Why do we need to leave machining allowance on CNC machining parts?
With the emergence of various processing technologies in the market, they have gradually become familiar to us, or we have come to realize that CNC machining is still a commonly used processing technology in industry. But according to many users' feedback, there is a machining allowance left on CNC machining parts during production. Why do we operate in this way? The following is an introduction to the titanium processing parts company for everyone.
The thickness of the metal layer cut off in each CNC machining process is called the machining allowance between processes. For the torsion of outer circles and holes, the machining allowance is considered based on the diameter, so it is called symmetrical allowance (i.e. the allowance on both sides), which means that the actual thickness of the metal layer cut is half of the machining allowance on the diameter. The machining allowance of a plane is the unilateral allowance, which is the actual thickness of the metal layer cut.
The goal of residual machining allowance for workpieces is to remove the machining errors and external defects remaining in the previous process, such as the cold hard layer, porosity, interlayer, external oxide skin of forgings, decarburization layer, external crack, internal stress layer and external roughness after cutting. Then, improve the accuracy and external roughness of the workpiece. The size of machining allowance has a significant impact on machining quality and production capacity.
Excessive machining allowance not only increases the labor volume of mechanical processing and reduces productivity, but also increases material, target, and power consumption. CNC machining has improved processing costs. If the machining allowance is too small, it will be too late to eliminate various defects and errors in the previous process, and too late to compensate for clamping errors during the processing of this process, forming waste. The standard is to minimize allowances while ensuring quality in CNC machining. Generally speaking, the more processing, the less process margin.
When determining the CNC machining sequence, it is necessary to clarify whether the parts are pre processed before processing. Pre processing is often completed by ordinary machine tools. If the precision of the blank is high, the positioning is also reliable, or the machining allowance is abundant and uniform, it can be directly processed on a CNC machine tool without pre processing. At this point, it is necessary to consider the differentiation of CNC machine tool processes based on the accuracy of the rough benchmark of the blank, so one process can be completed by dividing it into several processes.
