Form honing
2Pages

Form Honing At present, the most important objective when developing internal combustion engines for vehicles is the reduction of fuel consumption and pollutant emissions. The focus is currently on the CO2 value (g/km). The reduction of internal engine friction is considered a contribution to the targeted limits. Principle of form honing The ideal cylindrical bore distorts during operating conditions. By means of form honing, this deformation is reproduced during manufacturing which results in an almost cylindrical shape during operation. Objective of form honing The earlier production of internal combustion engines required cylinder bores with high cylindric form and surface qualities. During operating conditions there are complex distortion mechanisms which deform the cylinder bore. We have therefore developed a process which does not have the cylindrical bore shape as a target but the deformation in the manufacturing process. By honing non-cylindrical free forms, the component deformation in operating mode is taken into consideration. The deformation in the operating condition depends on: --------------- actual form --------------- target form Form honing result: • form-honed free form in processing on eight gauging levels with target and achieved geometry • high degree of approximation to the target form within 2 to 3 µm • static assembly distortions • dynamic distortion • thermal cylinder distortions The cylindrical free form is determined either by FEM calculation or simulations using torque plates and tempering. 10 0µm -10 Conventional Honing, cylindrical after honing Problem: deformtion in function Solution: form honing, machining with negative form Operating mode: cylindrical form arises in operating mode Cylinder bore was machined with form honing. The desired free form serves as allowance for a cylindrical functional geometry.

Your benefits Form honing components In order to implement form honing from a manufacturing point of view, a number of innovations to control the work surfaces of the diamond honing stones are required. For this reason, a tooling concept was developed featuring four expandable honing stones. The form data of the negative cylinder shape are converted into honing tool feeding parameters for each cylinder of a block using the form honing control. The feeding system and the form honing tool dynamically transfer this feeding profile to the form honing stones during honing. In the next step, a...