Piezo-actuated hybrid tool for the micro structuring of cylinder liners in an energy-efficient process chain

Automotive traffic is one of the largest drivers of greenhouse gas emissions in Europe. In order to achieve energy savings both, during the process and during the use phase of passenger cars, the powertrain components and their process chains will be optimized as part of the "Powertrain 2025" project. For this purpose, the implementation of an innovative process chain for the production of non-circular, microstructured and honed cylinder liners is being researched. Therefore, the paper introduces a new piezo-actuated hybrid tool, which was developed for the combination of non-circular turning and microstructuring of the cylinder liners in one tool. An integrated optical distance sensor measures after the process the workpiece geometry. This is used for quality control and as an input value for a process chain control that optimizes the process parameters and thus reduces the reject rate. After a short introduction of the new, energy-efficient process chain, the paper focuses on the concept and dimensioning of the new hybrid tool

Sensitivity of process signals to deviations in material distribution and material properties of hybrid workpieces

Hybrid components, made of multiple materials, can meet the increasing demands for lightweight construction and functional integration in the automotive and aircraft industry. Hybrid semi-finished components are produced by applying a high-alloy cladding to a low-alloy base material before hot-forming and machining the workpiece. Throughout this process chain, workpiece deviations in the form of material distribution and material properties can occur that influence the component’s lifetime. This paper investigates whether such workpiece deviations can be detected within the process chain by analyzing process signals obtained from subsequent process steps. For this purpose, artificial workpiece deviations were introduced to hybrid semi-finished workpieces made of C22.8/X45CrSi9-3. Then, process signals during forming and machining were analyzed to determine their sensitivity to the artificial deviations. The results revealed that deviations in cladding size can be effectively monitored using signals from both forming and machining. Cladding position deviations can only be detected during machining, while forming signals are more responsive to detecting the introduced hardness deviations of approx. 100 HV0.1

Antriebsstrang 2025 : „Energieeffiziente Prozessketten zur Herstellung eines reibungs-, gewichts- und lebensdaueroptimierten Antriebsstrangs“

Abschlussbericht zum BMWK-Verbundprojekt "Antriebsstrang 2025". Laufzeit 01.09.2018 - 28.02.2022.BMWK/„Forschung für eine umweltschonende, zuverlässige und bezahlbare Energieversorgung“/03ET1531A-H/E

Material identification during turning by neural network

A design concept for high-performance components involves the combination of different materials in hybrid workpieces. Different material properties and chemical compositions influence the machining quality of hybrid workpieces. To achieve a constant workpiece and process quality, it is necessary to adjust the process parameters to the individual material. Thus, it is mandatory to classify the material during machining for the relevant range of process parameters. This paper examines teaching strategies for neural networks to determine the machined material in process by a small amount of cross points. For this purpose, different training sets are compared. Process parameters with different cutting speeds, feeds and with constant and varying depth of cut are examined. In addition, the signal sources necessary for robust material classification are compared and investigated. The investigation is performed for the cylindrical turning of friction welded EN AW-6082/20MnCr5 shafts. The study shows that an F1 score of 0.99 is achieved at a constant cutting depth, provided that only the corner points of the process window and the machine control signals are used for training. With an additional variation of the cutting depth, the classification rate is significantly improved by the use of external sensors such as the acceleration sensor

Controlled turning process for the production of friction-reduced cylinder liners with a defined free-form geometry

Friction in the piston-cylinder system of combustion engines has a great influence on fuel consumption. To reduce the friction of combustion engines, free-form cylinder liners and microstructured cylinder liners have proven to be advantageous. However, the combination of both processes is not industrially realized today because of an increased manufacturing effort due to a higher number of process steps. To save resources in form of honing oil in the production, the free-form can be machined by a dry turning process instead of form honing. A combination with the microstructuring process in a single manufacturing step would furthermore reduce non-productive time. This paper presents a piezo-actuated hybrid tool that can carry out both processes. The tool wear and the behavior during free-form fine machining of cylinder liners are investigated. A process control system is introduced that controls the cylinder liner geometry by adapting the process parameters during free-form turning