Vocabulary Flashcards
(157 cards)
1
Q
Air Burn
A
Air Burn: A patch or streak of brown or black material on the component caused by air or gases that have not been properly vented from the mold and have caused the material to overheat and burn.
2
Q
Antioxidant
A
Antioxidant: Additive used to help protect plastics from degradation through sources such as heat, age, chemicals, stress, etc.
3
Q
Anti Static Agent
A
Antistatic Agent: Additive used to help eliminate or lessen static electricity from the surface of the plastic part.
4
Q
Aspect Ratio
A
Aspect Ratio: Ratio of total flow length to average wall thickness.
5
Q
Back Pressure
A
Back Pressure: The pressure applied to the plastic during screw recovery. By increasing back pressure, mixing and plasticating are improved; however, screw recovery rates are reduced.
6
Q
Backing PLate
A
Backing Plate: A plate used as a support for the mold cavity block, guide pins, bushings, etc.
7
Q
Blistering
A
Blistering: A raised or layered patch of material on the surface of the component.
8
Q
Boss
A
Boss: Protuberance on a plastic part designed to add strength, facilitate alignment, provide fastening, etc.
9
Q
Broken Mold Marks
A
Broken Mold Marks: Filled in areas not per drawing specification due to mold damage.
10
Q
Bubbles
A
Bubbles: Air pockets that have formed in the material of the component. Bubbles may vary in size.
11
Q
Cavity
A
Cavity: The space inside a mold into which material is injected.
12
Q
Charge
A
Charge: The measurement or weight of material necessary to fill a mold during one cycle.
13
Q
Clamp
A
Clamp: The part of an injection molding machine incorporating the platens that provides the force necessary to hold the mold closed during injection of the molten resin and open the mold to eject the molded part.
14
Q
Clamping PLate
A
Clamping Plate: A plate fitted to a mold and used to fasten the mold to a platen.
15
Q
Clamping Plate
A
Clamping Plate: A plate fitted to a mold and used to fasten the mold to a platen.
16
Q
Clamping Pressure
A
Clamping Pressure: The pressure applied to the mold to keep it closed during a cycle, usually expressed in tons.
17
Q
Clarifiers
A
Clarifiers: Additive used in polypropylene random copolymers to improve clarity.
18
Q
Closed Loop Control
A
Closed-loop Control: System for monitoring complete, injection molding- process conditions of temperature, pressure and time, and automatically making any changes required to keep part production within preset tolerances.
19
Q
Cold Flow/orange peel/lumps
A
Cold Flow/Orange Peel/Lumps: Any material that has not cooled uniformly causing the appearance of either a speck of material lighter than what was used or a rippling effect on the surface of the component.
20
Q
Cooling Channels
A
Cooling Channels: Channels located within the body of a mold through which a cooling medium is circulated to control the mold surface temperature.
21
Q
Crack/Splits/Chips
A
Crack/Splits/Chips: A physical separation or tearing of the part.
22
Q
Cushin
A
Cushion: Extra material left in barrel during cycle to try and ensure that the part is packed out during the hold time.
23
Q
Cycle
A
Cycle: The complete sequence of operations in a process to complete one set of moldings. The cycle is taken at a point in the operation and ends when this point is again reached and moving platens of the clamp unit in the fully open position.
24
Q
Delamination
A
Delamination: When the surface of a finished part separates or appears to be composed of layers. Strata or fish-scale-type appearance where the layers may be separated.
25
Diaphragm Gate
Diaphragm Gate: Used in symmetrical cavity filling to reduce weld-line formations and improve filling rates.
26
Dimensional Problems
Dimensional Problems: Parts not made to drawing dimensional specifications due to internal part stress warping, mold damage, incorrect mold manufacturing, etc.
27
Direct Gate
Direct Gate: The sprue that feeds directly into the mold cavity.
28
Discolartion
Discoloration: Any change from the designated color of the material or component. Incorrect color of the component.
29
Dispersion Aids
Dispersion Aids: Perforated plates placed in the plasticator nozzle to aid in mixing or dispersing colorant as it flows through the perforations.
30
Draft
Draft: The degree of taper of a mold-cavity sidewall or the angle of clearance designed to facilitate removal of parts from a mold.
31
Drag Marks
Drag Marks: A form of deep scratch or scratches on the surface of the component that have no visible signs of loose chips or material.
