Development of a method and an innovative machine for the industrial application of environmentally friendly, mineral oil free lubricants in deep drawing processes
Currently deep drawing with application of mineral oil based forming lubricant is state of the art. Usage of these lubricants is increasingly considered negative due to envi-ronmental and health reasons by national and European legislative bodies. Problem-atic issues are the waste management process as well as the stress of healthiness at the working place because of the application by using atomised spray. An additional strain is the cleaning process afterwards, which is caused by the need to remove the lubricant completely before further processing.
By means of new laws, promotions and voluntary ambitions of the industry, mineral oil based lubricants will be replaced by environment friendly alternatives like biodegrad-able wax based emulsion in future. At the beginning of this project there was no tech-nical solution for industrial application of such lubricants in a controlled process avail-able. Available solutions was based on handwork and was not suitable for mass pro-duction processes.
The target of this project was to develop a technical concept and a prototype. With this system it should be possible to transfer the wax based emulsion contact based to the steel sheet. To do so, there was some technical problems to be solved, because of the pressure and temperature sensitivity of the wax based emulsion. As a result of these circumstances it is necessary to have a controlled area to superimpose a layer with constant thickness and unchanging viscosity with high feed and cycle speed. The determination of the physical parameters and based on it the development of a proto-type we considered as a major technical challenge. During the complete time of the project we made continuously tests over the characteristics of the medium under the different terms of pressure, temperature, and so on.
By permanent further development of the medium, there was no steady base available for us during the project period. As a result of unavailable possibilities to accomplish tests with the wax based medium at customers plants, it was necessary for us to do practice tests with a thin fluid, hydrocarbon contained medium, which the customer has in use. The medium was completely different to the wax based medium. But oth-erwise it wasn´t possible for us to make tests under real conditions. With this medium we had the possibility to do the tests for the stability under load with our prototype at a potential customer. We tried to transfer the medium with a pressure-less transport sys-tem, through special wide area jets (which we have developed), in contact to the steel sheets. To make a constant, bounded to cycle application possible at different working widths we tried to use step less and immediately stopped low pressure pumps. The pumps should stop after cut off at once, to avoid the continue of the flow from the me-dium. There for we adapted and tested different pumps. The mutable working width could be realised with several wide area jets, which are switchable individually by spe-cial manual operated control valves, to adjust the necessary working width. The spe-cific development of the special wide area jets was done within this project. After dif-ferent versions with tests we could find a optimized jet for a constant distribution of the wax based medium over the complete width of the jets.
The on-road test showed us, that we won´t get an adequacy process stability with the current versions of the wax based medium. Problems with the circumstance, that the medium development wasn´t finished as yet and that it is subjected to heavy changes, doesn´t show us a way to a successful solution for a process stability in near future.
This is for us a very fundamental knowledge, which will give us a considerable ad-vance of the knowledge in future.
Out of this project for us it is an additional important knowledge, that you only could be successfull with a new medium at the market, in connection with a functioning clean-ing solution. In the beginning of the project it seemed for us, that the cleaning solution was solved and available inert a short time. The circumstances are different. For the future on this account there is an additional development exercise to do.
In view of the reorientation with the new medium in the production companies there is an additional sticking point, that it is necessary to aircondition the steel coils. This is necessary, because of the small temperature range which is needed for superimpose the medium at the coil. There will be a significant modification in the production proc-ess, to do this with a airconditioned stock or with a airconditioned equipment which is connected upstream to the molding press.
Walter Karl Kröss, Pfaffstaller Kröss GmbH
- Bernd Bürgermeister
- Walter Bereuter
- Gernot Böckle
Walter Karl Kröss
Pfaffstaller Kröss GmbH
Treietstrasse 50, A-6832 Sulz