Blade mounted on coconut shell crusher machine was frequently having damaged while being operated in making of coconut shell powder at small and medium industries. This took place repeatedly during the operation, therefore blade repairing and replacement has to be done for every 16 hours at the wear rate of 24.28%. A research was carried out to find out the cause of damage to the metal blade material on the coconut shell crusher machine. The scope of this research included the observation on visual examination, dimensions examination, chemical composition, hardness, and metallography. The results of observations and tests showed that blade was broken due to abrasion and deformation during operation. The metal material used for the blade was low carbon steel. Chemical composition of the metal content of the blade were: C (0.103 up to 0.144 %) and Mn (0.657 up to 1.400 %). Hardness value of blade metal materials were 146 up to 148 Hv. Microstructure consisted of ferrite and pearlite. This low carbon steel material is not suitable to be used as a blade on coconut shell crusher machines for producing of coconut shell. Repairing and maintenance of welding coating methods on blades using low carbon electrodes does not give increased significant value of hardness. Blade replacement in coconut shell crusher machines must comply with the requirements of tool steel with suitable heat treatment or the use of low carbon steel with the carburization process.

The small industry of casting aluminum alloy produces four-wheeled motorized tire rims that have been used in various vehicles. However, in general, these products do not yet have the quality and safety guarantees required by SNI 1896: 2008. Failure analysis research must be conducted to examine the causes of failure. The research method is to compare the products of small industry with products made by local and imported products by analyzing test results. Observation on visual and penetrant test showed porosity at the center of the rim. Tensile strength was (111-145)MPa much lower than local and imported product (260-285)MPa. The impact value was (500-570)kg (rim broken) and this value was lower than the SNI requirement (936 kg). The content of iron element was (0.401-0.433)%, this content was higher than local and imported rim (0.120-0.135)%. This element will cause a tendency to form micro crack and reduce the strength of mechanical properties. Microstructure observation showed a dendritic structure, porosity, and AlFeSi phase resembles needles. It was concluded that the failure of this rim product is caused by the material and the casting process. Small industries should make efforts to know the casting defects aiming to minimize product failure.

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