Research on rigid flexible coupling dynamic characteristics of clamping unit in injection molding machine（a）

Date：2014/11/3 16:48:09

The clamping device is one of the most important parts of precision injection molding equipment, its function is to achieve the opening and closingmovement of the mould is closed, the elastic deformation generated systemto the clamping force, mold locking. Five oblique double toggle type mould clamping mechanism is the current domestic and foreign precision injection molding equipment widely used structure form, its characteristic is good movement performance, rigid body, clamping speed, through the self-locking mechanism characteristics of locking die.

Design of double toggle clamping mechanism, long-term since the mainexperience, mainly by manual calculation, calculation model of rough,conservative design. At present, designers often unilaterally by means of finite element software on static mechanical locking mechanism analysis, orthe establishment of the mathematical model of mechanism motioncharacteristics. Kinematic analysis of the key components of structural analysis and mechanism of double toggle clamping mechanism are isolated from each other, it is difficult to explain the problem of mutual couplingdeformation locking mechanism of large displacement clamping motion and small displacement, so it is necessary to carry on analysis and Research onthe rigid flexible coupling dynamics of the clamping mechanism of injection molding machine for double elbow.

In this paper, the combination of Solidworks and ADAMS software, to flexible multi-body dynamics as the theoretical basis, key parts of flexible compounddie mechanism, set up a certain type of injection molding machine double toggle clamping mechanism of rigid flexible coupling multibody dynamics model. We could get the motion behavior of die mechanism and dynamic characteristics of simulation, and provide the scientific basis for the design and optimization of Engineering mould clamping mechanism.

1 rigid flexible coupling dynamics theory foundation

The rigid flexible coupling model modeling theory is based on the multi body dynamics theory of flexible body.

1.1 flexible body coordinate system

In the flexible body system, coordinate system consists of two parts, the inertial coordinate system G (ER) and the moving coordinate system B (EB),P'after deformation coordinates of the point P. Inertial coordinate system is fixed, does not change with time. The moving coordinate system established in the flexible body, used to describe the movement of flexible body. The moving coordinate system relative to the inertial coordinate system arelimited motion and rotation. Coordinate the moving coordinate system in theinertial coordinate system as the reference coordinate.

1.2 flexible body of any point on the displacement, velocity and acceleration

Analysis of plane motion of rigid body, can take the plane motion of a rigid body complex is considered as a combination of several simple movement.In the analysis of flexible body motion especially under the condition of smalldeformation, can also use a similar analysis method. As a flexible body from the coordinates of L1 movement to coordinate L2, its movement can be regarded as rigid move, rotate and combination deformation of three kinds of motion. For an arbitrary flexible body on the point of P, the displacementvector:

R=r0+A (sp+up) (1)

In the formula, R is the P vector in inertial coordinate system; R0 vectorcoordinate origin is floating in the inertial system; A is the direction cosine matrix; SP is the flexible body without deformation P vector in the floatingcoordinate system; up P unit relative deformation vector, with the sameplane problem discussion the up can be obtained by different discretization methods. For some P, can be used to describe the deformation modal coordinates of the unit, i.e.:

Up= P in diameter and QF (2)

In the formula, P diameter as point P conforms to the Rizki vector requires the assumption that the deformation mode of matrix; QF is the deformation of the generalized coordinates.

The 2 locking mechanism of rigid flexible coupling model

The multi rigid body system dynamics modeling of 2.1 clamping mechanism

A hydraulic injection molding machine with double toggle clampingmechanism as the research object, using Solidworks three-dimensional modeling software to establish the main parts of mould clamping mechanism of template, rod, toggle etc. the entity model, simplified assembly, get thelocking mechanism of three-dimensional entity model.

The 3D solid model is imported into MSC.ADAMS, define the part material properties, according to the connection and restriction relation among partsof locking mechanism applied constraint pair, established the analysis model of mould clamping mechanism of multi rigid body dynamics. Using ADAMS in the fixed vice, a rotating pair, ball hinge movement pair,constraints imposed on the model, several basic side used to eliminateredundant constraints. Model constraints include: 16 fixed side, 6 rotating pairs, 4 ball hinge, 1 mobile side, 5 point line side, 4 side, 1 parallel vice.

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