3D printed tube bending mold

Roboze 3D printing for the thermoforming of plastic tubes in vehicles

Cars are machines whose ease of use contrasts with their complexity. Over the decades automakers have greatly increased the power and efficiency of their vehicles to better meet the needs of customers thanks to innovative part designs and by employing many different types of materials, from metals to glass to ceramic, to plastic.

In the automotive industry, plastic is used for a variety of parts for example fenders, headlamps, dashboards, and steering wheels. One other use that is less visible is as tubing that snake around the vehicle, transporting fluids such as air, fuel, oils, and water. These tubes come in many different shapes, sizes, and curvatures depending on the vehicle they need to be mounted into and their function. Examples include:

  • oil cooling lines;
  • secondary air tubes;
  • brake lines;
  • air suspension lines.

The types of plastics employed by the automotive industry range from polystyrene (PS) to nylon (PA) to Teflon (PTFE).

How do you bend tubes?

There are various ways to bend tubes and one of the most common is via thermoforming of plastics. Within this there are many techniques, one of the simplest involves artisanal molds and heating in an oven.

Starting with straight tubes of the correct diameter and cut to the wanted length, a spring is inserted into the tube, then it is placed in a metal mold and heated up to 180°C. After being cooled in water, the bent tube is removed from the mold, the spring extracted, and the cycle repeats with a new straight tube. The spring is there to help preserve the circular cross-section and to make insertion and extraction into the mold easier. Many different types of bent tubing can be produced with this method for many different car models.

Limits in the production of molds for the thermoforming of plastic tubes

Companies that produce small volumes of bent tubing with complex geometries will often opt for this type of artisanal thermoforming process since it is simple and produces the wanted results. There is a big bottleneck though: the manufacturing of the molds.

As previously mentioned, since they are hand-made by welding together sheet metal and rods, manufacturing a single former can occupy a resource up to two entire days. Batches of bent tubes can number between 10 and 30 individual tubes, meaning that each one needs its own mold. This means that for a single batch of 30 identical tube configurations, two months of work are needed to manufacture all the formers, which of course results in a major slow-down of the manufacturing process.

The metal mold must be configured with different angles and dimensions according to the types and sized of the plastic tubes to be thermoformed. Therefore, companies often can end up with more than 20 different custom configurations, each one repeated between 10 and 30 times. When new designs or modifications to existing ones are needed, the entire artisanal manufacturing process has to be repeated again.

Producing tube bending molding with Roboze PRO Series 3D Printers

Fused Filament Fabrication 3D printing (FFF) is the ideal solution for the manufacturing of low-volume complex parts that need to withstand high mechanical and thermal loads like the molds for automotive tube bending. With this technology, the artisanal manufacturing process of the molds is replaced with a digital file that can be 3D printed on demand, without the need to store spares. Thanks to the exceptional design flexibility of 3D printing, novel mold configurations can be developed and changes to existing ones are easy and fast to implement, greatly shortening the lead times and costs. With the right combination of printer and material, it is possible to produce low-cost, high-quality molds that can have a large variety of shapes and can accommodate many different tube cross-sections and dimensions.

The properties of Roboze’s ToolingX CF will greatly surprise you!

The Roboze ecosystem offers a large variety of materials each with their own incredible characteristics and purpose; the ideal plastic for tube bending is a blend of Polyphenylene Sulfide (PPS) and short carbon fibres: Roboze’s Tooling CF. This is a high-performance thermoplastic that is extremely strong (82 MPa of tensile strength, 9.1 GPa elastic modulus), with a very high continuous use temperature of 220°C, and a low water absorption.

Thanks to these incredible characteristics, molds manufactured with ToolingX CF can withstand both the mechanical loads of tube bending and the heating needed, working many times without deformation, and enabling the production of superior quality tubing. Thanks to plastic being light compared to metal, operators will also have a much easier time handling the molds.

3D printed tube bending mold
3D printed tube bending mold made with ToolingX CF

The other half of the equation is a 3D printer that can use the characteristics of ToolingX CF to the maximum.

Roboze Plus PRO: extreme performances for your company

The Plus PRO 3D printer solution, the entry level of high performance additive manufacturing, is a robust, precise and reliable system for functional prototyping and small series production. Developed on the process needs of end users, it is the most complete professional 3D printing solution to increase the value creation of your company and generate new competitive advantages quickly and efficiently.

Find out more about the PRO series and the application opportunities offered by the wide range of high performance Roboze materials. Not only molds, but also finished components and tools are easily achievable with a single solution. A valuable tool for integrating traditional production, producing small customized batches, digitizing the warehouse and reducing costs and delivery times for finished products.

For a personalized consultancy, do not hesitate to contact us at info@roboze.com.

Get ready to #PrintStrongLikeMetal

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