Gas turbines are one of the most significant components for the aviation and energy production. The heat resistant carrier wheels fitted with blades represent the core piece of gas turbines. The connection of the blades with the disk in the field of turbines is realized through a form locking connection. Today, these profile grooves are exclusively brought in with the procedure of broaching, which is characterized by a very high precision and process reliability. The disadvantage of this process lies within the weak flexibility and that according to the state of the art the cutting material used for cutting nickel-based-alloys is high-speed-steel, which only allows low cutting speed. Furthermore, broaching means a break in the process chain because ... More...


 

The use of light metal alloys such as magnesium and aluminum alloys are demanded strengthened by the vehicle technology. Magnesium alloys cause tool wear at small wear rates and allow high material removal rates. By wet and dry cutting however professional chip handling is necessary, in order to minimise fire and explosion risks. For this reason an exhaust system was developed, which sucks off the chips completely from the rake and removes the chips through the tool, the clamping and the spindle. By finishing of transmission boxes the material removal rate could be additivly increased by an unorthodox path strategy. In addition the straight-line tool path was replaced by a circular path adapted to the workpiece outline. More...


 

Milling of titanium alloys is known as a difficult process due to a high thermal tool load and a low modulus of elasticity. The high thermal tool load only allows low cutting speeds. Nevertheless, premature tool wear and failure occurs due to thermal wear mechanisms during the process. The low modulus of elasticity of titanium alloys leads to an elastic push back of the workpiece material. Behind the cutting edge the workpiece material springs back and grinds at the flank face of the tool. Additionally, the low ... More...


 

On the other hand, the physical and chemical properties of nickel based alloys place them amongst the difficult-to-machine materials. Properties such as great high-temperature strength, thermal resistance and low thermal conductivity as well as the abrasive effect of carbides and intermetallic phases impose high thermal and mechanical stresses on the tool cutting edge. These materials often show a strong tendency to sticking, build-up edges, strain hardening and creating unallowable residual stresses. The performance of broaching processes for nickel based alloys can be improved only by using more effective cutting materials at optimum cutting parameters. Apart from powder metallurgy high-speed steels, these materials include micro grain carbides. WZL offers a fast and targeted approach, ... More...


 

Drilling of titanium alloys make high demands on the cutting fluids, the cutting strategies and the cutting tools in use. Due to the low thermal conductivity of titanium alloys, a great proportion of the heat generated during the cutting process has to be removed through the cutting tool. This leads to a high thermal tool load and results in elevated tool wear. In consequence of the process the accessibility for cutting fluid is limited during drilling. A conventional flood cooling is only able to remove a small amount ... More...


 

For the increase of the durability of cutting tools modified kinematics can be used beside coolants. By turning the primary motion is superposed by longitudinal oscillations within the ultrasonic range. The investigations are focused on improvements of the cutting tool durability and the surface quality on the manufactured faces. The clarification of the physical mechanism of chip formation is researched under dynamic conditions. Furthermore developments are targeted on the adjustment of the dynamic system to the manufacturing task. More...


 

Surfaces in hone quality cannot be produced neither by grinding with cBN nor by hard cutting. By reason of this problem, it can be necessary to use an additional machine tool for finishing. Therefore in this project the combination of roller burnishing, hard cutting and grinding with cBN in one machine tool will be realised. Thus a sequential and simultaneous maching of hardened, rotationally symmetric components in ... More...


 

Do you have questions concerning this research area?

Your contact:
Martin Seimann, M.Sc.
Workgroup Leader
Herwart-Opitz-Haus 54B 304
Tel.: +49 241 80-28020
Fax: +49 241 80-22293
Mail: M.Seimann@wzl.rwth-aachen.de

 

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