General description

When you let the glass substrate loose by releasing vacuum suction that was holding the substrate onto the work table, the glass substrate may fracture.Since this is mainly caused by a shock of the rapid release of vacuum suction, it can be avoided by controlling the vacuum release gradually.

Explanation

・To make the glass substrate lightweight and cheaper to produce, the substrates are becoming thinner and larger.This trend is also making the glass substrates more susceptible to fractures during vacuum suction and release.In order to shorten the production cycle time, the vacuum suction and release may be performed in a shorter period, which causes more fracture accidents of the glass substrates.This section introduces the countermeasures for preventing glass substrate fractures by controlling the vacuum suction release.

(1)Causes of glass substrate fractures during vacuum suction release

・If the rate of vacuum release changes rapidly from the state it was suctioning the glass substrate, air may gush out from a small suction hole of the vacuum suction mechanism.
・This localized air pressure and rapid vacuum release will impact on the glass substrate, causing the substrate to fracture.

(2)Countermeasures for preventing glass substrate fractures during vacuum suction release

・To avoid the glass substrate fractures by the shock of vacuum release, it is effective to adopt the vacuum suction control design where the initial vacuum release occurs gradually in order to alleviate the shock from the release, followed by the time and speed control method until the release holes are fully open. (Fig.1)