Molding Machinery

Molding Machinery— How a Plastic Injection Molding Machinery Works

  • Plastics resin is manually or automatically vacuum fed from the hopper into the injection barrel. Dryers are used to remove excessive moisture.
  • The plastic resin is then pushed forward as it enters the barrel. What pushes it forward is the hydraulic motor powering the movement of the rotating screw.
  • Heated through the chamber, the resin melts as it reaches the nozzle. This process is called drag flow and it is drag flow that melts the plastic. The injection barrel has external heating bands that aid in the heating process.

Molding Machinery—Related Links

Plastic Injection Molding— Learn how plastic injection molding machinery works from resin being fed into the injection barrel, to where the heat that melts the material originates.
Society of Manufacturing Engineers

Plastic Injection Mold Design— Designer John Kreutzberger uses the SolidWorks program, a 3D CAD mechanical design program, to design plastic injection mold, and aluminum and zinc die casts.

Kreutzberger discusses the adjustments and revision processes that can easily be made when using SolidWorks by updating references and mold inserts, update 3D data that is used to machine the mold or die. The drawing files are conveniently linked directly to the part models making it easy to revise and resend any drawings out on the floor. SolidWorks is used primarily to quickly market the molds.

Molding Machinery —What do Injection Molds Make?

Injection molds are used to create an array of plastics instruments such as surgical tools, hearing aids, orthodontics, corrective eye surgery, and high-end electrical devices.

TIP-L Vertical Injection Molding Machine
An example of a vertical injection-molding machine in use.

Double vertical injection molding machine K40-40
Shows time saved for labor, production, and machine energy.

Injection Molding Basics
Manual, semi-automatic and automatic machine settings and when to use each.

Plastic Processing Machinery—The Basics of Injection Molding

3 Methods of Operation an Injection Molding Machinery Utilizes

  • Manual Operation— The operator controls each separate function when utilizing manual mode. During startup, shut down, for temporary holds when mold adjustments are being made and material is being removed from the barrel is when this method of operation is employed. The manual mode is also used during maintenance and when opening and closing the mold.
  • Semi-automatic Operation— When components are required to be removed during the process, for startup or for troubleshooting, the semi-automatic operation is utilized. The process consists of one cycle and then comes to a stop until the operator manually starts the machine again.
  • Automatic Operation— This operation is used when minimal participation from an operator is needed. Robotics are used instead and the ejection of the molds happen automatically while components are continuously molded.

Molding Machinery—Blow Molding Machinery

The Basics of Blow Molding Machinery and How it Works

  • The Crosshead type is the most common of the extruder head and die assemblies. The crosshead type deflects the flow of melted resin 90 degrees to vertical orientation from horizontal orientation.
2 Primary Types of Die Tooling—Converging and Diverging
  • Converging—Converging die tooling flares inward
  • Diverging—Diverging die tooling flows outward
2 Primary Types of Crosshead Die Assemblies—Center Feed and Side Feed
  • Center feed—Center feed assembly forces the melt to move downward in a vertical flow surrounding the mandrel or pin tip. This produces a straight flow around the pin.
  • Side feed—Side feed assembly forces the melt to move around the mandrill perimeter exiting at the die as a parison.

Molding Machinery—Blow Molding Machinery Related Links

How Plastic Bottles are Made
Reprocessed plastic, polyethylene, is melted and injected into a mold. This creates a pre-form. As it hardens, air is blown into the pre-form and then further molded in plastic process machinery creating bottles.

Blow Molding, Plastic Injection Molding Machinery
Pioneers of some of the first plastic molding machines used to make plastic pallets, bottles, containers and other parts.

Blow Molding Machinery FMA-4T-BL5L
All electric driven blow molding machine.

Blow Molding—How a blow molding machinery works.

Extrusion Blow Molding Machinery
Controlled by proportional hydraulics, this machine is used to make bottles, tubs, and motor oil containers to name a few examples.

Blow Molding Machinery
Used to produce a variety of bottles. This plastic auxiliary equipment can feature single or double workstations and can be equipped with up to a sextuple mold head and liquid level marks. Blow Molding Machinery uses a technique in which a method of fabrication produces a heated hollow tube of plastic.

Molding Machinery—Blow Molding Machinery

3 Main Types of Blow Molding Machinery

  • Extrusion blow molding machinery
  • Injection blow molding machinery
  • Stretch blow molding machinery

Molding Machinery—Blow Molding Machinery Process

  • The blow molding machinery process starts by melting the plastic.
  • It is then formed into a hollow resin tube. This tube is called a parison.
  • The parison is next clamped into a mold.
  • Air is pumped into it.
  • The air pressure pushes the plastic out to match the mold.
  • When the plastic has cooled and hardened, the mold opens.
  • Finally the part is ejected.

Extrusion Molding Machinery— Molding Machinery

Expert mold designers create plans for precision extrusion machinery. Plastic components are created using thermoplastic and thermosetting plastic resins that are injected into molds. The designer crafts the mold shape that resin is injected into. From hearing aids and surgical tools to car parts to children’s toys, Extrusion machinery’s plastic injection molding is everywhere.

Extrusion machinery is also used for making links of plastic sections like profiles, rods, tubes, and sheets. There are 5 essential elements of extruder machines.