32
Drooling
Drooling: The extrudation or leakage of molten resin from a plasticator nozzle or nozzle sprue bushing area while filling or shooting the mold.
33
Dwell
Dwell: A pause in the applied pressure to a mold during the injection cycle just before the mold is completely closed. This dwell allows any gases formed or present to escape from the molding material.
34
Ejection Pin Marks
Ejection Pin Marks: See Raised Ejector Site.
35
Ejector Pins
Ejector Pins: Pins that are pushed into a mold cavity from the rear as the mold opens to force the finished part out of the mold. Also called knockout pins.
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Ejector Return Pins
Ejector Return Pins: Projections that push the ejector assembly back as the mold closes. Also called surface pins or return pins.
37
Ejector Rod
Ejector Rod: A bar that actuates the ejector assembly when the mold opens.
38
Embedded Particulate
Embedded Particulate: Any completely embedded foreign particulate such as grease, metal, paint chips, burnt material, etc. that cannot be smeared or removed from the component.
39
Family Mold
Family Mold: A multi-cavity mold where each of the cavities forms one of the component parts of an assembled finished part.
40
Fan Gate
Fan Gate: A gate used to help reduce stress concentrations in the gate area by spreading the opening over a wider area. Less warping of parts can usually be expected by the use of this type of gate.
41
Fill
Fill: The packing of the cavity or cavities of the mold as required to give a complete part or parts that are free of flash.
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Fin
Fin: The web of material remaining in holes or openings in a molded part which must be removed for final assembly.
43
Flash
Flash: Any excess material that is formed with and attached to the component along a seam or mold parting line.
44
Flow
Flow: A qualitative description of the fluidity of a plastic material during the process of molding. A measure of its moldability generally expressed as melt flow rate or melt index.
45
Flow Line
Flow Line: Marks visible on the finished items that indicate the direction of the flow of the melt into the mold.
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Flow Marks
Flow Marks: Wavy surface appearances on a molded part caused by improper flow of the melt into the mold.
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Gate
Gate: An orifice through which the melt enters the mold cavity.
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Gate Trim
Gate Trim: Remnant of plastic left over from cutting the component from the runner or sprue, usually to be cut flush with the edge of the component.
49
Hob
Hob: A master model in hardened steel. The hob is used to sink the shape of a mold into a soft metal block.
50
Homopolymer
Homopolymer: Plastic that results by the polymerization of a single monomer.
51
Hopper Dryer
Hopper Dryers: Auxiliary equipment that removes moisture from resin pellets.
52
Hot Runner Mold
Hot-Runner Mold: A mold in which the runners are insulated from the chilled cavities and are kept hot. Hot-runner molds make parts that have no scrap.
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Injection Pressure
Injection Pressure: The pressure on the face of the injection screw or ram when injecting material into the mold, usually expressed in PSI.
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Insert Molding
Insert Molding: Insert molding is the process of molding plastic around preformed metal inserts. This process is compatible with both thermoplastic and thermoset materials.
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Insulated Runner
Insulated Runner: See hot-runner mold.
56
IZOD impact test
Izod Impact Test: Test to determine impact strength of a sample by holding a sample bar at one end and broken by striking. Sample specimen can be either notched or unnotched.
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Jetting
Jetting: A turbulent flow in the melt caused by an undersized gate or where a thin section rapidly becomes thicker.
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Jig
Jig: A tool for holding parts of an assembly during the manufacturing process.
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Knit Lines
Knit Lines: Where melted material flows together to form a line or lines that may cause weakening or breaking of the component.
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Knockout Pins
Knockout Pins: A rod or device for knocking a finished part out of a mold.
61
L/D Ratio
L/D Ratio: A term used to help define an injection screw. This is the screw length-to-diameter ratio.
62
Melt Flow Rate
Melt Flow Rate: A measure of the molten viscosity of a polymer determined by the weight of polymer extruded through an orifice under specified conditions of pressure and temperature. Particular conditions are dependent upon the type of polymer being tested. MFR usually is reported in grams per 10 minutes. Melt flow rate defines the flow of a polypropylene resin. An extrusion weight of 2160 grams at 446°F (230°C) is used.
63
Melt Index
Melt Index: Term that defines the melt flow rate of a polyethylene resin. An extrusion weight of 2160 grams at 310°F (190°C) is used.
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Mold
Mold: A series of machined steel plates containing cavities into which plastic resin is injected to form a part.
