Additive Manufacturing as a Secondary Process 231

"Additive Manufacturing as a Secondary Process" provides a comprehensive overview of the way in which manufacturers can use additive manufacturing (AM) as a secondary, or indirect, process. AM methods can make a variety of tooling, such as molds and patterns, for use in several different casting, forming, and molding processes. Using AM as a secondary process benefits traditional manufacturing processes by reducing costs associated with lead time, tooling, and labor. An individual must understand the different advantages and disadvantages associated with AM as a secondary process prior to determining whether or not to utilize it.

Knowledge about AM secondary processes and their benefits is important in order to understand the full impact that AM has upon traditional manufacturing. After completing this class, users will be able to identify the traditional manufacturing areas that benefit from using AM as a secondary process and the advantages and disadvantages of doing so.

Class Details

Class Name:
Additive Manufacturing as a Secondary Process 231
Description:
"Additive Manufacturing as a Secondary Process" provides a comprehensive overview of the way in which manufacturers can use additive manufacturing (AM) as a secondary, or indirect, process. AM methods can make a variety of tooling, such as molds and patterns, for use in several different casting, forming, and molding processes. Using AM as a secondary process benefits traditional manufacturing processes by reducing costs associated with lead time, tooling, and labor. An individual must understand the different advantages and disadvantages associated with AM as a secondary process prior to determining whether or not to utilize it.

Knowledge about AM secondary processes and their benefits is important in order to understand the full impact that AM has upon traditional manufacturing. After completing this class, users will be able to identify the traditional manufacturing areas that benefit from using AM as a secondary process and the advantages and disadvantages of doing so.
Version:
2.0
Difficulty:
Intermediate
Number of Lessons:
20

Class Outline

  • Additive Manufacturing as a Secondary Process
  • AM as a Secondary Process: Advantages and Disadvantages
  • Investment Casting
  • AM for Investment Casting
  • Sand Casting
  • AM for Sand Casting
  • Die Casting
  • AM for Die Casting
  • Review: AM for Casting Processes
  • Silicone Molding
  • AM for Silicone Molding
  • Composite Molding
  • AM for Composite Molding
  • Review: AM for Molding Processes
  • Other Forming and Molding Processes
  • AM for Other Forming and Molding Processes
  • Electrical Discharge Machining
  • AM for Electrical Discharge Machining
  • AM Jigs and Fixtures
  • Review: AM for Other Processes

Objectives

  • Distinguish between additive manufacturing as a primary process and a secondary process.
  • Describe the advantages and disadvantages associated with using AM as a secondary process.
  • Describe investment casting.
  • Describe ways in which AM can be used as a secondary process for investment casting.
  • Describe sand casting.
  • Describe ways in which AM can be used as a secondary process for sand casting.
  • Describe die casting.
  • Describe ways in which AM can be used as a secondary process for die casting.
  • Describe silicone molding.
  • Describe ways in which AM can be used as a secondary process for silicone molding.
  • Describe composite molding.
  • Describe ways in which AM can be used as a secondary process for composite molding.
  • Distinguish between sheet metal forming, thermoforming, and paper pulp molding.
  • Describe ways in which AM can be used as a secondary process within sheet metal forming, thermoforming, and paper pulp molding.
  • Describe electrical discharge machining.
  • Describe the way in which AM can be used as a secondary process for electrical discharge machining.
  • Describe the benefits provided by using AM methods to build jigs and fixtures.

