The advancement of fineblanking technology with more efficient presses and complex tools also gives rise to the need for more effective fineblanking oils. On top of this, some of the materials being processed are high-strength. The development of new fineblanking oils can only succeed when all parameters and the tribology of the overall process are taken into consideration. We highlight some fundamental aspects.
Why lubricants are essential to fineblanking
Tribology, the study of friction, wear and lubrication is not mere theory, but is indeed very helpful when it comes to improvements and thus cost-savings in technical processes. Tribology can also be applied to sheet forming, punching and fineblanking.
But let’s start from the beginning. Why is lubrication required for forming in the first place? The fundamental reasons for the use of lubricants are:
- safe separation of tool and workpiece,
- longest possible service life of the tool,
- defined workpiece surface, and
- minimization of tool wear.
With the initial adhesion, or the initial tool wear, a self-sustaining process is set in motion. The lubricant should therefore guarantee reliable lubrication of the tool’s active elements and should be unproblematic from the perspective of occupational safety and environmental protection.
A lubricant is of course not a cure-all. It cannot improve badly designed or poorly produced tools, rectify positional errors in the tool, make up for insufficient or faulty coatings, or “heal” already damaged tools and/or their surfaces.
The integration of the lubricant in the overall process
With regard to the following aspects, it’s essential that the lubricant fits perfectly into the overall process:
- Application of the lubricant – oiling the workpieces
- Punching / fineblanking / forming (perhaps with another interim application of oil)
- Post-treatment of the parts produced (cleaning / grinding / vibratory grinding)
Optimum application of a lubricant (image 1) requires compatibility between the lubricant and the application technique. It must be possible to apply the viscosity required for the forming or punching operation in a way that is not only consistent with the equipment, but is also economical and ecological (no misting of the surrounding area), and, most importantly, that can be reproduced in the necessary coating thickness.
Other influencing factors
Along with an even layer of lubrication, the physicochemical interaction of the additives within the lubricant also plays an important role in the process of optimal viscosity and long tool service life. Lastly, the existing structures on the metal surface are responsible for the type of interaction with the lubricant and the additives it contains. It’s like a key and a lock, either they both fit together or they don’t.
Application of lubricant in practice
On the basis of these considerations, Fuchs Wisura GmbH managed to develop a new, innovative fineblanking oil – free from chlorinated paraffins chloroparaffins and with the best performance. Image 2 shows the time scale of the development.
For a long time, chlorinated paraffin containing oils were considered the pinnacle of fineblanking oils. The chlorine-free oils of Generation 2.0 were often not able to match the capacity of the chlorinated oils. Generations 3.0 and 4.0 are equal to the chlorinated oils, if not superior to them.
Furthermore, a fineblanking oil was developed that contained neither chlorinated paraffins nor classic sulfur carriers. The initial tests with this oil were carried out by Feintool Technologie AG in Lyss directly with a customer’s tool. The result was surprising – even in the first instance it was possible to confirm new, purely theoretical findings on the interaction between additives and metal surfaces in practice. The customer was also satisfied and introduced the new product to the company’s standard range. The new product wasn’t only suitable for fineblanking, but was also excellent for forming. Its high power density means that, on the one hand, it makes it possible to form even hard-to-form materials, such as rust-free stainless steel, while on the other, delicate metals like non-ferrous metal or aluminum do not become discolored.
A look to the future of fineblanking oils
Numerous other cases of application in practice confirm that the consistent application and utilization of tribological findings leads to significantly higher tool service life and is therefore an economically significant factor.
And developments continue: new, high-strength materials that can no longer be worked economically with conventional lubricants are being tested by our customers. In these cases, we are guiding our customers on fineblanking oils. Likewise, we are working with Feintool and some of our customers on the temperate fineblanking project. Industry 4.0 is another factor that influences fineblanking oils. We are working with renowned institutions to develop custom-made lubricants that are adapted directly at the press depending on the metal surface.