MC Assembly via Test Cell Crane FPA Stage

MC Assembly via Test Cell Crane FPA Stage 3 Peer Review August 12, 2005 T. Brown 1

A Peer review has been organized to review the results of the MC assembly simulation using the crane AND Make the decision to redirect the assembly approach 2

Charge: 1. Does the block test simulation adequately predict the ability to successfully move the MC over the VV within the installation tolerances? 2 Can the laser screens be fabricated and adequately located within some specified tolerances to properly define the path of motion? Is there a better approach? 3 If the MC is moved in some manner that places it off the required path, is there a method to find where it is, then retract and reposition it to be on the correct path? 4 Technicians are required to stabilize the MC (in close proximity to it) while it is supported by the crane. Are there any safety issues that need to be addressed prior to making this decision? 5 Is there additional work or documentation that should be done prior to making this decision? 3

Redirect MC Assembly Approach? Mechanical Assembly Crane Supported – hand assisted assembly 4

MC Crane Assisted Assembly Simulation Test Set-UP 25, 000 lb concrete block 120” long, 40” wide and 60” high 5

The laser holder consisted of a two machine parts that held laser pens (two horizontal and one vertically pointing downward). A horizontal bar was used to connect the horizontal pen holder with the vertical pen holder 6

The path traveled by each laser was plotted on sheets of velum and mounted to the screens, aligning pre-marked crosshairs located on the screen with marks on the printed paper One-quarter inch circles were used to define the required laser positions along the curve path. 7

One portion of the path on the right side screen was quite involved. 8

MC Crane Assisted Assembly Simulation Results The concrete block motion was controlled by using a combination of the D-site crane, three chain-fall supports mounted to the crane hook and hand manipulation of the block for rotation. With Mike Viola calling out lift instructions the block was manipulated to follow the sequential points with an occasional maximum deviation of about ¾” to 1”. 9

Impact on Assembly Schedule Three days were allocated for assembly and this should still be a reasonable time frame – Right. . . Mike Viola? 10

Cost Considerations. There’s no doubt that the Crane Supported hand assisted assembly approach is a lower cost approach. The current budget allocation is: MC Turning fixture and base - $64 k MC Gantry Crane - $12 k Total $76 k The Mechanical Assembly approach cost ranges from $¼ M to $2 M (including design & engineering cost). 11

Crain System Improvements A number of observed improvements were identified to aid in assembling the module coil and reducing the extent of mark overshoots. These include: 1. The chain falls required pulling at an angle which imparted a small amount of lateral motion on the block, requiring compensation. An improvement could be made by going with a motorized chain fall or using a mechanized screw system. 2. Adding encoders with a mechanized screw system would aid in the positing process. 3. Four technicians will be needed to manipulate the modular coil and observe the laser positions. 4. The screen plexiglass cover sheets should be increased to ¼” to provide greater rigidity. 12

Crain System Improvements (Continued) 5. Greater space between the right side screen and concrete block was needed and will be provided in the real assembly. 6. A fourth laser is needed to provide a positional check. 7. Mylar will be used instead of velum for printing the curves. 8. To precisely define where the MC is at all times, tooling ball reflectors will be added to the MC surface and tracked by the Leica laser tracker. With this addition we can tell if we are on or off the proper path. 9. A temporary strip of “protective substance” could be placed in regions where interferences may occur to protect the surface components 10. It would be helpful to have on-site a laptop computer running a Pro. E model simulation which tracks the assembly operation. 13

Charge: 1. Does the block test simulation adequately predict the ability to successfully move the MC over the VV within the installation tolerances? 2 Can the laser screens be fabricated and adequately located within some specified tolerances to properly define the path of motion? Is there a better approach? 3 If the MC is moved in some manner that places it off the required path, is there a method to find where it is, then retract and reposition it to be on the correct path? 4 Technicians are required to stabilize the MC (in close proximity to it) while it is supported by the crane. Are there any safety issues that need to be addressed prior to making this decision? 5 Is there additional work or documentation that should be done prior to making this decision? 14