Building a Better Horizontal Carousel

The Benefits of Modular Carousel Design

By William Ledoux, Vice President of Operations

Over the years, horizontal carousels have proven one of the most reliable and cost effective means of storing products, as they achieve high pick rates with excellent cube utilization. The size and use of carousel systems varies significantly, from small stockroom applications and hand picking point-of-use items to large fully integrated systems moving thousands of boxes per day in a fully automated, highly sophisticated design. As a result of value engineering, horizontal carousel systems have evolved throughout several permutations to achieve a very flexible and versatile product.

Original carousel products were built on a per job basis. A family of carousel sizes was eventually developed to satisfy storage requirements that used totes or dedicated boxes for individual parts storage. Early models were based on 18" and 24" requirements and were partially driven by the advent of plastic and/or reusable returnable totes.

The challenge before the manufacturer was to design a system that met customer needs and delivered a material handling solution in a reasonable amount of time. Although each carousel has common components - a track, load carrying yoke and load bars, bins, shelves and controls, varying capacity and available space made for widely different carousel sizes (length, height and weight capacity). It was nearly impossible to stock components across all of the designs and still expect a cost effective and timely solution. Expected deliveries of a few weeks are common in the industry and are frequently the result of fierce competition.

Diamond Phoenix engineers set out to resolve this dilemma. In previous designs, the space between bins was fixed so that they were evenly spaced and the carousel track (the oval that supports and guides the bins as they move around and around) had to be a unique size to suit the evenly divided carousel chain. By adopting a small variation in the design - fixing the carousel frame and simply varying the space between bins - a common track was produced to suit all bin sizes.

The carousel chain path had to be divided into smaller lengths (a chain design to keep cordial action to a minimum yet large enough to keep the number of components small) and then combined in groups of two and three pitches to accommodate the most common bin widths. Common track meant that frames could be stocked for any number of forecasted carousel projects and could be used for any job. Only the "odd" carousel track section that made the track length unique to the application had to be made specifically for that job - all other components came out of stock. Gone were the days of missed forecasts and stranded carousel frame sizes. Every stock carousel frame met the design requirements when combined with the "odd" section. Today, stock components are manufactured for both the top and bottom track sections and the variation in height based on the bin is simply adjusted with common stanchions cut to length as required.

The next piece of the flexibility formula was to make sure the individual line component used to make up the chain and moving gear remained common across all models and weight requirements. Carousel capacities vary greatly from small light loads in the six hundred pound per bin category to monster two thousand pound bins used to store packaged meats or heavy industrial hardware. Early designs used appropriately sized components to keep costs down; however, ever expanding inventories were required to keep an abundant supply of the least expensive components in stock. Again, the Diamond Phoenix engineering team came up with a solution. Why not use common bearings and load bars across all weight capacities and combine them in different groupings to support varying loads? In this scheme, a smaller number of bearings carries a light load and larger group of the same bearing carries heavier loads. Combine this with a selection of material for load bars and you have the same "stock" components carrying widely different loads.

The third requirement was probably the easiest to solve for our "can do" group of designers. Something in the Maine environment makes people self-reliant…attribute it to long winters or stubborn Yankee pride, people around here are used to making things and are darn good at it. As a result Diamond Phoenix became the only carousel manufacturer to design and build its own wire product (bins and shelves) in-house. With roughly a million combinations of capacity, height, width, depth and shelf spacing, stocking ”standard product" was not feasible. However, the design of flexible jigs and fixtures to suit various sizes allowed for modularity on the manufacturing side and made for versatility in building product when combined with the ability to cut, form and spot weld wire product in-house. Engineering tools allowed the design of wire product to closely follow the order entry function. There is never a long lead time in the manufacturing chain - an order entered is an order started in production.

Finally, a common platform of control components provides the ability to build controls from foot switches to sophisticated control schemes using “off the shelf” components from electrical equipment suppliers. This has two advantages: easily obtainable components and the ability to allow the customer to dictate the “make” of electronic/electrical components used in a given project. Customers stock fewer spare part components and there is a high degree of reliability in the final product, avoiding the pitfall of proprietary electronic/electrical design in a world of fast moving and changing component availability.

Diamond Phoenix’s combination of common base frames and components, in-house wire manufacturing and the use of standard electrical components is a recipe for quick and reliable deliveries – no one in the industry is faster and no one is better. The customer wins with the lowest possible price, quick deliveries, in stock spare/replacement parts, and the ease of expanding the system in the future.