Extrusion Machinery—Essential Elements of Extruder Machines

  • Tubular barrel
  • Electrically heated
  • Revolving screw
  • Barrel with Internal Ram or Plunger
  • Die

The extruder machine pulls raw material, like plastics or resin into configuration guides that create stock components. A hopper is at one end of the molding machinery where the resin is fed to the screw, ram or plunge. The opposite end where the resin is pushed holds the die that will shape the resin. There are 3 types of extruders.

Extrusion Machinery—3 types of Extruders

  • Single Screw
  • Twin or Multiple Screw
  • Ram

Horizontal Injection Molding—Machinery and How it Works

Injection molding machinery is used to create plastic components. These plastic components start out as resin flakes, shavings or pellets, are melted and injected into a mold, cooled, and then removed from the mold by an operator. The operator may also need to open the operator’s gate to remove the plastic components after they have cooled and operate the control panel.

Horizontal Injection Molding—Injection Molding Operator Tasks

  • Opening Operator's Gate
  • Maintenance and Servicing
  • Manual Feed of Plastics Materials
  • Operation of Control Panel
  • Removal of plastics materials after they have cooled

Horizontal Injection Molding—Safety Measures

  • Make sure that ventilation and exhaust systems are in proper working function. This is mandatory in order to ensure the prevention of inhaling harmful gases.
  • Operators should be familiar with Manufacturer's Material Safety Data Sheets (MSDS).
  • Wear the proper protective equipment (PPE). Heat-resistant equipment prevents injuries and burns and protects against contact with hot surfaces, fluids or gases.
  • Keep floors clear of debris to prevent slips and falls due to spilled resin on the work floor.
  • To control noise, apply hearing conservation per OSHA's Noise and Hearing Conservation Safety and Health Topics Page.

Horizontal Injection Molding—Related Safety Links

An example of a plastic injection machine with low safety regulations in use as well as no visible use of safety switches.

Plastic Auxiliary Equipment—Horizontal Injection Molding Machinery Related Links

Hot Runner Controllers— Injection molding machine for Heel
Uses hydraulic horizontal closing, injection feeding system, and proportionally controlled pressure.

Horizontal Injection Molding—Related Plastics Links

Plastics Machinery—Horizontal Injection Molding Machinery

Vertical Injection Molding —Vertical Injection Molding Machinery

Advantages to Vertical Injection Molding Machinery

  • Space Saving—Vertical injection molding machinery takes up half the space compared to horizontal machines used for the same functions.
  • Vertical injection molding machines allow for insert or plastic-metal combined component molding.
  • Gravity dislocation is eliminated due to the vertical injection machine mold alignment. Molds are aligned and supported in the vertical machine with more durability.
  • Vertical clamp units are versatile and accommodate attachments.
  • Automatic operation is ideal for the vertical clamp injection molding machinery without the use of an attendant.
  • A wide selection of the vertical clamp unit options also makes it appealing.

Plastic Auxiliary Equipment

Plastic Auxiliary Equipment—Hot Oil Units

    Hot oil units, or portable hot oil units, are engineered to perform at high operating temperatures. Plastic auxiliary equipment—hot oil units, depending on the make and model, heat to temperatures running between 450° and 650° F.

Plastic Auxiliary Equipment—Low-watt Density Heaters

    Hot oil units are equipped with low-watt density heaters to eliminate risk of charring oil. Low-watt density heaters are used to maintain and extend the life of oil used in plastic auxiliary equipment and to prevent the oil from “coking” or “charring.” Coking adversely affects the processing equipment and breaks down the oil compounds rendering it useless.

    Precautions taken by the use of low-watt density heaters resolve coking and charring issues. A vacuum pump, or positive displacement gear pump, is used to provide the correct flow over the heaters needed even during the cold start-up process.

    Unlike conventional temperature control units that use a pressure process, the hot oil unit employs a vacuum pump. The vacuum pump pulls heated materials through the mold rather than forcing it through with pressure.

Plastic Auxiliary Equipment—3 Factors for a Successful Vacuum Pump
Negative Pressure Temperature Control System

  • Vacuum Pressure—A pulling force is used to move matter instead of the use of forcefully pushing materials.
  • Vacuum CFM—Measuring cubic feet per minute.
  • Process Fluid GPM—Measuring gallons per minute.

Plastic Auxiliary Equipment—Hot Oil Unit Features

  • Factory Tested—For safety and pragmatic purposes, the units are quality tested and checked for performance in the factory prior to shipping. This alleviates any unforeseen product flaws or defects.
  • Easy to Operate—Controls of plastic auxiliary equipment are specifically designed for easy operation for practical use and safety precautions.
  • Welded Pipe construction—Flanged and welded pipe construction prevents and eliminates any leakage of oil material from the equipment.
  • Space Saving—The use of multiple heaters minimizes the size of the hot oil unit while maintaining proper temperature controls with consistent low-watt density.
  • Portable—These units can be transported and stored. Plastic auxiliary equipment is space saving and portable.
  • Safety Precautions—Safety measures are taken so that hot oil units are effective and easy to operate with diagnostic control panels and start and stop switches. Precautions are taken regarding high temperature fluid spray and other risks to the operator.