| 1. |
- Berglund, Johan C, 1978, et al.
(författare)
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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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| 2. |
- Berglund, Johan C, 1978, et al.
(författare)
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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
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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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| 3. |
- Berglund, Johan, et al.
(författare)
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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. - Skövde : Skövde University. - 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<1µm) with satisfactory accuracy using a handheld profiler. However, it was also found that, in contrast to what is common practice, Ra is not a suitable parameter to use for evaluation. Instead, using Rz or Rp is suggested. To be able to control quality, the machining process (selection of cutting tool, cutting data, workpiece material etc) as well as limits for the evaluated parameters first have to be established.
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| 4. |
- Bååth, Lars B., et al.
(författare)
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Surface topography with PDI holography
- 2008
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Ingår i: Proceedings of the XII. International Colloquium on Surfaces. - Aachen : Shaker Verlag. - 9783832269128 ; , s. 10-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents topographic measurements of metal surface with Point Diffraction Interferometer (PDI) technique. Interferogram of a surface is created and recorded with different phase offsets. These are then combined to create a phase offset map of the surface. We demonstrate the use with the presentation of our first surface topographic map
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| 5. |
- Cabanettes, Frédéric, 1982-
(författare)
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Cam Roller Contact : The topographical aspect
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The automotive industry and the design of engines are strongly ruled by performance and legislation demands. First order aspects defining the main functions of a component are well known and new challenges appear at a lower scale. Wear reduction is defined as a second order problem and requires decreasing the scale of observation of components down to roughness. This thesis work and its aim lie within the scope of wear improvements and are focused on the injection cam/roller contact of heavy duty diesel engines. In order to reach the aim several material and methods are used: a valve train rig test, roughness characterisation and different manufacturing processes. It is shown by experiments that the flank and nose of injection cams are specific areas with specific roughness (higher density of summits Sds) compared to the rest of the cam. The wear is characterized by rounded-off of summits (Ssc). From those results and since wear processes are strongly linked to the pressure generated between the mating surfaces, the development of a rough contact model is of great interest. An elastic rough contact model is implemented and improved later on by an elasto-plastic description of materials. The simulations are validated by a wear test and are used to rank the ability of surfaces (both cam and roller) to face wear problems. The ratio of plastically deformed peaks shows that the flank and nose of the cam are reacting badly to pressures. Additionally the rough contact allows ranking/optimization of different machining processes with respect to their expected functional contact performance. Future work will be to use such a model to choose a good combination of surfaces (cam and roller) in order to reduce wear.
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| 6. |
- Cabanettes, Frédéric, 1982-, et al.
(författare)
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Evaluation of cam surfaces by wear testing and functional characterization
- 2008
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Ingår i: Synopses / 35th Leeds-Lyon Symposium on Tribology. - Leeds : Leeds University.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Friction and wear are constant problems encountered in camshaft development. The contact between roller and cam is a mix of sliding and rolling which leads to a wide range of failure modes. The uniqueness of this contact is also due to variations all around the cam of a multitude of parameters such as load and radius. A previous study described surface topography as a function of cam shape. The different types of wear mechanisms are strongly linked to contact pressures which are also dependent on roughness. The aim of the paper is to develop a rough contact model which will be utilized as a tool to rank surfaces and their ability to face wear problems. In order to verify the tool, rough contact results are compared to roughness parameter variations due to wear produced in a cam roller rig test. The surface measurements used for this study are made by a non-contact light interferometer. The Greenwood-Williamson contact model has been developed in a deterministic way and the elasto-plastic behaviour of the material has been integrated to the model. The outputs of the simulation give a ranking of surfaces which is compared to their roughness variations due to wear. The study shows that the model developed is a reliable tool to rank and define surface quality since the results are correlated to wear. However, the results show as well some discrepancies which could be corrected in the future by integrating to the model two new features: a rough to rough contact including sliding between surfaces. This new model should be verified by an accurate experimentation using relocation between unworn and worn surfaces.
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| 7. |
- Dimkovski, Zlate, et al.
