Two-dimensional drawings show the product or part in a series of views. Each view has dimensions that show the measurements of the features. In addition, the dimensions also commonly include tolerances (see glossary). Two-dimensional drawings are usually made by an engineer and are commonly drawn by using a program called AutoCAD.

3D Solid Model File

Three-dimensional solid model files are 3D representations of a part in a computer program. Within the computer program this part can be rotated to see different features and split to see the inside. In addition, the software can make calculations to determine the amount of material that is required to make the part. Also, 3D solid model files can be exported to machines that will make prototypes (see SLA) and make production tooling. Any custom made plastic parts require 3D solid model files to be produced before tooling can be made. 3D solid model files are commonly made with software such as SolidWorks and Pro/ENGINEER.

Assembly Instructions

When a custom product is to be assembled, the manufacturer and workers need assembly instructions to teach them the proper method of assembly. These instructions break down the assembly process into a series of steps and give specific instructions. It is common for parts of these assembly instructions with pictures to be posted at the individual workstations of the assembly staff.

Blow Molding

Blow molding is a method of making hollow custom plastic parts. Blow molding machines heat up plastic and inject air blowing the hot plastic up like a balloon. As this balloon of plastic expands it presses against the walls of the mold taking on the shape that is carved in the wall. After the "balloon" completely fills the mold, the mold is cooled, solidifying the plastic part and the mold is opened releasing the part.

Casting

Casting is a method of molding metal. Casting molds are made from different materials and are carved with the desired shape. When the mold is ready molten metal is poured into the mold. When the metal is cool and solidifies, the mold is opened and the solid metal part is removed.

Cavitation

Cavities are the molding term for the imprints or carvings of shapes into a mold that are used to produce a part. If a mold has one cavity, it will produce one part for every molding cycle (see glossary). If a mold has two identical cavities, the mold will produce two parts for every molding cycle. In some cases molds will produce two or more different parts per molding cycle. These molds are called family molds.

Contract Assembly

Contract assembly or contract manufacturing is the process of using a third-party manufacturing company to manufacture a product. A contract assembler does not own the product design or rights. The design of the product and all details of its production can be dictated to the contract manufacture by the product owner although the product owner may defer certain decisions to the contract manufacture because of their level of experience.

Critical Dimension

Some parts are very complex and the only way to communicate every dimension is via a 3D solid model file (see glossary). When an individual desires to measure the part to see if it is correct, it is unwieldy to have to measure every dimension. For this reason, part designers commonly create special 2D drawings (see glossary) that illustrate critical dimensions of the part. These critical dimensions are the most important dimensions and are meant to be checked more often than other dimensions. Also see "From Fit and Function."

Cycle (molding/casting)

A cycle is the process of putting a raw material into a mold turning that raw material into a part and ejecting the part. In the molding industry we often talk about cycle times. This is the time it takes to complete the aforementioned process.

Design Sketch

A design sketch is either a computer or hand drawn sketch meant to illustrate the look or basic function of a product.

Emboss

Embossing is the process of creating a three dimensional shape (such as a logo) or text on a manufactured part. It is part of the molding/casting process and requires no further effort to complete after the initial molds are fabricated.

Engineering Drawings

Engineering drawings are drawings that are designed to communicate important information about the subject of the drawings such as dimensions, tolerances, material. Engineering drawings are drawn and information is provided using industry wide standards and conventions.

Extrusion

Extrusion is the process of making parts of either plastic, metal or rubber that have a fixed cross-sectional profile. Drinking straws, hoses, and pipes are examples of extruded products. Please note that extruded parts do not need to be round but they need to have the same shape along the length of the part. Extruded parts are made by squeezing hot raw material through a custom die. A simplistic visualization would be like squeezing Play Doh through a shaped hole.

First Article Sample

In the mold fabrication process, the first part manufactured by a freshly made mold is called the first article sample.

Fixture

In manufacturing, a fixture is a term used to describe any custom apparatus used to help standardize a process or make a manual task easier.