Job Roles

Certifications

Glossary

Vocabulary Term Definition
acrylonitrile butadiene styrene ABS. A thermoplastic material with good heat, chemical, and impact resistance. Acrylonitrile butadiene styrene is a common polymer used in additive manufacturing processes.
additive manufacturing AM. The process of joining or solidifying materials to make an object based on a three-dimensional computer model. Additive manufacturing methods typically build up layers of material to create an object.
aerospace The industry that covers machines or vehicles of flight. Aerospace manufacturers generally require workpiece materials with very specific properties.
aluminum A lightweight metal that is silvery white in color. Aluminum resists corrosion and is a good conductor of electrical and thermal energy.
AM Additive manufacturing. The process of joining or solidifying materials to make an object based on a three-dimensional computer model. AM methods typically build up layers of material to create an object.
assembly The process of fitting components together into a larger or completed part. Assembly includes inserting components into a final part or mechanically joining components together.
automated Run by a preprogrammed mechanical system with little to no human intervention. Automated machines operate more efficiently and precisely than those directly controlled by an operator.
binder A material that holds together two or more other materials. Binders promote adhesion and cohesion.
binder jetting An additive manufacturing process in which liquid binder is used to join powdered materials to create part. Binder jetting systems use powdered plaster, metal, or sand.
blister packs Packaging with clear plastic cavities or pockets on a rigid backing that is used for a variety of products. Blister packs are often thermoformed.
bonded Held together by a force of attraction or by the application of a chemical agent. Bonded components must first be assembled together.
build rates The time it takes to build a part or the number of parts that can be made in a set period of time. Build rates, or production rates, for additive manufacturing are considerably lower than traditional manufacturing.
burrs A rough edge remaining on material, such as metal, after it has been machined. Burrs must be removed during finishing processes to increase the functionality and appearance of a part.
carbides A material developed by combining carbon with chromium, tungsten, or titanium, among other materials. Carbide is used in metal cutting tools for its hardness and wear resistance.
carbon fiber Material made from slender, thread-like strands of carbon, a strong non-metallic element. Carbon fibers are a commonly used composite reinforcement material.
casting A general category of metalworking processes that involves pouring a liquid material into a hollow mold and allowing the material to cool into a solid shape. Casting is a traditional manufacturing process and includes methods such as investment and sand casting.
cavity inserts A piece of tool steel placed inside the cover base and ejector base to form a portion of the die cavity shape. Cavity inserts are brittle and must be handled with caution.
ceramic An inorganic material that consists of both metallic and nonmetallic atoms held together by a strong primary bond. Ceramics include metal oxides, nitrides, and glasses.
chemical bath A specialized solution that an engineer dips an AM part into in order to remove support structures. A chemical bath is formulated to dissolve support structures without harming the part.
clamps A workholding device that grips and holds a workpiece in place. Clamps maintain the position of a workpiece by applying inward pressure.
composite A material made by mixing together two or more of the following groups: metals, plastics, and ceramics. Composite materials are categorized by their matrix material.
composite molding A manual molding process during which reinforcement material is positioned into a mold and saturated with a resin. Composite molding is also referred to as lay-up molding.
computer numerically controlled machines CNC machines. A sophisticated, precise machine tool run by a computer that requires programmed speed and feed rate values. Computer numerical control machines are very rigid and are capable of fast cutting speeds.
conformal cooling The creation of cooling channel configurations that curve and closely correspond to a part's shape. Conformal cooling provides manufacturers with better heat management and allows them to reduce tools wear and cycle time.
contoured cooling channels A type of cooling channel that are curved and closely follow a part's shape in order to better circulate cooling fluid and maintain the desired die temperature. Contoured cooling channels are created by additive manufacturing processes.
conventional EDM A common electrical discharge machining method that uses a customized electrode. Conventional EDM is also referred to as ram EDM.
coolant A fluid used to decrease the temperature of a tool and workpiece to prolong tool life. Coolants may also serve other purposes such as helping to flush away metal pieces removed during machining processes.
cooling channels A passage through which a cooling fluid is circulated to maintain the desired die temperature. Cooling channels, which may also be called cooling lines, may be straight or contoured.
cope The top half of the mold in a casting operation. Most molds have two halves that are used together to shape the casting.
