Development On New Vertical Apparatus For Measuring Five Strengths Of Molding Sand

Strength is one of the important physical property indexes of molding sand.At present,the strength of molding sand was measured widely by horizontal hydraulic strength tester.Due to the horizontal hydraulic strength tester adopt the way of the hydraulic oil,manual shaking wheel to load,and the hydraulic oil table to display measurement results,there are:(1)the results of hydraulic table is limited,and the display process is not intuitive enough;(2)in the process of testing,because the manual loading process is not stable and the no-load process generate high friction,so the data repeatability is poor;(3)the leakaging of hydraulic oil is easy to pollution tester and sand sample,and so on prominent shortcomings.According to the above situation,this paper developed a new type of vertical casting sand five strength tester.It can be used to test sand tensile strength,compressive strength,shear strength,bending strength and the splitting strength.The tester is based on the actual situation and the needs of the experiment,on the basis of the theory of molding sand micro deformation,and it is developmented in the light of the latest national standard GB/T2684-2009 standard sand strength test.The tester adopts linear electric push to load evenly for the standard sand under computer,using high precision pressure sensor to realize the accurate measurementthe for loading capacity(0~3000N),and by the high precision linear displacement sensors to realize real-time measurementthe for compressive stress and the displacement change,finally,measurement results recording and real-time curve drawing by computer.By replacing the five groups of measuring the strength of different pressure head,can realize the measurement of sand tensile strength,compressive strength,shear strength,bending strength and anti splitting strength of five kinds of parameters.The tester adopts vertical structure design,machinery is substituted by the installation frame,balance board,sand bucket,guide bar,pressure sensor,lineardisplacement transducer,linear electric putter,pressure head components etc.ADAM module as the core,the hardware system mainly include regulated DC power supply,pressure sensor,displacement sensor,signal conditioning,ADAM4117 module,ADAM4520 module,ADAM4050 module,relay board,electric putter,computer,etc.measurement and control system software of the tester is writed by the Visual Basic6.0,the human-computer interface is establish,it can realize in the process of sample loading stress data collection,display,storage,and other functions,and can automatically draw the pressure-time,displacement-time curve in real time.Finally,the clay sand and resin sand are respectively tested by using the developed vertical casting sand five strength tester and traditional horizontal strength tester,to test compressive strength,shear strength,splitting strength and tensile strength of.standard sample.Comparison results show that the error testing of compressive strength,shear strength and the splitting strength by the developed vertical casting sand five strength tester is smaller than hydraulic universal strength tester,this shows,on the compressive strength,shear strength and splitting strength of green sand performance parameters,the tester is superior to the universal hydraulic device,by contrast,the tester has high precision,good stability,and convenient operation.