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Mold Changer
Mold Changer: An automated device for removing one mold from a machine and replacing it with another mold.
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Mold Frame
Mold Frame: A series of steel plates which contain mold components, including cavities, cores, runner system, cooling system, ejection system, etc.
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Mold Release Problems
Mold Release Problems: Excess use of mold release may leave parts oily and weaken the material.
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Mold Temperature-control Unit
Mold-Temperature-Control Unit: Auxiliary equipment used to control mold temperature. Some units can both heat and cool the mold. Others, called chillers, only cool the mold.
69
Moving PLaten
Moving Platen: The platen of an injection molding machine that is moved by a hydraulic ram or mechanical toggle.
70
Multi Cavity Mold
Multi-Cavity Mold: A mold having two or more impressions for forming finished items in one machine cycle.
71
Multi Material Molding
Multi-Material Molding: The injection of two-or-three materials, in sequence, into a single mold during a single molding cycle. The injection molding machine is equipped with two-or-three plasticators. (See also co-injection)
72
Nest PLate
Nest Plate: A retainer plate in the mold with a depressed area for cavity blocks.
73
Non-Fill
Non-Fill: See short shot.
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Non-Return Valve
Non-Return Valve: Screw tip that allows for material to flow in one direction and closes to prevent back flow and inject material into the mold.
75
Nozzle
Nozzle: The hollow-cored, metal nose screwed into the injection end of a plasticator. The nozzle matches the depression in the mold. This nozzle allows transfer of the melt from the plasticator to the runner system and cavities.
76
Nucleating Agent
Nucleating Agent: Additive used with polypropylene to increase crystallization rate by providing additional sites for crystal growth.
77
Orange Peel
Orange Peel: A surface finish on a molded part that is rough and splotchy. Usually caused by moisture in the mold cavity.
78
Packing
Packing: The 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 finished parts. Over- or under-packing results in less than optimum fill.
79
Part Picker
Part Picker: An auxiliary unit usually mounted on fixed platen, which reaches into the open mold to grab parts and remove them prior to next molding cycle. Also called a robot, the device is used when you do not want to drop parts from mold upon ejection.
80
Parting Line
Parting Line: On a finished part, this line shows where the two mold halves met when they were closed.
81
Peeling
An open blister
82
PET
PET: Polyethylene Terephthalate, a type of polyester and a leading recyclable plastic material.
83
Pin Marks
Pin Marks: See Raised Ejector Site.
84
Pinpoint Gate
Pinpoint Gate: A restricted gate of 0.030 in or less in diameter, this gate is common on hot-runner molds.
85
Piston
See Ram
86
Plasticate
Plasticate: To soften by heating and mixing.
87
Platens
Platens: The mounting plates of a press on which the mold halves are attached.
88
Plasticator
Plasticator: The complete melting and injection unit on an injection molding machine.
89
Plate Out
Plate-out: The blooming of additives onto machinery during processing of plastics.
90
Plunger
See Ram
91
Preform
Preform: A plastic test tube shaped part produced by injection molding systems in the first step of a two-stage injection molding and blow molding process used to produce PET bottles or containers. The perform is subsequently re-heated and stretch blown through a blow molding process into the final container shape.
92
Pressure Pads
Pressure Pads: Reinforcements of hardened steel distributed around the dead areas in the faces of a mold to help the land absorb the final pressure of closing without collapsing.
93
Pulled Gate
Pulled Gate: Area where the part was connected to the sprue or runner that has been drawn out or stretched from the surface.
94
Purging
Purging: The forcing one molding material out of the plasticator with another material prior to molding a new material. Special purging compounds are used.
95
Raised Ejector Site / Ejection Pin Marks / Pin Marks:
Raised Ejector Site / Ejection Pin Marks / Pin Marks: Where the ejector site is either heightened or raised above the surface of the component.
96
Ram
Ram: The forward motion of the screw in the plasticator barrel that forces the melt into the mold cavity.
97
Recovery Time
Recovery Time: The length of time for the screw to rotate and create a shot.
98
Regrind problems
Re-grind Problems: See Silver/Splay. Use of re-ground material increases susceptibility for moisture problems as well as polymeric chain length degradation.
99
Restricted Gate
Restricted Gate: A very small orifice between runner and cavity in an injection mold. When the part is ejected, this gate readily breaks free of the runner system. Generally, the part drops through one chute and the runner system through another leading to a granulator and scrap reclaim system.
