Adjustable fixtures for Neuron structure

Dedicated assembly tooling and sometimes robots are generally used for the manufacture of high volume products within the aviation industry. For single unit production however, it is not economically viable to invest in that kind of tooling. Therefore, Saab Aerostructures has developed state of the art solutions for single unit production which for example will be used for parts and assemblies of the Neuron structure.

Saab Aerostructures primarily do series production of structural parts and assemblies for civil and military aircraft, but in certain cases single unit production is done. This is the case with Neuron, which is a demonstrator of an unmanned combat aerial vehicle that is being developed by several European aviation companies, one of which is Saab. Saab Aerostructures is to manufacture parts and assemblies of the single unit structure for the demonstrator utilising a cost effective production method.

In order to manufacture single unit products in an efficient way, Saab Aerostructures, together with Linköping University and a range of other industrial partners, have developed a method with adjustable fixtures called FlexAA, flexible and accurate automation.
“We cannot economically justify production using robots when it comes to single unit production. FlexAA provides us with a solution that enables us to replace the robot with a person who carries the work out as thoroughly”, explains Magnus Engström, project leader at Saab Aerostructures.

The solution consists of a framework, a number of adjustable tool modules called hexapods, a measuring instrument and a computer to analyse the measuring data. With the aid of these parts flexible, precise, easy and cost effective manufacturing can be achieved relatively quickly. The actual jig and all corresponding components can be quickly and easily created and defined in CAD tools.

The tool modules, the hexapods, are adjusted by the securing points at the top of the hexapod being continuously measured by a measuring system. The measuring system is connected to a computer where a calculation is made of how much each leg must be extended, or shortened, in order for the fixing point to reach its desired position. Adjustments are made manually and each hexapod takes 5-10 minutes to adjust.
“This method is unique in assembly production and is like nothing else we have seen before within the aviation industry. Hexapods are in themselves nothing new, but we are probably the first to use them for this application”, says Magnus Engström.

There are many advantages in using the method. The lead-time in producing the tool is reduced as all parts are standard parts. Costs are also reduced as expensive dedicated assembly tooling is not required. The possibility of easily changing the settings of the hexapods manually also means that later changes in airframe design become easier to introduce. A further advantage is that the entire tool system can be reused for a different purpose after manufacturing is complete.

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