| Polycrystalline diamond(PCD)tools are widely used in precision and ultra-precision cutting due to their high hardness,good wear resistance and low thermal expansion coefficient.Brazing is an important part of PCD tool manufacturing process.High frequency induction brazing has been the main brazing method of PCD tools on account of less investment in equipment,fast heating rate,safety and low pollution to the environment.At present,the traditional manual brazing method is still used for the brazing of PCD tools in China,which has low brazing efficiency,high requirements for operators,high labor intensity and unstable brazing quality.Therefore,in order to fill up the blank of the country,the hi-frequency induction automatic brazing device for PCD tools is designed and studied in this paper.Firstly,the mechanical structure of high-frequency induction automatic brazing device for PCD tools is designed by referring to the manual brazing process.The device includes position conversion mechanism,positioning clamping mechanism,pressing mechanism,transverse inlet-out mechanism,horizontal and vertical adjustment mechanism.The cam mechanism is skillfully used to realize the automatic clamping and loosening of tools.The positioning structure meets the requirement of complete positioning.The pressing mechanism is driven by crank and slider,and the force sensor is integrated into it,so that the brazing pressure can be adjusted accurately.At the same time,the pressing mechanism can adjust the pressing angle to meet the requirements of PCD tools with different blade inclination angles.In addition,the automatic brazing device is designed in detail.Processing and assembly are carried out according to the design drawing.After debugging and improvement,the device fully meets the design requirements.Afterwards,the control system of automatic brazing device is designed with STM32 microcontroller as the control core.The control mode includes manual mode and automatic mode,which can control and adjust the automatic brazing device under different conditions.Serial touch screen is used as man-machine interface to set and modify brazing process parameters.It is easy to operate and convenient to adjust.Finally,the brazing test was carried out with automatic brazing device,and the brazing seam of brazed specimens was observed by means of ultra-depth-of-field microscopy.The results show that the edge inclination error of automatic brazing tool specimen is less than 1 degree,which meets the requirement of brazing accuracy.The measured thickness value of brazing seam is substituted into empirical formula to calculate the shear strength of automatic brazing tool specimen,and its size meets the usage requirement of PCD tool.Therefore,the designed hi-frequency induction brazing device for PCD tool meets the design requirements.In addition,compared with manual brazing samples,it is found that the brazing quality and consistency of automatic brazing PCD tools are improved. |
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