100
Retainter PLate
Retainer Plate: The plate on which demountable pieces, such as mold cavities, ejector pins, guide pins and bushings are mounted during molding.
101
Retractable Cores
Retractable Cores: Used when molding parts in cavities not perpendicular to the direction in which the part is ejected from the mold. The cores are automatically pulled from the mold prior to the mold opening and reinserted when the mold closes again and prior to injection.
102
Rib
Rib: A reinforcing member of a molded part.
103
Ring Gate
Ring Gate: Used on some cylindrical shapes. This gate encircles the core to permit the melt to first move around the core before filling the cavity.
104
Robot
Robot: Automated devices for removing parts upon ejection from an open mold rather than letting the parts drop. Also see parts picker. Robots also can perform secondary functions, such as inspection, degating, precise placement of parts on a conveyor, etc.
105
RMS Roughness
RMS Roughness: A measure of the surface roughness/smoothness of a material. The root mean square (RMS) average of the "peaks and valleys" of a surface is determined using a Profilometer. The lower the number, the smoother the surface: a reading of one or two would be a very polished and smooth surface.
106
Rockwell Hardness
Rockwell Hardness: A measure of the surface hardness of a material. A value derived from the increase in depth of an impression as the load of a steel indenter is increased from a fixed minimum value to a higher value and then returned to the minimum value. The values are quoted with a letter prefix corresponding to a scale relating to a given combination of load and indenter.
107
Runner
Runner: The channel that connects the sprue with the gate for transferring the melt to the cavities.
108
Runnerless molding
Runnerless molding: See hot-runner mold.
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Scratch
Scratch: Mark made via abrasion, not as specified in visual or cosmetic specification criteria.
110
Screw Travel
Screw Travel: The distance the screw travels forward when filling the mold cavity.
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Short Shot
Short Shot: Failure to completely fill the mold or cavities of the mold. Edges may appear melted.
112
Shot
Shot: The complete amount of melt injected during a molding cycle, including that which fills the runner system.
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Shot Capacity
Shot Capacity: Generally based on polystyrene, this is the maximum weight of plastic that can be displaced or injected by a single injection stroke. Generally expressed as ounces of polystyrene.
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Shrinkage
Shrinkage: The dimensional differences between a molded part and the actual mold dimensions.
115
Side Bars
Side Bars: Loose pieces used to carry one or more molding pins and operated from outside the mold.
116
Side Draw Pins
Side-Draw Pins: Projections used to core a hole in a direction other than the line of closing of a mold and which must be withdrawn before the part is ejected from the mold. See also Retractable Cores.
117
Silver
Silver: See Splay.
118
Sink/Shrink
Sink/Shrink: A depression or valley on a component surface that would not normally have a depression.
119
Silver Streaks
Silver Streaks: See splay marks.
120
Single Cavity Mold
Single-Cavity Mold: A mold having only one cavity and producing only one finished part per cycle.
121
Sink Mark
Sink Mark: A shallow depression or dimple on the surface of a finished part created by shrinkage or low fill of the cavity.
122
Slip Agent
Slip Agent: Additive used to provide lubrication during and immediately following processing of plastics.
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Slip Plane
Slip Plane: Marks evident in or on finished parts due to poor welding or shrinking upon cooling.
124
Spiral Flow
Spiral Flow: Test performed by injection molding a sample into a spiral mold and used to compare the processability of different resins.
125
Splash Marks
Splash Marks: See splay marks.
126
Splay
Splay: A shiny area on the surface that is usually small in size and may have the appearance of a lightly tinted or silver streaks.
127
Splay Marks
Splay Marks: Marks or droplet type imperfections on the surface of the finished parts that may be caused by the splaying of the melt through the gates and into the cool cavity where they set up.
128
Split Ring Mold
Split-Ring Mold: A mold in which a split cavity block is assembled in a channel to permit the forming of undercuts in a molded piece. These parts are ejected from the mold and then separated from the piece.
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Sprue Bushing
Sprue Bushing: A hardened-steel insert in the mold that accepts the plasticator nozzle and provides an opening for transferring the melt.
130
Sprue Gate
Sprue Gate: A passageway through which melt flows from the nozzle to the mold cavity.
131
Sprue Lock
Sprue Lock: The portion of resin retained in the cold-slug well by an undercut. This lock is used to pull the sprue out of the bushing as the mold opens. The sprue lock itself is pushed out of the mold by an ejector pin.
