INFLUENCE OF INITIAL SETUP OF PARTS BEFORE ROUGHNESS EVALUATION

Transcription

1 10th International DAAAM Baltic Conference "INDUSTRIAL ENGINEERING May 2015, Tallinn, Estonia INFLUENCE OF INITIAL SETUP OF PARTS BEFORE ROUGHNESS EVALUATION Melichar Martin, Kutlwašer Jan, Kubátová Dana Abstract: This article deals with issue of initial setup of the tested part before roughness measuring process. In cooperation with industry partners it has been tested the influence of accuracy of the positioning of parts for measuring parameters inside high precision holes with small diameter. During the experimental phase it was evaluated by high-end stationary laboratory roughness device thousands of samples of one type of high precision hole to get statistical relevant data. The other part of the article deals with results and current research about possibility of solving the problem with noncontact unit. Key words: Surface Metrology, Roughness, Initial 1. INTRODUCTION The meaning of machining quality of the individual components increases recently. It has the major impact on the functionality of the entire device. Especially by the contact surfaces (eg. bearings) quality is roughness one of the decisive factors. It can influence the operation and use of the device as a whole. The surface quality has a significant effect on the life and reliability of components, such as machine parts running accuracy, their noise, friction losses, heat transfer, or wear resistance. Therefore, it is preferable to monitor surface roughness of functional surfaces and evaluate the measured parameters. [ 6 ] The surface structure has a decisive weight on how the component will behave in practice and what will have functional properties. General surface contains a number of unevenness (roughness, waviness, the surface shape) forming the surface structure, especially its differing pitches having a different effect on the function surface. Therefore, the development of measurement equipment and metrology surface structure needs to pay more and more attention. Since the surface structure control for single-use measuring machines, it is clear that their manufacturers sharing the metrology enhancing the focus. The system of assessment and evaluation of the structure of the surface is defined by a plurality of standards that describe the evaluation, measurement, marking texture or calibration of measuring instruments etc. These are called. Standard GPS (Geometrical product), which specify the geometric requirements for the product [ 2 ]. These standards are continuously gradual development of measurement equipment and general metrology developed, refined and supplemented. 2. ISSUE OF INITIAL SETUP When analyzing the surface integrity, especially roughness, one of the key factors in achieving relevant results is the correct setting of the mutual position between the measuring device and controlled products [ 4 ]. The ideal position in terms of measurement seems (when application of contact evaluation methods) theoretically so that the stylus moves perpendicular to the tracks roughness e.g. ideally etalon roughness perpendicular to the lines cuts. How much can a potential difference of perpendicularity affect the relevance of the

2 results of the measurements was investigated in experimental metrology conditions. Fig. 1 During the test phase has been under controlled entry conditions experimentally measured several thousand precision holes (this is specific and often solved metrology operation [ 5 ]) machined with a reamer. The quantity of the obtained results was necessary for reliable statistical evaluation experiment. The actual parameters detection was performed on Roughness/Contour Hommel-ETAMIC T8000 (see Fig. 2), which is capable of in a controlled environment to detect and measure the parameters in the accuracy of fully meeting the requirements of aerospace and automotive industries. The device Hommel Etamic T8000 has an optimal combination for surface roughness measurement and after replacing the sensor head can be used for profile control components (control contours). This dual measurement is made possible thanks to the intelligent arrangement of both probing systems. Roughness and contour are measured using two different imaging systems. Outline of the probe can be easily interchanged and, in some cases it is possible to parallel roughness and profile part. An experiment was carried out using a measuring system HOMMEL-ETAMIC T8000. This is a measuring system that allows measurement of surface roughness and waviness profile and topography of different part types. The design of the system has a modular design that allows the interconnection of different shift units, sensor types, columns and granite slabs. This allows relatively high usability measurements for different sizes, types of surfaces etc. Fig. 2 Hommel-Etamic T8000 This equipment as well as other manufacturers equipment provides measurements in only two axes and a possible shift the third axis is solved by manually or CNC controlled table, which can be obtained from the manufacturer in the supplementary equipment of machine. Fig. 3 Measured sample [1] Fig. 4 Detail of contact measurement in the hole [1] With an accurate manual micrometer stand holes were always tested in an ideal position to measuring machine and installed as incorrect assumption. The angular extent of "false" positioning was limited diameter holes (12mm) in relation to input roughness parameters given in ISO 4288 [ 3 ]. The output is clear that the initial phase of testing was clearly distinct influence of the initial system setup machine - controlled piece.