(författare)
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Complementing 3D Roughness Parameters for Monitoring of Improved Honing of Cylinder Bores
- 2008
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Ingår i: Proceedings of the Swedish Production Symposium (SPS) - 2008. - 9783939026952
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Konferensbidrag (refereegranskat)abstract
- It is of common interest to reduce the oil consumption and frictional losses in the internal combustion engines which are in a great deal influenced by the quality of the cylinder liner surface. Its criss-cross patterned topography consists of a communicating system of grooves of different density, width, and depth, somewhere covered by folded metal, and somewhere totally interrupted and unbalanced as a result of the honing process imperfections. These features are crucial for a good liner’s function and are inspected from scanning electron microscope images by experts, which is subjective and time consuming process. Today, a fast automatic quality control is possible by using optical instruments to measure the liner’s topography, and a computer to calculate and check if the standard roughness and groove parameters are in tolerance. Therefore, combining the profile and image analysis, algorithms were developed to compute liner’s groove parameters from 3D interference measurements taken from three different types of cylinder bore surfaces of passenger cars. One of the surface types was a result of a test of an improved honing and the other two being currently in use. Then, the standard and new parameters (groove interruption, number of grooves, holes, etc) were incorporated in a characterisation tool to objectively and quickly evaluate the improvement of the liner’s quality for an updated monitoring in production.
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| 8. |
- Dimkovski, Zlate, 1974-, et al.
(författare)
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Quantification of Blechmantel Effect on Wear of Cylinder Bore Microtopography
- 2008
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Ingår i: Proceedings of the 13th Nordic Symposium on Tribology, Nordtrib 2008. - Tampere : Tampere University Press. - 9789521519611 ; , s. 13-
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Konferensbidrag (refereegranskat)abstract
- The presence of cold work material (blechmantel) smeared out on cylinder liners by faulty honing is undesirable as it seals the oil-bearing honing grooves. It is also believed to correlate with increased bore wear, presumably due to its loosening and together with the carbon build-up from the piston’s top land form an increased quantity of abrasive particles. An attempt has been made to estimate the extent of removal of blechmantel for different wear regimes present at the middle and top region (near the top dead centre) of the liner surface using the unworn bottom region as a reference for comparison. A number of truck cylinder liners were axially sectioned after varying periods of engine running under similar conditions of load, engine speed and lubrication. 3D surface measurements were taken at the three regions and a range of standard parameters was extracted. Combining the profile and image analysis, an algorithm was developed to identify and quantify the blechmantel covering the grooves that is most likely to break and act as abrasive wear particles and at the same time it represents the part of blechmantel which covers the most of the surface. It was found out that a mere portion of the blechmantel from the middle and bottom section was removed, while the blechmantel from the top section was greatly removed and thereby it represents one of the possible causes for wear. Axial wear scratches more emphasized on the thrust side of the liner were observed not only through the whole stroke area, but also in the bottom region. The fact that the most of the blechmantel is not removed from the running surface of the liner (except for the very small portion of the polished areas at the dead centres), points out that the blechmantel plays only a minor role on wear of the cylinder liner surfaces.
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| 9. |
- Dimkovski, Zlate, 1974-, et al.
(författare)
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Towards 3D Characterisation of Cylinder Liner Surfaces
- 2008
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Ingår i: Proceedings / XII. International Colloquium on Surfaces January 28th and 29th, 2008, Chemnitz, Germany = XII. Internationales Oberflächenkolloquium. - Aachen : Shaker Verlag. - 9783832269128 ; , s. 15-24
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Konferensbidrag (refereegranskat)abstract
- Cylinder liner surface has a direct impact on the oil consumption and frictional losses in the internal combustion engines which are in common interest to be as lower as possible. Thus, the optimisation of the liner surface, its function and manufacture is often on the agenda of the automotive industry. Since the liner surface finish is a subject of improving, there is a need of improving and facilitating of its 3D characterisation preliminary when the parameter control limits are unknown, as well as later when it is experimentally verified and the limits are better determined. For that purpose a method for quality control in 3D of cylinder liners is proposed here. A tool was developed and implemented for rating of cylinder liner surfaces, computing of 3D groove parameters (groove width, height and distance between grooves) and determination of a needed number of measurements.
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| 10. |
- Johansson, Staffan, et al.
(författare)
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New cylinder liner surfaces for low oil consumption
- 2008
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Ingår i: Tribology International. - Oxford : Elsevier. - 0301-679X .- 1879-2464. ; 41:9-10, s. 854-859
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Tidskriftsartikel (refereegranskat)abstract
- Anticipated emission legislation and reduced fuel consumption are the main driving forces when developing new engines. Optimization of the active surfaces in the piston system is one possible way to meet the above demands. In this study the effects of surface topography and texture direction of the ring/liner contact on oil film thickness and friction were simulated and experimentally tested. "Low wear" results from the experimental wear tests with "glide honed" smooth liner surfaces supported the "low friction" simulation results. In addition a new wear volume sensitive surface roughness parameter, Rktot, based on the Abbot-Firestone bearing area curve was introduced.
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