Assembly in Action: Storage and Retrieval System Reduces Storage Space for Parts
To improve its operating efficiency and space utilization, the company analyzed parts storage and retrieval operations to determine if improvements could be made. Small assembly parts were being stored in totes on traditional shelving units, and personnel were spending nonproductive time searching aisles and shelves for correct part numbers. Vertical storage and retrieval systems appeared to be the solution to reduce the amount of space required for parts inventory and improving part-picking productivity.
Multi-Shifter chose the Shuttle Vertical Line Module (VLM) developed by Remstar International Inc. (Westbrook, ME). The Shuttle comprises vertically arranged storage trays, a workstation-type extraction platform and computerized push button controls for part retrieval. It stores and retrieves various component containers on specially designed trays and delivers them to an ergonomically positioned workstation. The Shuttle has a travel speed of 138 fpm and an extraction speed of 10.63 ips.
By installing two 21.5-foot Remstar Shuttle 250NT VLMs, the company has reduced necessary floor space for storing assembly parts from 1,125 square feet to only 140 square feet. The shuttle VLMs also freed up space in two of the plant's four product assembly areas, doubling the areas' production. Now, parts are consoli-dated vertically on 44 trays within each lockable 10- by 7-foot Shuttle VLM. One Shuttle VLM contains some 800 stock keeping units, the other about 1,400. Presently, only 70 percent of the trays are in use, so the company can serve future assembly operations.
The system provides inventory control for both the production and service departments. One of the Shut-tle VLMs is stocked with assembly parts and is installed within the assembly area. Previously, the parts had to be stored remotely, which added to an already excessive retrieval time. The other Shuttle VLM is stocked with both assembly items and replacement parts that are shipped to customers. By integrating the Shuttle VLMs, Multi-Shifter eliminated building an addition to its 20,000-square-foot plant and enabled it to introduce a new product line.
The Shuttle VLMs provide en-closed, point-of-use protection for densely packed, vertically stacked parts trays. When called for by a worker, a 72- by 33-inch tray is automatically lowered from the stack to a waist-high extraction platform, where it advances out toward the operator for easy part removal or return. Tray-to-tray cycle times range from 32 to 47 seconds for the company's 21.5-foot-high lifts. Load capacity is 550 pounds per tray. Balancing the load is unnecessary, because trays are chain-driven from both ends. Parts as tall as 29.5 inches can be accommodated.
Retrieval is assisted by the Controls 2000 operating system, which is inte-grated with Fastpic inventory manage-ment software loaded on adjacent personal computers (PCs). Using passwords and keying either a Controls 2000 operator panel or the Fastpic PC, workers retrieve the needed parts. Retrieval times have been cut approximately in half.
To retrieve a part, an assembler enters the part number plus quantity desired. The computer instructs the lift module to present the appropriate tray. After the pick, the assembler hits a confirmation button, which auto-matically subtracts the inventory and returns the tray. Before and after extraction, a light curtain sweeps the tray looking for parts extending beyond its edges or for parts taller than the last height seen by the software for that tray.
The latter information is especially helpful for pointing out unclosed carton flaps and plastic bags that are sticking up. Multi-Shifter maximizes storage density by minimizing part storage heights and by placing parts of similar heights on the same tray. The Shuttle VLM automatically nests trays as closely as possible.
Even more helpful to picking operations, workers can enter subassembly kit numbers, and the Fastpic program will sequence a VLM through a series of trays in the most efficient order. The company can adjust both the vertical travel and extraction speeds of each tray individually to reduce forces placed on more sensitive parts.
The company has reduced the floor space formerly consumed by small parts by almost 90 percent. The parts consolidation has also successfully delayed a costly building expansion, and increased worker productivity and overall operations efficiency.
For more information on storage management systems, call Remstar International Inc. at 908-832-9337, visit www.remstar.com or Reply 3.