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MEC 1012
Design Communication II

MEC 1012 Assignments

MEC 1012 - Assignment 5
Tolerancing for  Process Capability and Fit, and  Revision Control
Due in lab week 9

Produce a full set of working drawings for your functional mechanical assembly from Assignment 4. Write a manufacturing plan. Release your first version of the design, revise the design, and then release the revisions.

Checklist: (hit links for details)
    1. Working Drawings with new title block
      1. Assembly Drawing
        1. Balloons
        2. Parts List 
        3. Explosion with Correct Trails
      2. Weldment Drawing
        1. Weld Notes
        2. Parts List
      3. Part Drawings
        1. Fully Dimensioned
        2. All Tolerances Consistent with Minimum Tolerances
    2. Plan of Manufacturing Processes and Fit Classes
      1. How will each part be made? 
      2. What class describes the fit between each part? (Clearance or Interference)
    3. Three Sets of Models and Drawings (Developing, First Release and Second Release)
      1. At least 3 parts revised between first and second release
      2. Complete revision blocks and revision tags on revised part drawings
Related Links

Definitions
Details
First,  make an A5 project file and then copy your models from A4 to your A5 workgroup folder. Make sure all files have meaningful names. Feel free to simplify your design as long as it still meets the minimum requirements of A4.
  1. Working Drawings
Title  Blocks
  • Please use the new title block located in V:/MEC/1012/Template & Blocks/VTC A.idw. This new block uses the file name as the drawing title (to enforce naming consistency). 
HOW TO access and use this modified ANSI A title block:
  • Open the modified .idw. COPY the ANSI A block from the VTC A.idw resource/title block folder. Delete the ANSI A block from the resource/title block folder of your destination .idw. PASTE into the destination resource/title block folder and INSERT the title block.
or
  • Copy this .idw file and paste it into C:/Program files/Autodesk/Inventor 7/Templates and use it as your template.
    1. Assembly Drawing
      1. Balloons
      2. Parts List - Following this theme of creating and maintaining consistency you now will want to modify the PARTS LIST standard to use FILENAME as a column in place of the PART NUMBER default.
        To do this, in the drawing mode, go to Format/Standards/Parts List/Column Chooser/
        Remove description and part number and add  filename.
        Insert the modified parts list.
      3. Explosion with Correct Trails - Please pay close attention to your trails.
    2. Weldment Drawing
      1. Weld Notes
      2. Parts List - as above
    3. Part Drawings
      1. Fully Dimensioned
      2. All Tolerances Consistent with Minimum Tolerances
Minimum Tolerances (for this assignment)
Casting/Molding/Forging
+/- 0.10 mm
Milling
+/- 0.05 mm
Turning
+/- 0.03 mm
Drilling
+/- 0.10 mm
Reaming  
+/- 0.02 mm (diameter only)

A real matrix of process capabilities would be much more specific as to process an supplier
(here's an example from ISM - Institute for Supply Management)
  1. Plan of Manufacturing Processes and Fit Classes - (use a common document format like .doc, .rtf or .htm and save inside your project folder - not your workgroup folder)
    1. How will each part be made? 
    2. What class describes the fit between each part? (Clearance or Interference)
  2. Three Sets of Models and Drawings (Developing, First Release and Second Release) - Here's  how to proceed:
    1. Your first set of Models should be developed in the normal manner with a Revision level of AX (the X indicates that revisions are ongoing).
    2. When you complete the first set and you are ready for your first release, copy all of your files from your workgroup folder into a new folder called 'mm/dd/yy-release' or  some plain language name.
    3. From Windows Explorer right-click on one of the files in your First Release folder and select Design Assistant. Use Design Assistant to remove the X from your released drawings and to increment the revision level of developing drawings (in your workgroup folder) from AX to BX.
    4. Add a Library search path to your First Release folder and be sure to name the library after the release ('mm/dd/yy-release' or  some plain language name)
    5. Your First  Release is due half-way through lab in week 9.
    6. Revise your design:
      1. Make changes to at least 3 parts (and Assy drawing if necessary) between first and second release
      2. Complete revision blocks and revision tags on revised part drawings
    7. Release your revised drawings by copying the files (not just .idw) into a new folder  (named 'mm/dd/yy-release' or  some plain language name).
    8. Once again, use design assistant to remove the X from your released drawings and to increment the revision level of recently released developing drawings from BX to CX .

Related Links (use the Back button to return to this page)
Please send us any other good sites you find so we can add to this list:
  1. Process Capability from the NIST Information Technology Laboratory
  2. Process Capability at isixsigma.com
  3. Process Capability Analysis For Production Tolerance Assignment
  4. Engineers Edge Handbook  (You will LOVE this link)
  5. Autodesk Tutorial on Managing Properties with Design Assistant
  6. Op-Ed by Thomas Friedman on outsourcing and innovation

Developed by Mary Waldo and Paul Johnson
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