copper A reddish nonferrous metal that is very ductile. Copper is thermally and electrically conductive as well as corrosion resistant.
cores A part that forms the hollow area or internal feature of a casting. Cores are solid components that are placed inside a mold cavity prior to pouring in the molten metal.
cover die One half of a die, which holds the casting during cooling and solidification, that is attached to a die casting machine. Cover dies help to form a hollow cavity that holds heated liquid metal when paired with ejector dies.
cracks A visible fracture or point of separation in the surface of a material. Cracks can originate from pores on the surface of additively manufactured metal parts and are a type of defect.
cure To cause a material to bond and solidify by permanently cross-linking its molecules through heat, time, or chemical means. Curing often occurs as a molten material cools and solidifies.
current The rate and amount of electrical flow, which is measured in amperage. Current flowing through an electrode and to a workpiece creates the electrical arc used in electrical discharge machining.
cutting forces A force generated by the motion of the cutting tool and the resistance of a workpiece. Cutting forces are not produced during electrical discharge machining.
cycle time The amount of time required to to complete one manufacturing process from its beginning to its end. Cycle times for casting and molding processes include the time it takes to close a mold or die, fill a cavity with molten material, cool the material, open the mold or die, and release the final part.
cylinder head A component in an automotive engine that helps form the combustion chamber. Cylinder heads are often created by casting processes using cores to shape their internal components.
defects An imperfection in a part that prevents it from operating correctly. Defects sometimes appear in additive manufacturing parts when layers do not adhere to each other correctly or when surface porosity occurs in a part.
degrade To break down slowly over time due to exposure to various environmental conditions. Dies degrade over time and use due to their exposure to extreme temperatures.
design The process of creating the actual part specifications. Design involves creating the blueprints and prototypes for a part.
die A reusable mold that holds heated liquid metal and imparts its shape as the metal cools. Dies are made of two halves instead of being one solid object.
die casting A thermal, high-pressure metal casting process that involves injecting molten metal into a mold at high velocity and pressure. Die casting is a metal shaping process used in traditional manufacturing.
die casting machine A machine that holds the two halves of the die together while molten metal is quickly injected into the die cavity under high pressure. Die casting machines often clamp the two halves closed when they are mounted onto the machine.
die cavity The recessed, enclosed space between two die halves. Die cavities form the shape of the final part as well as hold the casting as it cools and solidifies.
dielectric liquid A fluid that does not conduct an electric current under normal circumstances. Dielectric fluid insulates and cools an electrode and workpiece, conveys the spark, and flushes away the removed metal during electrical discharge machining.
direct metal laser sintering DMLS. An additive manufacturing process that uses a laser to bond successive layers of material in a bed of powdered metal. Direct metal laser sintering can produce complex metal parts, such as dies with contoured cooling channels.
directed energy deposition DED. An additive manufacturing process in which focused thermal energy is used to melt materials as they are deposited. Directed energy deposition is often used with powdered or wire metal.
dissipate To spread out, or disperse, and disappear. Contoured cooling channels allows heat to dissipate evenly.
downtime Unproductive blocks of time during which machine operations cease, often due to mechanical problems. Downtime raises a company's financial costs, which leads to financial losses.
drag The bottom half of the mold in a casting operation. Most molds have two halves that are used together to shape the casting.
drilling The use of a multi-point tool to machine a new round hole into the surface of a workpiece. Drilling is often performed on a drill press.
EDM Electrical discharge machining. A widely used nontraditional machining process that removes metal through the repeated sparking of an electrical current. During electrical discharge machining, a workpiece and an electrode are immersed in a dielectric fluid.
ejector die One half of a die that helps form the die cavity, which holds the casting during cooling and solidification. Ejector dies move in order to eject castings from die cavities.
electrical discharge machining EDM. A nontraditional machining process that erodes unwanted material from a workpiece using an electric arc. During electrical discharge machining, a workpiece and an electrode are immersed in a dielectric fluid.
electrically conductive The ability of a material to act as a medium for conveying electricity. Electrically conductive materials include carbides, polycrystalline diamond, and a variety of metals.
electrodes A device used to convey an electric current, which can either leave or enter the electrode. Electrodes are used during electrical discharge machining, which generates an electric spark between an electrode and a workpiece.