Flash

In the molding and casting industry, the word flash is used to describe extra part material that leaks out of the cavity during the molding process. It will appear as a thin fin like shape that protrudes off the side of a part at the parting line (see glossary).

Form Fit and Function

As molded parts typically have hundreds of measurable dimensions, designers and engineers developed a different method of checking to see if a newly molded part was correct. Checking a part's form fit and function imply that the tester will review some or all of the following:

Form: Shape, size, dimensions, mass, look, center of gravity
Fit: How the part fits and interacts with the other parts it is used with
Function: Whether the part competes the action that it was designed to perform

Gate (molding/casting)

A gate or sprue is the hole where molten material enters the mold.

Industrial Designer

An industrial designer is an individual who designs the look and usability of a product. Industrial designers are commonly used in the early phase of the product development process to design the concept of the product. These concepts are then usually transitioned over to an engineer to create the engineering drawings (see glossary)

Injection Molding

Injection molding is the process of making custom plastic parts by injecting molten plastic material into a metal mold. This mold contains a carving or imprint of the desired part. After the molten plastic is injected into the mold, the mold is cooled, the mold is split open and the solidified plastic part is ejected. The process is then repeated. Injection molding is a widely used process for making high volume custom plastic parts. (for more info, see cavitation)

Machining

Machining is the process of carving a piece of raw material into a desired shape. It is one of the most precise manufacturing methods but also one of the most expensive for mass production.

Part Volume

Part volume is the volume of material that is required to make a part. This is important in the quoting of parts. Since the cost of raw material is a main component in the cost of a finished part, suppliers will often want to know the volume a part. This information is commonly found by either examining a sample part or by analyzing a 3D solid model file (see glossary)

Parting Line

Parting line is the line that is commonly seen on a molded part that is caused by the two halves of the mold coming together.

Prototype Tooling/Mold

In some cases, it is preferable to make a low-cost mold that will quickly wear out. This mold is called a prototype mold. The reasons for its production could be to test a design before full production or to produce a small number of accurate production parts. Prototype molds are made with low-grade material, are faster to fabricate and can usually produce 500-1000 production parts.

Rotational Molding (Rotomolding)

Rotational molding is a method commonly used to made large hollow plastic parts. To produce a part, powdered plastic resin is placed in a metal mold. This mold is then heated causing the plastic to melt. The mold is then slowly rotated around 2 perpendicular axes spreading the plastic around the inside of the mold. As the plastic cools and hardens, the part takes shape. After the part is cool, the mold is opened to reveal it. This process is rather slow compared with other manufacturing processes. Rotomolding is an efficient way to make large, low-volume, hollow parts.

Screen Printing

Screen-printing is a method of painting a custom graphic on a surface. Paint is pushed over a custom metal screen that acts as a stencil and paints a repeatable graphic onto parts.

Secondary Operation

A secondary operation is a generic term that is defined by any follow-up operation that must be completed after the main production process is complete. For example if a part is molded and a hole must be drilled into the molded part, the drilling would be a secondary operation.

SLA - Rapid Prototype

SLA stands for Stereolithography and is a method of producing a 3D physical sample from a 3D solid model file (see glossary). The easiest way to visualize it is to imagine that an SLA machine is like a printer that prints parts rather than pages. SLA's are very useful to review and test a newly designed part. Their expense and limited material choice makes them impractical for production.

Sprue (molding/casting)

A sprue or gate is the hole where molten material enters the mold.

Stamping

Stamping is a generic term that is used to describe all forms sheet metal work. These processes include stamping, bending forming and coining. Stamping uses large machinery to manipulate the shape of pieces of sheet metal. It is an efficient manufacturing method commonly used to make production parts.

Tolerance

While part dimensions are typically only one number, it is impossible to produce anything to an exact dimension. Every manufactured part is subject to variation. How much variation is allowed is defined by the measurement's tolerance. The tolerance is determined by the designer of the part. A "high" or "tight" tolerance is more difficult to achieve than a "low " or "loose" tolerance. Some manufacturing processes can deliver tighter tolerances than others.