We’re passionate about our abilities and diversity of offerings for our customers. We manufacture plastic extrusions in standard profiles, commodity plastics, engineering polymers, and coextruded and hollow profiles.
What is extrusion and what are its benefits? Let us explain to you why plastic profiles are amazing
We offer a number of extruded profiles for different uses, made from a variety of materials.
Over the years, variations of plastics have been invented, each with unique qualities. These polymers can be made into advanced profiles.
Coextrusion is a key capability. At Keller, we can provide coextrusion to inexpensively combine the properties of two different material
Hollow profiles and plastic tubes look like simple designs, but not every extrusion house can manufacture them. We can.
Plastic Extrusion is a process in which very small pellets are fed into a machine with a rotating screw and a barrel that supplies heat. The small pellets (typically referred to as the “resin”) are slowly heated and melted to form the melt. The melt is then forced or squeezed through a die which forms the shape of the profile. The die may be in the form of a tube, rod, sheet, coating, film or as custom profile (see custom plastic extrusions).
The heat is then removed and the melt which was created by the melting of the pellets, now takes the shape of the die as a permanent profile. The key to this process is that it is “continuous”. Other Plastic Processes could make a profile but it would be much shorter than the lengths that are created through the creations of Plastic Profiles Or Polymers. The beauty of Plastic Extruders is that the lengths can be extremely short (less than .250″) or they can be extremely long and/or spooled into lengths of 1,000 feet or more.
The machine that is used to create Extruded plastic can also do many different materials and colors. There are many post extrusion processes that can be applied to the plastic extrusions such as cutting to length, laminating, punching holes, embossing, and printing. The size of an extruder is generally based on the size of the screw. A 1 inch machine is relatively small and contains a screw that is 1 inch in diameter.
Call us at (603) 627-7887 for your Custom Plastic Extrusion needs
Keller Plastics is one of the industry leading plastic extrusion companies. These machines are typically used for medical products, R & D, and/or expensive materials. The output is generally low, around 501bs/hr. On the other side of the spectrum, a 6 inch extruder, has a screw diameter of 6 inches and is capable of putting out over 2,500 lbs/hr. The extruder in essence is generally a simple machine in which a screw turns, heat is applied and pellets are melted.
The parts of an extruder consists of a hopper in which the pellets are placed. The hopper has a feed throat in which the pellets drop through onto a screw which is turning. The screw and barrel is similar to a standard meat grinder which melts the material and conveys it to the front where the die sits. A filter is placed in front of the oncoming melt to filter any un-melted material or contaminates and create back pressure on the melt.
The die is extremely important in that it determines the final shape of the product. Most of the time an Engineering Print is created so that the die can be cut so the Plastics Extrusions will ultimately meet the print and give the customer what they are looking for. The final part of the extruder itself is the Control Panel that monitors the pressure in the barrel, the temperatures, RPM of the screw, and motor load.
As the molten plastic exits the die, a water bath (with roughly 50°F water) is next to accept the hot profile and cool it back to room temperature. This water bath locks the shape so that it will match the Engineering Print. A puller is placed after the bath that feeds the cutter so that various lengths can be cut. The screw is probably the most important (of course the added heat is important too) part of the extruder in that it must properly melt the material.
Here at Keller Products we use specially designed screws to manufacture Plastic Extrusions. They are engineered to give us the best melt along with a high degree of mixing for excellent color dispersion. The ratio of the length of the screw to the diameter of the screw is typically expressed as the L/D ratio. Common length to diameter rations run at a low of 20/1 to 24 to 1. L/D’s ratios can be as high as 30/1 to which we use here at Keller Products to get the best dispersion in regards to color.
Give us a call at (603) 627-7887, we know you will have a wonderful experience the moment you make contact with us regarding your Plastic Extrusion needs.