BIIL RINI, Project manager for materials management improvement

Even though the localized stockroom system had supported production of more than 2,000 C-130 cargo planes since the early 1950's, Lockheed was not satisfied with inventory accuracy below 95%, excessive inventory shortages, and work-in-progress scattered around the production floor. Lockheed also wanted to reduce its reliance on expediting to meet production deadlines throughout the facility.

The new system - 18 carousels and extensive shelving and racks - overcomes these deficiencies and improves kitting efficiency 300%, says Rini, project manager for materials management improvement. Improved availability of the right parts is expected to reduce work-in-progress.

Until earlier this year, parts coming out of Lockheed's fabrication department could follow any of 100 possible routings to the shop floor, notes Altgilbers, a material handling engineer. All too often the right parts did not make it to the right stockrooms.

Feeding the stockroom

All but a small percentage of parts now have only one possible destination as they leave fabrication - the new 60,000sq ft central stockroom. The system holds enough inventory for production of the next 15 aircraft, but distributes parts in kits daily to 12 small staging areas on the shop floor.

Parts arrive from fabrication at one of four induction stations in the central stockroom. After scanning an accompanying bar code shop order, the worker counts the number of parts and keys the quantity into a terminal. Local area network feeds that information to the stockroom's central database controlled by a customized warehouse management software package.

During startup of the stockroom, the software assigned permanent storage locations to each SKU in the carousels, shelving, and racks.

Following this pre-assigned storage scheme, the software initiates printing of a bar coded stock route ticket at the induction station. The parts and the ticket are placed in a 24 in. by 36 in. by 6 in. deep bar coded tote. The worker then scans the bar code on the ticket and the one on the tote, linking the two in the database.

Totes of slow-moving small parts travel by inclined conveyor across a major traffic aisle that divides the stockroom. Putaway on shelving is from lift trucks.

Oversized parts, some handled on pallets and others individually, are carried by cart to the rack storage area for putaway by lift truck.

A light tree at each carousel indicates the location of parts to pick and the quantity to select. A display panel above the totes indicates where the worker should place the parts. It is common to place the same SKU into different totes and in different quantities during a pick.

In a typical day, nearly 500 cycle counts (the new measure of inventory accuracy) are made, many at the same time as parts are picked for an order. Simultaneous cycle counting and order picking greatly reduce the time needed to confirm inventory accuracy, explains Altgilbers.

When the light panel above a tote indicates it has received all necessary parts, a worker pushes the tote onto a parallel staging conveyor that returns it to the central conveyor that originally delivered the parts.

Building kits

Totes arrive from the carousels at a kitting station in the stockroom. After the worker scans the tote's bar code, an on-demand printer runs a route tag with a unique order number and a list of parts that should be in the tote for quality checking. About two-thirds of the totes are ready for immediate delivery by cart to the staging area indicated on the list.

Those totes that still require additional parts are carried to another kitting area in the stockroom. Parts needed to complete the kit from the rack and shelving areas are also delivered to that kitting area. The parts list in the tote guides workers through final order picking of oversized and low-moving parts. Completed kits are then released to the pre-designed staging area.

According to Rini, the system is so successful that Lockheed plans to adapt the same inventory and kitting scheme at other locations. "By simplifying where ever possible, we stand to do a much better job of getting the right parts to the right places," he says.