The Experts below are selected from a list of 777 Experts worldwide ranked by ideXlab platform

L De Chiffre - One of the best experts on this subject based on the ideXlab platform.

  • Micromilling of hardened tool steel for mould making applications
    Journal of Materials Processing Technology, 2005
    Co-Authors: Giuliano Bissacco, Hans Norgaard Hansen, L De Chiffre
    Abstract:

    Abstract The implementation of replication techniques for mass production of microcomponents relies on the availability of tooling technologies for manufacturing of tools and moulds. Micromilling is a suitable technique for manufacturing of microstructures characterized by high aspect ratios and complex geometries as those characterizing injection moulding moulds. The realization of the Micromilling Process in connection with hardened tool steel as workpiece material is particularly challenging. The low strength of the miniaturized end mills implies reduction and accurate control of the chip load, which requires high positioning accuracy. Size effects, mainly related to the microstructure of the workpiece material and to the limited scalability of tool geometry and surface topography, critically influence the performance of the Process in terms of part accuracy, surface roughness, cutting forces and tool wear. This paper presents the Micromilling Process applied to the manufacturing of microinjection moulding moulds in hardened tool steel, presenting experimental evidence and possible solutions to the above-mentioned issues.

Li P. - One of the best experts on this subject based on the ideXlab platform.

  • Design of micro square endmills for hard milling applications
    'Springer Science and Business Media LLC', 2011
    Co-Authors: Li P., Langen H.h., Hoogstrate A.m., Oosterling J.a.j., Munnig Schmidt R.h.
    Abstract:

    In experiments of machining hardened tool steels (such as AISI H11, H13, and D2, up to 56 HRC) by commercial Ø 0.5 mm square endmills, it is observed that the tested micro endmills showed severe wear at an early stage of the Process due to chipping off around cutting edge corners, resulting in unsatisfactory tool life and product appearance (burr formation). Detailed examination of current tool geometry shows that it is mainly inherited from that of macro endmills, making the cutting edge corners the weakest part on the tool. As the Micromilling Process is characterized by small values of machining parameters, the cutting edge corners of the micro endmill are the most loaded part of the cutting edges. New design rules are studied for improving the stiffness and strength of micro endmills used in micro hard milling applications. Analytical modelling and finite element method analysis are used to aid the design of tool geometry. By using a larger neck angle, optimizing tool core geometry, and choosing a negative rake angle, tool stiffness and cutting edge strength are improved. The new endmill designs, both two-flute and four-flute, are tested in experiments on hardened tool steels and showed considerable lower tool wear and increased tool life. Furthermore, the geometrical accuracy and appearance of the workpiece (burr formation) has been improved drastically.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin

  • Design of micro square endmills for hard milling applications
    2011
    Co-Authors: Li P., Langen H.h., Hoogstrate A.m., Oosterling J.a.j., Munnig Schmidt R.h.
    Abstract:

    In experiments of machining hardened tool steels (such as AISI H11, H13, and D2, up to 56 HRC) by commercial Ø 0.5 mm square endmills, it is observed that the tested micro endmills showed severe wear at an early stage of the Process due to chipping off around cutting edge corners, resulting in unsatisfactory tool life and product appearance (burr formation). Detailed examination of current tool geometry shows that it is mainly inherited from that of macro endmills, making the cutting edge corners the weakest part on the tool. As the Micromilling Process is characterized by small values of machining parameters, the cutting edge corners of the micro endmill are the most loaded part of the cutting edges. New design rules are studied for improving the stiffness and strength of micro endmills used in micro hard milling applications. Analytical modelling and finite element method analysis are used to aid the design of tool geometry. By using a larger neck angle, optimizing tool core geometry, and choosing a negative rake angle, tool stiffness and cutting edge strength are improved. The new endmill designs, both two-flute and four-flute, are tested in experiments on hardened tool steels and showed considerable lower tool wear and increased tool life. Furthermore, the geometrical accuracy and appearance of the workpiece (burr formation) has been improved drastically. © 2011 The Author(s)

  • Micromilling of thin ribs with high aspect ratios
    Institute of Physics, 2010
    Co-Authors: Li P., Zdebski D., Langen H.h., Hoogstrate A.m., Oosterling J.a.j., Munnig Schmidt R.h., Allen D.m.
    Abstract:

    Micro features with high aspect ratios are one of the commonly encountered geometries found in micro products. In the literature, these structures are often used in demonstrator products machined by a Micromilling Process. In this paper, the challenges in Micromilling thin ribs ith high aspect ratios have been studied. Due to the scaling effect, micro-ribs have relatively low stiffness but high natural frequency. Therefore, on the one hand, average forces have to be controlled well to avoid structural bending or even damage, while on the other hand, micro features are unlikely to be excited by the dynamic forces. The characteristics of Micromilling forces and their relationships to the machining parameters, namely, feed per tooth, depth of cut and width of cut, were studied theoretically by force models. In addition, the effects of different milling strategies (up-/down-milling) and tool paths on the quality of thin features have been investigated using FEM. The results allow measures to be taken to minimize the force effects and support the micro features during machining. The experimental results verify the theoretical studies. Thin ribs about 15 ?m wide and with an aspect ratio of more than 50 were machined with good form and surface quality

