Surface processing with a KR QUANTEC and KUKA.CNC

The smoothing or finishing of milled dies and molds – such as deep drawing dies for body components, inlay molds for components made of composite materials or injection molds for plastic components – is today still largely carried out by hand. Even at other companies with high levels of automation in production, polishing larger free-form surfaces can take up to 20 man-days. In the development of a new technology for surface processing, the emphasis was placed on making the process as flexible, precise, reliable and cost-effective as possible.

The goal here was to transform metallic surfaces into high-quality functional surfaces through automation. This is now possible through the “Machine Hammer Peening” application; a hammering process in which the surface of the workpiece is smoothed out. In order to automate the machining of complex workpiece surfaces with this process, SEMATEK turns to a KUKA robot with KUKA.CNC software.

KUKA KR QUANTEC guided by KUKA.CNC

On the flange of the KR QUANTEC series KUKA robot there is a pneumatically operated tool with a linearly oscillating hammer head (FORGEfix from 3S-engineering GmbH) for the machining of the surface. Once the robot has measured the workpiece, the robot guides the hammer head over the surface along the “hammer peening path” using KUKA.CNC software. In doing so, the milling peaks are pressed down into the milling grooves. The sphere diameter, feed rate, path distance, feed motion angle as well as pitch angle between the hammer stroke and the surface must be selected and set to suit the process.

SEMATEK uses a 5D measurement system from LEONI GmbH to measure the processing head. Besides measuring the Tool Center Point (TCP), this procedure primarily ensures that the tool orientation is calibrated as precisely as possible. The tool orientation is a particularly important factor for the processing of 5-axis CNC programs so as to achieve the highest possible process accuracy.

The hammer peening not only smooths the milled surface, but it also strain-hardens it and optimizes the distribution of residual stress. The surface becomes uniform and reproducible. The hammer peening process enables a surface roughness of Ra smaller than 0.1 μm that would not be possible through milling alone. Thanks to strain-hardening, the surface hardness can be increased by up to 30 percent – depending on the material being machined. As a result, additional surface finishing may be completely omitted in some cases.

But above all, the automated hammer peening process eliminates manual grinding and polishing activities. The time for the finishing – and, thus, for the overallmanufacturing process – is significantly shortened, above all due to the reduced finish-machining requirements. Using the KUKA robot, even complex free-form surfaces can be machined. It is often possible to machine the complete component here – thus eliminating the need for costly and time- consuming reclamping. Thanks to extremely precise path planning, the robot can also move at high velocities with minimal overlap. This ensures maximum results in a minimum amount of time.

The smoothing or finishing of milled dies and molds – such as deep drawing dies for body components, inlay molds for components made of composite materials or injection molds for plastic components – is today still largely carried out by hand. Even at other companies with high levels of automation in production, polishing larger free-form surfaces can take up to 20 man-days. In the development of a new technology for surface processing, the emphasis was placed on making the process as flexible, precise, reliable and cost-effective as possible.

The goal here was to transform metallic surfaces into high-quality functional surfaces through automation. This is now possible through the “Machine Hammer Peening” application; a hammering process in which the surface of the workpiece is smoothed out. In order to automate the machining of complex workpiece surfaces with this process, SEMATEK turns to a KUKA robot with KUKA.CNC software.

KUKA KR QUANTEC guided by KUKA.CNC

On the flange of the KR QUANTEC series KUKA robot there is a pneumatically operated tool with a linearly oscillating hammer head (FORGEfix from 3S-engineering GmbH) for the machining of the surface. Once the robot has measured the workpiece, the robot guides the hammer head over the surface along the “hammer peening path” using KUKA.CNC software. In doing so, the milling peaks are pressed down into the milling grooves. The sphere diameter, feed rate, path distance, feed motion angle as well as pitch angle between the hammer stroke and the surface must be selected and set to suit the process.

SEMATEK uses a 5D measurement system from LEONI GmbH to measure the processing head. Besides measuring the Tool Center Point (TCP), this procedure primarily ensures that the tool orientation is calibrated as precisely as possible. The tool orientation is a particularly important factor for the processing of 5-axis CNC programs so as to achieve the highest possible process accuracy.

The hammer peening not only smooths the milled surface, but it also strain-hardens it and optimizes the distribution of residual stress. The surface becomes uniform and reproducible. The hammer peening process enables a surface roughness of Ra smaller than 0.1 μm that would not be possible through milling alone. Thanks to strain-hardening, the surface hardness can be increased by up to 30 percent – depending on the material being machined. As a result, additional surface finishing may be completely omitted in some cases.

But above all, the automated hammer peening process eliminates manual grinding and polishing activities. The time for the finishing – and, thus, for the overallmanufacturing process – is significantly shortened, above all due to the reduced finish-machining requirements. Using the KUKA robot, even complex free-form surfaces can be machined. It is often possible to machine the complete component here – thus eliminating the need for costly and time- consuming reclamping. Thanks to extremely precise path planning, the robot can also move at high velocities with minimal overlap. This ensures maximum results in a minimum amount of time.