Research On The Laser Liquid Level Detection Technology Of Mask Projection Stereo Lithography System

With the formation of economic globalization, in order to improve the competitionability, to meet customers various growing demand in the variety, quantity and delivery time,require enterprise has a strong flexibility of manufacture technology, and be able to productsmall and single batch without significant increase the cost of the production. The traditionalmethods can not satisfy the needs of the market, rapid prototyping came into being in thiscontext, raised the research upsurge in the world today.This paper keen on researching the Surface Exposure Of Rapid Forming Technique，itis one kind of the Rapid Prototyping Technology. Operating principle：through variousmeans put CAD model into data graphics, using ultraviolet light as the light source put thedata graphics exposure to the surface of photosensitive resin and Create view. Take the viewas the mask，and carry on selective curing，then congeries layer upon layer，finally formedparts model. The generator that created view have a best imaging position, only when theresin level keep in this position，can guarantee the precision of production parts, based on therequirement，this paper developed a set of resin level detection system，It is based on lasertriangulation measurement principle，choose red light semiconductor laser as light source，Use position sensor (PSD) for reflection spot’s change of position signal to detect liquid levelheight.First of all, analyse the error in the process of exposure of rapid forming，high precisionlevel detection system can reduce the error. According to the characteristics of the resin andthe resin level fluctuation factor，finally choose non-contact laser level assay, in-depth studythe assay method, introduce the one-dimensional PSD work principle and the principle oflaser triangulation method, and improve the laser triangulation method to meet therequirement of experiment.Secondly, design the level detection system overall scheme, and proceed hardwareselection and design to the level detection system on the basis of the scheme. Including thered light semiconductor laser selection, one dimensional PSD selection, PSD signalprocessing circuit design, data acquisition and display circuit design and the design of themachinery installation and commissioning, Designed circuit,make use of software renderingprinciple chart, drawing PCB circuit boards according to the principle chart, thecorresponding electronic components after welding, circuit board made complete.thenensure that these hardware in accordance with our requirements accurately firm installed onthe surface exposure rapid forming test bench, through the debugging can stable operation. Then, developed laser level detection system software system. according to therequirement of function and hardware circuit. Software using the modularized structure,realize of the data acquisition and processing and the basic display function. The resin liquidlevel height display through the liquid crystal display LCD line.Finally, carrying through linear calibration by using least square method to the PSD,and find out the better linearity part as a range. Through the resin level testing measurementin2mm range, maximum detection error is48.054μm, in the detection error permittedrange, show the rationality and reliability of design of laser level detection system.