Introduction to CAD and CAM for Machining 241

3D assembly modeling

CAD/CAM software-generated representations of a part, device, or machine that include all of the smaller parts of which that part, device, or machine is composed. 3D assembly design allows designers to thoroughly test parts before they are actually manufactured.

American Standard Code for Information Interchange

ASCII. The United States standard for information exchange. The American Standard Code for Information Interchange uses numbers to represent letters, characters, and figures.

assembly modeling

A CAD process that allows a designer to assemble and manipulate multiple part models. Assembly modeling is also known as 3D assembly design.

CAD

Computer-aided design. The use of a computer to design parts. CAD software is used to create a virtual model of a part.

CAD/CAM programming

The computer calculation and creation of a toolpath based on part geometry information created in CAD. CAD/CAM programming means that toolpaths do not have to be created manually.

CAM

Computer-aided manufacturing. The use of a computer to assist in part manufacturing. CAM generates instructions for machining a part.

computer numerical control

CNC. The use of computerized program instructions to execute the sequence of machining operations needed to make a part. Computer numerical control program instructions are created either by a part programmer or automatically by CAD/CAM software.

computer-aided design

CAD. The use of a computer to design parts. Computer-aided design software is used to create a virtual model of a part.

computer-aided manufacturing

CAM. The use of a computer to assist in part manufacturing. Computer-aided manufacturing generates instructions for machining a part.

cutter location file

CL-file. A neutral language file that helps transfer instructions from CAM to a CNC machine. Cutter location files are useful for sharing part designs.

cutting tool

A device with one or more edges used to create chips and remove metal. Cutting tools are either single-point or multi-point tools.

cycle time

The full time it takes to manufacture a part. Lower cycle time can be achieved with the use of CAD/CAM software.

data

Any information or knowledge which can be stored. Data is often kept electronically in computer databases.

database

Computer storage that holds data and is searchable. A database both stores and organizes information.

detail drawings

A drawing of a part giving a complete and exact description of its form, dimensions, and construction. Detail drawings include all possible aspects of a part's description.

documentation

A CAD process in which a part design is converted to a computer file or hard copy for reference and storage purposes. Documentation creates a record of a part design.

drafting

Manually creating a complex technical drawing or blueprint of a part. Drafting has been almost entirely replaced by CAD/CAM.

Drawing Exchange Format

DXF. A standard format for translation between personal computer-based CAD/CAM platforms. The Drawing Exchange Format allows for data interchange between different CAD/CAM programs.

DXF

Drawing Exchange Format. A standard format for translation between personal computer-based CAD/CAM platforms. DXF allows for data interchange between different CAD/CAM programs.

engineer

A person who designs, creates, or maintains a system. If the CAD/CAM user is not also an engineer, an engineer may examine a CAD/CAM part and its associated toolpaths to avoid errors.

fixture

A customized workholding device that is designed to effectively support, locate, and hold a specific type of workpiece. A workpiece with multiple, complex dimensions often requires a dedicated fixture.

G codes

A programming language that determines the type of operation performed on a CNC machine. G codes are usually generated by CAD/CAM software.

geometric modeling

A process in which a designer creates an accurately scaled representation of a desired part's shape. Geometric modeling is the first step in CAD.

geometry

The measurement, properties, and relationships of the lines and points of an object that make up its shape. Geometry describes a shape using its components.

hard copy

Graphic and textual information printed on paper. A hard copy of a blueprint is a physical version of the blueprint.

heat transfer

The transference of heat from one part to another. Heat transfer can cause undue wear in an assembled part.

IGES

International Graphics Exchange Specification. A neutral communications platform that allows two different CAD systems to communicate. IGES is used by manufacturers to exchange information with one another.

Initial Graphics Exchange Specifications

IGES. A neutral communications platform that allows two different CAD systems to communicate. Initial Graphics Exchange Specifications are used by manufacturers to exchange information with one another.

International Organization for Standardization

ISO. An organization based in Switzerland that develops and publishes standards for various aspects of manufacturing and industry. The International Organization for Standardization is responsible for standards across a number of different industries.

ISO 10303

The International Organization for Standardization's standard for CAD data. ISO 10303 allows manufacturers to share CAD data easily with one another.

laser probe

A device that uses lasers to measure, record, and transfer design parameters from a prototype to a computer. Laser probes can create digital images from physical models.

