Research On The System Of Resin Level Detection On-line In Stereolithography

Stereolithography (SL) has been researched earliest in Rapid Prototyping (RP), which can generate parts with high accuracy and has been widely used. The technology of resin level and control is one of important component in the resin recoating system of SL, which make great effect in improvement of SL stability, efficiency, precision, Therefore the research on the resin level detection is meaningful and valuable.Based on the research of many kinds of resin level detection and control techniques at home and abroad, the paper adopted the high precision of position sensitivity detector(PSD) as the detect component, and detected the resin level on-line based on the principle of laser triangular surveying. The paper analyzed the basic process of the resin detection, selected and designed the hardware for the system, designed the application software for the system at the same time, which can accomplish the display of the resin level through graph and digital; designed the mechanical equipment for the system, which make various components of the system at accurate position, also make the system install on the SL apparatus reliable, stable and adjustable.In order to amend the non-linear error of the PSD, insure the precision of the resin level system, designed the special equipment for calibration demarcation experiment, and calibrated the PSD and the whole system, using the mathematics model of the least squares linear to fit the experiment data. Meanwhile, validated the precision of the system and analyzed the factors which generate the system error. The precision experiment proved that the system can tell apart 10μm of resin level fluctuation, and the error within 3μm, which can meet with the precision requirement for SL.At last, a new resin level control method was put forward, it can be use the system of resin level detection combined with the overflow control level method on SL apparatus to detect and control the resin level, which can change the shortcoming of the control method at present, improve the precision of the resin level control and enhance the accuracy of the parts accordingly.