillings, false teeth, dentures, etc. 

Hollow prints, by contrast, are more susceptible to wear and do not last as long. They’re also more likely to crack or break, e.g., with resin jewelry. 

There are undoubtedly advantages to solid prints; however, it all depends on what you’re printing and how durable you need the finished product to be. After all, you can make many things with a resin printer that range from practical to aesthetic. These include jewelry, prosthetics, figurines, ornaments, décor, and art (e.g., installation). 

So, a doorknob would likely need to be quite durable in case it gets slammed into the wall. But small pieces of décor that have no function could be hollow to save time and money.

Frequently Asked Questions 

Can You Make Money With Resin Prints?

It is possible to make money with resin prints, be it jewelry, art, or figurines. There is currently a large market for resin and epoxy products, extending to online spaces like Etsy. Items like cutting boards and coasters are hugely popular, as are earrings and bespoke chess pieces.

Despite resin and epoxy art being a somewhat niche market, it’s expected to reach $10.3 billion by 2027, with individual pieces selling from anywhere between $165 to $15,000. 

Is Resin Printing Bad for the Environment?

Resin printing is not bad for the environment, unlike many other forms of 3D printing. Resin printing is a form of additive manufacturing, meaning it generates no waste. So, the most wasteful aspect of resin printing is experimentation while trying to get a design right. 

In contrast, most manufacturing methods are subtractive, meaning that a solid object is cut to shape and the offcuts are discarded, generating a lot of waste that ends up in landfills. 

Conclusion 

There are pros and cons to both solid and hollow resin prints. Ultimately, hollow resin prints are more convenient, cheaper, and overall more popular than solid resin prints, except specialized fields or designs with specific functions that require them to be solid.