Chapter 18 cont.

Sub Assemblies Smaller assembly that is part of a larger

assembly Drawings for subassemblies are shown in their

own assembly drawings They are shown assembled in product

assembly drawing

Parts list (Bill of Materials, BOM) List of parts included in an assembly Can be on assembly drawing or its own page

Items on parts list: Item number-corresponds with balloons Quantity-number of each part needed Part number-company part number Description-part name or brief description of the part Material-what part is made of Information-misc info, vendor names, tool numbers, etc.

Engineering changes Parts of products are frequently changed Once a product reaches production there are

still many things that will change over it’s lifecycle

Changes are made to: Fix problems with performance Fix problems with manufacturing Fix problems with tooling Change color of parts Update shape of parts Change to information on the drawing (notes)

All changes need to be recorded There are several methods of recording,

depending on what kind of change is made

Revisions Usually used to note minor changes to

drawings or design EX: making a change to the dia of a hole

Revisions cont. Labeled with letters in balloons typically Don’t use I, O, S, X, Z If end of alphabet is reached, labeled as AA,

AB, AC, etc. Then BA, BB, BC, etc.

Engineering change notice Used when major changes are made Involves a report explaining the changes to

the drawings Assigned numbers and kept in a database A.K.A. ECN

Engineering change request How an ECN gets started Someone who would like to see a change

made to a design submits a formal request Request can come from anyone involved in

the product Marketing Production Manufacturing Assembly Customer service Management

Functional Drafting Purpose of a drafting department is to provide

sufficient information to produce, assemble or change parts

To do this the drafter must understand: How the parts will be produced Which dimensions are critical and which are

not

Ways to reduce time needed to produce drawings Streamlined approval process

Fewer signatures Less time for drawing to sit and wait for someone to

look at it Eliminate drawing checks

Must be done correctly by drafter Only done when experienced people are involved Or, when project is behind schedule

Standard drafting processes Everyone in drafting dept. following the same practices Use of standard layers for CAD files Files and drawings stored properly Use of company standards

Ways to reduce time needed to produce drawings Team drafting

Using more than one person to work on drawings Products require many parts Can use best people to do the complicated work One person can be designing parts while others work

on drafting Training

Keeping all employees up to date on: CADD Company standards Manufacturing processes

Use standard or existing drawings Modify existing drawings to make new drawing Change title block information, etc.

Test Review Detail drawing Info required on detail

dwgs Types of detail dwgs Layout assembly dwg Installation assembly dwg Catalog assembly dwg Exploded assembly dwg Detail assembly dwg Set of working dwgs

contains? List 4 possible uses for

assembly dwgs

Sub assembly Items on parts list (all) Engineering changes List 2 things that

changes can be made to by an engineering change

Engineering change request

Explain why changes must be recorded

List 3 items that can speed up drafting time