Lifestyle Products: Marusenko – EOS Technology enables Rapid Prototyping for new 3D Puzzle
Tricky to Play, Easy to Design: Additive Manufacturing paves the way to functionality and smooth series production
From the mid-1970's on, Rubik's cube – a 3D mechanical puzzle – became one of the world's most popular toys. As of January 2009, more than 350 million cubes had been sold worldwide. However, in the age of new approaches to product design, the time had come to create a worthy successor. And of course it had to be something more testing, and something that could only be created using modern technology. The result of that process is Marusenko Sphere, the new 3D logic puzzle game and educational toy. It can be ordered at five levels of difficulty, depending on the configuration and colour combination of its 32 exterior pieces. The pieces themselves are arranged in a sphere, a fact that made the design process pretty fiddly for its inventors. Rapid prototyping supported by EOS' FORMIGA P 100 played an important role in making the new toy ready for sale.
In spite of all the capabilities offered by 3D computer aided design programs, there is always a point where simulation must end and real life begin. Reaching that point often means spending enormous sums of money and effort on building lots of prototypes – a time-consuming method that often provides only little space for refinements. When Marusenko Sphere's manufacturer, Marusenko S.L. – a Spanish company formed by Quipplan, Hiruden and Palcan & Bin – had completed the design phase, the team had to decide whether using classic prototype models would be the best way forward. As it turned out, due to the challenges of the toy's design and the mechanical complexities, it was an easy decision to go for rapid prototyping using an Additive Manufacturing method whereby a laser hardens specific granules, layer by layer.
To understand why this method was the best for Marusenko Sphere's prototypes, it is helpful to take a closer look at how the new educational toy works: Perfect functionality requires the precise meshing of the sphere's mechanics and depends, therefore, on assembly by micro clipping, tops positioning, and adjustments for these to slide between the components. Next, functionality had to be tested for proper durability, both mechanically and physically – this is, after all, an educational toy that will find its way into the hands of both adults and children. As such, avoiding any adhesive, springs, screws, or shafts was important in increasing child safety.
One of the project's main challenges was the building of the prototypes and the subsequent testing that was conducted step by step. The partial realization of the sphere's constituent pieces was key to achieving the above mentioned commitment to perfect functionality. Of course, the partial realization, the mid-process adjustments and the possibility of both easily and quickly amending the single pieces could only be achieved with rapid prototyping.
The prototype of Marusenko Sphere consists of 54 pieces in total, as does the final version. The many stages of adjustments to geometry and tolerance were made in an EOS FORMIGA P 100, a system that produces plastic products from polyamide within a few hours and directly from CAD data. The machine is ideally suited to the economic production of small series and prototypes with complex geometry – requirements which applied to this complex toy. Quipplan deployed one of these systems at its facilities and has used it successfully ever since. It made sense to utilize it for the Marusenko Sphere prototype. After the first prototype was built, multiple trial and error tests were needed in order to
refine the mechanics until the final level of perfection was achieved. The high degree of flexibility and the speed of the FORMIGA P 100 were an essential premise for being able to conduct the changes in the required way. In the end, the continual testing and the ongoing building of slightly varied prototypes was key to ensuring the success of the functional, sales-ready product that is so highly dependent on the geometry and fit between parts.
The intensive testing phase also resulted in a smooth start for batch fabrication as only very minor changes had to be made once the product had been declared ready for production. As such, the rapid prototyping method not only made the production of the toy possible in the first place, but also guaranteed cost-effective full-scale mould production: the analysis of “bridging“ between the behaviour of the additive manufactured PA 2200 material and the hypothetical real behaviour of the final material after the injection moulding was also an important factor in finalizing the preparations for production. “Our toy is designed around free movement in predetermined directions. The design initially seemed to be quite challenging, but once we had fully discovered the possibilities of rapid prototyping, we knew that we could make it.
We were able to make our vision a reality, to make it touchable and useable for everyone", says Victor Troyas, General Manager at Marusenko S.L. “Additive Manufacturing with EOS' FORMIGA P 100 and PA 2200 material was the only way to ensure the feasibility of the 3D sphere. By using this system we laid the foundations of our success."
An idea became reality – for Marusenko Sphere this meant the integration of 54 components – 32 of them external – to a sphere that is set to become one of the most innovative 3D mechanical toys of our time. Rapid prototyping made it possible to show several prototypes at the International Puzzle Design Competition in San Francisco (USA) 2009. It was also an aid both for design and production, and it was the key factor in getting the sphere not only ready for batch production but also for doing so efficiently. The world is neither flat, nor is it a cube – it is a sphere.
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