Clamping System Specification

Clamping Force (Tons):

the maximum clamping force holding the mold closed as determined by SPI standard;.

Clamping Opening  Force )Tons): the maximum force that a machine will exert to initiate the opening of the mold.

Clamp Stroke(Max) Inches:

the maximum distance that the opening and closing mechanism can traverse a platen. This meet mold or molding requirements.

Open Daylight (Max.) Inches:

the maximum distance that can be obtained between the stationary platen and the moving platen when the actuating mechanism is fully retracted with or without ejector box and/or spacers.

Closed Daylight or Minimum Mold Thickness (Inches):

the distance between the stationary platen and the moving platen when actuating mechanism is fully extended with or without ejector box and/or spacers Minimum mold thickness will vary, depending upon the size and kind of ejector boxes and/or spacer used.

Maximum Closed Daylight (Inches):

the distance between the stationary platen and the moving platen when the actuating mechanism is fully extended without ejector box and/or spacers.

Minimum Closed Daylight (Inches):

the distance between the stationary platen and the moving platen when the actuating mechanism is fully extended with standard ejector box and/or spacers.

 

Machine Operation Terminology

Manual Operation:

operation in which each function and the timing of each function are controlled manually by an operator.

Semi-Automatic Operation:

operation in which a machine performs a complete cycle of programmed molding functions automatically and then stops. It then requires an operator to manually start another complete cycle.

Automatic Operation:

operation in which machine performs a complete cycle of programmed molding functions repetitively, and stops only if there are a machine or mold malfunctions or it is manually interrupted.

 

Screw Terminology

Screw: 

a helically flighted shaft that when rotated within the barrel mechanically works and advances the material being processed.

screw

Screw Flight:

the helical metal thread of the screw.

Screw Root:

the continuous central shaft, usually cylindrical or conical in shape.

Flight Land:

the surface at the radial extremity of the flight constituting the periphery or outside diameter of the screw.

Screw Shank:

the rear protruding portion of the screw to which the driving force is applied.

Feed Section of Screw:

the portion of a screw that picks up the material at the feed opening (throat) plus an additional portion downstream. Many screws have an initial constant lead and depth section, all of which is considered the feed section.

Transition Section of Screw:

the portion of a screw between the feed section and metering section in which the flight depth decreases in the direction of discharge.

Metering Section of Screw:

a relatively shallow portion of the screw between the feed section and metering section in which the flight depth decreases in the direction of discharge.

Screw Diameter:

the diameter developed by the rotating flight land about the screw axis.

Helix Angle:

the angle of the flight at its periphery relative to a plane perpendicular to the screw axis.

Axial Flight Land Width:

the distance in an axial direction across one flight land in a direction perpendicular to the flight.

Flight Lead:

the distance in an axial direction from the center of a flight at its outside diameter to the center of the same flight on turn away. The location of measurement should be specified.

Full Flighted Length os screw:

overall axial length of the flighted portion of the screw, excluding non-return valves, smear head, etc.

Screw Channel: 

with the screw in the barrel, the space bounded by the surface of flights, the root of the screw, and the bore of the barrel. This is the space through which the stock is conveyed and pumped.

Enclosed Volume of Screw Channel:

the volume of screw channel starting from the forward edge of the feed opening to the discharge end of the screw channel.

Screw Efficiency: 

the volume of material discharged from the machine during one revolution of the screw expressed as a percentage of the developed volume of the last turn of the screw channel.

Screw Speed:

the number of revolutions of the screw per minute.

 

 

Inside the Molding Machine

Clamping Unit:

That portion of an injection molding machine in which the mold is mounted, and which provides the motion and force to open and close the mold to hold the mold closed with force during the injection. The mold can be closed in a horizontal or vertical direction.

Moving Platen or Plate:

That member of the clamping unit is moved toward a stationary member. The moving section of the mold is bolted to this moving Platen. This member usually includes the ejector (Knockout) holes and mold mounting pattern of bolt holes or “T” slots.

Stationary Platen or Plate:

The fixed member of the clamping unit on which the stationary section of the mold is bolted. This member usually includes a mold mounting pattern of bolt holes or “T” slots, A standard pattern is recommended by the SPI (Injection Machinery Division Methods and Procedures, Sep 1958). In addition, the stationary platen usually includes provisions for locating the mold on the platen and aligning the sprue bushing of the mold with the nozzle of the injection unit.

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Tie Rods, Bars, or Beams:

Those members of the clamping force actuating the mechanism that serves as the tension members of the clamp when it is holding the mold closed. They also serve as a guide member for the movable platen.

Ejector (Knockout):

A provision in the clamping unit that actuates a mechanism within the mold to eject the molded part(s) from the mold. The injection actuating force may be applied hydraulically or pneumatically by a cylinder(s) attached to the moving platen, or mechanically by the opening stroke of the moving platen.

Fully Hydraulic Clamp:

A Clamping unit attached to a hydraulic cylinder that is directly connected to the moving platen. Direct fluid pressure is used to open and close the mold, and to provide the clamping force to hold the mold closed during the injection.

Toggle Clamp (Hydraulic Actuated, Mechanical Actuated):

A clamping unit which toggle mechanism directly connected to the moving platen. A hydraulic cylinder. or some mechanical force device is connected to the toggle system to exert the opening and closing force and hold the mold closed during the injection. The clamping force to hold the mold closed during injection is provided by the mechanical advantage of the toggle.

Slow Mold Breakaway:

A provision in the machine designed to provide a slow platen movement for an adjustable distance before the mold face comes in contact.

Clamp Close Slow Down:

A provision in the machine designed to slow down the moving platen for an adjustable distance before the mold faces come in contact.

Clamp Open Slow Down:

A provision in the machine designed to slow down the moving platen for an adjustable distance before it reaches its maximum open position. This sequence is often employed to reduce the effect of knockout impact when the mechanical knockout is used. It is sometimes referred to as the ejector or clamps open cushion.

Clamp Close Stroke Interruption:

A complete stop of the clamp closing stroke to allow an auxiliary operation(s) before completion of the closing stroke.

Clamp Open Stroke Interruption:

A complete stop of the clamp opening stroke to allow an auxiliary operation(s) before completion of the opening stroke.

Clamp Open Preposition

A provision in the machine circuit to allow the clamp to open fully and then close to a predetermined position. It is generally used to allow the ejector (knockout) mechanism to retract so that inserts can be placed in the mold.

Low-Pressure Mold Closing:

A provision in the machine to lower the clamp closing force during the clamp closing cycle. The lower clamp forces minimize the danger of mold damage caused by parts caught between the mold faces. Provisions are also provided for parting mold faces at a time interval in case of an obstruction.

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