Molding material flow speed measuring method and flow speed measuring device

Abstract

An optical fiber sensor (2) for projecting a light beam toward the flow front (F) of a molding material (M) passing inside a cavity (3) is installed on the cavity wall surface (4) of a mold (1). A calculating unit calculates the elapsed time representing the difference between a first detection time at which the sensor output of the optical fiber sensor (2) lowers and a second detection time at which the sensor output becomes stable on the basis of the sensor output and calculates the passing speed of the flow front (F) of the molding material (M) by using the elapsed time and a function defining the fiber diameter of the optical fiber sensor (2) and a function defining the shape of the flow front of the molding material (M). According to the invention, a molding material flow speed measuring method and device for measuring the flow speed of the molding material in a mold by means of a single small sensor, without needing to assemble two or more sensors and to use a special mold into which glass is incorporated such as a visualization mold is provided.

Description

technical field [0001] The present invention relates to a method and system for measuring the flow velocity of a molding material in a mold used in injection molding, compression molding, transfer molding, and the like. Background technique [0002] Currently, as a technique for measuring the flow velocity of a molding material in a mold, Japanese Patent Application Laid-Open No. 2000-102959 (Patent Document 1), Japanese Patent Laid-Open No. 11-165318 (Patent Document 2), Japanese Patent Laid-Open No. 11-165318 (Patent Document 2), and Publication No. 2002-160263 (Patent Document 3), Japanese Unexamined Patent Publication No. 9-19954 (Patent Document 4). [0003] In the molding material flow sensor disclosed in Patent Document 1, three detection devices consisting of strain gauges are installed in the cavity into which the molten material is injected, and the flow direction and speed of the material are calculated from the time difference of the material passing detected by ...

AI Technical Summary

Problems solved by technology

However, in such a technique, in the method (1) above, although the average speed between two points can be measured, it is necessary to bury a plurality of sensors close to each other, and it is necessary to accurately determine the distance between these sensors. In addition, the detection error It is also large, and there is a problem that accurate speed measurement cannot be performed.

In addition, in the method (2) above, a special model such as a visualization model is required, and there is a problem that the speed in a normal model cannot be measured.

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