Detail, Assembly, and Subassembly Prints
Components of weldments are shown in detail by prints that are called detail or working prints. A detail print contains all the information needed to make a part, including the views required for a complete description and the dimensions that are needed for its construction, and may include the directions (indicated by notes and symbols) for the operations required.
It is preferred practice to prepare a detail print for every member of an assembly. However, if the parts are small and similar operations are involved, they are sometimes grouped on one print, Figure 9.1. When a part is a unit within itself, only one print is usually required to describe it.
When a unit consists of several parts, and they are to be shown on one print, each part must be identified. One method of identification commonly used gives each part a name and a circled letter or number. A similar letter or number is given to the part on the assembly print so that the detail can be identified readily with the part shown on the assembly.
Detail prints may include only that information that applies to welding operations, or they may include the information needed for all the operations required to make the part.
In the detail print, Figure 9.1, note the complete dimensioning and how each part is identified.
FIGURE 9.1 ■ Multiple - detail print (represents several detail drawings).
An assembly print, often identified as a main or top assembly, shows the complete and assembled object. This type of print is intended to show the relationship of one part to another when assembled as a unit, and to give an indication of the general appearance of the assembly. Broken lines are usually omitted to simplify reading of the print. This type of print is used as a guide for assembling finished parts.
Certain assembly prints may be used as detail prints when complete dimensions are applied to all of the assembled parts. Prints of this kind are sometimes prepared for comparatively simple weldments; however, this is not a preferred practice.
Assembly prints may consist of one or more views of the assembled unit. Several views are shown when the assembly is complex. More than one print may be used for a complex assembly to show these views. All views are shown by the same scale size throughout except for enlarged detail views.
To show certain portions of the assembly more clearly, enlarged details of parts are drawn to an enlarged scale size, and may be included on the assembly print or as an attachment.
Figure 9.2 illustrates the assembly print of a simple assembly, including several parts shown in the details of Figure 9.1. Note that, in this case, no dimensions are applied. Also, the parts are identified by letters corresponding to those shown on the detail print. Standard hardware used in the assembly is described in the bill of materials (refer to the detail print for the Adjustable Bumper Hitch on the next page). Note that standard hardware items are not usually dimensioned in the detail print. Such items may also be shown in a listing of specifications.