ELIMINATION OF THREAD "RE-TAPPING"

      

Faculty Sponsor:   Dr. Paul Cohen

Technical Contact:  Mike Lendacki

  Fall 2003 Penn State Project Team:

Virginia Houck

 Abdallah Dada Mahdi

 Jessica McGuire

 Jay Nealis

 Steve Tracy

  Hannah Wang

                     

          Project Overview:  JLG Industries is the world's leading producer of mobile aerial work platforms and the

          leading producer of telescopic material handlers.  In the final assembly process, JLG utilizes countless

          threaded fasteners to build an aerial work platform.  Prior to final assembly, most fabrications are

          exposed to a shotblast and paint operation.  During this process, the threads can be damaged.  Currently,

          plugs and inserts are inserted prior to these operations to protect the threads; however, they do not

          provide full protection.  As a result, final assemblers must "re-tap" the holes to restore thread integrity.

          "Re-tapping" holes is a non-value added activity that requires much additional labor.  The purpose of this

          project is to eliminate final assembly "re-tapping" without adding to the overall product cost.

 

          Project Summary:

  

Text Box:  ¼"      5/16"     ⅜"         M8   Text Box: TESTING NEW BOLTS Obtained new bolts from ILS. Purchased 4 steel samples for each bolt size from Olympic Steel. Shot blasted parts via same method as actual production. Painted samples. Inserted standard and new fasteners Compare/contrast new/old fasteners.

Text Box: STRUCTURED APPROACH Created Cause-and-Effect Diagram Pinpointed occurrence of problems on linear diagram Developed Failure Modes and Effects Analysis Evaluated Ideas in Solution Criteria Matrix                                                    

Text Box: Damaged Threads

 

 

 

 

 

 

 

     

 

      Recommendations:

 

           Short Term Alternatives:  Use the new fasteners which have shown through testing that they start in the

           hole easier than the standard fasteners.  Although these new bolts are not currently economically justified,

           cost could be negotiated with ILS.  The alternative is to continue re-tapping while using the standard bolts.

 

           Long Term Alternatives:  A chemical treatment could be used to clean the holes instead of a shot blast. 

           It would take approximately 8.2 years to implement this solution based on a $1 million cost estimate.  In 

           the meantime, lean manufacturing principles to reduce rust damage due to the threaded holes.