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Surface finish variation of common workpiece defects in CNC machining and milling

Posted by: Mu Ju 2021-10-30 Comments Off on Surface finish variation of common workpiece defects in CNC machining and milling

One of the common problems when Cnc milling is used in mold machining is the surface finish. There are many reasons for the poor surface quality or change of the workpiece processed by the mold:

The first reason is that the tool is too blunt. A blunt knife will deform the workpiece more. This will result in an increase in the cutting force, and as the deformation accumulates, the cutting edge will go deeper into the part, leaving a small hole if the chip breaks suddenly. This will greatly reduce the surface finish of the die parts.

Another reason is CNC milling strategy. There are two milling strategies: climbing and conventional. The first strategy is that the rotation direction of the tool is consistent with the feed direction of the worktable. When using climb milling, the tool will be impacted into the workpiece, and then exit the workpiece slowly with the least material (the surface created after machining). This produces a good surface finish. When the number of revolutions is opposite to the feed direction, conventional milling will be carried out. In this way, the tool enters the workpiece from the finished surface. Due to slight vibration and process changes, the tool may slightly damage the surface of the finished part. However, this is enough to change the final surface finish

The final reason for the poor surface finish of the die parts is the improper selection or lack of coolant. Many people underestimate the effect of coolants and lubricants, in fact, the use of appropriate coolant lubricants can improve the quality of the entire surface.


In order to achieve the highest possible surface finish of the die part, you should maintain the cutting tool, use the correct strategy and pay attention to the selection of the appropriate coolant.

Surface burn of common workpiece defects in CNC milling

Surface burn refers to burn along the surface of processed parts. Burn means that the workpiece is overheated.


The wrong cutting parameters will lead to the defects of the workpiece processed by the die. Improper selection of feed and speed can seriously damage the workpiece, cutting tools and even the machine itself.

terms of settlement:

One way to solve this problem is to reduce the cutting speed and feed ratio. Slow down the processing and reduce the temperature.

Another way is to increase the cooling rate in the process. In some extreme cases, such as titanium with poor thermal conductivity, both methods are necessary.



About PTJMould Industrial Company Limited

PTJmould is a China mold maker of plastic molds- injection mold, die casting moulds, plastic blow molding, rotational molding, medical plastic injection molding, two shot plastic injection molding, insert molding, overmolding, metal injection molding, micro injection molding, powder injection molding, ceramic injection molding, liquid injection molding, husky injection molding, household mold, casting mold, die mold tool, custom molds, china moulds, rapid prototyping tooling, plastic prototyping tooling, punch press tooling, die and tooling for mobile/ cell phone parts, automotive parts, vacuum cleaners, rechargeable tools, telephones, copiers, computers, multimedia speakers, and many other electronic products and household appliances. And also a plastic product manufacturer, mold manufacturer China– plastic parts, plastic water tank, plastic balls, plastic containers, plastic buckle, plastic anchor, plastic hanger, plastic spoon, plastic pipe fitting, plastic tumble, plastic tableware, plastic cups, plastic bottles, plastic tray, plastic cosmetic container, plastic case, plastic food container, plastic chairs, plastic caps, plastic cap closure, plastic tubes, plastic water pipes, plastic knobs, plastic tubing, plastic utility boxes, plastic racks and so on.

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