Reverse Engineering for creating a protective cover for an airbag vest

Benefit of airbag vests for motorcyclists

Airbag vests for motorcyclists have existed for several years. That means in case of emergency, a mechanic or electronic sensor triggers a gas cartridge that charges the vest with lightning speed. Thus, the rider is protected manyfold by the vest, e.g. against the bounce; moreover, the vest secures the helmet.

Gas cartridges are made of metal and are located at the outside of the vest since the cartridge is often connected to the motorbike by means of a strap that serves as a trigger.

The problem is the following: Sporting riders, who sit very aerodynamically on the bike, know the metal cartridge rubbing on the tank (e.g. in the case of bumps). This abrasion can damage the tank's coating.

Lederspeed airbag vest

Lederspeed develops  problem-solving approach

The company Leder-Speed from Limbach Oberfrohna (Germany) is dealer of airbag vests, primarily in the field of racing. Leder-Speed is one of just a few companies that is authorized to edit airbag vests, for instance attaching numbers or patches of sponsors.

Some holders of airbag vests contacted Nico Bachmann, owner of Leder-Speed, and asked for a solution for the difficulty. Since just a very small group (sport riders) is faced with this problem, the manufacturer couldn't provide a solution at that time.

The idea of Leder-Speed was to cover the gas cartridge with a protective cover. For this purpose, he has to develop the design and a tool. After several tests, the design has been developed successfully and produced as a prototype in a 3D printer. The final design should serve as a model to produce manufactured parts. That`s a classic case for reverse engineering.

The best way was to scan the existing part and to develop a tool based on the scan. Felix Berberich of the company "Being Fast" supported us for the reverse engineering.

The following steps were necessary for reverse engineering:

1. 3D scan of the original part

A Steinbichler Comet 3 scanner was used for this job. This scanner works very accurately in the field of hundredths of a millimeter; furthermore, it has a high resolution, too.

Comet 3 is a structured light scanner. A structured light scanner projects a light patterns to the part and, then, used one or more cameras to monitor it. Thanks to triangulation, the scanner can generate a 3D surface.

Steinbichler Comet L3d for reverse engineering

2. Import of STL file in Catia V5

Imported STL file in Catia V5.

3. Creation of an object-related coordinate system

4. Capture of basic geometries such as cylinders, planes, spheres

Capture of basic geometries such as cylinders, planes, spheres

5. Entire surface reconstruction of the part in a parametric and modifiable data set (adjustment of the model possible at any time – e.g. enlargement of recesses, length/width/height, holes, wall thickness, etc. – All dimensions are modifiable!)

Airbag cover reconstructed  Airbag cover reconstructed

6. Construction pf a press tool for creating a series of prototypes in silicone rubber

Vents for excess material, centerings and screw holes for diccrimping the halves of the tool are integrated. (Press tool parametric to the reconstructed part. That means: If a dimension of the reconstructed part is changed, it is changed in the tool at the same time.)

Tool - View from above  Tool - View from below

Tool from above, with silicone part  Tool from below, with silicone part

7. 3D print of prototype tool using FDM procedure (affordable since the project budget was small  – further procedures: SLA tools temperature stable till 280°C for injection molding applications in small batch series.)

Prototype of tool as 3D print

Further fields of application for reverse engineering

Aprt from tools, all parts can be reconstructed and represented due to rapid prototyping.

Fields of application

  • Orthopedic technology (protheses, masks (soccer), etc.)
  • Ergonomic studies (handles, products, etc. – reconstruction, adjustment, production-ready design and prototyping in numerous polymer and rubber mixtures)
  • Machine engineering
  • Automotive industry
  • Product design
  • and many more

This project was a joint work of Laserscanning Europe, Leder-Speed and Being Fast.