end-use Designed to be used directly by a consumer or directly in another manufactured product. End-use products created by additive manufacturing include medical implants, custom dental devices, and camera equipment.
engine block A solid automotive part that contains cylinders and other components. Engine blocks are often created by casting processes using cores to shape their internal components.
epoxy A thermoset polymer that is very tough and heat resistant. Epoxies are common polymers used in silicone molding to create final parts.
features A distinguishing characteristic that performs a function on a part. Features include grooves, shoulders, hinges, among many others.
ferrous A metal in which iron is the main ingredient. Ferrous metals commonly used in additive manufacturing include different types of steel.
fiber molding A shaping process that forms paper pulp into a finished part. Fiber molding, also called paper pulp molding, is used to create protective packaging.
fiberglass Material made from extremely fine strands of glass. Fiberglass is a commonly used composite reinforcement material.
finishing processes The treatment of a surface to remove roughness and irregularities and improve its appearance. Finishing processes include sanding, heat treating, and painting.
fixture A customized workholding device used to position and hold a workpiece during a manufacturing process. Fixtures are often built to hold a specific part design.
flask A tool used in sand casting that contains the mold. Flasks, which are usually made from metal or wood, frame the sides of a sand mold.
forming A general category of manufacturing processes that involve bending, separating, or shaping material using punches and dies. Forming is a traditional manufacturing process and includes methods such as rolling and extrusion.
foundry sand A material consisting of sand mixed with additives, such as clay, coal, and water. Foundry sand, which is the primary molding material for sand casting processes, is also called green sand.
gates An opening at the end of a runner, which directs the flow of molten material into the mold cavity. Gates connect runners to a die cavity.
gating system A network of channels in a mold or die. Gating systems deliver molten metal into the mold or die cavity.
gel coating A layer of material that is usually applied to the mold's surface before forming the composite part. Gel coatings protect the surface of the composite and give it a smooth finish.
geometric complexity The linear and curved shapes that characterize a part. Geometric complexity is one of the key advantages of additive manufacturing.
graphite A soft, black form of carbon. Graphite is commonly used to make electrical discharge machining electrodes.
green sand A material consisting of sand mixed with additives, such as clay, coal, and water. Green sand, which is the primary molding material for sand casting processes, is also called foundry sand.
hand tools A tool that is not powered by an external source but rather by the individual using the tool. Hand tools include hammers, screwdrivers, and wrenches.
heat resistant Able to withstand high temperatures. Heat resistant parts will not deform or lose their shape when exposed to heat.
high-performance composite A composite made from specially formulated resins and high-performance fibers. High-performance composites are often used in applications requiring parts with high strength, stiffness, and resistance to heat.
high-pressure casting A type of casting process that involves injecting metal into a mold at very high velocity using a pumping system. Die casting is a high-pressure metal casting process.
hydroforming A process that shapes ductile metal sheets using hydraulic pressure and a die. Hydroforming is one method of sheet metal forming.
implode To collapse inward. Hollow wax pattern designed to implode help reduce the chance of an investment mold developing cracks.
indirect rapid prototyping Using additive manufacturing processes to create patterns or molds for parts and tooling rather than final products. Indirect rapid prototyping processes are sometimes referred to as secondary processes or indirect rapid tooling.
indirect rapid tooling Using additive manufacturing processes to create patterns or molds for parts and tooling rather than final products. Indirect rapid tooling processes are sometimes referred to as secondary processes or indirect rapid prototyping.
interlocking Two parts that connect by overlapping or fitting together. Interlocking often ensures each individual part is unable to move or operate without the other part.
internal cavities An empty space on the inside of an otherwise solid part. Internal cavities in parts are made using cores during casting processes.
investment casting A casting process that creates intricate shapes using an expendable wax pattern and mold. Investment casting is also called precision casting and lost-wax casting.
jig A customized workholding device used to position and hold a workpiece while guiding the location and motion of a tool. Jigs are often built to hold a specific part design.
kraft paper A type of durable paper that has high elasticity, strength, and tear resistance. Kraft paper often composes some of the slurry material used in paper pulp molding.
lay-up molding A manual molding process during which reinforcement material is positioned into a mold and saturated with a resin. Lay-up molding is also referred to as composite molding.
