REPORT TITLE

Screen conditioning

with feed FORWARD control

1997-04-04

TVR-654-97-EK/D054

PPD Glass and coatings

Philips Components

Abstract

Report no:TVR-654-97-EK/D054 Date: 97-04-04

Title:Screen conditioning

Keywords:Conditioning, coatings, feed forward control

Author(s):E. Keetels

Place a summary of the reports after this heading. Keep in mind that the summary is meant to enable someone to decide whether the report is of interest to him or her. Include purpose, intended audience, scope and conclusions. If there are many or long conclusions, dont include them all, but just the main points or state that they can be found in the report.

Summary and Conclusions:

Before application of screen coatings, the screen must be conditioned to a uniform temperature in order to realise a stable process and uniform distribution of the coating layer over the screen. The conditioning units that are presently used in all coating lines are not capable to fulfil these requirements.

For screen processing an alternative screen conditioning unit was developed by I. Durlinger [4]. This conditioning unit was modified and tested for conditioning of 17"CMT tubes.

An excellent homogeneous screen temperature ((T + 1(C) can be achieved with the tested conditioning unit.

The unit can be used for feed forward control: The heating time is dependant on the incoming temperature and the desired outgoing temperature. The heating times can be easily calculated.

The conditioning unit is almost independent on the starting temperature of the tube (Tested range Tin is 15 - 24 (C).

An equilibration time of approx. 1 min. is required to reach a stable temperature.

After equilibration the cooling rate is appr. 0.4 (C/min.

The total spread in average screen temperature is estimated as (T + 1 - 2(C.

Number of pages of complete report: 14

Place a list of copyholders of the Abstract between the Copylist abstract heading and the Copylist complete report (including abstract) heading:.

Copylist complete report (including abstract):

B. Meier, A vd Poel, H. vd Avoort, R. Hartman, J. Compen, H. v Huisseling, H. Meeske, S. vd Heijkant, W. Wakelkamp, P. Derks, B. Zwerver, G. Aben, I. Durlinger, H. Geurts, A. vd Voort, J .Heymbeeck, A vd Eeden (Aachen), G. Devulder, O. Salasca (Dreux), R. Lamprecht, M. Ebner (Lebring), L.Z. Lin, Y.M. Cheng (Taiwan).

1. Introduction.

Before application of screen coatings, the screen must be conditioned to a uniform temperature in order to realise a stable process and uniform distribution of the coating layer over the screen. The requirements for the conditioning process are:

( T between different tubes: + 1 (C

( T over screen: + 1 (C

The conditioning units that are presently used in all coating lines are not capable to fulfil these requirements. The capability of the present conditioning units was studied by H. Meeske [1,2]. Measurement with IR-camera in Dreux and Lebring show differences upto 14 (C within 1 screen

Also measurements of the temperature stability (temperature between different tubes) show differences upto 9 (C. This is one of the main problems for the poor process capability of IRIS coatings production (Cpk