AIA: Over-under Machines Speed Parts Handling
Ford Motor Co.'s (Detroit) 2.8-million-square-foot Chicago Assembly Plant is the first car plant in North America that uses the company's flexible manufacturing system. The system enables the plant to produce up to eight different models based on two architectures, thanks to technologies such as a flexible body shop where one set of tooling builds multiple vehicle configurations.
To ensure parts and subassemblies arrive at their workstations quickly and efficiently, Ford is using a number of automated material handling machines from SailRail Automated Systems Inc. (Markham, ON). These include over-under machines for handling components like body side apertures, rear floorpans, front structures, front subframes and roofs; and a larger side-by-side machine for handling rear suspensions. Many of the parts are robotically picked, calling for precise coordination between the material handling equipment and the actual workstation.
Over-under machines provide a continuous, uninterrupted supply of rack-filled components, while enabling the automated removal of empty racks from the workstation. The machines incorporate two conveying lanes, one above the other, with a vertical lift between them. Air-film technology is used to provide safe, clean, quiet movement of the racks. The air film "floats" a horizontal reciprocating transportation bed that can index large groups of containers simultaneously. The vertical lift raises the containers after they have been emptied and moves them back toward the two-tier entry point, for removal by lift truck. The same lift truck that deposits loaded racks removes the empties, keeping lift trucks productive all the time.
By operating on a two-tier basis, over-under machines conserve valuable floor space in the area immediately adjacent to the assembly line. They can be installed with tilts and turntables, as well as at variable pick heights and with walk-in capabilities flush with the floor. Cycle times are customized according to the size of the machine and the application, the average being around 32 seconds. The machines make for a safer workplace by acting as a buffer between assembly line workers and forklift traffic.
The side-by-side machine is similar to the over-under machines, but the conveying lanes run alongside one another in opposite directions, with a 90-degree cross-transfer device shifting empty racks onto the reverse lane for transportation back to the rear. Load accumulation in the full-parts lane is with zero pressure, and as many as eight racks can be loaded at a time. Again, the same lift truck fetches loaded racks and carries away empties.
For information on efficient material handling, call 905-948-1500, visit www.sailrail.com or eInquiry 7.