[3D Printing Knowledge] Application Guide to Creating Thermoforming Templates using SLA 3D Printing

High-quality stencils for thermoforming can be created through various manufacturing methods, including 3D printing. In the previous article , we explored the techniques and practical applications of SLS for creating thermoforming stencils! In this article, we will delve deeper into creating thermoforming stencils using SLA 3D printing, including best practices, advantages, and more.

What is resin 3D printing ?

What are the benefits of SLA?

Smooth surface treatment
SLA 3D printing can produce parts with smooth surfaces without any post-processing, saving a lot of time! Smooth surfaces are very useful in thermoforming , making it easier to demold in some applications, reducing steps without compromising product quality.

In the image below, you can see that the resin 3D printed part (SLA) has no obvious layers, while the same part made with wire 3D printing ( FDM ) has clear layered textures.

Printing complex patterns
SLA 3D printing can achieve very fine results. This is extremely useful in thermoforming, especially when creating stencils with specific surface patterns, textures, or even text.

Compatible with various materials
SLA 3D printing is compatible with dozens of resins, each with specific properties. Some of these resins, such as Formlabs' high-temperature resin, are ideal materials for making thermoforming templates.

Formlabs high-temperature resin (Source: Formlabs)

Design and manufacture of thermoforming templates
Here are some tips and best practices to keep in mind when designing and creating thermoforming templates using SLA 3D printing.

Pore ​​size
Because SLA 3D printing is extremely precise, you can create pores so small they are almost invisible. For the Mayku Multiplier, we recommend pores not exceeding 0.4 mm. Larger pores may result in noticeable porosity on the final printed part or cause the plastic sheet to crack during molding. We also recommend testing the minimum pore size of the stencil during the prototyping phase.

Thermoforming template with air holes

Here are two techniques for achieving optimal porosity:

• Add 0.4 mm tapered pores to the surface of the template, with the pores becoming larger (approximately 2 mm) on the back side of the template. This prevents resin retention.
• Before post-processing and curing the template, remove any uncured resin from all pores with a needle or air gun.

Printing direction
When printing stencils, be sure to determine the orientation of the parts to minimize the visible support material on them. This will result in a better-looking printed template and save post-processing time.

Hollow template
In some cases, creating hollow templates can reduce printing time and material usage .

When making hollow formwork, a supporting structure should be added inside the object to increase its resistance and allow for multiple uses. The internal structure can then be filled with plaster or a similar material to restore the solidity of the part, but it is important not to cover the pores, and the density inside the formwork depends on the application and its overall dimensions.

Finally, if your template will be used with a Mayku Multiplier benchtop compression molding machine , we recommend using a shell of at least 5 mm on the hollowed-out object.

floor height
Layer lines in SLA 3D printing are not as noticeable as in filament 3D printing (FDM). If your stencil requires a smooth surface, use a layer height of 0.05 mm on the final stencil to minimize the visibility of the layer lines.

It's also important to note that if the template's geometry has many curved features, the layers may be more noticeable. In this case, you can better hide the layer lines by printing thinner layers and changing the print direction.

Applications of SLA thermoforming templates
Thermoformed stencils created using SLA 3D printers play a crucial role in applications across various industries. These include:

• Industrial Design: High levels of detail and complex geometry are very important to industrial designers, and resin 3D printing can meet their needs to create housings for products or other parts or tools that are suitable for harsh working environments.

• Chocolate: Clean surface textures and small details are crucial for chocolatiers. Resin 3D printing is a near-perfect technique for creating unique and intricate designs.

• Packaging: When creating packaging prototypes, a high level of detail and template dimensional tolerances are crucial, and SLA 3D printing technology can achieve just that.