Forming tools are complex, large components with high demands on production accuracy. Until now, repairs and modifications to such tools have been carried out in large machining centres. However, they could be carried out on site to reduce transport distances and throughput times.
After welding and milling work, a time-consuming polishing process is required, which is currently carried out manually by skilled labour. In this project, we are automating the polishing process on a mobile machine tool and thus achieving the required surface quality and accuracy more efficiently.
Team:
Hendrik Voelker
Year:
2023
Funding:
Central Innovation Programme for small and medium-sized enterprises – ZIM
In microelectronics, optics, aerospace and medical technology, submicrometre tolerances and surface qualities are required for the production of parts and components. Ultraprecision machining is therefore unavoidable. Guiding systems are affected by interference effects such as friction and stick-slip effects. The DFG project "Media-free and contactless multicoordinate positioning system using ultrasonic levitation and magnetic guides" is researching a friction-free guide system used to precisely guide and move workpieces and tools.
Chucks are used to securely clamp workpieces during turning operations. The chuck has a significant influence on the manufacturing accuracy. The main cause of dimensional and shape deviations is the clamping force applied to hold the workpiece in place. This leads to elastic tensioning of the workpiece during machining.
In the ‘DefCon’ project, we minimise workpiece deformations and thus increase machining accuracy. This means that even thin-walled workpieces and small batch sizes can be machined without increasing production costs.
Team:
Eike Wnendt
Year:
2023
Funding:
Central Innovation Programme for small and medium-sized enterprises (ZIM)
Efficient production planning and control is in principle heavily dependent on precise and forward-looking maintenance planning. Based on sufficient data quality, machine failures should be correctly predicted in order to initiate necessary countermeasures such as rescheduling or rescheduling of orders as quickly as possible. Small and medium-sized enterprises (SMEs) are often unable to maintain such a database due to limited resources and the non-economic retrofitting of existing machines. Therefore, the goal of the joint project "BaSys4iPPS" is to develop a method for integrated production and maintenance planning for machine tools in the inventory of SMEs.
Led by:
Siebo Stamm (Lauscher Präzisionstechnik GmbH)
During milling, the internally guided cooling lubricant is distributed to all cutting edges regardless of the angle of rotation, even though only a few are engaged depending on the angle of engagement. Only a small proportion reaches the chip formation zone, while the rest causes spray mist and increases the demand on the high-pressure pumps. The project aims to achieve selective cooling lubricant supply with rotation angle-dependent activation of the cooling channels, so that non-engaging cutting edges are temporarily closed. The results are a demand-oriented volume flow, improved energy efficiency, and optimal cooling of the active cutting edges.
In the joint project ARGONAUT - "AircRaft GearbOx desigN And manUfacturing of Tomorrow", the Institute of Manufacturing Technology and Machine Tools (IFW) at the University of Hanover, in collaboration with the company Liebherr Aerospace and other research centers, is investigating the optimization of the design and manufacturing process of gearboxes for aircraft. On the one hand, the IFW is investigating resource-efficient machining by means of adapted cooling lubrication strategies and, on the other hand, the design of innovative turning processes to increase productivity and process reliability by means of virtual process design.
Led by:
Prof. Dr.-Ing. Berend Denkena
Team:
Marita Murrenhoff (IFW Hannover), Felix Zender (IFW Hannover), Niklas Gärtner (IFW), RWTH Aachen, Fraunhofer-Gesellschaft, TU München, TU Chemnitz
The purpose of a guide is to limit the movement of an element to movement in a single direction. Guides are used in machine tools to precisely guide tools and workpieces. Within the scope of this research project, a new frictionless grip-free guide is being developed that actively compensates for unevenness in the guide surfaces and significantly reduces the manufacturing costs of guides. The area of application is to be large machine tools.
The susceptibility to vibration and chatter of long projecting BS leads to lower productivity. In the KSS-Puls project, a novel system is being developed to reduce the vibration of long projecting boring bars (BS). So far, the market only offers options for active damping of thicker boring bars. Pulsation of the cooling lubricant is to be used to achieve space-saving vibration damping, which can be used in boring bars with diameters of 16 mm and less.