lead times The amount of time it takes from the beginning of a project, including initial design and prototyping, to the completion of the finished part. Lead time can be dramatically shortened through the use of additive manufacturing processes.
lights-out manufacturing Facilities that are fully automated and can operate without any employees on site. Lights-out manufacturing allows for processes to operate overnight and during the weekend.
lost-wax casting A casting process that creates intricate shapes using an expendable wax pattern and mold. Lost-wax casting is also called lost-wax casting and precision casting.
low-pressure casting The process of pouring the molten metal into the mold at a very low velocity. Sand casting, investment casting, and some forms of permanent mold casting are low-pressure casting processes.
machine tool A power-driven machine that holds a variety of tools. Machine tools can hold a variety of cutting and manufacturing tools.
machining A subtractive manufacturing process that involves removing material to form an object. Machining includes methods such as milling, turning, and drilling that remove metal using cutting tools.
manual process An operation that is entirely controlled by trained personnel. Manual processes include composite molding.
mass customization The ability to quickly create a large number of uniquely-designed variations on a part. Mass customization is one of the key advantages of additive manufacturing technology.
master pattern A replica of a part or casting that is used to create a negative impression in a mold. Master patterns for silicone molding are traditionally made of plastic, wood, or metal.
material extrusion An additive manufacturing process that uses a nozzle to dispense material, usually a thermoplastic filament, onto a support. One example of material extrusion is the FDM process.
material jetting An additive manufacturing process in which droplets of build material are selectively deposited onto a build platform. Material jetting systems use a photopolymer that is cured by ultraviolet light.
mates To connect and fit tightly together. Mating components, such as molds, usually fit one inside of the other.
matrix material The viscous material that binds together the reinforcing fibers of a composite and hardens to give the part shape and protect the fibers from damage. Matrix materials can be a variety of polymers, metals, or ceramics.
megapascals Mpa. A unit of pressure derived from the International System of Units (SI). A kilopascal is equal to one million pascals (Pa).
molding Manufacturing processes that involve pouring heated liquid material into a reusable cavity that shapes the material as it solidifies. Molding is a traditional manufacturing process and includes methods such as injection and transfer molding.
molds A hollow cavity that holds heated liquid material and imparts its shape on the metal as it cools. Molds with exceptional accuracy can be created using an additive manufacturing process.
negative impression A mark or indentation that has resulted from pressing an object into the surface of mold material, such as sand or wax, and then removing the object. Negative impressions retain the details and characteristics of the original object from which they are made.
nonferrous A material that does not contain iron. Nonferrous metals include aluminum, copper, and zinc.
open mold An open cavity that has no rigid second piece to enclose the part and apply pressure. Open molds are used in composite molding.
optimize To improve a process to the point where it is as effective and functional as it can be. Optimizing a manufacturing process involves taking steps to eliminate waste and maximize profits.
paper pulp molding A shaping process that forms paper pulp into a finished part. Paper pulp molding, also called fiber molding, is used to create protective packaging.
part complexity The degree of intricacy in the design of a part. Part complexity can be increased through the use of additive manufacturing processes.
parting line The line along a part where the mold halves separate. Parting lines may be straight or curved.
patterns A replica of the part or casting that is used to create a negative impression in a mold. Patterns with exceptional accuracy can be created using an additive manufacturing process.
plastic A lightweight polymer material that has high corrosion resistance, a high strength-to-weight ratio, and a low melting point. Plastics are usually easy to shape and form.
plug A replica possessing the same shape and dimensions as a part to be formed. Plugs are used to make open molds used in composite molding processes.
polycrystalline diamond The manufactured formation of diamond that has a level of hardness that approaches that of a natural diamond. Polycrystalline diamond can be machined using electrical discharge machining.
polyetherimide PEI. A manufactured thermoplastic that possesses excellent strength and high resistance to chemical corrosion and thermal degradation. Polyethermides is often used by additive manufacturing methods to make molds for use in metal sheet forming processes.
polymers A natural or synthetic material group that consists of very large molecules held together by either a secondary bond or a primary bond. Polymers include silk, nylon, rayon, and plastics.
porosity The measure of a material's ability to absorb or allow the flow of liquids and gasses. Porosity is often determined by the number of small spaces or voids within a solid material.
pounds per square inch psi. A unit of pressure used in the English system. Pounds per square inch measures the amount of load pressure that is applied over an area of one square inch.
