Site: MultiShifter Inc

A Shuttle VLM gave us 87% expansion in floor space and saved $450,000 to $500,000 in new construction costs.

Application: Point-of-use assembly for manufacturing and service parts

Equipment: Two Shuttle Vertical Lift Modules (VLMs) with Controls 2000, FastPic™ Inventory Management Software

Summary: Increase productivity by 50% while saving 87% of wasted floor space

A new approach to assembly and service parts storage and retrieval has helped Multi-Shifter, Inc., Charlotte, North Carolina, add a new spark to its industrial battery handling systems manufacturing operations. Multi-Shifter, Inc. is a fully integrated manufacturer of industrial battery handling vehicles and storage systems. The company produces battery changing vehicles for batteries weighing up to 5,000 lb., plus battery washing, storage, and waste water filtration systems and miscellaneous battery room equipment. The company’s battery handling systems increase operating efficiency, worker safety, and space utilization in plants employing electrically-powered materials handling trucks, counter-balance trucks, turret and narrow-aisle trucks, pallet jacks, and automatic guided vehicles in multiple-shift or continuous operating environments.

Taking Advantage of Overhead Space
In order to help improve its own operating efficiency and space utilization, Multi-Shifter management decided to analyze parts storage and retrieval operations to determine if improvements could be made. Small assembly parts were being stored in totes on traditional shelving units—500 square feet of floor space in one area, 625 square feet in another. Product assemblers and service parts personnel were spending increasingly more non-productive time searching aisles and shelves for correct part numbers. Vertical storage and retrieval systems appeared to be the solution to reducing the amount of space required for parts inventory and improving part picking productivity. Improved space utilization is a key advantage of vertical storage and retrieval systems. Depending on useable building interior heights, 75 percent and more of a conventional storage system’s occupied floor space can be recovered. The small unit footprint makes vertical storage and retrieval systems especially for point-of-use storage, allowing more floor space to be used in value-added operations such as manufacturing and assembly.

Multi-Shifter chose The Shuttle Vertical Lift Module (VLM) developed by Remstar.

The Shuttle is a standalone, modular, enclosed system of vertically arranged storage trays, a workstation-type extraction platform, and computerized pushbutton controls for part retrieval. It stores and retrieves a variety of component containers on specially designed trays and delivers them to an ergonomically positioned workstation. The Shuttle has a fast vertical travel speed, 212 feet per minute, and an extraction speed as fast as 24 inches per second.

By installing two 21.5-foot tall Remstar Shuttle 250NT VLMs, the company has reduced the floor space necessary for storing assembly parts by 87percent, from 1,125 square feet to only 140 square feet. The Shuttle VLMs allowed Multi-Shifter to free up space in two of the plant’s four product assembly areas sufficient to double the two areas’ production. Now, the parts are consolidated vertically on 44 trays within each lockable 9.7' D x 7' W Remstar Shuttle VLM. One Shuttle VLM contains some 800 SKUs (part numbers), the other about 1,400. At present, only 70 percent of trays are in use, which means the company has capacity to serve future assembly operations.

The systems provide inventory control for both the production and service departments. One of the Shuttle VLMs is stocked with assembly parts and is installed within the assembly area it serves. 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. Integrating the Shuttle VLMs into operations at Multi-Shifter also eliminated the need for the company to build an addition to its 20,000 square foot plant—a costly and time consuming undertaking.

The Shuttle VLMs also helped the company introduce a new product line. The manufacture of a new line of man-aboard battery changers is extensively supported by the Remstar Shuttle VLMs. Known as the Cubemaster Series, the mobile changers have eliminated lift chains and rack-in-pinion mechanisms for leveling the roller bed. Instead, a self-adjusting hydraulic equalization system performs this function. Benefits include 30% fewer components, lower maintenance, and fewer adjustments.

No Walking by Assemblers
Conventional static storage systems like the shelving used by Multi-Shifter require workers to spend up to 70 percent of their time traveling aisles searching for items. Vertical storage and retrieval systems can virtually eliminate wasted travel and retrieval time. Although the specifics of each installation differ, typical productivity can increase by more than 2.5 times when vertical systems are compared with static systems.

At the Multi-Shifter facility, the Shuttle VLMs provide enclosed, point-of-use protection for densely packed vertically stacked trays of parts. When called for by a Multi-Shifter assembler, a 72”W x 33”D 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 Multi-Shifter’s 21.5-foot high lifts. Load capacity per tray is 594 lb. and balancing the load is unnecessary because trays are chain-driven from both ends. Parts as tall as 29.5 inches can be accommodated.

Quick retrieval is assisted by Remstar’s state-of-the-art Controls 2000 operating system, which is integrated with Windows® based FastPic inventory management software loaded on adjacent PCs. Using passwords and keying either a Controls 2000 operator panel or the FastPic PC, assemblers retrieve parts without walking through rows of shelving. Retrieval times have been cut approximately in half as a result.

Automation Simplifies Storage
To retrieve a part, an assembler simply enters the part number plus the quantity desired. The computer instructs the lift module to present the appropriate tray—in FIFO order if the part number is stored in more than one location. After the pick, the assembler hits a confirmation button, which automatically decrements inventory and returns the tray. Before and after extraction, a light curtain sweeps the tray looking for parts extending beyond its edges and for parts taller than the last height seen by the software for that tray.

The later 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, assemblers can enter sub-assembly 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.

Because it could expand storage capacity by using the plant’s unused vertical cube, Multi-Shifter has reduced by 87 percent the floor space formerly consumed by small parts. The parts consolidation has also successfully delayed a costly building expansion and increased worker productivity and overall operations efficiency.