In the future, cooling channel structures are to ensure more efficient molds and more precise as well as faster process control in the injection molding sector. Within the framework of the "Central Innovation Program for SMEs", or ZIM Guideline for short, Konstruktionsbüro Hein GmbH (KB Hein), the IFW - Institute for Manufacturing Technology and Machine Tools and the IKK - Institute for Plastics and Closed-Loop Technology, both institutes of Leibniz University, are working together on this development.
Metallically bonded diamond grinding wheels mostly use a bond system based on copper or bronze. A chemical bond, e.g. by forming a carbide layer between the bond and the diamond, has the potential to increase the grain retention forces and the wear resistance and thus to improve the performance of the grinding wheel. The process parameters during the sintering process, as well as the composition of the bond system used, play a significant role in the bonding of the diamonds to the bond matrix. At present, the influence of the manufacturing process on the subsequent application behavior of grinding wheels - in contrast to geometrically determined cutting tools - has not yet been coherently developed.
Continuous generating grinding has proven to be an innovative process for the manufacturing of cutting tools in previous projects at the IFW. However, this approach has not yet been investigated for carbide tools, as the specific material properties pose significant challenges. The aim of the project is to adapt the generating grinding process for carbide, to understand the associated wear mechanisms, and to develop strategies for process stabilization in order to significantly increase efficiency and tool quality.
Cylindrical grinding tools are used to produce flutes on carbide shank tools. This leads to different loads and varying degrees of wear, which increases non-productive times and production costs. Up to now, grading has only been implemented in two layers, which has already improved the wear behaviour. However, a grading design based on the load during grinding has not yet been considered, as an analytical model is lacking. With the help of graded grinding tools that are adapted to the load during flute grinding, wear can be levelled out and non-productive times reduced.
Knowledge of the loads during internal turning allows an application-specific cutting edge design for industrial processes and use in tool development. Targeted cutting edge preparation can increase the cutting edge stability and thus lead to an increase in performance, especially for specialised tools. Furthermore, an industrial design of the brushing process allows customer and process-specific cutting edge micro-geometries to be offered from batch size 1 at a reasonable cost.
Team:
Philipp Pillkahn
Year:
2022
Funding:
German Research Foundation (DFG) Knowledge Transfer
Forces are an important source of information for process and condition monitoring in machine tools. Structure-integrated force measurement makes it possible to measure forces without negatively influencing machine properties such as stiffness or workspace size. However, previous approaches to structure-integrated force measurement have not been able to establish themselves, as they are associated with a high level of integration effort and costs.
The main objective of the planned project is to reduce energy requirements in the manufacture of carbide tools along the entire process chain. This includes researching and optimizing the processes of raw material synthesis, shaping, green machining, sintering and grinding.
Led by:
Prof. Dr.-Ing. Berend Denkena, Dr.-Ing. Nicolas Beer
Production planning faces the challenge of efficiently managing production systems despite high demand volatility and scarce human resources. Traditional planning methods focus primarily on maximizing productivity in the short term and often neglect system stability. Fluctuating machine availability, varying process times and complex production processes make robust planning difficult. MultiPEP addresses these challenges by integrating robustness analyses into production planning.
In deep drilling, boreholes with a length-to-diameter ratio of more than 200 can be productively produced. To ensure the functionality of deep holes, they must have the lowest possible center course in addition to typical quality requirements (e.g. diameter accuracy). The center course is the offset of the real bore axis from the ideal bore axis. The aim of the project is to develop a compensation unit that detects the center course in the process and corrects it simultaneously by means of an active tool system. Among other things, a measuring system is being developed for this purpose.
Self-stimulated vibrations are the main reason for poor surface quality of the work piece and reduced productivity of machine tools. A high level of expertise is required for setting up a high-productivity process with high process reliability. The development of an "intelligent machine tool", which adapts process parameters such as cutting depth / width, spindle speed and feed rate autonomously to the specific conditions in order to enable a productive and at the same time stable process is the objective of this project.
