In the field of CNC machining, tool change time is one of the key indicators affecting the machining efficiency of turret lathes. Excessive tool changing time not only reduces the output per unit time, but may also affect the stability of the production cycle. Tracing back from multiple aspects such as equipment design, operation and maintenance, to operation management, the root causes of long tool changing time can be summarized into four categories: mechanical structural wear, control system lag, unreasonable turret configuration, and non-standard operating procedures.
The wear and excessive clearance of mechanical structures are the most common root causes. The indexing mechanism, positioning components, and driving parts of the turret will gradually experience accuracy degradation during long-term high-frequency operation. For example, when the clearance between the indexing plate and the positioning pin exceeds the design threshold, additional adjustment actions will be generated when the turret rotates into place; The aging of the sealing of hydraulic or pneumatic components in the turret clamping mechanism can lead to a decrease in clamping speed, thereby extending the tool change cycle. In addition, problems such as loose connection between the knife holder and the knife tower, poor lubrication of the guide rail, etc. will increase the resistance to movement, causing a decrease in the start stop and rotation speed of the knife tower.
The parameter settings and signal transmission issues of the control system can also cause delays in tool changing. Some equipment did not reach the designed motion state due to unreasonable initial parameter configuration, conservative settings for turret rotation speed and acceleration/deceleration time; The signal interference between the control system and the turret drive module can cause a lag in command response, resulting in the phenomenon of "delayed action of the turret after the command is issued". In addition, the redundant design of tool changing logic in PLC programs, such as redundant detection steps, will also increase the total time consumption of the tool changing process.
The mismatch between turret configuration and processing requirements is a root cause that is easily overlooked. If the number of tool positions in the turret is insufficient, frequent tool loading and unloading replacement is required during the machining process, naturally extending the total tool replacement time; However, the type of tool holder is single and cannot adapt to multiple specifications of tools, resulting in the need to adjust the fixture and increase auxiliary time when changing tools. At the same time, the tool pre adjustment accuracy is insufficient, and after installation, it needs to be repeatedly adjusted on the machine tool, which indirectly prolongs the tool changing process.
The non-standard operation process further exacerbates the time required for tool changing. The operator did not strictly follow the tool pre adjustment process and transferred the tool setting process to the machine tool; Or the storage of cutting tools is disorderly, and searching for tools when changing them wastes time. In addition, inadequate daily maintenance of the equipment and failure to regularly clean the chips inside the turret and inspect the lubrication system can lead to frequent mechanical failures, indirectly prolonging the tool change time.
Overall, the prolonged tool changing time of CNC turret lathes is the result of multiple factors. Improvement plans need to be developed from four dimensions: mechanical maintenance, system optimization, configuration adjustment, and operational standards in order to fundamentally shorten tool change time and improve equipment processing efficiency.