powder bed fusion An additive manufacturing process that uses adhesives, heat, or light to bond areas in a container of powder plastic, metal, ceramic, or other material. Powder bed fusion may use a variety of different channel configurations.
precision casting A casting process that creates intricate shapes using an expendable wax pattern and mold. Precision casting is also called investment casting and lost-wax casting.
process development The design and development of the activities that make a product. The goal of process planning is to make the manufacturing process as efficient and effective as possible.
production rates The time it takes to build a part or the number of parts that can be made in a set period of time. Production rates, or build rates, for additive manufacturing are considerably lower than traditional manufacturing.
profit margins The difference between cost and selling price of a product or service. Profit margins usually decrease as quality costs increase.
proving To verify the accuracy of a part design. Proving includes fully testing a part's capabilities and functions.
pumping system A mechanical device used to move liquids and gases. Pumping systems quickly inject molten metal into die cavities during die casting processes.
quality assurance The overall effort by a manufacturer to ensure all parts and products meet consumer or regulatory standards. Quality assurance is a challenge for additive manufacturing operations because the layering process can be highly variable.
ram EDM A common electrical discharge machining method that uses a customized electrode. Ram EDM is also referred to as conventional EDM.
rapid prototyping A product development technique where additive manufacturing processes are used to create prototypes for a traditional manufacturing operation. Rapid prototyping allows engineers to quickly create a number of prototypes in a short time period, reducing lead time.
refractory A type of ceramic that can withstand extremely high temperatures. Investment casting makes a part by surrounding a pattern made of wax in a refractory slurry.
reinforcement material The part of the composite that provides strength, stiffness, and the ability to carry a load. Reinforcement materials can be in the form of whiskers, particles, or fibers.
release agent AA substance that is applied to a mold surface to make it easier to remove the molded part. Release agents are commonly used in composite, or lay-up, molding processes.
repeatability The ability of a manufacturing process to produce consistent and uniform results. Die casting enables the production of parts with a high degree of repeatability.
resin A raw polymer, usually in the form of liquid, beads, or pellets, that is not yet molded into its final shape. Resin is applied to reinforcement fibers during composite molding processes.
rigidity The measure of a material's ability to resist bending or stretching. Rigidity is characterized by being stiff and inflexible.
room temperature vulcanizing molding RTV molding. A manufacturing process in which a liquid polymer is poured into a heat-resistant, flexible silicone mold to create plastic parts. Room temperature vulcanizing molding is also known as silicone molding.
runners A channel in a die that provides the path and delivers the molten material to the mold cavities. Runners are often located in the ejector die.
sacrificial cores A disposable component that forms an internal feature in a final part. Sacrificial cores are often used during composite molding processes.
sacrificial mold A mold that can be used to produce only one part. Both sand casting and investment casting use sacrificial molds.
sacrificial patterns A disposable replica of the part or casting that is used to create a negative impression in a mold. Sacrificial patterns are destroyed during some casting processes, such as investment and sand casting.
sand casting The process of making a part by pouring molten metal into a sand mold. Sand casting uses a sacrificial mold.
seam A line along which two materials or components are joined together. Seams can be weaker and more prone to failure than solid areas.
secondary process Using additive manufacturing processes to create patterns or molds for parts and tooling rather than final products. Secondary processes are sometimes referred to as indirect rapid tooling or indirect rapid prototyping.
sheet metal Flat metal stock that is no greater than 0.25 inches (0.64 centimeters) thick. Sheet metal is often sheared, bent, or drawn.
sheet metal forming A manufacturing process that forms parts by shearing, stretching, bending, or compressing sheet metal using punches and dies. Sheet metal forming includes hydroforming and stamping.
silicone molding A manufacturing process in which a liquid polymer is poured into a heat-resistant, flexible silicone mold to create plastic parts. Silicone molding is also known as room temperature vulcanizing molding (RTV molding).
silicone rubber A rubber-like material composed of a silicone polymer that is used to create flexible parts. Silicon rubber has good strength and resistance to heat.
slurry The channel where molten metal enters the mold. At the beginning of the casting process, molten metal is poured into the mold cavity through the sprue.
soluble A material that dissolves when exposed to a solvent, such as water or a liquid chemical. Soluble materials are often used to create cores for use in some casting and molding processes.
