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