Looking to fully understand the basic design principles of vacuum forming and mold making before you get started? We've asked Digital Fabrication Expert, Professor at UFV Madrid nd WikiFactory Content Developer, Agustín Arroyo to explain it all. If you enjoy this article, you can see how Agustín applies these principles to a 3D printed electronics enclosure project in his next article.
Aug 22, 2018 They are mass-produced on a vacuum forming machine. While the mass production machines cost well over $100k, you can build your own simple former for less than a $150. FormBox takes on 3D printers with an instant vacuum former. The past decade has brought on a new kind of industrial revolution, a lot of which is thanks to how prevalent 3D printers have become. From full-sized versions to mini-desktop styles. Until recently only industrial vacuum-forming equipment was available, with prices ranging from $4,000 to over $125,000. Because of the large investment in money and space required to obtain and use the machines designed for mass production, very few medical facilities have made use of the vacuum-forming process. Sep 19, 2019 We use vacuum forming to make products for use in many sectors such as automotive, industrial, retail display and signmaking. Vacuum forming projects require additional processes throughout the manufacturing process and we are able to complete the vast majority inhouse – that ensures we can maintain high production standards, control costs and reduce timescales.
Vacuum Forming for Free: I recently needed 12 fake candlestick phones for a musical ("Crazy For You"). Real candlestick phones are incredibly expensive, and even replicas were too much for my budget. All 12 needed to match as well. I decided to make them all.
A Beginner's Guide to Vacuum Forming and Mold Making
Before we get started on any project, we need to make sure we understand the design principles that apply to vacuum forming and the Mayku FormBox. As it happens with 3D printing, there are some best practices that you should know before you start designing. You can design from scratch of adapt an existing 3D design that you already have access to.
No undercuts
This one is pretty easy. If you vacuum form a model that has ledges or indents, you won’t be able to remove the object once the plastic sheet cools down. If you’re used to FDM 3D printing, you know that overhangs must be avoided. Well, when 3D printing a model for vacuum forming, all overhangs must be avoided, even the smallest ones. Think that every overhang is an undercut.
Add draft angles
Draft angles are all about manufacturability. A draft angle is a slant that is applied to the faces of your model and it helps when releasing the template from the plastic sheet. This means that if your model had infinite height, it would become a cone. For 3D printing it’s recommended to add at least 1º of draft for every 2cm of height. Draft angles should be present in all the large faces of your model.
Draft angles also allow you to make bigger molds as vertical walls can only be used for small details. Large faces with vertical walls can generate a vacuum, which means the part would get stuck to the plastic sheet.
Don’t forget about textures
3D printed objects usually have a unique surface texture as a result of the manufacturing process. Even though there are many materials that visually hide the layer lines, they’re still there and the FormBox is great at picking up textures.
If you want to have a smooth surface on your mold, the first thing you need to do is to 3D print using thin layers. 3D printing using 0.1mm layers offers a smooth surface. However, if you want a perfect surface, you will need to post-process the part. Using fillers and sanding is the easiest method, although it doesn’t work with small details. In those cases, sandblasting is a better option.
Avoid sharp angles
Due to the manufacturing process, vacuum forming doesn’t always work with templates that have sharp angles (>90º). The main reason is that the plastic sheet may fold onto itself on sharp edges, reducing the mold quality.
For example, if you use a star-shaped object as a template, the points of the star may cause webbing as they’re quite sharp. On the other hand, a pentagon-shaped template or a star-shaped template with rounded corners would generate a high quality mold as there are no sharp angles.
Round all corners
In the injection molding industry it’s common to round the edges of the models. Rounding edges not only increases ergonomics but it also helps with releasing the part from the mold.
With a 2mm fillet you can make a big difference, reducing webbing and improving the mold’s surface finish.
Add air holes
The better the air flows, the more details the mold has. When the plastic sheet is deposited over the template, there’s a very small time window in which the sheet is hot enough and the air is moving. You want air to move as fast as possible, as that means the sheet will capture better details.
This is especially relevant if your design has parts where the air can get stuck. In those areas it’s recommended to add small holes where the air can move. A 1mm hole may not even be visible in the mold, but it will greatly improve the mold quality.
Height vs. Width
The maximum mold size you can make with the FormBox is determined by the overall shape complexity. However, you should always remember that wide parts are easier to make than tall ones.
Make Money With Vacuum Forming Services
If you take into account all the best practices, you will be able to make molds of tall parts. In any case, try to use templates that are wider than taller or use generous draft angles to compensate.
Vacuum Forming Equipment
Now you understand the basic principles of designing for vacuum forming and mold making, you are ready to select your next project. To find out how I applied these principles to an open source 3D printing project to save time and money read my guide on making a Laser Cat Toy Enclosure.
Diy Vacuum Forming
Want to know more about the Mayku FormBox? Request to speak to a specialist today and a local expert will contact you to discuss how the FormBox could transform your workflow. For more inspiration and ideas, follow @TeamMayku on Twitter, Facebook, Instagram and YouTube.