The machining process of casting parts is different from products directly machined from steel rods. The raw cast quality has a significant impact on the machining cost, which mainly shown from the difficulty of machining, machining cost and machining quality.
Firstly, casting quality directly affects the difficulty of machining. The casting quality issues, such as pinholes, slag inclusion and cracks etc, will increase the difficulty of machining. The machining tool damage easily because of pinholes and slag inclusion, and cracks on the castings may cause work-piece fracture during machining. These problems not only affect the machining efficiency, but also increase the work-piece scrappage.
Secondly, casting quality affects the machining cost. High-quality castings could reduce machining time and repair work, thus reducing the overall cost. For example, the roughness and flatness of castings directly impacts on the machining allowance and time, high-quality castings can reduce the time and cost in grinding. In addition, the design of casting structure will affect the machining cost as well. Reasonable structure can help to reduce the waste of material and the difficulty of machining, thus reducing overall cost.
Lastly, casting quality have a great impact on machining quality. High-quality casting can guarantee the dimensional accuracy and surface quality after machining, thereby improving the performance of products and service life. For example, the improper wall thickness design of casting leads to stress concentration and deformation, which in turn affects the strength and stiffness of work-piece. So casting quality control is the key link to make sure the final product quality.
In summary, the impact of casting quality on machining is multifaceted, including increasing the difficulty of machining, improving machining cost and affecting machining quality. therefore, it needs to control the casting quality seriously during production, ensure to meet the required mechanical property and dimensional accuracy, in order to reduce the difficulty and cost in subsequent machining, and improve final work-piece quality.