Modelling of Vacuum Holding Force in Pick-and-Plce Machine

Abstract

Presently manufacturers of surface mount assembly machines used predefined solutions for vacuum nozzle selection and acceleration level according to the package size. Usually this results lower production efficiency than maximum possible. The focus of this research is to make pick-and-place machines more intelligent in a way to determine operational parameters based on the input values of vacuum level and package size. Based on experimental data, mathematical model was developed which from the input values of vacuum level and package size, determines operational parameters, such as nozzle selection and acceleration level, hence minimizing operators influence. MYDATA MY9 pick-and-place machine used in this work is equipped with two placement units; single and multi nozzle unit. Different nozzle materials are used at the nozzle tip such as plastic, rubber, ceramic and steel. The model is based on experimental data regarding Area of Contact, friction coefficient, acceleration, and off centred pick-up, after which compensation factors are included into the basic Newtonian law. Using MATLAB® script based on the mathematical algorithm, a case study was done to validate the model. The solutions regarding nozzle selection and acceleration level, obtained from the case study, proved increase in operational range of the nozzles, resulting with 8% to 11% lower cycle time for PCB assembly.