In the scenario of mass production of components, the core of optimization for China's machinery industry revolves around three goals: "shortening the single-piece production cycle, enhancing processing consistency, and reducing overall costs". It is not a single adjustment but a systematic optimization from process design to on-site execution.
Firstly, the integration of processes is carried out. Relying on the power tool turret of CNC lathes and the Y-axis function, processes that originally required multiple equipment or multiple clamping operations can be combined. For example, the original process needed to first turn the outer circle and then reverse the clamping to drill the side hole. After optimization, through one clamping operation, the power tool head directly completes the drilling, tapping, and other processes, reducing the positioning error from two clamping operations and stabilizing the coaxiality and other geometric tolerances within 0.02mm. It also saves about 30% of clamping and production changeover time. For components with an annual production volume of tens of thousands, the compression of single-piece working time directly translates to an increase in production capacity.
Secondly, the scientific matching of cutting parameters is carried out, which requires considering the cutting tools, workpiece materials, and equipment rigidity, rather than blindly pursuing high indicators. When processing 45# steel for rough machining, using coated hard alloy cutting tools, setting the back clearance to 2-3mm, feed rate to 0.3mm/r, and cutting speed to 150m/min, the cutting efficiency is improved by more than twice compared to traditional high-speed steel cutting tools; in the finishing stage, using small allowances (0.2-0.5mm) and high rotational speeds (above 200m/min), ensuring a surface roughness of Ra1.6 or less, while stabilizing the tool life. For mass production of components, the tool change time accounts for 10% of the single-piece working time. With stable tool life, the tool change interval can be increased from the original 50 pieces to 200 pieces, indirectly reducing equipment downtime.
The optimization of the clamping process is the key to improving efficiency in mass production. The clamping time of a common manual chuck is usually 15-20 seconds per piece. By replacing it with a hydraulic pneumatic-driven automatic chuck, combined with soft jaws for pre-processing, the single-piece clamping time can be compressed to 3-5 seconds. For the mass production of specific components, a dedicated quick-change fixture can be designed, such as a rapid positioning structure combining positioning pins and V-blocks. The workpiece does not need additional alignment but only needs to be aligned to complete the clamping. For slender shafts, a hydraulic center frame that can follow the tool can be used, avoiding processing vibrations and ensuring straightness, while reducing the scrap rate from 2% to below 0.5%.
The optimization of NC programs and inspections is also important. Using CAM software to simulate the tool path, optimizing short paths for rapid movement, shortening non-cutting time; using subroutine calls to handle repetitive drilling and tapping processes, reducing the error probability; introducing an online measurement system, after rough machining, the outer diameter can be directly measured, automatically adjusting the finishing allowance, without the need for machine downtime for manual inspection, the dimensional consistency of each batch of workpieces can be improved by about 15%, and the inspection time proportion can be reduced.
Equipment maintenance and blank selection are the foundation for the implementation of optimization. Establish a preventive maintenance system, regularly inspect the accuracy of the tool turret and the gap of the guide rails to avoid sudden machine stops; blanks should preferentially use cold drawing or precision forging parts, compared to hot-rolled parts, the cutting allowance is reduced by more than 40%, directly shortening the cutting time; under the premise of meeting performance requirements, using easy-to-machine materials can further improve tool life and efficiency. These measures work together to compress the single-piece CNC processing time from the original 1 minute to within 30 seconds, reducing the overall cost by about 40%, and truly achieving efficient and stable operation in mass production.
China machinery industry https://www.hexincnclathe.com/the-machinery-industry-maintained-stable-production-and-operation-in-the-first-five-months.html