Multi-stage forming of steel cup
Sheet metal forming operations of materials such as advanced high strength steels (AHSS), stainless steels, aluminium alloys and titanium alloys usually requires lubrication by environmentally hazardous chlorinated paraffin oils in order to avoid lubricant film breakdown and subsequent pick-up and galling, which may lead to unwanted scratching ot the surfaces of the metal sheets or require repolishing of the tools and thereby increasing production costs.
For several years attempts have been made to substitute these oils with more environmentally friendly oils without compromising the oil performance in the metal forming operation. These attempts have however only been partially succesfull. It is therefore the aim of this project to adress how to replace environmentally hazardous oils with more environmentally friendly oils.
It will be achieved by studying fundamental properties of oils such as viscosity at high pressures, shear rates and elevated temperatures to mimic conditions encountered in sheet metal forming operations in order to carry out numerical simulations of lubrication mechanisms in the sheet forming production.
This also requires accurate reproduction of sheet metal forming operations by means of physical simulation. It is beneficial if this can be conducted using off-production-line test equipment, thereby avoiding the use of production tools for testing. Therefore a recently developed, advanced sheet forming tribotester, available at DTU's laboratory, will be applied.
PLC/PC controlled fully automatic sheet tribotester
Tailored polishing of tool surfaces to promote lubrication may also be a posibility and will be adressed in the project using a robot assisted polishing machine developed by the partner STRECON.
Adding coatings such as Diamond-like-carbon to the tool surfaces may also reduce the tendency to pick-up and galling. Testing will reveal whether it is possible to perform metal forming operations without lubrication or with minimum quantity lubrication, using such tool surface coatings.