BTA – repeatable quality
Bearings are only seemingly simple mechanisms. Their internal structure, a very high sensitivity to the production accuracy, type of materials used, the method of thermo-chemical treatment components, challenges us, what and how should be checked to ensure they are repeatable quality.
The quality of the bearings is directly related with the quality of the materials they are made of made, the process of thermo-chemical treatment and the precision of all elements. Analysis of the frequency of typical failures was included in the quality control process. Based on the PARETO analysis developed quality plans to be implemented principles of continuous improvement. In order to fully use the potential of Statistical Quality Control, it is necessary, therefore take into account many parameters, both material and geometric. Important the question is the choice of research methods, yes to effectively detect inconsistencies.
Study of geometric parameters – dimensions and surface roughness
The bearings are very special narrow tolerance ranges execution. Down dimension control typical bearings and wheel hubs should therefore be used measuring devices that enable measurements geometric with accuracy to thousandths millimeters, or micrometers. Important is also the roughness of the raceway bearings. Way machining accuracy recent lapping operation will have significant impact on the friction resistance of the elements rolling resistance, too high resistance will increase the operating temperature of the bearing and consequently accelerated wear.
Shape testing – circularity and cylindricity
Shape errors of cylindricity or cylindricity cause distortion of the bearing raceway, stress concentration and jamming of parts rolling. This results in rapid bearing wear. In the process of research and control devices are used that allow mapping the surface of the rolling element raceway with an accuracy of 0.01 micrometer! Shape studies are crucial for detection of surface shape discrepancies which affect the silent operation of the bearings. In typical wheel bearings, the maximum difference in unevenness should not be exceed 5 micrometers.
Control test measurement card roundness of BTA bearings
The tested bearing is characterized by the correct distribution of unevenness, there is none abrupt faults, maximum difference rises is 1.84mm < 5mm.
Material research
Critical to load capacity and durability bearings have: the chemical composition of the steel and the type thermo-chemical treatment. Any errors in bearing manufacturing process are affected accelerated wear of the bearing surface layer. For example, incorrect selection grinding parameters results in a grid of micro-cracks on the surface, which can reduce life by 50%. To detect any incompatibilities of this type in the Labo-Tech laboratory was established full path of preparation of spare parts elements. Computer controlled cutter and grinder-polisher are necessary devices at the preparatory stages for microstructure research. Only after proper preparation samples, material tests can be carried out: hardness and microstructure of steel. Condition for the sale of bearings and wheel hubs is a positive transition of all both geometrical and strength tests. This is to work out the quality standards they must meet the bearing suppliers. Research is carried out periodically repeated so as not to drop product quality.
