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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP
"A" Cavity Retainer Plate - Part of the stationary section of the mold into which the leader or guide pins are mounted. Also used to hold core, cavity blocks, and sprue bushing. "A" Clamping Plate - Part of the stationary section of the mold into which the leader or guide pins are mounted. Also used to hold core, cavity blocks, and sprue bushing.
"A" Half of Mold - The non moving parts of the mold including the Locating Ring, the Sprue Bushing, the Front Clamping Plate, the Front Cavity Plate, and the Leader Pins.
Accuracy - The condition or quality of being true, correct without error.
ACIS - A standard computer file format for exchanging CAD data, typically from AutoCAD programs. ACIS is an acronym that originally stood for "Andy, Charles and Ian's System". Additive - Substance compounded into resin to improve certain characteristics, such as plasticizers, initiators, light stabilizers, catalysts, flame retardants, etc.
Aging - The chemical and/or physical changes which occur in a material after exposure to environmental conditions over a period of time.
Amorphous Polymer - A polymer with a randomly ordered molecular structure which does not have a sharp melt point but rather softens gradually as the temperature increases. These materials change viscosity when heated. They are clear, rigid, fast cycling, and have low shrinkage.
Assembly - Two or more parts combined to make another.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP "B" Clamping Plate - Holds the moving portion of the mold to the movable platen of the injection machine.
"B" Core Retainer Plate - Top plate of the movable section of the mold. Forms the parting line of the mold with cavity retainer plate.
"B" Half of Mold - The assembly of the mold that is attached to the moving platen.
Back Pressure - The resistance of plastic material to flow during processing, due to its viscosity.
Baffles - Plugs or spiraled rods placed in the waterways of molds to direct water flow through the molds.
Ball Screw - A shaft containing teeth used to transmit power from a source to a ball bearing collar.
Band Heater - Electrical heaters used as the primary source of heat on barrels and nozzles of injection molding machines and extruders.
Barrel - The part of the molding press where resin is melted.
Base Position Mode - This is a mode that sets the molding parameters based on the pressure profile rather than injection/pack parameters.
Bead Blasting - Using abrasives in a pressurized air blast to create a surface texture on the part. Bearing - A support and guide for a rotating, oscillating, or sliding shaft.
Bevel - Also known as a chamfer, it is a flat truncated corner. Blush - Cosmetic blemish at the point of injection in the finished part.
Boss - Any cylindrical extension of plastic which rises above the surface of a part.
Breakaway Velocity - The velocity of the clamp from the 0 position to the open 1st position.
Bridge Tool - A temporary or interim mold made for the purpose of making production parts until a high-volume production mold is ready. Brinell Hardness - Indentation hardness test using a calibrated machine to force a hard ball into the surface of material under test. The diameter of the resulting impression is measured.
Bushing - An insert made of one piece pressed into a hole in the housing. A type of bearing.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP CAD - Short for "computer aided design".
Cam - A moveable block, roller, ball or any other shape that has a repetitive action having an effect causing a reciprocating action on another object. Cam Locks - A piece of metal attached to a mold which keeps the cam in position when the mold is closed.
Cam Pin - The pin mounted in the "A" half which when upon opening or closing of the mold causes the cam to move.
Cam Position Pin - A spring loaded pin that holds the cam in position when mold is open.
Cam Springs - Springs used to force the cam back to its original position.
Cam Stops - A bar which prevents the cam from over-travelling as the mold opens.
Carriage - Movable assembly that changes the distance of the nozzle in relationship to the mold.
Cartridge Heaters - Electrical heaters mounted in mold to heat the mold. Used when the desired mold temperature is above 180 degrees Fahrenheit.
Cavity - Female section of the mold which generally gives the external shape to the part to be molded.
Chamfer - Also known as a bevel, it is a flat truncated corner. Chiller - A self-contained system comprised of a refrigeration unit and a coolant circulation mechanism consisting of a reservoir and a pump. Chillers maintain the optimum heat balance in thermoplastic processing by constantly circulating chilled cooling fluids to injection molds.
Chute - Container or slide directly under the mold which catches the molded product.
Clamp Manual Speed - The speed for the clamp advancing and retracting during manual mode operation.
Clamp Open Time - The time when unclamping and ejection are completed to when the next clamping is started.
Clamping Area - Largest molding area an injection molding machine can hold closed under full pressure.
