New Test Method for Detection and Analysis of Burrs and Slivers in Trimming and Punching Aluminium Sheet Metal

 A large problem when trimming or punching aluminium sheet is thecreation of burrs and slivers which degrade the quality of the produced parts. A semiindustrial test for evaluating trimming of aluminium has been further developed toinclude pre-stressing and pre-straining of the sheet material before trimming. Thesemi-industrial test results now show good correlation to industrial productionoutcomes

On finishing of pressing die surfaces using machine hammer peening

Machine hammer peening (MHP) is a new method for finishing of surfaces. With this method, the workpiece surface is hammered with a spherical carbide tool. The main objective of the study was to evaluate whether the MHP method could become a plausible substitute for manual polishing in pressing die manufacturing where nodular cast iron is a common workpiece material. To do this, sample nodular cast iron surfaces were hammered and evaluated. Changes to the surfaces were evaluated using surface roughness measurements, hardness measurements and optical images. First of all, the workpiece surface was smoothened. Secondly, the surface hardness was increased significantly. Thirdly, the nodules on the workpiece surface were affected. They appeared to be smaller and not as visible. This effect would likely create a die surface less prone to galling since the cavities would not be filled with sheet metal to the same extent in a forming operation. In addition, with MHP, the amount of polishing needed to manufacture a die surface can be reduced because of the smoothening effect

On finishing of pressing die surfaces using machine hammer peening

Machine hammer peening (MHP) is a new method for finishing of surfaces. With this method, the workpiece surface is hammered with a spherical carbide tool. The main objective of the study was to evaluate whether the MHP method could become a plausible substitute for manual polishing in pressing die manufacturing where nodular cast iron is a common workpiece material. To do this, sample nodular cast iron surfaces were hammered and evaluated. Changes to the surfaces were evaluated using surface roughness measurements, hardness measurements and optical images. First of all, the workpiece surface was smoothened. Secondly, the surface hardness was increased significantly. Thirdly, the nodules on the workpiece surface were affected. They appeared to be smaller and not as visible. This effect would likely create a die surface less prone to galling since the cavities would not be filled with sheet metal to the same extent in a forming operation. In addition, with MHP, the amount of polishing needed to manufacture a die surface can be reduced because of the smoothening effect

Machine Hammer Peening – A Substitute for Polishing of Pressing Die Surfaces?

Machine Hammer Peening (MHP) is a new method for finishing of surfaces. With this method the workpiece surface is hammered with a spherical carbide tool. The main objective of the study was to evaluate whether the MHP method could be used as a plausible substitute for manual polishing in pressing die manufacturing. To do this, sample surfaces were hammered and evaluated. Changes to the surfaces were assessed using surface roughness measurements, hardness measurements and optical images. First of all, the workpiece surface was smoothened. Secondly, the surface hardness was increased significantly. Thirdly, the nodules on the workpiece surface were effected. They appeared to be smaller and not as visible. It is probable that they had been plastically deformed and that some of the graphite in the nodules was replaced by material from the surrounding steel matrix. By replacing the graphite in the larger nodule cavities by surrounding steel material, a die surface is created which would be less prone to galling. In addition, with MHP, the amount of polishing needed to manufacture a die surface can be reduced because of the smoothening effect

Machine Hammer Peening – A Substitute for Polishing of Pressing Die Surfaces?

Machine Hammer Peening (MHP) is a new method for finishing of surfaces. With this method the workpiece surface is hammered with a spherical carbide tool. The main objective of the study was to evaluate whether the MHP method could be used as a plausible substitute for manual polishing in pressing die manufacturing. To do this, sample surfaces were hammered and evaluated. Changes to the surfaces were assessed using surface roughness measurements, hardness measurements and optical images. First of all, the workpiece surface was smoothened. Secondly, the surface hardness was increased significantly. Thirdly, the nodules on the workpiece surface were effected. They appeared to be smaller and not as visible. It is probable that they had been plastically deformed and that some of the graphite in the nodules was replaced by material from the surrounding steel matrix. By replacing the graphite in the larger nodule cavities by surrounding steel material, a die surface is created which would be less prone to galling. In addition, with MHP, the amount of polishing needed to manufacture a die surface can be reduced because of the smoothening effect

Friction in Sheet Metal Forming - A Comparison Between Milled and Manually Polished Die Surfaces

The evolvement of product requirements in the automotive industry, e.g. reduced weight, means that the use of advanced high strength steels (HSS, EHSS,UHSS) in automotive applications is continuously increasing. The introduction of high strength steels in production implies increased tool wear and calls for functional tool surfaces that are durable in these severe tribological conditions. In this study the influence of tool surface topography on friction has been investigated. The frictional response was studied in a Bending Under Tension test. The results did show that a low frictional response was generated by low slope of roughness profiles combined with a strong anisotropy applied perpendicularly to the sliding direction. An improved machining strategy has a high potential to significantly reduce the need for manually polished surfaces

Friction in Sheet Metal Forming - A Comparison Between Milled and Manually Polished Die Surfaces

The evolvement of product requirements in the automotive industry, e.g. reduced weight, means that the use of advanced high strength steels (HSS, EHSS,UHSS) in automotive applications is continuously increasing. The introduction of high strength steels in production implies increased tool wear and calls for functional tool surfaces that are durable in these severe tribological conditions. In this study the influence of tool surface topography on friction has been investigated. The frictional response was studied in a Bending Under Tension test. The results did show that a low frictional response was generated by low slope of roughness profiles combined with a strong anisotropy applied perpendicularly to the sliding direction. An improved machining strategy has a high potential to significantly reduce the need for manually polished surfaces