M codes

A code used to signal an action from a miscellaneous group of commands. M codes change cutting tools and turn on or turn off the coolant, workpiece clamps, or spindle.

machine control data

Manufacturing instructions created in CAM and carried out on a CNC machine. G codes and M codes are examples of machine control data.

machine control unit

MCU. A small, powerful computer that controls and operates a specific CNC machine. Machine control units read part programs and translate them to machine movement.

neutral format

A CAD/CAM file format designed to be shared between different CAD/CAM programs. Neutral format files store information in a manner that can be interpreted by various CAD/CAM systems.

notes

An additional instruction or general comment added to a blueprint. Notes contain information about the material, finish, tooling, tolerances, and other miscellaneous information.

part drawing

A handmade drawing that includes specifications for the production of a part. Part drawings have been made largely unnecessary by CAD/CAM software.

part program

A series of alpha-numeric instructions that direct a CNC machine to perform the necessary sequence of operations to machine a specific workpiece. Multiple part programs can be stored in a CNC at one time.

plotter

A large printer used to print blueprints. Plotters support vector graphics, unlike some other printers.

post-processing

The process of converting CAM information into instructions for a specific CNC machine. Post processing is the translation of CAM data into a machine-specific part program.

post-processor

A software link in the CAD/CAM chain that communicates instructions from CAM to a CNC machine. Post processors translate CAM information into machine-specific instructions.

preliminary blueprint

A design representing the rough dimensions of a specific part. Preliminary blueprints may be used to create a digital part design.

process planning

Utilizing a CAD/CAM system to help establish the necessary steps in creating a part. Process planning helps create route sheets.

programmer

A person responsible for programming a part in CAD/CAM software. Since CAD/CAM software is versatile and comparatively easy to use, programming, design, engineering, and testing are often all done by the same user.

prototype

A test model of a part. Prototypes are physical objects created as scale models.

puck

A hand control that digitizes designs from hard copy blueprints to a computer. A puck is similar to a computer mouse.

raster image

Graphics in which closely spaced rows of dots form an image on a computer screen. Raster images are also known as bitmapped graphics.

route sheets

A map of a part's manufacturing steps in a manufacturing facility. Route sheets are guiding and organizing tools.

scale

A uniform size decrease or increase that allows a large object to be accurately depicted in a smaller form or a small object to be accurately depicted in a larger form. Scaling an object up or down in size changes the size of the object but not the relationship of its dimensions to one another.

scanner

A computer device that converts hard copy drawings into digital form. Scanners capture an image of the paper drawing.

software

The instructions, formulas, and operations that structure the actions of a computer. Software often consists of a computer program or application.

solid modeling

A type of geometric modeling in which a part is represented as a solid object. Solid modeling most closely resembles an actual part.

specifications

The design parameters that set the limits of acceptable deviation for a part's intended application. Specifications are established either in a blueprint or directly in CAD/CAM software.

Standard for the Exchange of Product Model Data

STEP. An international neutral platform for information exchange. The Standard for the Exchange of Product Model Data was developed by ISO.

strain

The physical change that takes place in an object when it is under stress. Strain is a measurement of stress.

stress

A force that attempts to deform an object. The effects of stress are called strain.

surface modeling

A type of geometric modeling that only shows the visible surfaces of a part and not the interior volume. Surface models are constructed from two-dimensional surfaces attached together.

temperature distribution

The distribution of heat through an object. Improper temperature distribution can cause a part to fail prematurely.

three-dimensional modeling

3D modeling. A type of geometric modeling in which part features are represented as three-dimensional shapes. Three-dimensional modeling can be used to represent both surface and solid models.

title blocks

A portion of a blueprint that contains information such as the company name, part name, part number, designer, scale, and material. Title blocks are generally written in a block-shaped section of the blueprint document.

tolerances

An unwanted but acceptable deviation from a given dimension. Tolerance is specified in blueprints and part designs.

toolpath

The series of coordinate positions that determine the movement of a tool during a machining operation. The toolpath is usually determined during the creation of a computer-aided design program.

two-dimensional modeling

2D modeling. A type of geometric modeling in which part features are represented by a two-dimensional line drawing. Two-dimensional modeling is usually the first step to creating a part program.

variant process planning

A type of process planning in which similar types of parts are grouped together with a standard manufacturing plan. Variant process planning can make a manufacturing facility more efficient and save costs.

vector graphics

Graphics that use geometric formulas to represent images. Vector graphic images are more easily manipulated than raster graphics.

vibration

Rapid, repetitive back-and-forth movement in a machine part or other component. Excessive vibration can cause premature component or machine failure.

views

A drawing that consists of all the lines that illustrate the shape of the part. The multiple views often contained within a blueprint convey all of a part's design elements.

volume

A measurement of the amount of space contained within a three-dimensional shape. Volume is always calculated for solid modeling in CAD/CAM.

wireframe model

A type of geometric modeling in which part features are represented by a line drawing. Wireframe models can be two-dimensional or three-dimensional.

work drawings

A drawing of a part providing data for manufacturing. Working drawings provide only the information necessary for a manufacturing process.

workholding

A device used to support, locate, and hold a workpiece. Workholding is specific to the machine tool and cutting operation.