Body Brace Collaboration on Late Changes

Digital serviceability support from USE* Automotive promotes and enculturates a design for serviceability mindset into product development activities. USE* classify these services as SERP (Service Evaluation and Repair Process), reflecting both the competent expertise that we provide to support this function and our out of the box process toolset that we can deploy and adapt to any of our clients’ product development PLM systems.

This case study provides a good example of working in the development arena to support a late change.

The Challenge

As the development of the proposed body structure design for one of our client’s vehicles progressed, it became apparent that in order to meet structural integrity targets additional engine bay bracing was required. The bracing strategy was introduced to the programme at a relatively late stage in the product development process and included two removable braces secured to the suspension turrets on each side and then to the centre of the engine bay to cabin bulkhead.

Due to manufacturing concerns regarding the ergonomic implications of a line side operator having to apply a tool to fasteners securing the brace bars to the centre of the bulkhead at the rear of the engine bay, the main body structure was subsequently extended above the engine bay, reducing the length of the removable brace section and therefore reducing the required reach to secure the in-board fasteners.

In resolving the manufacturing concerns, the extension of the bulkhead body structure had a potentially major impact on the service requirements for the programme.

Specifically, due to the extent of the non-removable body overhang, it would not have been feasible to remove and refit the engine assembly for service via the top of the engine bay. This would have meant that engine removal and refit would have needed to be undertaken from beneath the vehicle. This procedure would have required the transmission and front subframe to be un-decked from the vehicle body. In addition to the significant increase in labour time, this procedure implied the potential issue that the maximum lifting weight of service transmission and engine lifting jacks would be exceeded, requiring a new tool to be developed and mandated to the service dealerships.

In addition to these concerns, the body overhang would have meant that service operations such as diesel fuel pump replacement, vacuum pump replacement, emissions recirculation system replacement, engine oil seal replacement, wiper motor replacement and cabin heating and ventilation module replacement, along with to other service operations, would no longer have been feasible without removing the engine from the vehicle.

The challenge was to engage with product development and manufacturing to drive a solution that met the requirements of each area. However, with the programme progressing the time available to achieve an alternative solution was minimal.

The Solution

The first objective when attempting to resolve a serviceability issue is to quantify the issue on the basis of warranty saving. Expenditure avoided composes the justification for an engineering change.

In this case, with the number of service operations that would have been affected, this would have not been feasible in the time available. However, based on service CAD geometry for tool access and component withdrawal, along with digital manikin representation of service technician access, it was possible to illustrate the scale of the negative impact on service operations to senior management through impromptu service package and design reviews led by SERP engineers engaged with the programme.

Two main proposals were evaluated - either the current brace design should be completely removable in service as per the original proposal prior to manufacturing concerns being raised. Or the brace, bulkhead cowl panel and secondary NVH bulkhead panel could be redesigned so that they were multiple piece items that could be removed individually in service.

As it was, it was deemed that the negative impact on service outweighed the concerns of manufacturing and the programme reverted to the original design proposal, with some minor design changes to improve the assembly process.

Its Benefits

The decision not to incorporate the proposed bracing strategy has the potential to realise a potential multi-million pound warranty expenditure saving on the lead vehicle programme alone.

In addition to this, some critical components could have been completely unserviceable without the development and deployment to dealerships of special heavy lifting equipment that could facilitate the un-decking procedures detailed above. By reverting to the original proposal, the tool research and development and purchase costs to the dealerships has also been avoided.

Our Achievements

SERP engineers were responsible for significant engineering input to drive a major late change to key structural components. It was necessary to engage with senior engineering management and work in a way that was both proactive and reactive and within the strictest of timeframes.

This involved several key SERP team members from both the mainstream team and SERP engineers deployed in upstream Concept Design support.

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