solvent A chemical material that attempts to dissolve another material. Solvents are used after some additive manufacturing processes in order to remove support material.
sprue The channel where molten metal enters the mold. At the beginning of the casting process, molten metal is poured into the mold cavity through the sprue.
stamping A sheet metal forming process that shapes metal sheets using a press and a die. Stamping is one method of sheet metal forming.
straight cooling channels A type of cooling channel that does not conform to a part's shape. Straight cooling channels are created by drilling and other traditional machining processes
surface finish The degree of smoothness on a part's outer surface after it has been manufactured. Surface finish quality varies depending on the additive manufacturing process used and the build parameters.
thermoforming A secondary plastic shaping process that forces heated plastic sheets around a mold. Thermoforming processes use mechanical, air, or vacuum pressure.
thermoplastic A group of plastics that can be repeatedly heated, cooled, and shaped. Thermoplastics are often used in during many additive manufacturing processes.
thermoplastic sheets Flat pieces of solid plastic resin that will be reheated and shaped during a secondary shaping operation. Thermoplastic sheets are produced by injection molding or extrusion.
thermoset A group of polymers that are permanently hardened by heating. Thermosets, also known as thermosetting plastics, have high rigidity and thermal stability.
thick-gauge thermoforming A thermoforming process that heats and forms thick plastic sheets into parts. Thick-gauge thermoforming can be used to create coverings for large medical equipment.
thin-gauge thermoforming A thermoforming process that heats and forms thin plastic sheets into parts. Thin-gauge thermoforming is often used to create packaging materials and other small parts.
three-dimensional 3D. Having a length, depth, and width. Three-dimensional parts are created during additive manufacturing processes.
tolerance An unwanted but acceptable deviation from a given dimension. Tolerances indicate the allowable difference between a physical feature and its intended design.
tooling Assorted tools used in various manufacturing processes. Tooling that can be created by additive manufacturing processes include molds, assembly fixtures, and medical guides.
traditional manufacturing A manufacturing process that involves creating a part by shaping or removing material from a workpiece. Traditional manufacturing operations include metal cutting and forming.
tree A cluster of wax patterns that have been attached to a sprue prior to the slurry-dipping step in investment casting processes. Trees allow for more than one wax pattern to be coated in slurry at a time.
turbine blades A flat component attached to the rotary axis of a turbine to direct air, steam, or gas flow. Turbine blades can be made using composite molding processes.
undercuts A part feature that will not allow a mold to separate along the parting line. Undercuts, which can be protrusions or depressions as well as internal or external, require additional mold pieces.
urethane A manufactured thermoset that is made of isocyanate and alcohol, which are mixed together and undergo a chemical reaction to enable curing. Urethane is a common polymer used in silicone molding to create final parts.
vacuum pressure Negative air pressure caused by a pulling or sucking force. Vacuum pressure forces slurry material against a mold during paper pulp molding.
vacuum system The several components that work together to pull or suck materials out of an area via the application of pressure. Vacuum systems are used to remove excess resin during composite molding processes.
vaporize To transform a material into a gas through the application of heat. Electrical discharge machining uses an electric arc to vaporize unwanted material from a workpiece.
vat photopolymerization An additive manufacturing process in which a part is built by curing layers of a photo-reactive resin with a UV laser. Vat photopolymerization may also be called stereolithography.
vises A workholding device with two jaws that grip and hold a workpiece in place. Vises are mostly used to hold rectangular or cubic workpieces with fairly simple dimensions.
warp To physically bend, twist, or deform. Warpage is commonly caused by poor heat exchange and uneven cooling.
waste Any element of the manufacturing process that does not add value to a product. Waste includes metal scraps and chips as well as parts with defects.
wax A variety of organic substances characterized by the ease with which they can be shaped. Waxes are used to make sacrificial patterns for investment casting.
wear The erosion of material as a result of friction. Wear typically is caused by two or more objects in contact with one another.
wear resistance A material's ability to resist the gradual wearing away caused by abrasion and friction. Increased wear resistance can lengthen the life of a tool or part.
welding A joining process that permanently bonds two separate components together. Welding uses heat, pressure, or a combination of elements to make one new part.
workholding devices A device used to support, locate, and hold a workpiece for manufacturing purposes. The workholding device establishes a relationship between the cutting tool and the workpiece.
workpiece A part that is subjected to one or more manufacturing procedures. Workpieces may be subject to cutting, welding, forming, or other operations.