MONOLAYER CAST FILM LINES
INTRODUCTION: Extruded cast film is defined as film less than 0.010 inch thick. Cast films are made by an extruder that melts and pumps the polymer through a slot die. The polymer is then pulled from the die (becoming thinner as it is drawn) and cooled continuously on chilled rolls. Randcastle Cast Film Lines make film from 2 to 20 inches wide making them ideal for research, development, quality control, and thermoforming applications.
EXTRUDERS: Randcastle is a technology driven company focusing on small diameter extrusion lines. Our cast film lines start with the patented Microtruder vertical screw extruder. Microtruder screws are two to four times stronger, feed much better and surge far less than other small bore extruders. Our patent pending Recirculator turns your single screw into a superb compounder with multiple elongational flow fields for direct compounding. . Randcastle’s exclusive smooth bore feed sections are an unparalleled tool to enhance your processing flexibility. Add our in-line rheometer to measure the melt viscosity and establish relationships between flow and film properties.
SLOT DIES: The next part of a cast film line is the die. Our flexible lip slot dies are engineered with a unique interchangeable distribution manifold. A manifold is the major polymer distributor in a die so it must match the polymer viscosity. Change the manifold to suit viscosity of your polymer for maximum processing range. Remember, a fixed manifold limits film uniformity over a wide range of materials. A flexible lip only makes minor adjustments to the film.
CHILL ROLL TAKE OFF: Chill rolls are the cooling and pulling system for cast film. Chill rolls are available with horizontal and vertical discharge. In many bench applications, horizontal discharge dies make for a compact, space saving design such as the lines on the preceding page. Vertical designs, below and on the cover, are best for very low melt strength materials and extrusion coating.
COEXTRUSION CAST FILM LINES
Study film properties, adhesion, develop new films, and make customer samples. Unique for their performance and size, the line below is a mere 36 inches by 60 inches. Our sequential, modular feed-block lets you change structures (say from ABCDBA to ABCD), match stream velocities, and correct non-uniform layering (due to mismatched viscosity) without taking the feed-block apart. Critical to success in multi-manifold dies, our unique interchangeable manifold (see page 3) lets you match the manifold to the viscosity of each material on site for uniform individual layering. Then, the flexible lip die lets you adjust the overall film thickness.
COATING/LAMINATION/EMBOSSING LINES INCLUDING COEXTRUSION
The ultimate in lab lines, our multipurpose take-off allows you to make cast film, extrusion coat or laminate (see cover picture). For embossing applications, the primary cooling roll is customized to suit your needs. Randcastle slot dies feature our unique manifold (see page 3). Chill rolls cool both sides of the extrudate and air cylinders push the pressure roll into the web. A cooling roll, not visible in the pictures, keeps the pressure roll surface cool. The coextrusion line (left below) shows an AB multi-manifold die that coats one side of the substrate while a single manifold die coats the other side. The coextrusion line (right below) shows a five layer line in an extrusion coating application. Coextrusion lines are also available for lamination and embossing. See page 3 for additional information on our feed-blocks and multi-manifold dies.