The productivity and working accuracy of machine tools are limited not only by the drive power, but mainly by the dynamic machine properties. Under unfavorable conditions, the static and dynamic forces occurring in the process can lead to chatter vibrations. These self-stimulated vibrations are also noticeable on the work piece surface due to so-called chatter marks. The chatter marks can cause surface tolerances not to be met. The occurrence of chatter vibrations depends on various process variables, such as the depth of cut / and width or the spindle speed. The selection of suitable parameters requires a lot of time for experiments and calculations, expensive measuring equipment and a high level of expert knowledge. The objective of this project is the development and prototypical implementation of an "intelligent machine tool". During the process this machine successively learns at which parameters the process is stable and at the same time as productive as possible. By doing so, the parameters in the process are then adjusted autonomously in such a way that chatter vibrations are avoided, but nevertheless the highest possible material removal is achieved.
For this project, the investigations are carried out on the "feeling machine", which uses process-internal sensors to determine the process forces. Methods from the field of artificial intelligence are used for the autonomous adaptation of the process parameters. In this way the feeling machine becomes a learning and intelligent machine in this project.
Mobile rope grinding is a widely used method for cutting large-volume components. The process is used in the construction industry, demolition and natural stone quarrying. Nowadays, productivity and process reliability are determined exclusively by the experience of the machine operator. For example, process errors, such as the pushing up of cutting beads or eccentrically worn cutting beads, can only be identified manually by the machine operator during process interruptions. Accordingly, the aim of the research project is to develop a process monitoring system for mobile rope grinding. To this end, new types of measuring systems are being developed for rope grinding, among other things.
Additive Fertigungsverfahren (AF) haben in den vergangenen Jahren stark an
Bedeutung gewonnen. Der Einsatz von AF bietet die Möglichkeit, individuelle,
funktionsgerechtere Bauteile mit minimalem Materialeinsatz zu fertigen, die mithilfe
herkömmlicher Fertigungsverfahren nicht oder nur mit großem Aufwand zu fertigen
sind.
The fatigue strength of butt joints is significantly dependent on their residual stress state. Deep rolling is a manufacturing process for introducing residual compressive stresses that have a positive effect on fatigue strength. In this project, the deep rolling process for butt joints of thick plates is qualified and the influence of the process on fatigue crack growth is quantified.
The aim of this research project is to understand surface expression using flank milling as an example, with particular emphasis on tool microgeometry and process manipulated variables. An essential aspect of the project is the development of methods for the extension of machining simulations by higher order geometric features. For this purpose, the approach of the continuous wavelet transformation is used for the first time and further developed accordingly.
Nowadays, machine tool feed drives are mostly systems with one degree of freedom (dof). By combining multiple systems, movements in multiple dof become relizable. However, this leads to a reduction in dynamics and accuracy of the system. With a multi-dof feed drive system significant benefits can be achieved. The scope of this project is to investigate a system, consisting of a planar direct drive combined with a contactless electromagnetic planar guide. Firstly, a test rig will be designed, realized and tested. Then the feed drive system will be extensively analyzed in terms of accuracy, dynamics and structural behavior. In a second period it is pursued to investigate the system in cutting processes.
Different load histories of train wheels lead to high variance of material properties on the running surface. Thus, it is difficult to determine general machining parameters for reprocessing and to implement a robust process monitoring system. An online measurement of material properties by means of the Barkhausen effect is applied to allow the definition of individual machining parameters for each sample. In addition, the acoustic emission of the cutting tool is measured and evaluated in conjunction with the material properties to improve the process control.
Universal spindles currently on the market are often only suitable for one of the two very productive processes of high-speed or high-performance machining due to their limited working range. The aim of the project is to develop a "hybrid" spindle that can switch between these two operating areas depending on the process, since in this case a wide range of materials can be processed cost-effectively and efficiently on the same machine.
Micro strain gauges in notches allow highly sensitive force measurement. In combination with intelligent sensor placement and signal processing sensory properties can be added to structural machine tool parts without loss of stiffness. In order to reduce engineering effort, the development of sensing guide carriages as standard machine tool components is subject of this proposal.
