IGU, glass printing presentations end GANA fall conference
September 11, 2008
Bill Lingnell, Lingnell Consulting Services, Rockwall, Texas, gave an involved Thermal Stress Research Update for Insulating Glass on the last day of the GANA Fall Conference, Sept. 10, in Dallas. The update included an overview of thermal stress, thermal stress resistance, thermal stress evaluation, an edge strength failure prediction model, case studies for monolithic glass, plate and insulating glass units, a procedure for evaluating a specific IGU, and thermal stress parameters. General conclusions from the study: A numerical procedure has been developed that shows the magnitude of thermal stress in insulating glass; the procedure incorporates a thermal stress parameter table for each combination of insulating glass type and frame condition; for a specific unit of glass, the reflectance, transmittance, absorption and emittance for both inner and outer plates must be defined and spacer type is required; and to develop a generic procedure, dozens of thermal stress charts will have to be developed entailing a significant amount to be done.
Lingnell's presentation was part of GANA’s Insulating Division Meeting.
In the Decorative Division Meeting, Mike Young, regional sales manager for glass technology, Casso-Solar Glass Machinery Group, Pomona, N.Y., made a presentation on the Top Five Little-Known Secrets to Successfully Print Flat Glass.
“Glass is typically difficult to print on because it’s hard, smooth, shiny, clear, non-porous and fragile,” Young said. The five secrets to screen print on flat glass are: image-to-frame ratio, fabric selection, screen tension, squeegee length and floodcoater profile and length.
“Using larger frames will always improve print integrity and make crucial results easier to achieve, including ink uniformity and print accuracy,” Young said. And “smaller thread diameter or thinner mesh thickness yields less mesh interference for superior ink transfer, greater deposit uniformity and higher resolution.”
For suitable screen tension, “tension must be high enough, and maintained, to obtain exacting results and be checked prior to each job with a tension meter, both in the warp and weft direction,” Young said. Weakly tensioned screens will always allow background colors to “grin” through, producing an appearance of “color shift,” he said.
A long or small squeegee will result in uneven deposit of color, Young said. “Always use a squeegee that fits the job, not one that fits the frame.” And used creatively, a floodcoater blade or bar can be a powerful tool to manipulate deposit thickness and print’s finish without affecting registration, he said.
“Emulsion thickness would be the No. 6 secret to overwhelmingly improve the quality of print,” Young said.
Tracy Rogers, technical director, Edgetech, Cambridge, Ohio, presented a division video that goes hand-in-hand with IG 101. The script will be e-mailed to members for revision.
The Insulating Division Technical Committee Capillary Tubes Task Group talked about how both IGMA and GANA members will expand on IGMA's original document on capillary tubes. The document has been forwarded from IGMA to GANA and will be forwarded to the GANA task group members.