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The essence of the machining process is the interaction that occurs between machine tools and a workpiece under certain conditions of cutting parameters. Root cause identification (RCI) is critical to the quality control and productivity improvement of machining processes. The geometric error caused by fixture faults can be identified in most RCI m...
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... The role of this system is to prevent angular movements of the rotary table under the application of machining forces to workpieces. This role makes the clamping system a fundamental element of the RTM since it contributes to ensure the proper positioning of the part by suitably restraining it [11].This is a crucial aspect since it directly affects the accuracy of the machining process [12][13][14]. For this reason, the clamping system must guarantee high values of clamping torque so as to block the stations in the right position. ...
Modern direct-driven and high-speed rotary tables with torque motor are optimally suited for all handling and assembly applications that require the shortest indexing times and flexible positioning. The following paper is devoted to the study, the design, and the optimization of an innovative table clamping system (brake for accurate positioning) actuated by pneumatic energy, working at a maximum clamping pressure of 6 bar. The challenge for the aforementioned application is related to developing a solution able to provide a maximum tangential torque (with clamping actuated) in the range of thousands of Nm without leveraging the use of high-pressure hydraulic energy. The optimization of the proposed solution is based on the precise calculation of the stresses in order to perform a fatigue assessment and on the elastic deformation of the clamps in order to set the correct tolerances between the mating parts. Eventually, an experimental campaign is carried out in order to tune the numerical model, which is then used to validate the proposed design solution.
... Also, the operations are controlled by predefi ned operating variables to provide a high-quality product. Therefore, several factors aff ecting the manufacturing process should be considered to avoid machining defects [11]. An operating system includes machines, tools, and machining variables. ...
... The strategy aims to collect all data and information about machines, tools, product quality, productivity, etc. Due to the machining process's many parts and factors. Therefore, some techniques and programs must extract information and diagnose the production's fault from the measured data [11]. Some points should be taken into account during the manufacturing process to reduce downtime. ...
The producer focuses on producing parts that match the customer's requirements during manufacturing the automotive engine parts. One of the essential automotive engine parts is a crankshaft used to translate movement from the pistons to the car axle. The crankshaft is a complex shape and difficult to produce accurate dimensions during the machining processes. Many machines are used to create the crankshaft. Therefore, many defects happen during the machining process, reducing reliability and increasing the manufacturing process's production cost. This paper focuses on analyzing failure data and reliability of the crankshaft production line that occurs during the manufacturing process of one year. The common failure associated with the manufacturing process were ring screw, unbalanced crankshaft, broken drill screw, hub machining error, mains part machining error, and setup error. The paper aimed to determine and analyze the best failure fit between the distribution methods, such as Weibull, normal, lognormal, and exponential. Also, the reliability, hazard rate, surviving quantity, and failure density were calculated to evaluate the current situation and predict the reliability of the production line. Results proved the skewness of the data was positive equal to 3.33; the last months had the highest production failure rate, which is 53.8%, the normal method had a proper distribution of data depending on the Anderson-Darling (adj) values which is 1.367 when it compared with other methods, the normal method had the best fitting result depended on failure percentage, from 1% to 95% of the crankshafts production are expected to fail between 47.2676 and 1149.85 months respectively. The reliability of the production line decreased with manufacturing time increased. To reduce the failure and increase reliability, the maintenance system must be supported, analyze the sources that cause failure and downtime of the production line, continue the employee training system on an ongoing basis, and support the production line with modern technology. All analytical results and suggestions could be valuable to the production line to improve reliability and reduce the manufacturing process's failure.
... Here, n (p=255) , n (p=0) respectively represent the pixel number of character and the pixel number of background. After obtaining the proportion of each cell, combine them into a 1 × (m × n) vector, which is the feature vector of this character, as shown in Equation (11). ...
The rapid development of machine vision has prompted the continuous emergence of new detection systems and algorithms in surface defect detection. However, most of the existing methods establish their systems with few comparisons and verifications, and the methods described still have various problems. Thus, an original defect detection method: Segmented Embedded Rapid Defect Detection Method for Surface Defects (SERDD) is proposed in this paper. This method realizes the two-way fusion of image processing and defect detection, which can efficiently and accurately detect surface defects such as depression, scratches, notches, oil, shallow characters, abnormal dimensions, etc. Besides, the character recognition method based on Spatial Pyramid Character Proportion Matching (SPCPM) is used to identify the engraved characters on the bearing dust cover. Moreover, the problem of characters being cut in coordinate transformation is solved through Image Self-Stitching-and-Cropping (ISSC). This paper adopts adequate real image data to verify and compare the methods and proves the effectiveness and advancement through detection accuracy, missing alarm rate, and false alarm rate. This method can provide machine vision technical support for bearing surface defect detection in its real sense.
