Extrusion: Non-Motorized Puller Assemblies for Downstream Product Handling
Available in pinch-roll and caterpillar designs.
Non-motorized puller assemblies from Versa Machinery, Elkhart, Ind. are available in pinch-roll and caterpillar designs for a wide variety of downstream handling requirements. With speeds from 0 to 900 ft/min., and with a variety of belt- or pinch-wheel materials available, they are ideal replacements for existing puller assemblies or as components for specialized equipment for unique applications.
P series Pinch Wheel feeds are commonly used where materials are insensitive to pinching pressure, and in operations where minimal pulling force is necessary. They are available with roller widths from 2-in. to 5.5 in., with roll materials offering different traction and wear characteristics. Versa pinch roll pullers are ideal for the manufacturing of weed-whacker lines, 3D-printer filaments, moving and punching rigid profiles, and for capturing materials trimmed from the edges of various profile and film extrusions.
“C Series caterpillar feeds provide uniform pressure over the entire traction length, which enables greater pulling force without product deformation. Belt configurations range from 2 in. width × 9-in. length to 4-in. width × 18-in. length. Versa caterpillar pullers are ideal for pulling materials through braiding machines, feeding disc brake materials into grinders, pulling wire and cable, pulling extruded vinyl siding, and more.
A wide variety of belt and pinch wheel materials are available including sponge, gum rubber, silicone, neoprene, urethane, or nitrile some of which are FDA approved. Various durometer ratings are available to suit application requirements. Gear-driven units are recommended for applications to 250 fpm. For speeds exceeding 250 fpm, belt driven, low backlash units are recommended.
Standard non-motorized puller assemblies are equipped with a hand wheel to adjust the belt gap, which opens and closes around a constant centerline. Optional pneumatic operation of the belt booms along a constant centerline allows control of the pressure applied to the product being pulled and makes repeatable setup almost instantaneous. Additional options include left-to-right configuration, and OSHA guarding package.
All extrusion processes depend to some degree on the melt strength of the polymer, and this property is generally a no-show on data sheets.
Alloys of polyethylene and recycled PET were the highlight of the annual SPE Global Plastics Environmental Conference (GPEC) in Detroit in February.
A poorly designed profile die—one that does not permit the part to be extruded with the same dimensions from run to run—coupled with a lack of understanding of the extrusion process, is a recipe for scrap generation.