  • Micromilling of thin ribs with high aspect ratios
    'IOP Publishing', 2010
    Co-Authors: Li P., Zdebski D., Langen H.h., Hoogstrate A.m., Oosterling J.a.j., Munnig Schmidt R.h., Allen D.m.
    Abstract:

    Micro features with high aspect ratios are one of the commonly encountered geometries found in micro products. In the literature, these structures are often used in demonstrator products machined by a Micromilling Process. In this paper, the challenges in Micromilling thin ribs ith high aspect ratios have been studied. Due to the scaling effect, micro-ribs have relatively low stiffness but high natural frequency. Therefore, on the one hand, average forces have to be controlled well to avoid structural bending or even damage, while on the other hand, micro features are unlikely to be excited by the dynamic forces. The characteristics of Micromilling forces and their relationships to the machining parameters, namely, feed per tooth, depth of cut and width of cut, were studied theoretically by force models. In addition, the effects of different milling strategies (up-/down-milling) and tool paths on the quality of thin features have been investigated using FEM. The results allow measures to be taken to minimize the force effects and support the micro features during machining. The experimental results verify the theoretical studies. Thin ribs about 15 ?m wide and with an aspect ratio of more than 50 were machined with good form and surface quality.Department of Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin

Munnig Schmidt R.h. - One of the best experts on this subject based on the ideXlab platform.

  • Design of micro square endmills for hard milling applications
    'Springer Science and Business Media LLC', 2011
    Co-Authors: Li P., Langen H.h., Hoogstrate A.m., Oosterling J.a.j., Munnig Schmidt R.h.
    Abstract:

    In experiments of machining hardened tool steels (such as AISI H11, H13, and D2, up to 56 HRC) by commercial Ø 0.5 mm square endmills, it is observed that the tested micro endmills showed severe wear at an early stage of the Process due to chipping off around cutting edge corners, resulting in unsatisfactory tool life and product appearance (burr formation). Detailed examination of current tool geometry shows that it is mainly inherited from that of macro endmills, making the cutting edge corners the weakest part on the tool. As the Micromilling Process is characterized by small values of machining parameters, the cutting edge corners of the micro endmill are the most loaded part of the cutting edges. New design rules are studied for improving the stiffness and strength of micro endmills used in micro hard milling applications. Analytical modelling and finite element method analysis are used to aid the design of tool geometry. By using a larger neck angle, optimizing tool core geometry, and choosing a negative rake angle, tool stiffness and cutting edge strength are improved. The new endmill designs, both two-flute and four-flute, are tested in experiments on hardened tool steels and showed considerable lower tool wear and increased tool life. Furthermore, the geometrical accuracy and appearance of the workpiece (burr formation) has been improved drastically.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin

  • Design of micro square endmills for hard milling applications
    2011
    Co-Authors: Li P., Langen H.h., Hoogstrate A.m., Oosterling J.a.j., Munnig Schmidt R.h.
    Abstract:

    In experiments of machining hardened tool steels (such as AISI H11, H13, and D2, up to 56 HRC) by commercial Ø 0.5 mm square endmills, it is observed that the tested micro endmills showed severe wear at an early stage of the Process due to chipping off around cutting edge corners, resulting in unsatisfactory tool life and product appearance (burr formation). Detailed examination of current tool geometry shows that it is mainly inherited from that of macro endmills, making the cutting edge corners the weakest part on the tool. As the Micromilling Process is characterized by small values of machining parameters, the cutting edge corners of the micro endmill are the most loaded part of the cutting edges. New design rules are studied for improving the stiffness and strength of micro endmills used in micro hard milling applications. Analytical modelling and finite element method analysis are used to aid the design of tool geometry. By using a larger neck angle, optimizing tool core geometry, and choosing a negative rake angle, tool stiffness and cutting edge strength are improved. The new endmill designs, both two-flute and four-flute, are tested in experiments on hardened tool steels and showed considerable lower tool wear and increased tool life. Furthermore, the geometrical accuracy and appearance of the workpiece (burr formation) has been improved drastically. © 2011 The Author(s)

  • Micromilling of thin ribs with high aspect ratios
    Institute of Physics, 2010
    Co-Authors: Li P., Zdebski D., Langen H.h., Hoogstrate A.m., Oosterling J.a.j., Munnig Schmidt R.h., Allen D.m.
    Abstract:

    Micro features with high aspect ratios are one of the commonly encountered geometries found in micro products. In the literature, these structures are often used in demonstrator products machined by a Micromilling Process. In this paper, the challenges in Micromilling thin ribs ith high aspect ratios have been studied. Due to the scaling effect, micro-ribs have relatively low stiffness but high natural frequency. Therefore, on the one hand, average forces have to be controlled well to avoid structural bending or even damage, while on the other hand, micro features are unlikely to be excited by the dynamic forces. The characteristics of Micromilling forces and their relationships to the machining parameters, namely, feed per tooth, depth of cut and width of cut, were studied theoretically by force models. In addition, the effects of different milling strategies (up-/down-milling) and tool paths on the quality of thin features have been investigated using FEM. The results allow measures to be taken to minimize the force effects and support the micro features during machining. The experimental results verify the theoretical studies. Thin ribs about 15 ?m wide and with an aspect ratio of more than 50 were machined with good form and surface quality

  • Micromilling of thin ribs with high aspect ratios
    'IOP Publishing', 2010
    Co-Authors: Li P., Zdebski D., Langen H.h., Hoogstrate A.m., Oosterling J.a.j., Munnig Schmidt R.h., Allen D.m.
    Abstract:

    Micro features with high aspect ratios are one of the commonly encountered geometries found in micro products. In the literature, these structures are often used in demonstrator products machined by a Micromilling Process. In this paper, the challenges in Micromilling thin ribs ith high aspect ratios have been studied. Due to the scaling effect, micro-ribs have relatively low stiffness but high natural frequency. Therefore, on the one hand, average forces have to be controlled well to avoid structural bending or even damage, while on the other hand, micro features are unlikely to be excited by the dynamic forces. The characteristics of Micromilling forces and their relationships to the machining parameters, namely, feed per tooth, depth of cut and width of cut, were studied theoretically by force models. In addition, the effects of different milling strategies (up-/down-milling) and tool paths on the quality of thin features have been investigated using FEM. The results allow measures to be taken to minimize the force effects and support the micro features during machining. The experimental results verify the theoretical studies. Thin ribs about 15 ?m wide and with an aspect ratio of more than 50 were machined with good form and surface quality.Department of Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin

Giuliano Bissacco - One of the best experts on this subject based on the ideXlab platform.

  • Micromilling of hardened tool steel for mould making applications
    Journal of Materials Processing Technology, 2005
    Co-Authors: Giuliano Bissacco, Hans Norgaard Hansen, L De Chiffre
    Abstract:

    Abstract The implementation of replication techniques for mass production of microcomponents relies on the availability of tooling technologies for manufacturing of tools and moulds. Micromilling is a suitable technique for manufacturing of microstructures characterized by high aspect ratios and complex geometries as those characterizing injection moulding moulds. The realization of the Micromilling Process in connection with hardened tool steel as workpiece material is particularly challenging. The low strength of the miniaturized end mills implies reduction and accurate control of the chip load, which requires high positioning accuracy. Size effects, mainly related to the microstructure of the workpiece material and to the limited scalability of tool geometry and surface topography, critically influence the performance of the Process in terms of part accuracy, surface roughness, cutting forces and tool wear. This paper presents the Micromilling Process applied to the manufacturing of microinjection moulding moulds in hardened tool steel, presenting experimental evidence and possible solutions to the above-mentioned issues.

Cheng K - One of the best experts on this subject based on the ideXlab platform.

  • Experimental investigation on Micromilling of oxygen-free, high-conductivity copper using tungsten carbide, chemistry vapour deposition and single-crystal diamond micro tools
    IMechE Professional Publishing, 2010
    Co-Authors: Huo D, Cheng K
    Abstract:

    Insufficient experimental data from various micro tools limit industrial application of the Micromilling Process. This paper presents an experimental comparative investigation into Micromilling of oxygen-free, high-conductivity copper using tungsten carbide (WC), chemistry vapour deposition (CVD) diamond, and single-crystal diamond Micromilling tools at a uniform 0.4mm diameter. The experiments were carried out on an ultra-precision Micromilling machine that features high dynamic accurate performance, so that the dynamic effect of the machine tool itself on the cutting Process can be reduced to a minimum. Micromachined surface roughness and burr height were characterized using white light interferometry, a scanning electron microscope (SEM), and a precision surface profiler. The influence of variation of cutting parameters, including cutting speeds, feedrate, and axial depth of cut, on surface roughness and burr formation were analysed. The experimental results show that there exists an optimum feedrate at which best surface roughness can be achieved. Optical quality surface roughness can be achieved with CVD and natural diamond tools by carefully selecting machining conditions, and surface roughness, Ra, of the order of 10nm can also be obtained when using Micromilling using WC tools on the precision Micromilling machine.EU FP6 MASMICRO projec