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plastic mold company

Glossary of Terms (2)

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FLOW LINES See SPLAY
FREEZE TIME The time it takes to set the molded plastic resin for a variety of functions. For example, freeze time describes the time it takes to set the molded resin, in order for ejection to occur.
FRONT CAVITY PLATE See “A” PLATE
GATE An opening at the end of the runner through which the material enters the cavity.
GUIDE PINS See LEADER PINS
HARDENABILITY The ability of a material to become harder by the addition of alloying elements and heat treatment processes. It should not be confused with hardness.
HARDNESS The resistance of a metal to surface indentation (denting) or abrasion (scratching). Indentation hardness can be measured with the Rockwell or Brinell methods.
HEAT SINK A heat absorber or collector. It is used as a mold component or insert into the component to collect heat in an area that is hard to reach by typical cooling design. Materials typically used are copper, beryllium copper, tungsten alloys, and gas or liquid thermal pins.
HOT RUNNER MOLD A molding method in which the runner system is kept hot and insulated from the cavity portion of the mold. The mold parting line is typically at the gate. This runner system is not ejected to become waste or regrind material, as it is in the cold runner system.
INJECTION The process of forcing a plastic material or a molten alloy into a mold.
INJECTION MOLDING The process in which the plastic material is heated to a molten state in a heating cylinder, and then forced into a cooled mold to produce the desired shape.
INSERT Integral inserts – parts which are machined separately from the basic core and cavity, and are then installed in the proper position in the core and cavity, and which become part of the molded part after the molding material has hardened.
INSERTS, MOLDED-IN Loaded inserts – not part of the mold, but separate metal pieces placed in the mold which become part of the molded part after the molding material has hardened.
KNOCKOUT BAR See EJECTOR PLATE
KNOCKOUT PIN PLATE See EJECTOR RETAINER PLATE
KNOCKOUT PINS Term given to ejector pins.
LEADER PINS Hardened and ground steel pins pressed into one of the plates. They align the two halves of the mold base. (Also called GUIDE PINS)
LOCATING RING 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.
MACHINABILITY The relative ease of which a metal can be machined or worked on with tools.
MICROPROCESSOR A computer chip integrated circuit, capable of controlling the (Integrated Circuit) input and output functions, for which it was designed – such as automatically controlling the cooling cycle of a mold. 

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MIRROR FINISH A diamond finish that shines and reflects light.
MOLD The entire mechanism (cavities, cores, plungers, holder blocks, etc.) needed to mold parts from plastic materials or from non-ferrous alloys.
MULTIPLE CAVITY MOLD A mold which has a number of cavities and produces more than one part in each cycle.
ORANGE PEEL A condition caused by too much pressure, speed, or both when diamonding. When orange peel occurs the surface becomes bumpy and irregular.
O-RING A tire-shaped, round cross-section of a synthetic rubber gasket or seal. A coolant seal can be formed by a compression fit of the O-ring and itÆs mating parts.
PARALLELS Mounted on the bottom clamping plate under the support plate to form a space (ejector housing) which allows the ejection stroke when the piece parts are ejected. (Also called RAILS)
PARTING LINES Marks on a molding where halves of the mold meets in closing.
PIECE PART The article or part to be molded.
PILLARS Bars placed between the support plate and the bottom clamping plate. Bolted or doweled to the bottom clamping plate, they are used as additional support for the core retainer plate.
PLATENS The mounting plates of a press to which the mold assembly is bolted. 
PROFILER Profiler is a brand name commonly used to refer to any reciprocating hand piece.
PROTOTYPE MOLD A temporary or experimental mold construction made in order to obtain information on part design, tool design, and market reactions.
PUSH BACKS See RETURN PINS
RADIATE Emitting rays of heat, such as a mold-base radiating heat from the molding process.
RAILS See PARALLELS
REAMED HOLE A round, hard, multi-cutting edge scraping tool. It is used after a hole is drilled in order to improve the hole geometry. It will produce a rounder, straighter, and smoother hole than drilling.
REAR CAVITY PLATE See “B” PLATE
REAR CLAMPING PLATE See BOTTOM CLAMPING PLATE
REDUCE DEFORMATION Elements added to control the amount of change in a metal due to stress, thermal change, change in moisture or other changes.
RELEASE The ability of a mold to eject a part. 
RETURN PINS Located in the ejector retainer plate. These pins force the ejector plate and ejector retainer plate and, therefore the ejector pins, to the bottom position as the mold closes. (Also called EJECTOR RETURN PINS, SAFETY PINS, or PUSH BACKS)
REYNOLDS NUMBER A number used as a measure of turbulent flow for a liquid.
RUNNERS Channels through which plastics flow from the sprue to the gates of mold cavities.
RUST RESISTANCE The ability of a ferrous metal to resist oxidation in the presence of water (rust).
SAFETY PINS See RETURN PINS
SCAR An undesirable cosmetic mark left on the mold surface due to a variety of reasons, such as degating the part from the runner system.
SENSORS A variety of devices designed to detect, measure, or record physical phenomena such as temperature.
SHRINKAGE ALLOWANCE The additional dimensions that must be added to a mold to compensate for shrinkage of the plastic molding material on cooling.
SPACER BUTTONS Pressed into the bottom clamping plate, they are lands for the ejector plate. (Also called STOP PINS)
SPRUE BUSHING Butted up against the nozzle of the injection machine. Has a conical-shaped hole through which the material is forced into the mold runner. 

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