How to manufacture your tooling

Successful thermoforming heavily depends on a tool that is well-suited to the task at hand. Tools themselves, however, will differ depending on the manufacturing method used to create them. In this article, we’ll take a look at several popular manufacturing methods – such as 3D printing technologies – that can be used to create thermoforming tools, as well as a few points to consider about each.

 

Additive manufacturing

Additive manufacturing, also known as 3D printing, is the process of creating a 3D object from a digital model. It is done layer by layer – hence “additive” – typically with a material such as plastic, resin, or powder.

 

FDM 3D printing (filament)

Fused Deposition Modeling (FDM) 3D Printing is an additive manufacturing technology in which layers of materials are fused together. The material – in the form of plastic or composite filament – is first heated, then extruded following a pattern, creating an object layer by layer.

 

Ultimaker S5 (left) and Mayku FormBox (right)

 

FDM 3D printed templates on a Mayku FormBox

 

Here are a few points to consider when using FDM 3D printing to create a thermoforming tool:

• Affordability. FDM 3D printing is one of the most affordable manufacturing technologies. A wide range of 3D printers and materials available are compatible with the Mayku Multiplier and FormBox, from entry-level to industrial-grade.
• Ease of use. FDM 3D printing is a clean manufacturing process that generates almost no waste. You can remove prints from the 3D printer with your hands once they're ready. No post-processing is required unless you want to remove support materials or smooth the surface.
• Visible surface texture. Due to the manufacturing process itself, all 3D printed parts have a unique, layered surface texture.
• Limited feature size. Most FDM 3D printers feature a 0.4 mm nozzle. No tool feature such as text or surface details will be visible if they're smaller than 0.4 mm. 

Air holes are needed: This is to allow air to be evacuated through the tool to achieve the best forming result.

 

SLA 3D printing (resin)

Stereolithography (SLA) 3D printing, or resin 3D printing, is an additive manufacturing technology in which a light source – typically a laser or projector – cures liquid resin into hardened plastic.

 

Specifics for creating your tool for SLA

3D prints with supports should connect directly with the base. Opt for a thick durable outer layer (wall thickness should be a minimum of  3mm) with a strong interconnected core (1mm minimum vertical wall thickness) that transfers loads towards the base.

 

Formlabs Form 3 (left) and Mayku Multiplier (right)

 

Chocolate bonbon tool, SLA 3D printed

 

Here are a few points to consider when using SLA 3D printing to create a thermoforming tool:

• Level of detail. Tools made with resin 3D printers can exhibit incredibly small details such as text, logos, and unique textures.
• Surface finish. Because resin 3D printers can achieve precise results, you can more accurately control the surface texture of printed parts – including smooth, clean surfaces.
• Post-processing. All resin 3D printed parts must be post-processed. This is typically accomplished by rinsing finished parts in isopropyl alcohol (IPA) to remove uncured resin from their surface, then curing using UV light to reach the highest possible strength.
• Complex geometries. The efficient use of support material allows you to create complex designs without additional post-processing or tool modification.
• Air holes are needed: This is to allow air to be evacuated through the tool to achieve the best forming result.
  
  

SLS 3D printing (powder)

In selective laser sintering (SLS) 3D printing, a laser sinters polymer powder into a solid, three-dimensional object. Here are a few points to consider when using SLS 3D printing to create a thermoforming tool.

 

Formlabs Fuse 1 SLS 3D Printer (Source: Formlabs)

 

Here are a few points to consider when using SLS 3D printing to create a thermoforming tool:

• Great material properties. The nylon powder used in SLS gives printed parts excellent mechanical properties and temperature resistance, making them ideal for thermoforming.
• High levels of detail. SLS allows for a high level of detail, making it convenient for specific thermoforming applications.
• Textured surfaces. All SLS 3D printed parts have a grainy surface finish, although the layer lines are almost invisible. Tools can be post-processed to be smoother.
• Cost. SLS 3D printers are expensive – and so are consumables and post-processing stations. Because of this, parts created with SLS are usually outsourced.
• No need for air holes. SLS parts are usually porous, which means air holes are not necessary on certain tool designs. Air can instead be evacuated through the part itself.
  
  

SLS 3D printed tool being cleaned

 

Subtractive manufacturing

Whereas additive manufacturing places layers of materials on top of one another – whether it’s via FDM, SLA, or SLS 3D printing – subtractive manufacturing starts with a solid block of a particular material, then removes pieces or areas to arrive at a final shape

 

CNC machining

In Computer Numerical Control (CNC) machining, a computer-controlled CNC machine follows a coded program to process a material to meet certain specifications, typically through cutting or grinding, such as with a lathe.

 

Here are a few points to consider when using CNC machining to create a thermoforming tool:   

• High precision. Some CNC machines can produce fine tolerances needed specifically for thermoforming applications.
• Material availability. There are many types of materials compatible with CNC, including temperature-resistant polymers that are perfect for thermoforming tools.
• Large tool size. CNC machining enables the creation of large tools that may be difficult to manufacture using 3D printing technologies. 
• Cost. Complex thermoforming tools may require the use of a five-axis CNC machine, increasing the manufacturing cost. Because of this, manufacturing is usually outsourced.

 

Laser cutting

Laser cutting is a digital fabrication process in which a laser is used to cut through flat materials by vaporizing, burning or melting them, leaving an edge with a high-quality surface finish. 

 

CO2 laser cutter

 

Here are a few points to consider when using laser cutting to create a thermoforming tool:  

• Fast manufacturing. Laser cutting is the fastest manufacturing technique. You can make large tools in minutes, and post-processing is usually not required.
• Surface-etching details. Laser cutting machines not only cut, but also etch a material’s surface. This means you can easily add highly detailed text, logos, or unique textures to your tools.
• Accessible design process. Due to the flat nature of laser cutting, designing tools is quite simple. It can be done using graphic design software such as Adobe Illustrator or Inkscape.
• Only 2.5-D designs. Laser-cut tools are created by stacking different layers, each one with a unique shape. Tools are made by extruding 2D designs in one direction, creating a 2.5D tool, which limits the shapes that can be created from them.

 

Product prototype made with a lasercut thermoforming tool

 

Other methods:

Using real objects

Sometimes real objects can be used to create a thermoforming tool. Here are a few points to consider when doing so:

• Convenience. Using real objects to create a thermoforming tool can be convenient – and in some cases ideal – such as those scenarios when you want to make a mold of an existing object.
• Risk of damage. Fragile or soft objects aren’t recommended as they can easily be damaged during the forming process. 
• Design limitations. Thermoforming best practices must still be followed when using real objects, which means most objects can’t be easily used as thermoforming tools.

In general, using real objects as thermoforming tools is not recommended. It is usually best to reverse engineer an object’s design to create a 3D model, which can be modified to meet your specifications and then 3D printed, so that it looks similar, but it follows the fundamental design principles of thermoforming.

 

Sea shells being used as templates on the Mayku FormBox

Take tool creation to the next level

A quality tool can mean the difference between a successful and unsuccessful thermoforming experience. This means you should go into tool design and creation with the knowledge you need to adhere to the best practices of thermoforming.