132
Sprue
Sprue: The feed opening provided in injection molding between the nozzle and cavity or runner system.
133
Stack Molds
Stack Molds: Two or more molds of a similar type that are positioned one behind the other to allow for additional parts to be manufactured during a cycle.
134
Stationary PLaten
Stationary Platen: The large front plate of an injection molding press to which the front plate of the mold is secured. This platen does not move during normal operation.
135
Stress Cracking
Stress Cracking: There are three types of stress cracking: 1. Thermal stress cracking is caused by prolonged exposure of the part to elevated temperatures or sunlight. 2. Physical stress cracking occurs between crystalline and amorphous portions of the part when the part is under an internally or externally induced strain. 3. Chemical stress cracking occurs when a liquid or gas permeates the partís surface. All of these types of stress cracking have the same end result: the splitting or fracturing of the molding.
136
Striations
Striations: Marks evident on the molded-part surfaces that indicate melt flow directions or impingement.
137
Stringing
Stringing: Occurs between the finished part and the sprue when the mold opens and the melt in this area has not cooled sufficiently.
138
Strings
Strings: Strings of material due to poor gate cut off. See pulled gate.
139
Stripper PLate
Stripper Plate: A plate that strips a molded piece from core pins or force plugs. The stripper plate is set into operation by the opening of the mold.
140
Structural Foam Molding
Structural Foam Molding: Process for making parts that have solid outer skin and foamed core.
141
Submarine Gate
Submarine Gate: A gate where the opening from the runner into the mold cavity is located below the parting line. Also called a tunnel gate.
142
Suck-back
Suck-back: When the pressure on the sprue is not held long enough for the melt to cool before the screw returns. Some of the melt in the cavities or runner system may expand back into the nozzle and cause sinks marks on the finished part.
143
Tab Gate
Tab Gate: A small removable tab about the same thickness as the molded item, but usually perpendicular to the part for easy removal.
144
Thermoplastic
Thermoplastic: A polymer which melts or flows when heated. Thermoplastic polymers are usually not highly cross-linked, and act much like molecular solids: low melting and boiling points, high ductile strength.
145
Thermoset
Thermoset: A polymer that doesn't melt when heated. Thermoset polymers "set" into a given shape when first made and afterwards do not flow or melt, but rather decompose upon heating. They are often highly cross-linked polymers, with properties similar to those of network covalent solids, i.e., hard and strong.
146
Tie-bar Spacing
Tie-Bar Spacing: The space between the horizontal tie-bars on an injection molding machine. Basically, this measurement limits the size of molds that can be placed between the tie-bars and into the molding machine.
147
Toggle
Toggle: A type of clamping mechanism that exerts pressure by applying force on a knee joint. A toggle is used to close and exert pressure on a mold in a press.
148
Tonnage
Tonnage: The measure by which injection molding machines are typically categorized, representing the clamping force of the injection molding machine.
149
Undercut
Undercut: A protuberance or indentation that impedes withdrawal from a two-piece rigid mold.
150
Valve Gating
Valve Gating: A type of gate where a pin is held in the gate or channel by spring tension. As the injection stroke moves forward, this gate compresses the plastic in the runner. When this pressure build-up is sufficient to overcome the spring tension, the pin is then pushed back (pulled) and the fast decompression of the melt fills the cavity at extremely high speed.
151
Vent
Vent: A shallow channel or opening cut in the cavity to allow air or gases to escape as the melt fills the cavity.
152
Vented Barrel
Vented Barrel: Special plasticator unit with a vent port over the compression section of the screw to permit escape of gases prior to injecting melt into mold. Often used when molding moisture-sensitive resins.
153
Vertical Flash ring
Vertical Flash Ring: The clearance between the force plug and the vertical wall of the cavity in a positive or semi-positive mold. Also the ring of excess melt which escapes from the cavity into this clearance space.
154
voids
Voids: Air pockets in the part which have opened or were not filed with material, leaving an opening or hole.
155
Warpage
Warpage: Dimensional distortion in a molded object. Caused by internal stresses via un-even material flow, cooling, and compression.
156
Weld Line
Weld Line: Where melted material flows together during molding to form a visible line or lines on a finished part that may cause weakening or breaking of the component.
157
Wisps
Wisps: Similar to stringing but smaller in size. These also may occur as slight flashing when the mold is over packed or forced open slightly. Mold-parting-line wear or misalignment can also cause wisps
