Improvement of geometric tolerances of two‐component parts
In the automotive, windmills and ship building industries, the machining of components made of two parts, such as connecting rods, cushions and crank bearings, plays an important role. Improvement in tolerance machining of those components produces significant gain in efficiency, reduction of fuel consumption, vibration and CO2 emissions. The two-component are joined by screws which may deform the workpieces when they are tightened, thus provoking a lack of precision in the final product where they will be finally mounted.
In this research, numerical analysis by FEM and experimental work will be made in order to obtain tolerance reduction strategies in fixturing machining of two-component products. The main objective of the proposed study will consist of developing fixturing modelling techniques based on contact mechanics in order to take into account the components deflection due to the fixturing clamps and cutting forces action, machine-tool precision limits, and the active deformation produced by the screws when workpieces are tightened during machining.
The study will be focused on the machining of the head of a connecting rod with a shaft of 64 mm made of technological advanced materials such as titanium alloys and nickel based alloys.
Research Planning Work
- Numerical analysis of the two-component assembly joined by screws. (September- October)
- Machining of a feature hole in the head of a connecting rod and deflection testing at different screw torque. (November- December)
- Cutting force measurement for different cutting conditions and different materials. (January-February)
- Numerical analysis of the connecting rod assembly, fixture and cutting forces in order to improve deviations. (March-April)
- Machining and statistical treatment of the different strategies in order to reduce the geometric tolerance. (May-June)
- Publish work (July-August)
Necessary Equipment
- ANSYS multiphysics
- Milling Machine
- Dynamometric wrench
- Dynamometric plate
- Roundness measuring machine or a 3D coordinate measuring machine.
- Consumables
The research budget will be funded by the Fundación Séneca through the project "Improvement of geometric tolerances of two-component products" with reference 08779/PI/08 in which 7.200 € will be assigned to consumables.
The results of this research will produce 5 papers which will be jointly published by authors of both universities.