CIM Unit 2 KeyTermsReview

Fixture

A device designed and built for holding a particular piece of work for machining operations.

Jig

A device that holds and locates a piece of work and guides the tools that operate upon it.

Prototype

A full-scale working model used to test a design concept by making actual observations and necessary adjustments.

Bench Grinder

A grinding machine with both a coarse and fine wheel that has been mounted to a table. The grinding wheels mount directly onto the motor shaft.

Address Character

A letter used in G & M code programming to designate a class of functions.

Milling Machine

A machine that removes material from work by means of a rotary cutter.

Lathe

A machine tool used for turning cylindrical forms on work pieces. Modern lathes are often equipped with digital readouts and numerical controls.

Molding

A manufacturing process in which the industrial material is made into a liquid. The liquid is then introduced (poured or forced) into a prepared mold of proper design.

Electrical Discharge Machining (EDM)

A process by which an electrode spark is used to erode small amounts of material from a work piece.

Forging

A process by which metal is heated and shaped by plastic deformation by suitably applying compressive force.

Injection Molding

A process during which plastic is heated in a machine and forced into a cavity by a screw or ram. The material solidifies and is then ejected.

Electrochemical Machining (ECM)

A process in which a stream of electrolyte (typically salt water) is pumped at high pressure through a gap between the positively charged work and the negatively charged tool (electrode).

Sand Casting

A process of pressing moist sand around a pattern to make a mold. The pattern is removed, leaving a cavity in the sand. The cavity is the mold that will be filled with liquid metal. The result will be a casting that is identical in shape to the original pattern.

Forming Process

A process that changes the size and shape of a material by a combination of force and a shaped form.

Separating

A process that removes excess material to change the size, shape, or surface.

Water Jet Cutting

A process that uses a high speed jet of water emitted from a nozzle under high pressure (10,000-60,000 psi or greater). The advantage of water jet cutting is that it does not create a burr and it is a low temperature process.

Stereolithography

A rapid prototyping process that fabricates a part layer-wise by hardening a photopolymer with a guided laser beam.

Block

A single line of code in an NC part program.

V-Block

A square or rectangular steel block with a 90 degree V-groove through the center, provided with a clamp for holding round stock for drilling, milling, and laying out operations.

Incremental

A system in which each position is taken from the one prior. Also called relative.

ABS

Acrylonitrile Butadiene Styrene. A thermoplastic with rubber added for high toughness.

Laser

An acronym for Light Amplification by Stimulated Emission of Radiation. Common uses are cutting, measuring, and guidance systems.

Design Flaws

An imperfection in an object or machine.

Grinding

An operation that removes material by rotating an abrasive wheel or belt against the work.

Metals

Any of a category of electropositive elements that usually have a shiny surface, are generally good conductors of heat and electricity, and can be melted or fused, hammered into thin sheets, or drawn into wires.

Ceramics

Any of various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing a nonmetallic mineral, such as clay, at a high temperature.

Parameter

Attribute of a feature, such as a dimension, that can be modified.

Raw Materials

Basic substance in its natural, modified, or semi-processed state, used as an input to a production process for subsequent modification or transformation into a finished good.

Renewable Resources

Biological materials that can be replaced.

Preparatory Code

Codes that carry out machining operations or establish machine settings; G-codes.

Rapid Prototyping

Computer-controlled additive fabrication. Commonly used synonyms for RP are three-dimensional printing, additive fabrication, freeform fabrication, solid freeform fabrication, and stereolithography. Note that most of these synonyms are imprecise.

Economics

Dealing with production, distribution, and consumption of products or wealth.

Additive Process

Fabrication of a part by adding material.

FDM

Fused Deposition Modeling. Rapid prototyping process in which a filament of wax or polymer is extruded onto the existing part surface from a workhead to complete each new layer.

Defective

Imperfect in form or function.

Modal

Information that is retained by the CNC machine or system until new information is obtained.

LOM

Laminated Object Manufacturing. Rapid prototyping process in which sheet stock is cut and bonded into a stack.

Build Time

Length of time for the physical construction of a rapid prototype, excluding preparation and post-processing time. Also known as run time.

Clearance Fit

Limits the size of mating parts so that a clearance always results when mating parts are assembled.

Interference Fit

Limits the size of mating parts so that an interference always results when mating parts are assembled.

Photopolymer

Liquid resin material that utilizes light (visible or ultra-violet) as a catalyst to initiate polymerization, in which the material cross-links and solidifies. This technique is used by various rapid prototyping technologies.

Post Processing

Liquid resin material that utilizes light (visible or ultra-violet) as a catalyst to initiate polymerization, in which the material cross-links and solidifies. This technique is used by various rapid prototyping technologies.

M Code

M codes are miscellaneous functions that include actions necessary for machining but are not actual tool movements

Finishing Process

Machining a surface to size with a fine feed produced in a lathe, milling machine, or grinder.

Industrial Material

Material that has been changed from raw material so that it is ready to be used in manufacturing. Also referred to as standard stock.

Plastics

Materials that undergo a permanent change in shape or size when subjected to a particular amount of stress.

NC

Numerical Control. Any controlled equipment that allows an operator to program its movements through a series of coded instructions consisting of numbers, letters, symbols, etc

Concept Model

Physical model intended primarily for design review and not meant to be sufficiently accurate or durable for full functional or physical testing.

PLA

Polylactic Acid. A thermoplastic formed using organic material.

G Code

Preparatory functions that involve actual tool movements that control the machine.

Conditioning Process

Process in which the properties of a material are changed using mechanical, thermal, or chemical means.

Vacuum Forming

Process to heat a thermoplastic sheet until it softens and then force the hot and pliable material against the contours of a mold using vacuum pressure.

Subtractive Process

Processes that remove material to change the size, shape, or surface of a part. There are two groups of separating processes: machining and shearing.

G & M Codes

Programming code used to control CNC machines.

Competent

Properly or sufficiently qualified; capable or efficient.

RP

Rapid Prototyping. Computer-controlled additive fabrication.

Exhaustible Resources

Resources of which there are a limited supply.

Morality

Rules relating to principles of right and wrong in behavior.

SLS

Selective Laser Sintering. A rapid prototyping process that used a moving laser beam to sinter heat-fusible powders one layer at a time.

Die Casting

Similar to permanent mold casting except that the metal is injected into the mold under high pressure.

SLA

Stereolithography. A rapid prototyping process that fabricates a part layer-wise by hardening a photopolymer with a guided laser beam.

Absolute

System in which positions are given with respect to a fixed point, usually the origin.

Functionality

The ability of a product to do the job for which it was intended.

Tolerance

The acceptable amount of dimensional variation that will still allow an object to function correctly.

Feed

The distance advanced by the cutting tool along the length of the work for every revolution of the spindle.

Machinability

The ease or difficulty of machining as it relates to the hardness of a material to be cut.

Primary Processing

The first step in manufacturing where raw materials are processed into a usable form for further manufacture.

Part Program

The instructions written by the programmer to produce a work piece.

Spindle Speed

The number of revolutions per minute (rpm) that is made by the cutting tool of a machine.

Casting

The process in which a solid material is made into a liquid, poured into a mold, and allowed to harden in the shape of the mold.

Quality Control

The process of making sure that products or services meet consistently high standards.

Assembling

The process of putting a product together out of separate parts.

Word

The programming expression formed when a letter (address) is combined with a number.

Durability

The quality of equipment or goods of continuing to be useful after an extended period of time and usage.

Ethics

The standards for moral behavior of a particular group.

Purpose

What one intends to do or bring about.