... Total rigidity of a milling machine depends on geometrical characteristics of manufacturing system layout. However, errors in surface machining depend highly on tool deflection, electronic rigidity, coding and workpiece distortion [8]. ...
... Moreover, the Hirth coupling must ensure the accomplishment of strict specifications regarding the precise positioning of the rotating table, from the points of view of its angular position and especially its centering with respect to the machine axis, after rotation. The importance of correct alignment is also highlighted in [9,10], dealing with a similar issue. Hirth couplings, also regarded as curvic couplings, are widely used for torque transmission between mating discs in turbine machinery and are not covered by international standards (for instance ISO, DIN or AGMA). ...
... Moreover, the Hirth coupling must ensure the accomplishment of strict specifications regarding the precise positioning of the rotating table, from the points of view Actuators 2018, 7, 79 3 of 21 of its angular position and especially its centering with respect to the machine axis, after rotation. The importance of correct alignment is also highlighted in [9,10], dealing with a similar issue. ...
Rings with Hirth couplings are primarily used for the accurate positioning of axial-symmetric components in the machine tool industry and, generally, in mechanical components. It is also possible to use Hirth rings as connection tools. Specific industries with special milling and grinding machines are able to manufacture both tailor made and standard Hirth rings available on stock. Unfortunately, no international standard (for instance ISO, DIN or AGMA) is available for the production and the design of such components. In the best-case scenario, it is possible to find simplified design formulae in the catalogue of the suppliers. The aim of this work is to provide some accurate formulae and computational methods for design to provide better awareness on the limitations and the potential of this type of connection. The work consists of five parts: (i) a review of the base calculation derived mainly from the catalogues of manufacturers; (ii) an improved calculation based on a new analytical method including the friction phenomenon; (iii) an experimentation run for validating the method; (iv) a case study applied to a machine tool; and, (v) a closed form formulation to determine an upper threshold for friction, thus ensuring the Hirth coupling regular performance.
Infrastructure monitoring and rapid quality diagnosis comprise the key solutions to achieve zero-defect smart manufacturing. The most fundamental systems in manufacturing industries are computer numerical controlled (CNC) tools. Automating and optimizing their functionality is a highly challenging task because complex dynamics and non-linear relationships govern the overall machining operations. Recent scientific advances in machining processes, incorporate intelligence in CNC tools to improve both the reliability and the productivity of the real-time cutting operations, while reducing waste and cost. This study extensively reviews these advances focusing on three fundamental aspects: Surface roughness prediction, tool wear prediction, and chatter detection in CNC cutting processes.
XYZ adalah salah satu perusahaan manufaktur yang bergerak dalam produksi komponen otomotif, produk yang dihasilkan yaitu Brake Lining dengan formula non-asbase diantaranya formula Lf-4, KN-356, NA-109F, NA-135, dan NA-146. Dalam menghadapi persaingan yang ada, PT. XYZ berusaha meningkatkan kualitas produk yang dihasilkan dengan target reject sebesar 0,5% pada tahun 2018. Permasalahan manajemen quality control yang ada di PT. XYZ salah satunya pada area hot-press nomor 11 dan 12 tidak pernah bisa mencapai target produksi dan seringnya keterlambatan barang dari area pre-forming. Sehingga perlu adanya penanganan segera dengan melakukan analisis perbaikan kualitas guna menghasilkan produk yang sesuai spesifikasi dan dapat mencapai target produksi yang ditetapkan oleh perusahaan. Metode yang digunakan dalam penelitihan ini adalah Statistical Process Control (SPC) dan Root Cause Analysis (RCA). Hasil analisis check sheet dan diagram pareto dapat dilihat frekuensi defect paling banyak terjadi pada formula LF-4 model K-2252 dengan jumlah cacat sebanyak 69 produk pada bulan Agustus sampai September dengan presentase reject sebanyak 19%. Serta dari gambar control chart P data dalam keadaan tidak terkontrol. Hal ini terjadi karena faktor manusia, faktor metode, faktor mesin, dan faktor material.
Modeling high dimension sensory data is a key issue
for Cyber-Physical Manufacturing Systems especially for milling
process due to: (a) Sophisticated characteristics of input signals
and (b) The complex procedure of processing sensory data. In
this paper, we provide an End-to-End data modeling platform
i.e., a multi-bias randomly connected recurrent neural network
that makes use of recurrent structure and multi-bias to achieve
efficient and accurate modeling performances. In order to tune
the parameters of the proposed recurrent neural network (RNN),
we apply a sampling method called Zoom-In-Zoom-Out (ZIZO)
that helps RNN to quickly find a set of appropriate weights.
We apply our technique to an empirical data set collected from
NASA data repository and show that our method provides more
precise and efficient results than existing methods.
