Forging new generations of engineers

Assembly DrawingsAssembly Drawings,,BalloonsBalloons,,

and

Parts ListsParts Lists

A design that has been approved for prototype or full-scale manufacture requires a set of working drawings to communicate the object’s geometry to everyone involved with its manufacture and assembly.

Working drawings are a complete set of documents that include:

Working DrawingsWorking Drawings

• Individual part drawings• One or more assembly

drawings• A parts list

Assembly DrawingsAssembly Drawings

An assembly drawing shows how all of the parts of a multi-component design fit together, and are generally depicted as one or more orthographic projections.

One or more full section views are often used in an assembly drawing to show necessary internal features.

Example Assembly DrawingExample Assembly Drawing

Information from AssembliesInformation from Assemblies

• One or more views, including sections or auxiliaries• Enlarged views to show small details• Overall or specific dimensions needed for assembly• Notes on manufacturing processes required for

assembly• Balloons to indicate item numbers• Parts list or bill of materials (BOM)

Assembly drawings may contain the following:

• Design Assembly

• General Assembly

• Detail Assembly

• Erection Assembly

• Subassembly

• Pictorial Assembly

Types of Assembly DrawingsTypes of Assembly Drawings

Design assemblies are used to show various relationships between components.

The design assembly at the right shows the kinematic relationship that exists between the fly wheel’s 360° rotation, and the extreme angular motion of the piston cylinder body.

Design AssemblyDesign Assembly

Design assemblies are often made from sketches during the preliminary phases of a design process to study the relationships that exist between the components before the design is modeled.

Design AssemblyDesign Assembly

A general assembly is the most common type of assembly drawing. It is displayed as a multiview drawing and may contain a section view.

General assemblies do not contain dimensions.

General AssemblyGeneral Assembly

Detail AssemblyDetail Assembly

A detail assembly is a combination of an assembly view with several of its parts depicted as dimensioned multiview drawings on one drawing sheet.

This practice, though not common, reduces the number of drawing sheets needed, and is more appropriate for designs with small numbers of components.

Example Detail AssemblyExample Detail Assembly

Erection AssemblyErection Assembly

• Similar to general assemblies, except dimensions and fabrication specifications are commonly included.

• Typically associated with cabinetry or products that are made from structural steel.

• Used for both fabrication and assembly.

Subassembly DrawingSubassembly Drawing

Complex or large assemblies may be communicated through subassembly drawings.

Flashlight Subassembly

Pictorial AssemblyPictorial Assembly

• Usually depicted as an isometric or perspective drawing.

• May be rendered to imitate photographic quality.

• Uses include:- Sales promotion- Customer self-assembly- Maintenance procedures

Pictorial assemblies are often used in catalogs, journal articles, and advertisements.

This pictorial is sectioned to show interior details.

Pictorial Assembly DrawingsPictorial Assembly Drawings

Exploded pictorial assembly drawings are commonly used to show how individual components fit together.

Pictorial Assembly DrawingsPictorial Assembly Drawings

BalloonsBalloons

A balloon is a circle that contains a single number, which is connected to an assembly component with a leader line.

• All balloons on a drawing should be the same size.

• Balloons should be grouped together in an easy- to-read pattern.

• Balloon numbers must correspond to item numbers in a parts list.

• Balloons should not have horizontal or vertical leader lines.

Balloon GuidelinesBalloon Guidelines

A parts list is a table that contains information about each of the parts contained in an assembly. The item numbers correspond with the balloon numbers.

Parts ListParts List

Example Parts ListExample Parts List

Parts List InformationParts List Information

• Item number – from balloons.• Quantity – the number of a particular part needed

for the assembly.• Part or drawing number – a reference back to the

detail drawing.• Description – usually the part name or complete

description of a purchase part.• Material identification – the material of the part.• Information about vendors – for purchase parts.

Items commonly found in a parts list include:

Parts List LocationParts List Location

• Above the title block – most common

• Upper right corner

• Upper left corner

• A convenient location on the drawing

The location of a parts list usually depends on company standards. Common locations include:

Parts List LocationParts List Location