To solve difficulty of on-line measurement

a double-conical arc tool lapping pressure measuring instrument based on leverage is designed

also a mathematical model of lapping pressure between the arc tool and disc is established.The instrument uses cantilever load cell

and applies DSP2812 as main control chip

which achieves online acquisition

processing

storing and real-time display of lapping pressure.Experiments show that the precision of the instrument is prior to 0.15N and changing range of lapping pressure reduced by 28.8 %.The instrument is stable and has good practical value that can provide the support for manufacture of high quality arc tool and grating ruling.