Analyze the problem of poor surface quality of parts in special CNC machining centers!
For laypeople who are not familiar with CNC machining workshop operations, once the chips stop flying, special CNC machining center parts fall off, and another precision machine tool part is launched, they may think that the final product is accurate and meets the specifications. Unfortunately, this is not always the case. In any relevant CNC machining workshop, the finished product will not be delivered to the customer until it passes the inspection service process. The dimensions of the parts must comply with the tolerances set in their design, including a thorough inspection of the smoothness of all machined surfaces.
In general, parts may meet specific dimensions, but they must be scrapped due to inadequate overall appearance and surface finish. This not only leads to aesthetic issues, but more importantly, it can have a negative impact on the functionality of the parts.
The most important thing is that in the final stage of milling and machining processes, the amount of work that must be sent to the trash can is less than expected. CNC machinists are naturally meticulous, proud of their work, and eager to see a complete project. The waste parts caused by surface smoothness issues may also become a real profit killer for the processing workshop. Poor quality can lead to increased costs, increased downtime, delayed delivery, and in the worst-case scenario, loss of orders.
1. Increase tool speed
Faster speed (in surface feet per minute) means shorter contact time between the material and cutting tools. This reduces edge accumulation that leads to poor surface smoothness and extends the service life of the tool. Tool failure is the main cause of damage to precision machined parts. Do not estimate or speculate on the speed required for your work.
2. Always clear/control the chip
Removing excess chips or stacked edges during the machining process and not allowing them to come into contact with the workpiece is a critical task, as well as the key to producing high-quality surface finish. Chips and BUEs are easy to accumulate, and if not removed, it can easily damage the surface smoothness of the tool. Chip breakers, compressed air, and the best solution, overflow coolant can be used to remove chips for better control and reduce scratches/damage to parts.
3. Rough machining and precision machining should use different cutting tools for CNC machining
Do not use the same tools as rough machining to complete CNC precision machining services. On the contrary, a small amount of rough machining tools should be used to remove most of the material, while newer and sharper tools should be retained and only used for precision machining. When used in conjunction with rough or precision machining tools, the tool blade radius, rake angle, feed rate, and blade material itself can bring higher quality.
For laymen, once the milling process is completed and the delivery date approaches, it seems only necessary to check the aesthetics of precision machined parts. A thorough inspection of the completed work, regardless of the material, is a key factor affecting the functionality of the parts. Especially suitable for the aerospace and medical device manufacturing industries. Excessive chips, slow running speed, and improper tool use are the main reasons for the decrease in surface smoothness. Lack of machine maintenance, low coolant volume, improper settings, and CNC programming errors are also reasons for this situation.
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