Clamping Pressure - Pressure which is applied to an injection or transfer mold to hold it closed.
Clamping Tonnage - Rated clamping capacity of an injection or transfer mold to hold it closed.
Clamping Unit - The complete moveable assembly used to close the mold and apply the clamping pressure. See Schematic.
Close 1st Velocity - The clamp velocity from clamp open limit to close switch position.
Close 2nd Velocity - The clamp velocity fromclose switch position to mold protect start position.
Close Switch Position - The position at which the clamping speed is changed from the clamp close velocity 1 to the clamp close velocity 2.
Close Switch Velocity - The velocity at the close switch position. This is the second of three mold closing velocity adjustments for the press.
Closed Loop Process - A process in which there is feedback directly to a controller which then automatically makes adjustments.
Color Concentrate - Plastic resin which contains a high loading of pigment. Concentrates provide a dust-free method of handling colors.
Compression Ratio - The ratio of volume at the feed zone of the screw to the volume of the last flight of the screw.
Contamination - Any material in, on, or around the specified plastic which does not belong there. (Dirt, dust, grease, etc)
Continual Clean-up - The process by which the person responsible for a given area of production keeps that given area of production clean and safe throughout the shift.
Contoured Pins - Ejector pins with the ends shaped to match a sloping surface on the part. Control Panel - The panel on the injection molding presses that contains the controls and monitoring device readouts for the press and its process.
Cool Time - Time when pack operation is completed until clamp opening starts.
Core - Male part of mold which shapes the inside of a molded part.
Core Pin - Pin used to mold a hole.
Crazing - Fine cracks which may extend in a network on or under the surface or through a layer of plastic material.
Creep - The dimensional change with time of a material under load, following the initial instantaneous elastic deformation.
Crystalline Polymer (Partially Crystalline) - A polymer having a highly ordered molecular structure with sharp melt points. They do not gradually soften with an increase in temperature but rather remain hard until a given quantity of energy is absorbed and then rapidly change into a low viscous liquid. They tend to have high shrinkage, high strength, and are translucent.
Cycle - One full sequence in a molding operation, from a point in the process to the same point in the next sequence.
Cycle Sheet - A sheet filled out by the production department which lists all the information pertinent to the running of any given job.
Cycle Time - The time it takes to make one part including the closing of the mold, the injection of the resin, the solidification of the part, the opening of the mold and the ejection of the part. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Decompression - The retraction without rotation of the screw to reduce pressure after extruder is completed.
Delamination - The splitting of plastic material along the plane of its layers.
Density - Weight per unit volume of a substance.
Desiccant - A hygroscopic material which absorbs water vapor from the air and is the heart of dehumidifying hopper drying systems.
Die Clamps - Clamps used to attach mold halves to the platens when bolts cannot be used.
Dimensional Stability - In a molded part, the ability of the plastic part to retain its shape.
Direction of Pull - Refers to the motion of a part surface relative to a mold. Distortion - A part twisted out of its true shape.
DMR - Discrepant Material Report - Report filled out by inspector to explain to Anchor why parts are being rejected.
Dowel - Pin used to maintain alignment between two or more parts of a mold.
Draft - The tapered design of a mold wall which facilitates removal of the molded part.
Drooling - Leakage of resin from a nozzle or around the nozzle area during the injection step in injection molding. Also, the escape of low viscosity resins from the nozzle.
Drop Bar - Mechanical safety device that will keep the mold from closing during a press malfunction, providing the operator door is open.
Drying of Plastics - Many plastics absorb water and must be dried prior to injection molding to ensure good cosmetics and material characteristics. Ductility - Amount of plastic strain a material can withstand before it fractures.
Durometer - A measure of the hardness of a resin. It is measured on a numeric scale with numbers ranging from lower/softer to higher/harder. Dwell - A pause in the application of pressure to a mold, made just before the mold is completely closed, to allow the escape of gas from the molding material.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Edge Gate - An injection method that uses a gate on the parting line of the mold. It typically leaves a vestige on the outside of the part and is sometimes referred to as a tab gate.
EDM - Electrical Discharge Machine - A piece of carbon or copper is cut to a desired shape (an Electrode) Electrical current is supplied to the carbon. As the carbon is brought close to the steel the current arcs. The arc burns the steel to the shape of the carbon. Ejection - The process of pushing a completed part out of a mold. Ejector Backup Plate (Knockout Bar) - Bolted together with the ejector retainer plate to form a unit. Acts as a backup plate for the pins in the ejector retainer plate.
