Smoothing Press, Schaefer model SP, is a rotary lamination press (nip rolls) used to squeeze an adhesive coated sheet to a substrate. This smoothing press can be used to combine sheets that are coated with wet adhesive, or for the lamination of sheets using contact cements or film adhesives.
This laminating smoothing press has a fixed lower roller and a floating upper roll. The upper roll is designed to provide enough pressure to squeeze out bubbles,blisters, and wrinkles trapped between the substrates, giving a high quality lamination.
The nip pressure between the rolls is created by the weight of the upper roller. The pressure between the nip rolls is sufficient to squeeze air bubbles out of the layers of the lamination, but does not exert excessive pressure that would crush the flutes on corrugated or collapse foamcore board.
The floating upper roll can follow variations in substrate thickness while maintaining consistent nip roll pressure. Both nip rolls are powered to provide positive pulling force and eliminate any slippage between the layers of the lamination. The nip rolls are covered with urethane rubber for a positive grip and to conform to surface imperfections in the lamination substrates. Rolls can be separated for cleaning or shutdown periods.
The smoothing press is powered by a D.C. variable speed drive. Top speed is approximately 60 feet per minute, but it can also be operated at lower speeds to match the output of adjoining machinery.
Four versions of the smoothing press are available, with different maximum openings between the nip rolls.
SP Smoothing Press
The model SP smoothing press is designed for laminating of labels or paper face-sheets to substrates such as corrugated, chipboard and foam core board. The opening between the nip rollers can be adjusted from rolls touching to an opening of 1½ inches. The squeeze pressure between the rolls is the weight of the upper roll, which exerts a pressure of 2 lbs per linear inch. This is sufficient to create bubble-free laminations, but not so high that corrugated and foam core materials are crushed or deformed. The rolls are covered with a special non-tacky urethane rubber with other types of roll coverings available (see “other options” below). For laminating work requiring higher pressure between nip rolls, the SP can be equipped with the air cylinder option (see below) to increase the pressure between the nip rolls. With this option, the pressure between the rolls can be increased to approximately 500 lbs at 100-psi air pressure, and can be set at different levels by adjusting the air pressure on the cylinders.
SP3 Smoothing Press
The SP3 Smoothing Press is similar in design to the SP, but has the capability to open up to a 3 inch opening between nip rolls. It is used for foam lamination, lamination of rigid boards, or corrugated build-ups. This model is also available with the air cylinder option. When this model is equipped with the air cylinder option, pressure between the nip rolls can be up to 600 lbs.
SPL Smoothing Press
This model is built to allow the opening between the nip rolls to be adjusted to a 6-inch opening. The lower roll is fixed, and the upper roll is raised by means of two acme screws, both driven off a single handle. It is designed for foam fabrication or bonding of thick parts. Both upper and lower rolls are driven at the same speed. The SPL can also be equipped with the air cylinder option which allows the upper roll to have 1″ of vertical travel. When equipped with this option, the force on the upper roll would be approximately 500 lbs at 100 psi pressure.
ACP – Assembly Compression Press
For some types of assembly work, higher squeeze pressures are required. To meet these needs, the arms that hold the upper roll are changed to a style that connects to air cylinders, giving the upper roll the capability to exert a much higher squeeze pressure. The initial opening between the rolls is still adjustable and the squeeze pressure can be adjusted by setting the air pressure on the air cylinders. On the standard assembly compression press this option increases the pressure between the nip rolls to approximately 800 lbs (at 100 psi air pressure).
When the air cylinder option is installed on the smoothing press, a special guard and guard control circuit are added as well. A hinged guard plate is put in front of the roller nip point, and if the guard plate is moved, the rolls stop and open up. After activation, the machine can be re-started by depressing a reset button.
In many cases, the smoothing press can be adapted to particular process requirements. It is possible to add wipers for the rolls or utilize the press as a pulling device for sheets of material. Welded stands with locking casters are also available as an option. Stainless Steel rolls or rolls covered with other types of rubber (such as silicone) and in different hardnesses are also available as options.