Flexible Automotive First


We were asked by Sarginsons Industries to assist with the machining of an extremely complex B Pillar for a new car that was critical to the future success of a world renowned automotive OEM. Sarginsons are a specialist aluminium foundry who focus on using digital twin simulations with topological optimisation to design and manufacture ultra-lightweight cast components for the automotive and aerospace industries. 

The complexity of this component pushed the boundaries of machining, particularly as this was a production item that whose price points were challenging.


The B Pillar, which form part of the structural support of the vehicle is attached to both sides of the vehicle. The casting itself was approximately 1m in length and 0.3m in width with wall thicknesses of between 3mm and 5mm.The unit was flexible as it was designed to form only part of the structural integrity of the car. 

Machining a component designed to be flexible, particularly one that has been heat treated, and align it perfectly with other parts of a laminated multi-layered structure is extremely difficult. We were also charged with developing a production machining strategy.

Initial Challenges Faced

The length of this component, 1.1m, leant itself to a large amount of flexing which was compounded by the distortion and twist that resulted from heat treatment. With 5 separate faces that needed machining in precise alignment with 3 other components, that created the whole structure, necessitated a huge amount of original design work.

Specific Challenges Faced

The inconsistencies of machining and cast tolerances in light of the distortion and component flex presented massive challenges in designing competitive fixturing solutions because the location of the casting was nigh on impossible to determine within any machining fixture. 

A one operation solution being required to hit the cost structure was demanded as 2 operations would introduce inconsistencies that would negate accurate alignment. 

Solutions Presented

This component was designed for a 2 operation machining process due to the number of datums required across five surfaces. A total rethink led us to design and manufacture a window frame fixture on a horizontal trunnion allowing all machining to be completed in 1 operation; ensuring consistency for the end product as well as a huge improvement in cycle time; from 42 minutes to 19 minutes. 

Further investigation allowed us to machine both left and right hand components on the same trunnion fixture and allowed swapping from of different hands to take less than 10 minutes. By installing hydraulic fixturing incorporating 200 bar of pressure to 9 clamps over each datum point ensured the component would not move. 

Using indexable tools allowed for the easy replacement of worn edges with no technical setup needed.  Long reach shrink fit holders were used to ensure maximum run out of less than 5 microns. 


After many hours of effort and challenge after challenge in terms of design, opposite thinking paradigm shifting, this project has proved. The customer did not think that it would be possible to machine the component in 1 operation, let alone in 1 casting as the original design was for 3 casting.

Machine Used

Doosan VCF 850LSR

The VCF 850LSR is a large-capacity, travelling column-type 5-axis machining centre with a tilting B-axis head.  The head can rotate 110 degrees on either side of vertical, enabling the VCF 850LSR to machine large and complex parts in a single set up. The machine also has a large working envelope – 3000mm x 850mm x 800mm (X/Y/Z).

The machine supplied to NuMachine was equipped with the latest Heidenhain TNC 640 control, a 22kW/12,000rpm high-torque spindle, a 60 tool servo-driven ATC, linear scales on its X/Y and Z-axes for high positional accuracy and a touch spindle probe and 3D tool probe package.