Screen printing squeegee pressure

Fig 1 Scheme of the screen-printed process a typical thick-film screen consists of a finely woven mesh of stainless steel, nylon or polyester, mounted under tension on a metal frame, normally aluminium. The screen defines the pattern of the printed film and also determines the amount of paste which is deposited. The mesh is coated with a ultraviolet sensitive emulsion (usually a polyvinyl acetate or polyvinyl alcohol sensitized with a dichromate solution) onto which the circuit pattern can be formed photographically. The ink is placed at one side of the screen and a squeegee crosses the screen under pressure, thereby bringing it into contact with the substrate and also forcing the ink through the open areas of the mesh. The required circuit pattern is thus left on the substrate... 

Microcapsules (according to Section 2.4.6) were coated onto various textiles using the semi-automated screen printing machine RokuPrint SD05, with 4 bar pressure applied onto the squeegee. Printed samples were cured at 140 °C for 6 min. 

Apply paste to the screen and adjust the velocity and alignment of the print as necessary to optimize the definition and thickness of the print. The squeegee pressure adjustment should be used as a fine control. 

Fix a pattern template to the work-table with tape (position the pattern in the correct place with a screen placed in the printer frame and tape it to the table). Using a sharp probe, punch through the acetate over the holes in the work-table to allow the vacuum to be applied to the substrate. The substrate is surrounded by a piece of Melinex or PVC of the same thickness (taped to the work-table) so that the pressure between the squeegee and the working surface is even throughout the print stroke, and an even thickness of the printed layer is achieved. 

A pneumatic pump feeds the printing paste and a sensor helps ensure that its level within the screen is kept fairly constant application of the paste is by adjustment of the squeegee relative to the counter-pressure roller. 

Usually, for good printing, the tip of the squeegee blade should be arranged opposite the centre of the counter-pressure roller—where contact is made with the screen. Its vertical adjustment should be checked carefully on both sides of the screen to ensure an even alignment across the width. If coating with PVC, so as to raise the application weight, the tip can be placed above the centre of the counter-pressure roller. 

Zimmer flatbed printing machine (Peter Zimmer) - A carpet printing machine that uses flat screens and dual, metal-roll squeegees. The squeegees are operated by electromagnets to control the pressure applied. The unit also has a steamer for dye fixation. The Zimmer flatbed machine is normally used for carpets of low to medium pile heights. Very precise designs are possible, but speeds are slower than with rotary screen printers. 

Zimmer rotary printing machine (Peter Zimmer) - A rotary carpet printing machine in which each rotary screen has a slotted squeegee inside to feed print pastes through the screens to the carpet. Pressure of the print paste is adjusted by hydrostatic head adjustments. 

Zimmer Rotary Printing Machine (Peter Zimmer) — A rotary carpet printing machine in which each rotary screen has a slotted squeegee inside to feed print pastes through the screens to the carpet. Pressure of the print paste is adjusted by hydrostatic head adjustments. (Fairchild s dictionary of textiles. Tortora PG (ed). Fair-child Books, New York, 1997 Tortora PG, Merkel RS (2000) Fairchild s dictionary of textiles, 7th edn. Fair-child, New York Complete textile glossary. Celanese Corporation, Three Park Avenue, NY, 2000 Elsevier s textile dictionary. Vincenti R (ed). Elsevier Science and Technology Books, New York, 1994)... 

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