Analysis And Design About Mould-cut Main Mechanism With Clearance And Control System Of Trade-mark Moulding-machine

Laser trade-mark moulding-machines are cried for by market. In order to satisfy the need of mould-cutting precision, it must be high-precision. In this paper, by means of combining theory about clearance with project, the theoretical analysis and numerical calculation are conducted for the kiematics and dynamics properties of the mould-cut main mechanism of trade-mark moulding-machine. In the end, the analysis and design about control system of this machine are given. The main content is in the following.A kinematics model is developed for mould-cut main mechanism of trade-mark moulding-machine and the displacement, velocity, acceleration and the corresponding curves of each joint point in a motion period are obtained. Then the analysis of dynamic statics about mould-cut main mechanism is given and the analysis about force of each joint point in a motion period is put forward.The analysis of precision about mould-cut main mechanism with clearances is advanced. On the basis of analysis of slider displacement error influenced by the crank length tolerance, the coupler length tolerance and clearances in revolute joints for mould-cut main mechanism, some reasonable suggestions about tolerance distribution of bars length and fitting precision of joints are put forward.Considering joint clearances at both ends of the coupler, a continuous contact model is developed by modeling clearance as a massless rigid link. A set of strongly nonlinear equations is obtained by using angle displacement of clearances in kinematic pairs as generalized coordinates.Four order Rong-kutta method is adopted to solve the dynamical equations of continuous contact model. With different clearance value, displacement curves and velocity curves of generalized coordinates as well as slider displacement error curves in a motion period are obtained. These curves are discussed. Results show that if manufacturing cost is kept invariableness, in order to improve precision of mould-cuting, fitting precision of joint connecting the crank and coupler has priority to be considered to increase.A Dissertation Submitted for the Degree of Master in Xi'an University of TechnologyA three-mode model is developed for mould-cut main mechanism with clearance of pair. In this model, condition is considered for modeling coupler as a rigid rod with two masses at each end. A set of dynamical equations is obtained by using respectively Lagrange's equation, momentum-exchange principle and coefficient of restitution for the sliding mode, the free-flight mode and the impact mode.This paper investigates the control system of trade-mark moulding-machine. Results indicate that the tensile force autocontrol equipment should be added. Unfold dynamic process of web is modeled and analyzed and a kind of tensile force autocontrol system is researched.