Extruder With Vacuum Sizing Tank

Extruder With Vacuum Sizing Tank

 

Vacuum Spray Tank

Extruder With Vacuum Sizing Tank and Spray Tanks
 

Profile Extrusion Equipment

Profiles may consist of a single material or multiple materials. Single material profiles utilize one extruder that forces material into a single die. Multiple material profiles require more than one extruder to feed material into a central die.  Profiles can be as large as a 4 foot diameter sewer pipe or as small as a drinking straw.  Though the size of an extruder and the length of the line will vary greatly according to product size and the process steps necessary to achieve an end product; the overall process is basically the same for both single and multiple materials. 

Co-Extrusion

If two or more materials are required to make a product the co-extrusion process is used. For example, if a white drinking straw has 2 colors of stripes on it, a total of 3 extruders are needed.  Each extruder feeds a material into a central co-extrusion die. Other examples is the appllication of a weather resistant cap-stock onto a base that is not weather resistant, adding flexible barbs to a rigid frame member or various other combinations. For each additional material that is combined an additional extruder is always needed.

Regardless of size or how many extruders are used, they are combined with additional pieces of equipment to form the
extrusion line. The equipment employed after the material exits the actual extruder is referred to as “Downstream” Equipment.

    Downstream equipment is generally divided into three categories:

     

    • Cooling Equipment - The part must be cooled to maintain the desired shape.  Cooling equipment must be able to accept tooling that will hold the different parts on the line.
         
      • Air Rack
      • Cooling Tank
      • Vacuum Tank
      • Sizing Table
         
    • Puller - A puller pulls the material away from the die as it is being extruded and moves it through the cooling tooling and equipment.
       
    • Handling - Speical handling equipment may be needed to finsih the part after it comes through the puller.
         
      • Cutter
      • Saw
      • Takeoff Conveyor
      • Winder

     

    Cooling Equipment

    Air Cooling Equipment

    Air Cooling

    The use of air to cool parts is rarely used anymore because it is so inefficient. However, because it is inefficient, it gives the operator time to shape the part with inexpensive tooling for parts that are very complex and the volume does not justify the costly tooling needed to make the part with a water tank. The Air Rack is a simple frame, usually with cooling fans, and simple plates and fixtures to mount jigs and fingers to push on the part and hold it in the desired shape.

     

     

    Cooling & Sizing Tank

    The Cooling Tank allows for the circulation of water over the part as it is pulled through the tank. Some type of support is usually mounted inside the tank to hold the part while it is being cooled by the water. The water is either sprayed on the part from multiple directions to help the uniformity of the cooling or the tank is flooded with water so that the part is immersed in the water as it passes through the tank. If the tank is flooded, some provision must be made for the water that leaks around the part as it enters and exits the tank. Spray tanks generally offer more efficient cooling with the added cost and maintenance of the spray nozzles. Commonly, more than one cooling tank is used in any given extrusion line to ensure that the part is cooled sufficiently and maintains dimensional stability once it leaves the last tank in the line. The cooling section of an extrusion line may extend out to 160 feet or more.

    Vacuum Tanks

    Vacuum Tank

    A Vacuum Tank is essentially a Cooling Tank that is strong enough not to collapse under high vacuum and with the addition of a vacuum pump and plumbing. The vacuum can keep the water in a flooded tank from leaking around the part as it enters and leaves the tank. More importantly the vacuum can hold a hollow part outagainst the tooling to hold it to size and shape. Usually, at least the first tank in line for any hollow part such as pipe or tubing is a Vacuum Tank to set the outer skin of the part while under vacuum.

    Sizing or Calibration Table

    Sizing or Calibration Table

    A Sizing or Calibration Table is a piece of equipment with vacuum pumps and water circulation and a system to mount dry calibrationor other special tooling when needed for very complex parts thatrequire tight tolerances. This type of equipment is commonly usedfor window profiles and other profiles that require tight control of complex shapes.

     
    Puller

    Puller

    The Puller is a key component of the balance between the push of the extruder and pulling the part through the cooling and shaping stage. Speed control is critical, but so is the grip of the part so that it doesn’t slip. The puller will generally use two opposing belts made from either rubber or polyurethane to grip the part. Larger pullers that require greater grip will normally use cleats made from rubber or polyurethane.

     

    See Details About 4" & 6" Pullers for Plastic Profile Extrusions

     
    Cutter

    Cutter

    Small parts can be cut with the use of a sharp blade that passes through the part with high speed and high torque. Cutters are available that allow for the part to pass through and the blade is controlled by one of several methods to cut in an “On Demand Mode or "Continuous Mode” so parts can be cut to practically any length.

    Get Details on Cutters for 2" through 5" diameters and 

    profiles up to 4.5" x 7.5"

     
    saw

    Saw

    Larger and more solid parts require a saw to cut them to length. Saws can be made in a variety of configurations but generally they are mounted in a table below where the part passes. Then on demand when the part is to be cut the saw and blade is raised up through the part. Since the part is moving, it is necessary for the table top and saw to move with the part as the blade goes up through the part and back down to a neutral position. Grips of some type are actuated during the cut to hold the part to the table and keep it stable during the cut.

     
    Take Off Conveyor

    Take Off Conveyor

    It is typical to have some type of conveyor to take the parts after they are cut by the saw or cutter to where they are packaged. Otherwise, since the parts are no longer being pushed or pulled, they would back up at the cutter or saw and cause problems. This is generally a very simple conveyor that is running slightly faster than the line speed of the part.

     

    Winder

    For small or flexible parts it is often desirable to wind the part on a reel to have it in very long lengths or to be able to cut it to length later when ready for use. The winder allows the part to be wound on a reel continuously so that it does not get tangled or twisted and is easy to remove from the reel for later use.

     

     

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