Crucible Cradle Redesign - Project 42

Project Sponsor:  The Pennsylvania State University - Dr. Robert Voigt

IE 430 Advisor:  Dr. Edward De Meter

PSU Metal Casting Team:  Juliet Bauer, Melissa Brown, Brian Gavigan, Hasnaat Quraishi, and Janet Raudenbush

  Inductotherm Industries Incorporated        

                                                                                                                                                                                                                   After the heating process, a steel cradle, with attached arms, is fitted around the crucible for transport to the molds.  The cradle consists of two halves of a cylinder and a tang. Each half wraps around the crucible and the tang slides under the crucible through a slot in the pedestal, securing the crucible inside the cradle.  A pin is then placed into a tightly aligned hinge that connects the two halves of the cradle, locking it into place.

Currently there are two ways to transport the crucible cradle.  The manual system requires two students to lift the crucible cradle by the arms, carry it to the molds and pour the metal into the casts.  The second method is partially automated and involves the use of a crane that hooks onto the cradle.  The crane/cradle is then manually maneuvered to the molds where metal is poured into the casts.     

The Inductotherm furnace was purchased due to its flexibility in melting various metals.  However, if the current safety conditions associated with the system are not addressed, the furnace will not be used.  Dan Supko, FAME Lab technician, stated that he would not allow any student to operate the casting system unless he felt the safety concerns were resolved. 

Many safety issues are associated with the crucible cradle and the two methods of transportation.  

 ·        Safety problems with crucible cradle:

• Inexperienced students must secure the crucible in the cradle when using the system.
• Sliding the tang under the crucible could knock the crucible over and spill molten metal.
• Inserting the pins forces students to get close to  the crucible exceeding temperatures of 2000°F.
• Pouring the metal requires students to move in uncomfortable positions.

 ·        Safety Problems with manual transportation:

• Combined crucible, cradle, and arm weight exceeds 90 pounds, empty, and is difficult for students to lift.
• The current layout does not provide a direct path to the molds or enough space to maneuver the system.

·        Safety Problems with automated transportation:

• The crane’s control box is too close to the high temperature crucible.
• The vertical movement of the crane’s chain is erratic, making intricate movements nearly impossible. 

Goal:   Modify the crane design.

Objectives:       

• Analyze the crane’s current movement patterns.

•  Improve location of the crane control box to increase safety. 

Goal:   Redesign system to improve overall layout.

            Objectives:    

• Analyze current floor plan.

• Simplify transportation between furnace and molds.

• Allot additional space for operator and cradle movement.

• Move casting molds to improve material flow between the molds and the furnaces.

Goal:   Improve the system for operator use and safety.

            Objectives:

•  Reduce the weight lifted and carried by the operators.

•  Increase the distance between the operators and the high temperature crucible.

• Improve setup and control of the system.

• Improve the manual handling system.

The team developed possible redesigns for each aspect of the system: the cradle, the crane, and the layout.  Below are the recommended changes and benefits  for each component involved in redesigning the system.  Also shown below are pictures and diagrams of any applicable redesigns.

Cradle Redesign  

Crane Redesign  

System Layout