RKB BEARING KNOWLEDGE COLLECTIONS RKB Multi-Level Quality Control System for Rolling Bearings

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 2 RKB MULTI-LEVEL QUALITY CONTROL SYSTEM_4 2.1 Raw material supplier quality control 4 2.2 Pre-process quality control 6 2.3 In-process quality control 10 2.3.1 Forging quality control 12 2.3.2 Heat treatment quality control 12 2.3.3 Machining quality control 13 2.4 Post-process quality control 14

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 3 1 INTRODUCTION In this paper the multi-level quality control system for rolling bearings developed and implemented by the RKB Group is presented in detail. Along with state-of-the-art manufacturing technology, a well-organized quality control system is the other key element in the production of reliable and high performance products. Our quality control program is rooted in RKB top management’s insistence on quality and encompasses controls performed on multiple levels, from raw material...

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 4 2 RKB MULTI-LEVEL QUALITY CONTROL SYSTEM 2.1 Raw material supplier quality control The RKB Quality Control Bureau first comes into play during the raw material selection process. The choice of bearing steel is extremely important for bearing end quality, as this is largely depending on the technology used to produce steel (Fig. 3). This is particularly true for large size high-tech bearings, which are the core business of RKB, since the compliance to the international reference standards...

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 5 Fig. 4 – RKB raw material metallographic multi-test inspection protocol The RKB Metallographic Quality Control Laboratory (Fig. 5) performs regular checks on the incoming raw materials. Our advanced equipment and experienced personnel make possible the achievement of one of the most important tasks: the correct quantification of steel cleanliness. Fig. 5 – RKB Metallographic Quality Control Laboratory

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 6 Life prediction test is another important task regularly accomplished by our Mechanical Testing Laboratory to approve any new supplier of raw materials. By way of example, a contact fatigue life test was carried out to check the quality of the steels proposed by five potential raw material suppliers. The material test specimens were annealed and manufactured as washers, hardened in a gas protected electro-furnace between 835 and 845 „aC, and finally tempered between 150 and 160 „aC for 3...

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 7 Fig. 8 – RKB rolling bearing rings masterpieces production

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 8 Fig. 9 – RKB rolling bearing rollers masterpieces production

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 9 RKB’s decision of using masterpieces for all product lines rises from the need for more and more precise, and therefore reliable, products. The masterpieces are produced in the RKB Executive Headquarters and Technological Center (Fig. 10) in Balerna, Switzerland, by means of ultra-high precision machine tools endowed with the latest technologies. Fig. 10 – Machine tools in RKB Masterpiece Workshop in Switzerland The use of masterpieces permits to reduce manufacturing time and errors, ensuring...

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 10 2.3 In-process quality control The in-process quality controls refer to the controls performed throughout the strictly speaking “bearing manufacturing process”. They ensure consistency in product quality during all stages of bearing production by adopting modern quality control techniques in forging, heat treatment, machining and assembly. The two flowcharts from Fig. 12 and Fig. 13 present the production processes, and the related quality control steps (in orange), involved in rolling...

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 11 Fig. 13 – RKB rolling bearing rollers production

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 12 2.3.1 Forging quality control More in depth, after the raw material approval by the Product Approval Control Department, the forging process begins, encompassing steel bar or ingot cutting, heating, upset forging or upset pressing and rolling. Every steel bar or ingot lot enters the forging area accompanied by the related Control Data Sheet emitted by our Raw Material Warehouse that specifies the type and quality of steel and the dimensions and weight of the material. In this way, our technicians,...

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 13 Fig. 16 – Heat treatment quality parameters Fig. 17 – Measurement of heat treatment quality parameters 2.3.3 Machining quality control The quality controls connected to the machining process starts with the set-up of every machine tool according to the RKB production method. These settings are verified at regular breaks during production. At the end of every turning and grinding operation of rings and rollers, a check for compliance with the tight tolerances of masterpieces is performed....

RKB MULTI-LEVEL QUALITY CONTROL SYSTEM FOR ROLLING BEARINGS RKB BEARING KNOWLEDGE COLLECTIONS - No. 4/11 14 Fig. 19 – Measurements within integral calibrated system Specific non-destructive controls like the Magnetic Particle Inspection, for detecting superficial micro-cracks, and the Ultrasonic Micro-Crack Detection, for under-surface micro-cracks location, are regularly performed on rings and rollers during the production process (Fig. 20). Fig. 20 – Specific non-destructive controls Moreover, a visual check of the parts ready for assembly is always carried out to avoid any noticeable anomaly....