Ejector Interlock - A function to prohibit the ejector from moving when the machine does not get an input signal.
Ejector Manual Speed - The speed for advancing and retracting the ejectors operating during manual mode.
Ejector Pins - Steel pins incorporated into the B-side of a mold that push out the plastic part. Ejector Pulses - The number of ejector repetitions.
Ejector Push Mark - The product surface opposite the ejection surface that is distorted or discolored through stress from resistance to being ejected.
Ejector Push Plate (for press) - The plate that provides the force to cause the knockout bars to advance or retract.
Ejector Retainer Plate (Knockout Pin Plate) - Counterbored for the heads of ejector pins, ejector return pins, and sprue puller pin.
Ejector Return Springs - Compression springs mounted between the B-backup plate and the ejector return plate used to force the ejector plate back into the original position.
End Mill - A cutting tool that is used to machine a mold. ESD - Stands for "electro static discharge", an electrical effect that may necessitate shielding in some applications. Some special grades of plastic are electrically conductive or dissipative and help prevent ESD. Extruder Manual Speed - The rotation speed of the screw when operating in manual mode.
Extruder Process - The return stroke of the screw in which new material is added into the screw while rotation of the screw keeps the barrel filled.
Extruder Start Position - The screw position at the start of the extruder process.
Extruder Torque - The work done by the screw as it rotates, measured in percent of maximum output of the motor.
Eye Bolt - A bolt having a ring-shaped head.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Family Mold - Mold designed to produce several different parts.
Feed Hole - The opening in the barrel where the plastic resin enters from the Feed Hopper.
Feed Hopper - Conical feed reservoir into which molding powder is loaded and from which it falls into the molding machine through the Feed Hole and sometimes through a metering device.
Fixture - Means of holding a part during a machining or other operation.
Flash - Extra plastic attached to a molded part.
Flame Retardant - A resin formulated to resist burning. Reactive compounds become an integral part of the polymer structure, while additive chemicals are physically dispersed in the polymer.
Flammability - The measure of the extent to which a material will support combustion.
Flight Depth - The distance from the Screw Body to the outside edge of the Screw Flight measured perpendicular to the axis of the screw.
Flow - A qualitative description of the fluidity of a plastic material during the process of molding.
Flow Lines (Knit Lines) - A mark on a molded part made by the meeting of two flow fronts during molding. Flow lines that are fully filled and conform to the part surface are normal occurrences in molded parts.
Flow Marks - Distinctive surface marks caused when two flow fronts meet and weld together during molding.
Food Grade - Resins or mold release sprays that are approved for use in the manufacturing of parts that will be in contact with food. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Galling - Metal on metal rubbing that destroys one or both surfaces through pulling and redepositing of the metal. Gas Burns - Showing evidence of thermal decomposition through some discoloration, distortion, or localized destruction of the surface of the plastic. It is usually caused by out gassing.
Gate - The opening through which the plastic enters the mold cavity.
Disc Gate (Diaphragm Gate) - Gate used in molding annular or tubular articles. Gate forms a solid web across the opening of the part. Fan Gate - A shallow gate somewhat wider than the runner from which it extends.
Pinpoint Gate (Restricted Gate) - A restricted orifice through which molten resin flows into a mold cavity.
Ring Gate - Used on cylindrical shapes, this gate encircles the core to permit the melt to first move around the core before filling the cavity.
Spider Gate - Multi-gating of a part through a system of radial runners from the sprue.
Sprue Gate - A passageway through which molten resin flows from the nozzle to the mold cavity.
Submarine Gate - Submarine gate breaks item from the runner system upon ejection from the mold. Gate is located where opening from runner to mold is below parting line or mold surface (in conventional edge gating, the opening is machined into the mold surface). Tab Gate - A small removable tab of approximately the same thickness as the mold item, usually located perpendicular to the item. The tab is used as a site for edge gate location, usually on items with large flat areas.
Gibs - Guide blocks used to keep cams aligned with the cavity.
Glass-Filled - Refers to a resin with glass fibers mixed into it. Glass-filled resins are much stronger and rigid than the corresponding unfilled resin, but also more brittle. Resins can also be filled with carbon fiber, stainless stell, etc. In general, filled resins can be very susceptible to warp. Granulator - Machine used to reclaim scrap and reject parts by reducing the particle size of the scrap so that it can be reprocessed.
