| 1. |
- Berglund, Johan C, 1978, et al.
(författare)
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Machine Hammer Peening – A Substitute for Polishing of Pressing Die Surfaces?
- 2009
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Ingår i: Proceedings of the International 3'rd Swedish Production Symposium. - 9789163360060 ; :Day 1, s. 184-189
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Konferensbidrag (refereegranskat)abstract
- Machine Hammer Peening (MHP) is a new method for finishing of surfaces. With this method the workpiece surface is hammered with a spherical carbide tool. The main objective of the study was to evaluate whether the MHP method could be used as a plausible substitute for manual polishing in pressing die manufacturing. To do this, sample surfaces were hammered and evaluated. Changes to the surfaces were assessed using surface roughness measurements, hardness measurements and optical images. First of all, the workpiece surface was smoothened. Secondly, the surface hardness was increased significantly. Thirdly, the nodules on the workpiece surface were effected. They appeared to be smaller and not as visible. It is probable that they had been plastically deformed and that some of the graphite in the nodules was replaced by material from the surrounding steel matrix. By replacing the graphite in the larger nodule cavities by surrounding steel material, a die surface is created which would be less prone to galling. In addition, with MHP, the amount of polishing needed to manufacture a die surface can be reduced because of the smoothening effect.
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| 2. |
- Berglund, Johan C, 1978, et al.
(författare)
-
A method development for correlation of surface finish appearance of die surfaces and roughness measurement data
- 2009
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Ingår i: Tribology letters. - Berlin : Springer Berlin/Heidelberg. - 1023-8883 .- 1573-2711. ; 36:2, s. 157-164
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Tidskriftsartikel (refereegranskat)abstract
- In die and mould manufacturing, the method used for quality control of finished surfaces is usually visual and tactile inspection of the finish, which is not easily quantifiable. In the present study, an evaluation of the connection between surface finish appearance and measured surface roughness was carried out using scale-sensitive fractal analysis to find functional correlations and to determine suitable cut-off limits for functional data filtration. A selection of ball-nose end-mills in combination with two different tool steels (hardness 39 and 47 HRC) were used to manufacture surfaces that were inspected and measured. It was found that the method developed in the present study for evaluating functional correlations and designing filters worked well. It was also found that there is a correlation between the surface roughness parameter Sq and the surface finish appearance and that this correlation is stronger in certain wavelengths on the surface.
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| 3. |
- Berglund, Johan C, 1978, et al.
(författare)
-
Measuring strategies for smooth tool steel surfaces
- 2008
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Ingår i: Proceedings. - Aachen : Shaker Verlag. - 1610-4773. - 9783832269128 - 3832269126 ; , s. 110-119
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Comparisons between different measuring strategies were made on three types of smooth tool steel surfaces. Three replica materials were tested to study possibilities within replication techniques. An optical interferometer as well as a mechanical stylus was used to evaluate the surfaces. The results showed that the tested replica materials generated good representations of both the form and the surface roughness (Sq > 300 nm). The evaluated surfaces were quite homogeneous, thus, few measurements are needed to get representative results. However, it was found that caution must be taken regarding manually polished surfaces which can be less homogenous and therefore require more measurements to get representative results.
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| 4. |
- Berglund, Johan C, 1978
(författare)
-
Methods for Characterisation of Pressing Die Surfaces
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Design and manufacture of dies and moulds is a critical aspect of many production systems since the manufacturing and try-out of new dies and moulds often is essential in determining the lead-time and quality of a new production system. In the automotive industry, many new car models are introduced each year and for each of these models, a new set of pressing dies has to be designed and manufactured. In manufacturing of pressing dies, the effects of manufacturing processes on functional performance are not fully understood. One of the reasons for this is the lack of effective methods for characterisation. In the work described in this thesis, experimental work is conducted to establish such methods. First, the focus is on methods for obtaining measurement data. Second, the focus is on methods for relating the measurement data to functional performance. In contrast, the technique commonly used today for characterisation is visual and tactile inspection, with the help of reference surfaces, by an experienced operator. In this work, effective 3D measuring strategies were established for pressing die surfaces, including the use a surface replication technique. It was also found that machined surfaces are more homogeneous than manually polished surfaces and therefore require fewer measurements to give representative results. Furthermore, it was established that in production, a 2D profiler can be used for quality control of a finish milled steel surface, in regard to surface roughness, if an appropriate measuring strategy is used and limits for the evaluated parameters first are established for each combination of cutting tools, cutting data, workpiece material etc. In addition, using Rz (average peak-to-valley profile roughness) or Rp (highest peak) is better than using Ra (arithmetical mean deviation) if surface finish appearance is to be assessed. The method employed in this study, using scale-sensitive fractal analysis, for evaluating functional correlations and designing filters was very usable and gave good results. This method can surely be applied to other types of surfaces and functional correlations. Also, there is a correlation between the surface roughness parameter Sq (root-mean-square deviation of the surface) and the surface finish appearance of pressing dies and this correlation is stronger in certain wavelengths on the surface.
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| 5. |
- Berglund, Johan C, 1978, et al.
(författare)
-
Robust and Easy to Use Quality Control of Roughness on Milled Tool Steel Surfaces
- 2008
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Ingår i: Proceedings of the 18th International Conference on Flexible Automation and Intelligent Manufacturing. - 9789163327575 ; , s. 284-289
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Konferensbidrag (refereegranskat)abstract
- This study was an evaluation of measuring strategies using a handheld 2D profiler for quality control of finish milled tool steel with regard to surface roughness. A selection of ball nose end mills in combination with two different tool steels (hardness 39 and 47 HRC) were used to manufacture the surfaces that were to be measured. It was found that using an appropriate measuring strategy it is possible to measure the roughness of these relatively smooth surfaces (0.1
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| 6. |
- Berglund, Johan C, 1978, et al.
(författare)
-
Surface Finish and Roughness Measurement in Die and Mould Manufacturing
- 2008
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Ingår i: Proceedings of the 2'nd Swedish Production Symposium. ; , s. 385-391
-
Konferensbidrag (refereegranskat)abstract
- In die and mould manufacturing, the method used for quality control of finished surfaces is usually visual and tactile inspection of the finish, which is not easily quantifiable. In this study, an evaluation of the connection between surface finish appearance and measured surface roughness was carried out using scale-sensitive fractal analysis to find functional correlations and to determine suitable cut-off limits for functional data filtration. A selection of ball nose end mills in combination with two different tool steels (hardness 39 and 47 HRC) were used to manufacture surfaces that were measured. It was found that the method employed in this study for evaluating functional correlations and designing filters worked well. It was also found that there is a correlation between the surface roughness parameter Sq and the surface finish appearance and that this correlation is stronger in certain wavelengths on the surface.
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