The aim of this research project is to develop a user-friendly and reliable condition monitoring system for ball screws in machine tools, which parameters itself as autonomously as possible and adapts itself to the terms of use of the machine tool.
Influences of pitch and yaw angle in grinding operations are investigated to gain a deeper understanding of their effect on surface quality. Afterwards, new strategies on freeform grinding using a moving contact point will be developed.
During the operation of motor spindles, heat losses occur in the motor and bearings. This heat leads to a series of undesired effects within the spindle-bearing-system. Therefore, the aim of this project is to develop a shaft cooling system based on lamellar heat exchangers.
BTA deep-hole drilling is characterized by an external oil supply between the bore wall and the drill head. The oil transports the produced chips through the drill head and the drill pipe to the outside. To increase process reliability, the Institut für Fertigungstechnik und Werkzeugmaschinen (IFW) Hannover is developing a sensory drill pipe together with BTA-Tiefbohrsysteme GmbH. The aim is to be able to determine and monitor the center deviation during machining.
Qualification of the ESPI hole-drilling method for the measurement of residual stresses in steel, aluminium and titanium. Determination of optimal drilling and measuring parameters for reliable and reproducible residual stress measurement.
Year:
2018
Funding:
Wege in die Forschung / Leibniz Universität Hannover
The aim of the project is an overall model, which shows the grinding wheel characteristics and its application behavior fromthe production through the application and to the process result closely. For this purpose, it is necessary to work simultaneously and in close cooperation in the areas of sintering technology, grinding technology and modeling. In this way, adjustable properties and interactions can be identified and analyzed with regard to their process relevance and quantifiability.
The use of all-ceramic dental restorations based on zirconium oxide has steadily increased since the 1990s. The necessary manufacturing steps up to the finished restoration influence the bonding between the framework and the veneering material, often the restoration fails due to chipping. The exact mechanisms and relationships are currently not completely known, therefore the influence of the process chain on the bonding mechanisms between framework and veneering materials of all-ceramic dental restorations is examined in detail in this project.
The goal of this research project is to qualify multi-layered abrasive beads for the cutting of pure metal structures and thereby increase the productivity of the dismantling process. In order to compensate for the lack of self-sharpening effect, the multi-layered abrasive beads have to be sharpened in an adopted dressing process . Electro Contact Discharge Dressing (ECDD) will be used due to the metal binding of the beads.
The productivity in machining is often limited by self-excited vibrations, so-called chatter. To improve the process stability, flank face chamfers can be used, which have a damping effect due to the contact with the workpiece surface, but at the same time lead to a deteriorated surface quality. Therefore, in this project, a tool geometry is examined, which has both sharp and chamfered radially recessed tooths.
In profile grinding, the thermal load due to insufficient coolant supply is a challenge. The approach of microstructured grinding wheels faces this challenge as the coolant flow is increased and process forces are decreased by this method. Throughout this project, the capability to modify profile grinding wheels is investigated as well as the influence of such structures on the resulting workpiece properties.
Wire sawing process has become increasingly important when cutting steel within a dry process. Currently used tools does not meet the requirements of this application satisfactorily. The aim of the project „InnoSeil“ which is supported by the BMBF is to develop an innovative wire sawing tool, whose tool life and productivity are significantly superior to conventional reference tools.
Forming tools for sheet-bulk metal forming are under locally varying loads during the forming process. The grinding step during manufacturing of these tools can be used to induce locally optimized residual stresses. These stresses reduce the work loads of the tools and therefore extend its lifetime.
This project’s objective is to machine microscopic dimple to the inner surface of cylinder liners. These dimples improve the lubrication and thus reduce the friction and wear.
In the research project “Advanced Methods for Machine and Process Monitoring”, a modular process monitoring system is developed in cooperation with DMG MORI CO., LTD. It contains modules for single item- and series production process monitoring and focusses on minimizing the respective manual parameterization effort.
Indexable inserts made of polycrystalline boron nitride (PCBN) are characterized by high hardness and high heat resistance. Efficient and quality-optimized grinding strategies for these cutting tools enable a significant reduction in manufacturing costs and an increase in the surface quality of finished components. The systematic investigation of the grinding and dressing process of the PCBN cutting inserts will provide appropriate strategies.