Guided Ejectors - Pins and bushings that guide the ejector system to minimize wear by maintaining alignment.
Gusset - An added wall that gives addition strength and/or shrink resistance to another wall.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Haze - Cloudiness in plastic parts.
Hoist Pins - A bolt connected to a ring which can swivel and pivot, used to lift molds.
Hopper Dryer - A combination feeding and drying device for extrusion and injection molding of thermoplastics. Hot air flows upward through the hopper containing the feed pellets.
Hot Runner - A mold in which the runners are insulated from the chilled cavities and are kept hot. Parting line is at gate of cavity, runners are in separate plates, so they are not, usually, ejected with the part.
Hot Tip Gate - An injection molding method that uses a heated gate on the A-side of the part to eliminate the creation of any runner or sprue. The gate vestige will be a small sharp bump that can be trimmed if necessary. Hygroscopic - Capable of attracting and absorbing moisture.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP IGES - Stands for "Initial Graphics Exchange Specification". It is a common file format for exchanging CAD data.
Injection Molding - A repetitive process in which plastic is melted or plasticated, and injected into a mold containing a cavity in the shape of the desired article. With thermoplastics the mold is kept at a temperature below the solidifying point of the plastic, causing the injected polymer to freeze thus forming the article. After cooling, the mold opens and the article is ejected. Injection Pressure - Pressure applied to the injection ram to force the plastic from the barrel into the mold.
Injection Time - Time required for injection of liquid plastic into the mold.
Insert - An integral part of a plastic molding consisting of plastic, metal, or other material that has been preformed and inserted into the molding operation so it becomes an integral part of the finished molding.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Jetting - Flow marks caused by the resin entering a mold at high speed, typically occuring near a gate.
Judgment Points - Specified positions of the screw where pressure is monitored. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Knit Lines - Visible indications in a finished part, formed by the intersection of two hot plastic fronts. They are always formed downstream of through-holes and between multiple gates. They are also known as weld lines.
Knockout Bars - The linkage between the press ejector push plate and the ejector backup plate. Knockout Couplers - Quick disconnect couplers mounted on the ejector backup plate to facilitate quick setup. Used to attach the knockout bars to the mold.
Knockout Pins (Ejector Pins) - Pins used to eject part and runner system from core.
Knockout Studs - Threaded studs mounted in the ejector backup plate to provide a positive return ejector system. Knockout bars are screwed into these studs. Only used on hydraulic presses.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Laminar Flow - The movement of one layer of fluid past or over another layer without the transfer of matter from one to the other. Laminar flow is achieved by solidifying the layer in contact with the mold surface. This acts as an insulating tube through which material can flow to fill the remainder of the cavity. This process is essential to mold surface duplication.
Leader Pins - Hardened and ground steel pins pressed into one of the plates. Align the two halves of the mold base.
Leader Pin Bushings - Hardened and ground steel bushings which are pressed onto one of the plates. Serve as bearing surfaces for the leader pins.
Living Hinge - Very thin section of plastic used to connect two parts and keep them together while allowing them to open and close. They require careful design and gate placement. A typical application would be the top and bottom of a box. Load Current - The current being drawn by the AC servo motors.
Locating Ring - A ring that fits into a counterbore in the top clamping plate and is used to locate the mold on the platen of the press so the nozzle and sprue bushing are aligned.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Manifold - Configuration of piping that takes single channel flow and divides it into various flow channels to feed more than one outlet.
Master Chase - The unit that holds the mudset containing the A and B clamping plates and parallels.
Medical Grade - Resin that may be suitable for use in certain medical applications. Melt - A thermoplastic stock which is in a molten state due to heat.
Metal-Safe - A change to the part design that requires only the removal of metal to produce the desired geometry. Typically most important when a part design is changed after the mold has been manufactured, because then the mold can be modified rather than entirely re-machined. It is also commonly known as "steel-safe". Minimum Cushion - The furthermost position to which the screw advanced in the injection and pack pressure.
Mold (Tool) (Die) - A hollow form or cavity into which molten plastic material is forced to give the shape of the required component. The term generally refers to the whole assembly of parts which makeup the section of the molding equipment in which the parts are formed. The mold set including cavities and cores.