3 Fig. 7 Position 5mm off axis To eliminate potential errors were chosen methodology selected holes further evaluated by in terms of shape and parameters on the precise roundness Taylor Hobson Talyrond 585 LT. This device is equipped with automatic levelling and centering piece measured up in the order of tenths of a micrometer. Among its other features include the ability to scan the entire surface of contact both internal and external cylindrical profile and the profile mathematically evaluated. Fig. 5 Correct position of the sensor Fig. 6 Position 2,5mm off axis Fig. 8 Taylor Hobson Talyrond 585 LT Output value of this evaluation corresponds to the initial assumptions and again clearly demonstrates the effect of measurement methodologies and especially the initial position gauge - piece on relevant result. Fig. 9 3D data of evaluated hole

4 3. FIGURES Based on the experimental simulations it was found that the described device provides an effective way to initial setup of the third axis of the roundness instrument. Because exerted contactless nature of the methodology and the resolution of HD camera, we obtain high accuracy while keeping a significant increase in the success of initial setup cycle. This is achieved substantial productivity gains the control processes. Also, the value of standard uncertainty remains at the same level as touch setup. Advantage, the decreased cost of the non-contact components compared to standard method based on the manual or CNC table, savings in labor time and expense-consuming machines, to which the contactless setup realized, as there is no need to operator surveillance over the process because of the anti-collision procedure. The proposed device is therefore a significant improvement and streamlining the setup process. 4. CONCLUSION The model devices provides statistical stable results for the applications described above so the next step will be preparation next generation of these models and their applications by using high precision machines by support of Regional Technological Institute (RTI-UWB). RTI under research project cooperate with many companies, which allows the usage of the devices and procedures in the reality of industrial sector. 5. ACKNOWLEDGMENT This paper includes results created within the project SGS and project CZ.1.05/2.1.00/ Regional Technological Institute. The project is supported by the European Regional Development Fund and the state budget of the Czech Republic. 6. CORRESPONDING ADDRESS Ing.. Martin Melichar, Ph.D. University of West Bohemia Faculty of Mechanical Engineering RTI Univerzitni 8, Plzen, Czech Republic Phone: mech@rti.zcu.cz Fig. 10 Prototype of experimentary table Fig.11 HD sensoric head [1]

5 6. ADDITIONAL DATA ABOUT AUTHORS 1) Authors: Ing. Martin Melichar, Ph.D. Senior researcher Ing. Jan Kutlwašer Ph.D. student Ing. Dana Kubátová Ph.D. student 2) Title: Influence of initial setup of parts before roughness evaluation 3) Address: University of West Bohemia Univerzitní 8 Plzeň Czech Republic [ 6 ] M.J. KLOPFSTEIN, D.A. LUCCA, Recent Assessment of Surface Integrity Resulting from Fine Finishing Processes, Procedia Engineering, Vol. 19, 2011, Pages , DOI: /j.proeng REFERENCES [ 1 ] MELICHAR, M., KUTLWAŠER, J. The Issue of Contactless Setup before Measuring Process. Procedia Engineering. 2014, vol. 69, s DOI: /j.proeng [ 2 ] TICHÁ, Š., Engineering Metrology - Part 1 Ostrava: VSB-TU Ostrava, S., ISBN X [ 3 ] ISO 4288:1996. Geometrical Product Specifications (GPS) - Surface texture: Profile method - Rules and procedures for the assessment of surface texture. [ 4 ] MELICHAR, M., Replacement of initial contact setup of Roundness machine by contactless method, PhD thesis, ZČU FST, 2011 [ 5 ] AMRANA, M.A., S. SALMAHA, N.I.S. HUSSEINA, R. IZAMSHAHB, M. HADZLEYB, SIVARAOSB, M.S. KASIMB,M.A. SULAIMANB, Effects of Machine Parameters on Surface Roughness Using Response Surface Method in Drilling Process, Procedia Engineering Vol. 68, 2013, Pages DOI: /j.proeng