Manual post-processing of thermoformed parts

Discover the best ways to post-process thermoformed parts and their main advantages

If you're working with thermoformed parts made with the Mayku Multiplier, you'll need to do some manual or automated post-processing to achieve the desired finish. In this guide, we'll explore different manual post-processing workflows and tools that you can use to cut and finish your parts.

Here’s a list of different manual tools you can use to cut and finish your thermoformed parts.

Scissors are a versatile tool for freehand cutting thin materials, such as EVA 1.5mm or HIPS 1mm. They are particularly useful for cutting thin materials without the need for guides or templates. With their ease of use and accessibility, scissors are a great addition to your post-processing toolkit.

Kevlar scissors are designed to cut through tougher and thicker materials that could damage regular scissors. They are particularly useful for cutting thicker, soft Mayku materials such as UHMW. To cut parts made with UHMW, use a band saw first, followed by a second pass with kevlar scissors. Finally, neaten the edges with a file or sandpaper.

When dealing with tough materials like PETG or PMMA, ultrasonic cutters can make the task a lot smoother. To ensure optimum results, it is recommended to use a powerful ultrasonic cutter with a longer blade. Mastering the technique of using such a cutter might require some practice as it’s important to be mindful of the blade's access points and cut angle to avoid blade blunting or melting.

It is also crucial to stay safe by wearing protective equipment and operating in a well-ventilated area since plastic fumes are emitted during the process.

If you need to cut thin materials like EVA 1.5mm or HIPS 1mm, scalpels can be a useful tool. They are particularly effective for achieving precise cuts and finishing touches.

Handheld rotary power tools, such as the Dremel, come with a wide range of accessories for various tasks, including cutting and finishing parts. The cutting discs can be used to cut thin materials, and the sandpaper accessory can remove excess material from thicker parts.

To illustrate, the ABS car component was first post-processed with a band saw to remove excess material, and then finished and sanded with a Dremel to smooth the edges.

The band saw is an essential tool for cutting rigid materials. It is a fast and reliable way to remove excess material and can be combined with more precise tools like the Dremel or ultrasonic cutter for greater precision.

If your working area doesn’t have room for a band saw, an electric jigsaw can be a great alternative, offering similar results and material compatibility.

For example, when cutting an ABS part, you would first use the band saw to do two passes: one to remove excess material and a second to get closer to the outline. Then, the edges would be sanded with a Dremel for a more consistent finish.

When post-processing thin parts (1-1.5mm), it can be helpful to design and create a jig to guide you during the cutting process. This jig can be made using 3D printing or other technologies.

In the example below, you can see how a formed part (white) was cut with high precision thanks to the use of a 3D printed jig (black).

Here are some post-processing workflows we have tested using our materials.

Our HIPS sheets come in 1mm thickness, making them easy to post-process. After forming a blister packaging prototype, we removed the excess material with Kevlar scissors. Then, we used a 3D printed jig along with a cutter to trim the edges and achieve a consistent finish.

A band saw could have been used as an alternative, but we preferred Kevlar scissors because they didn't generate dust that would have required cleaning later.

Thanks to the flexible nature of EVA, de-molding small parts is extremely easy, and it also allows for easy part cutting using scissors, cutters, or scalpels.

If you're making a two-part mold using EVA, consider placing a piece of paper as the base below the template. This will create a permeable flat layer and prevent the EVA from capturing the dimple pattern produced from the Mayku forming bed.

PMMA offers excellent mechanical and optical properties. For better precision, we recommend cutting it with a band saw first and then with an ultrasonic cutter. Use a Dremel with a sanding accessory for finishing, and sand by hand using high grit sandpaper for best results.

If you want the part to be fully transparent, you'll need to sand and polish the template before forming. To eliminate fine scratches, plastic polish can be used on the final part.

UHMW is a great non-friction material, but that doesn’t mean it can’t be post-processed. We recommend using Kevlar scissors, a band saw, or a scalpel to cut this material. Note that an ultrasonic cutter does not work well on this material.

To finish the edges, you can either sand them or use a scalpel and jig for a clean cut.

Our 4mm ABS can be post-processed using many of the tools mentioned in this guide. Excess material is best removed using a band saw or an ultrasonic cutter, although automated processes such as CNCing are also possible.

For finishing, we recommend sanding with either a Dremel or by hand, and using a scalpel for deburring.

In the table below you can see the compatibility between some of our materials and the different post-processing tools we’ve presented in this guide.

This guide has presented manual post-processing tools and how to integrate them into your workflow. However, it's important to note that each team has a unique workflow, and each design may present unique challenges. We highly recommend testing different post-processing methods to find the one that suits you best.

Based on our experience, a band saw (or similar tool) is essential when working with thicker and more rigid materials. Other tools, such as ultrasonic cutters or the Dremel, are key to achieving high-quality part finishing.