Quality Control in the Machining of Cylinder Liners at Repair Enterprises
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ity Control in the Machining of Cylinder Liners at Repair Enterprises O. A. Leonova, *, N. Zh. Shkarubaa, Yu. G. Vergazovaa, P. V. Golinitskiya, and U. Yu. Antonovaa aRussian
State Agrarian University—Moscow Timiryazev Agricultural Academy, Moscow, Russia *e-mail: [email protected] Received February 13, 2020; revised February 18, 2020; accepted February 25, 2020
Abstract—The use of the following quality-control instruments in the machining of cylindrical liners at repair shops is considered: Shewhart charts (of moving-range and individual-measurement types) and histograms for analysis of the adjustment precision. A monitoring checklist has been developed for determining the losses due to all defect types. Interchangeability among groups for piston–liner assemblies completely eliminates wasted inventory. Keywords: quality control, monitoring instruments, cylinder liners, pistons, selective assembly DOI: 10.3103/S1068798X20090105
Repair shops play an important role in ensuring that complex systems remain in a working condition [1]. The quality of repair depends on many factors. In particular, monitoring detects faulty products and prevents their delivery to the customer [2]. Production at the repair stage differs from manufacturing production in the quality of the initial components and assemblies. The mobile machine parts sent for repair are worn, with near-limiting gaps [3]. Disassembly and assembly decrease the tightness of immobile machine joints [4]. There is a direct relation between the accuracy and reliability of joints [5, 6]. Therefore, the life of repaired systems is less than that of new systems. In repair, difficulties also arise in meeting the standards in a unified system of fits and tolerances [7]. Statistics show that the quality control methods and instruments employed at leading manufacturing enterprises permit the resolution of 80–95% of the problems encountered. However, they are not often used in smallscale production and production for repair. The introduction of quality control methods and instruments depends on the availability of reliable data on waste and losses; and on timely corrective and preventive measures to reduce inconsistencies in production. The quality of industrial processes, parts, and subassemblies also depends on optimal measuring systems, so as to decrease the risk of internal and external losses [8]. In the present work, the goal is to improve the machining quality of cylinder liners in repair by means of quality control instruments, with the elimination of wasted inventory on the basis of interchangeability among groups. We have developed a generalized method of employing quality control methods at repair shops and determining the primary monitoring points (Fig. 1): • MP1: monitoring of finishing;
• MP2: monitoring of defects in the worn liner in terms of accuracy (internal diameter and shape deviation, consistent diameters of the upper and lower centering bands, height from the top to the supporting rim) and mechanical parameters (scratches, cracks, and pores); • MP3: f
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