A Method And Device For Multi-parameter Automatic Testing Of Green Moulding Sand

The detection and control of the components and main quality parameters of green moulding sand is always an important research subject in the field of casting.In this paper,a method for detecting water content and available clay content of green moulding sand based on the detection of DC conductivity of green moulding sand and artificial neural network calculation is proposed.In order to simplify the testing procedure,the DC electrical conductivity of green moulding sand is studied again on the basis of analyzing the research progress and existing problems of the testing device for performance parameters of green moulding sand at home and abroad.Research results show that DC electrical characteristics of green moulding sand with its main composition,moisture content and available clay content has direct correlation,but the functional relationship is complicated and the result is not the only,the introduction of the actual sand compactability correction parameters can be set for DC conductive characteristic parameters and moisture content and the corresponding relation of available clay content.In order to realize the multi-parameter integrated testing of green moulding sand,the multi-station work of the testing device is realized through innovative mechanism design.The mechanism is mainly composed of assembly frame,multi-station turntable,driving motor,feeding hopper,sampling cylinder,sample making head,sample making electric cylinder and auxiliary components.The coaxes of the sampling cylinder and the compact electric cylinder are fixed on the working surface of the assembly frame with different heights to ensure the stability of the sampling and strength testing station mechanism to the maximum extent.After the measured sand is quantitatively put into the feeding hopper and screened into the sampling cylinder,the compaction of sand samples,compaction rate test,DC conductivity test,air permeability test,wet compression strength test and waste sand sample cleaning are successively completed through the lifting of pressure head driven by electric cylinder and orderly cooperation with multi-station turntable clockwise rotation.A computer measurement and control unit based on STC89C52 microcontroller is designed to complete the action control and information parameter acquisition of multi-station detection device.The hardware part of the measurement and control unit mainly includes: SCM minimum system,PCF8591 A/D converter,various types of sensors and supporting circuits;The software includes LED display subroutine,scan key subroutine,A/D conversion subroutine,stepper motor control subroutine,servo motor control subroutine,artificial neural network model conversion subroutine and detection parameter calculation subroutine,etc.Under laboratory conditions,the use of the effectiveness of multi-station detection device for green moulding sand multi-parameter detection test,the output from dropping by sand to detection device,takes about 80 seconds,available clay content,moisture content and compaction rate,permeability and wet strength parameters and standard method of comparison,the average relative error are: 2.04%,1.32%,0.18%,4.57% and 4.21%.It is proved that the sand parameter calculation method and model used in this paper and multi-station detection mechanism are feasible.