I 2.2 - AUTOMATIC GLAZING

Automatic glazing di Hers from manual glazing in that the use of machines reduces labour requirements and allows automation of glazing operations. Automatic glazing offers the advantages of excellent repeatability and, with breaks during work being unnecessary, better productivity; such improvements are often maximised by further automated quality control, conveying and handling systems upstream/downstream from the glazing stations.

There are two types of automatic glazing:

Electrostatic - features spray-gun units and electrostatically charged glaze;

Robotised - carried out via robots.

Several other machines are used to carry out automatic glazing; they will be briefly lescribed over -he following pages, in this chapter. More specifi< ally, we shall bt looking at the systems that allow the external parts of a sanitaryware item, and, to ,111 extent, its internal surfaces too., to be glazed. Phis IS achieved by way ol more sophisticated methods described in the next section.

12.2.1 Electrostatic glazing

This system consists of a turret w ith an array bank of (U-1 ti) spray-guns mounted on a reciprocato!* that allows vertical movement. The sanitarvware item is rotated on turntables so that all item parts can l>e reached by the glaze flow. The glaze is electrically charged (it is charged at l(K),(XX) Volts as it (lows into the spray guns;. Its charge is the opposite of that on the item surface; the piece thus attracts tin spray particles, aiding homogeneous coating of all parts. Throughput is very high {7OOO-1O0O pieces in 8 hours) because items are continuously fed into the booth on a conveyor.

Because spray-gun movement is limited, the system is not suitable for items characterised by highly complex geometry (i.e. with deep undercuts). Moreover, if the system is used for different models, the number of spray-gun must be adjusted before each new work cycle.

Date: 2015-04-20; view: 1296