Mold Heater - A self contained fluid heating unit used to maintain mold temperatures by circulating hot fluid through a mold.
Mold Height - Overall thickness of the mold as it is located between the platens of the molding machine.
Mold Protect - A safety feature which causes the velocity and pressure of the mold to decrease before the mold closes.
Mold Protect Start Position - The position at which the clamping speed is changed from the clamp close velocity 2 to mold protect velocity.
Mold Protect Velocity - The velocity from mold protect start position to mold touch position.
Mold Release Spray - A liquid applied to the mold as a spray to facilitate the ejection of parts from the B-side. It is typically used when the parts are difficult to eject because they are sticking to the mold. Mold Set - The assembly of plates, pins, etc excluding any molding machine parts that are used in molding plastic parts, and excluding cavities and cores.
Mold Touch Position - The position when the two mold halves initially touch.
Motor (AC Electric Servo) - A machine that converts electrical energy to mechanical energy in the form of a rotating shaft.
Mudset - A quick-change mold base that mounts into a master chase.
Multi-Cavity Mold - A mold with multiple copies of the same part, typically used to reduce piece-part pricing for higher volume runs. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Non-Return Valve Assembly - Valve that permits material to flow in one direction and then closes to prevent back flow; it consists of the Valve Tip, Valve Ring, and Valve Rear Seat.
Nozzle - Provides a leak proof connection between the injection mold and the molding machine, through which the melt flows.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Open 1st Position - The position at which the clamp open speed is changed from breakaway velocity to open 1st velocity.
Open 1st Velocity - The clamp opening velocity between the 1st and 2nd open positions. The press allows several opening velocities which are titled 1st, 2nd etc.
Open 2nd Position - The position at which the clamp open speed is changed from open 1st velocity to open 2nd velocity.
Open 2nd Velocity - The clamp opening velocity between the 2nd open position and the open limit.
Open Limit - The limit of the retraction open end for the movable platen.
Orange Peel - A defective type of granular finish resembling the peel of an orange.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Packing - Filling of the mold cavity or cavities as full as possible without causing undue stress on the molds or causing flash to appear on the molding.
Pack Pressure - The injection pressure when the mold is being packed.
Pack Velocity - The velocity of the screw during packing.
Parallels - Mounted on the bottom clamping plate under the support plate to form a space which allows the ejector bar to move when the piece parts are ejected.
Parasolid - A file format for exchanging CAD data. Parting Line - The line formed by the mating surfaces of the mold halves.
Peak Pressure - The maximum pressure level reached during the injection molding process.
PID Auto Tuning - The controlling process which holds the barrel, nozzle, and mold temperatures at a constant level with the least amount of variance.
Piece Part - A part used with another to form an assembly.
Pillars - Metal cylinders used to support the projected area of the cavity, runner, and sprue. They mount between the Rear Clamping Plate and the Support Plate.
Plastic - Natural and synthetic material and chemicals that can be transformed into a solid, as either or both heat and pressure is applied.
Plasticate - To soften by the introduction of heat.
Plastic Strain - Permanent deformation due to stress.
Platen - The steel plates on a molding machine to which the mold is attached. Generally, two platens are used; one being stationary and the other moveable.
Pneumatic - Operated by compressed air.
Polymer - A high-molecular-weight organic compound, natural or synthetic, whose structure can be represented by a repeated small unit, the MER; e.g., polyethylene, rubber, cellulose. Synthetic polymers are formed by addition or condensation polymerization of monomers. If two or more monomers are involved, a copolymer is obtained. Some polymers are elastomers, some plastics.
Post Gate - An injection method that injects plastic through an ejector pin hole. This gating technique leaves a gate vestige on the B-side of the part where it can often be less visible for cosmetic purposes. There is often gate blush opposite a post gate. PQR - Product Qualification Report - A form filled out with all the critical dimensions of a part measured against the specified print dimensions and specifications.
Precision - The state or quality of being exact in the repeatability of a process or an event.
Press - The injection molding machine that makes the plastic parts. It holds the mold closed, melts the resin, injects it into the mold, opens the mold and ejects the part. Process - The injection molding environment consisting of input variables such as temperature, pressure, injection rates and time that are controlled to fill the mold while optimizing the tradeoffs between cosmetics and dimensional accuracy. PSI - Pounds per square inch, units for pressure
Puddle Temperature - The temperature of the liquid plastic immediately as it leaves the nozzle.