This project is a common research project between German and Brazilian institutions. The funding is provided by DFG and CAPES. The goal of this project is the investigation of the relaxation of residual stresses and the underlying mechanisms. The finishing manufacturing steps are costumized based on the gained knowledge about the relaxation.
Turn-rolling is an efficient way of machining high-performance components. Simultaneous turning and deep rolling not only shortens process times, but also compensates for the adverse effects on the edge zone of the workpiece during turning.
Clamping heads are used for the clamping of workpieces and workpiece pallets in machine tools. They enable the clamping of workpieces with a high geometric repeatability. The aim of this project is the development of a new mechatronic clamping head to enable a force-based, continuous condition monitoring.
The research project deals with the development and investigation of a new damped tool holder based on friction damping.
The aim is to increase the damping and stiffness as well as the resulting productivity of the tool holder compared to existing tool holder for a wide frequency range.
Currently, the IFW develops a new method for the purpose of regrinding cemented carbide milling tools. This method allows a precise measurement of all signs of tool wear and thus increases the resource efficiency during the regrinding operation of the milling tools. Consequently, the reground milling tools lifetime as well as the economical efficiency and sustainability of its life cycle is increased.
The joint project FINISH investigates the exact and fast acquisition of geometry as well as data evaluation for increasing efficiency in the coating process of luxury yachts. At the IFW, a methodology is developed to generate an aesthetically and technologically optimized CAD target model from a point cloud of the raw state.
In the research project "CAxPoli - Technological CAD/CAM chain for the automated polishing of geometrically complex workpieces" the automated machining process is investigated using the example of tooth polishing by returning the actual machining results to process planning. The aim is to select and adjust the appropriate process parameters automatically depending on the processing status. The automatic machining of complex workpieces shall be achieved by the feedback of the machining result as well as by a continuous build-up of knowledge from previous machining processes.
Additive manufacturing (AM) offers high potential in the area of resource-efficient production of components with complex geometries, especially for expensive materials and small batch sizes. However, there are a number of challenges to these advantages. For example, the achievable dimensional accuracy and surface quality is generally not sufficient, so that machining of the components is necessary. Due to the different planning processes and technological boundary conditions in additive or machining production, there is currently only insufficient compatibility of the planning data and there is no continuous development chain. The BMBF-funded joint project PR0F1T aims to develop solutions for these challenges.
The objective of the research project Effective is the first-time development, research and demonstration of an efficient, intelligent and cost-effective machine tool for processing fibre-reinforced plastics using a combination of machine tool and robot technologies. By optimizing the design, machine costs are reduced by more than 25 %. In addition, intelligent control for the dust-exhaust and use of lightweight materials in the machine structure reduce the energy costs by 25 % compared to today's machine tools.
Year:
2018
Funding:
This research project is funded by the Federal Ministry of Education and Research (BMBF) within the programme "Innovations for the production, services and work of tomorrow" and is supervised by the Project Management Agency Karlsruhe (PTKA).
The aim of the transfer project T09 is to transfer the acquired basic knowledge into application. To this end, the method for adaptive work planning and production control will be further developed in an application-oriented manner and transferred to the Fauser MES of Fauser AG and linked to the BDE in Fauser. At the project partner Bornemann Gewindetechnik GmbH & Co. KG, the method is used in practice and is tested and validated in this way.
The machining has, as a final step in the process chain of solid components production over the manufactured surface and subsurface properties, a significant influence on the application behaviour and the life span of components. A possibility to use this knowledge already in the design phase of the component to define a machining strategy does not exist yet. Hence, the aim of the subproject B4 is to connect the design of a component with its process planning.
An important quality criterion in the process design is the prevention of geometric shape deviations due to interactions of process and workpiece. The deformation of the workpiece is primarily determined by the process forces, the material properties and the changing workpiece shape over time. Due to these relationships, a large number of experiments is required for the design of tool grinding processes until the process is customised. The aim of this project is the development and research of a method for the model-based design of individual tool grinding processes in industrial environments.