Design Of A Portable Micro-destructive Sampling Machine Used In Small Punch Tests

This paper designed a kind of micro-destructive sampling device which used diamond wire saw as its cutting tool,the device can be used in SMT(small punch tests).First this paper briefly introduced the research background of SMT,and listed some micro-destructive machines including their disadvantages.Then a new method to design a micro-destructive device was put forward.The new sampling method use diamond wire saw as cutting mode,and on the base of this,the paper made a whole scheme design.The sampling device was divided into several function modules,and a process was made to complete the sampling task.According to the sampling scheme and the cutting process,the paper made a mechanical design of the sampling device.The device was divided into three main parts including slotting machine,wire cutting machine and cutting platform.The slotting machine took abrasive cutter as prototype,and the paper designed a tool setting apparatus to ensure the cutting depth.The wire cutting machine use diamond wire saw as its cutting mode,the paper designed the wire drive mechanism and added swing mechanism and tension control system.As for cutting platform,it's the working platform for slotting machine and wire saw cutting machine,its main structure includes guide rail and clamping mechanism.The requirements of the device control are high speed spinning,low speed feeding and constant tension with low temperature.The stepping motor is used as the driver for wire cylinder,spinning in high speed to improve cutting efficiency,while the wire saw moves in low speed to improve cutting precision.To keep the tension on the wire saw in a reasonable value and reduce the temperature of the working environment,the paper also designed tension control system and cooling device.This requirements are realized by the MCU STM32 including hardware building and software design.In the end,the prototype of the micro-destructive device was successfully made and was applied to sample on pipe surface,the test shown that the design was practicable and met the requirements of SMT.