Purging - Cleaning one color or type of material from the cylinder of an injection molding machine or extruder by forcing it out with the new color or material to be used in subsequent production.
Pyrometer - A thermocouple activated device consisting of a readout device and a sensor.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Radiused - An edge or vertex that has been rounded.
Raw Material - Unprocessed polymer. Recess - An indentation in the plastic part caused by the impact of the ejector pins. Recover Time - The time it takes the screw to pullback into its original position where it is ready for another shot.
Reinforced Resin - Refers to base resins with fillers added for strength. They are particularly susceptible to warp because the fiber orientation tends to follow flow lines, resulting in asymmetric stresses. Typically these resins are harder and stronger but also more brittle. Resin - An organic substance of natural or synthetic origin characterized by being polymeric in structure and predominantly amorphous. Most resins are of high molecular weight and consist of long chain or network molecular structure.
Restart - The action taken to start a press anytime after initial start-up and approval of the production run.
Return Pushback Pins - Located in the ejector retainer plate. Forces the ejector plate and ejector retainer plate, and therefore the ejector pins, to the bottom position as the mold closes.
Rib - Configuration designed into a plastic part to provide lateral, horizontal, or other structural support.
Robot (Picker) - A pneumatically powered arm that "picks" the sprue and runners out of the mold upon its opening.
Rockwell Hardness - A test for hardness of a material in which a hardened steel ball or diamond point is pressed into the material under test. The depth of the indentation is measured.
Runner - The channel in an injection or transfer mold which connects the sprue with the cavity gate.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Screw - A helical flighted shaft which rotates within a barrel to mechanically process and advance a material being prepared for extrusion or injection molding.
Feed Zone - First section or zone of an extruder screw which is fed from the hopper.
Transition Zone - The section of an extruder screw in which the plastic resin is in both a solid state and molten state.
Metering Zone - The section of an extruder screw which has a pitch over a series of flights at the output end. Screw Body (Root) - The cylindrically shaped continuous control shaft.
Screw Flight - The helical metal thread of a screw in an extruder or injection molding machine.
Screw Manual Speed Percentage - The speed at which the screw will advance or retract when operated in manual mode.
Screw Pitch (Lead) - The distance in an axial direction from the center of a flight at its outside diameter to the center of the same flight one turn away.
Screw Shank - The rear protruding portion of the screw where the driving force is applied.
Screw Splines - The final section of the screw where the torque is applied to rotate the screw.
Sequence Selection - A menu system that allows the changing of modes for functions with alarms and unmanned settings.
Shear - The process when a force applied parallel to a surface slides against another.
Shear Heating - The heating of the material by the polymer layers sliding along each other or along the metal surfaces in the plasticating chamber of the processing machine.
Short Shot - Injection of insufficient material to fill the mold.
Shot - The amount of material injected into the mold in one cycle.
Shot Capacity - The maximum weight of material a machine can produce from one forward motion of the screw.
Shrinkage - The decrease in dimensions of a molded part through cooling.
Shut Down Sequence - The process which occurs when the temperatures remain out of tolerance for more than seven seconds. The temperatures for the nozzle, barrel, and mold will lower and remain at the shut down sequence set temperatures.
Side Action - A sliding cam arrangement within the mold that allows for the molding of parts with undercuts. The undercut-creating mold face is held in place during the injection process and then slides out of the way prior to ejection. Side Locks - Metal tongue and groove type pieces which provide alignment for molds with interlocking cavities and cores.
Sink - A depression or dimple on the surface of a molded part due to collapsing of the surface following local internal shrinkage after the gate seals.
Sleeve Ejectors - Tubular sleeves used to strip parts from the core.
Soak Timer - A timer allowing thirty minutes for the barrel and nozzle to reach the temperature set points upon the starting of the heaters. During this time, the screw cannot be moved.
Splay (Silver Streaking) - Lines found in part after molding, usually due to flow of material in mold.
Sprue - The channel or feed opening for the passage of material from the nozzle of the injection molding cylinder to the runners of the mold, also the plastic piece formed in this orifice.
Sprue Break - The process of molding when the screw retracts without rotating causing the resin to break from the sprue and the nozzle.
Sprue Bushing - A hardened steel insert in an injection mold which contains the tapered sprue and has a suitable seat for the nozzle for the injection cylinder. It is sometimes called an Adaptor.
Sprue Puller Pin - Pin located directly under the opening of the sprue. Used to pull the molded sprue out of the bushing after a shot has been made.
Staking - Pressure that joins two objects together. Inserts to plastic or plastic to plastic.
STEP - Stands for "Standard for the Exchange of Product Model Data". It is a common format for exchanging CAD data. Sticking - A problem during the ejection phase of molding, where a part becomes lodged in one or the other half of the mold, making removal difficult. This is a common issue when the part is not designed with sufficient draft. STL - Originally stood for "STereoLithography". It is a common format for transmitting CAD data to rapid prototyping machines and is not suitable for rapid injection molding. Straight Pull Mold - A mold without side actions. It is less expensive than a comparable mold with side actions. Strain - Elastic deformation due to stress. Measured as the change in length per unit of length in a given direction, and expressed in percentage or inches per inch.
Stress - The force per unit area, or intensity of the forces distributed over a given section.
Striation - A separation of colors resulting in a linear effect of color variation.
Stripper Bolts - Bolts used in a three plate mold which link the X-Plate and "B" half of the mold together in such a way that when the mold opens, these bolts pull the X-plate back.
Stripper Plate - Plate used to eject parts rather than a sleeve or pin.
Suck Back - Technique used to partially clear the resin from the injection nozzle after the injection cycle by pulling the screw rearward, thus drawing the resin back into the injector.
Sucker Pins - Pins used to hold runner system back on the X-plate.
Support Plate (Back Up Plate) - Mounted behind the core retainer plate to keep this plate from bending under the high pressure used in injection molding.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Tare Weight - The empty container weight.
Telescoping Shutoff - An area within a mold where metal slides among metal, usually creating a hole in the part. A three degree draft angle is required on any related part surfaces. Texture - A surface treatment applied to the mold to create texture on the parts. Thermocouple - A device which uses a circuit of two wires of dissimilar metal or alloys, the two junctions of which are at different temperatures. A net electromotive force (EMF) occurs as a result of this temperature difference. The minute electromotive force, or current, is sufficient to drive a galvanometer or potentiometer.
Thermoplastic - A material that will repeatedly soften when heated and harden when cooled.
Three Plate Mold - A Moldset consisting of an extra "X" plate used to separate runners and sprue from the parts.
Tie Bar (Strain Rods) - In molding machines, the bars that tie the stationary platen and the hydraulic clamping mechanism together. The moveable platen rides on tie bars. During mold clamp-up, the tie bars resist the strain created by the hydraulic cylinder clamping the moveable against the stationary mold.
Tolerance - A specified allowance for deviations in weighing, measuring, etc., or for deviations from the standard dimensions or weight.
Transducer - A force measuring device. It has the characteristics of providing an output, usually electrical, which serves as the measurement of load, force, compression, pressure, etc., when placed along the sensitive axis of the force cell.
Tumbler - A rotating machine that holds the container for mixing material with colorant or other additives or regrind.
Tunnel Gate - An injection method that uses a small gate located off the parting line in one of the mold halves. It leaves a vestige a short distance from the parting line of the part. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Valve Rear Seat - The bushing positioned behind the Valve Ring which prevents back flow when the Valve Ring comes in contact with it.
Valve Ring (Check Ring) - The ring of a nonreturn valve that permits flow in one direction and closes to prevent back flow.
Valve Tip - The tip of the reciprocating screw is the ram face that pushes the melt into the mold, and it is part of the nonreturn valve assembly.
Vent - A small hole or shallow channel in a mold which allows air or gas to exit as the material enters.
Vestige - A visible mark created by the manual process of finishing parts when the gate is trimmed. Ejector pins also may leave a vestige where they impact the part. Viscosity - The measure of the resistance of a fluid to flow.
V-P Position - Pressure Transfer Screw Position - The screw position at which the pressure changes from injection pressure to pack pressure.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP Warp - The curving or bending of parts that typically occurs after ejection as the part cools. Warp is often caused by glass-filled resins.
Water Fittings - The fittings mounted to the mold which connects the mold to the water lines. Water Lines - Water channels in a mold and core used to control the temperature of the mold.
Wireframe - A type of CAD model consisting only of lines and curves, in 2D or 3D. Wireframe models are not suitable for rapid injection molding. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z TOP X-Plate - The center plate of a 3 part mold, it usually separates the runners and sprue from the parts.
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