For example, PQ (product type/quantity) analysis is used to assess the current product mix. The first step in converting a work area into a manufacturing cell is to assess the current work area conditions, starting with product and process data. Step 1: Understanding the Current Conditions. The following steps and techniques are commonly used to implement the conversion to cellular manufacturing.
The parts make their way through the various functional departments in large "lots", until the assembled products eventually are shipped to the customer. The figure to the left illustrates the production flow in a batch-and-queue system, where the process begins with a large batch of units from the parts supplier. Primarily, this is due to substantial "work-in-process", or WIP, being placed on hold while other functional departments complete their units, as well as the carrying costs and building space associated with built-up WIP on the factory floor. In many instances this system can be highly inefficient and wasteful. The system also requires companies to produce products based on potential or predicted customer demands, rather than actual demand, due to the lag-time associated with producing goods by batch and queue functional department. Batch and queue entails the use of large machines, large production volumes, and long production runs. Batch and queue systems involve mass-production of large inventories in advance, where each functional department is designed to minimize marginal unit cost through large production runs of similar product with minimal tooling changes. Method and Implementation ApproachĬellular manufacturing requires a fundamental paradigm shift from "batch and queue" mass production to production systems based on a product aligned "one-piece flow, pull production" system. Using this technique, production capacity can be incrementally increased or decreased by adding or removing production cells. While plant-floor workers may need to feed or unload pieces at the beginning or end of the process sequence, they are generally freed to focus on implementing TPM and process improvements. This transformation often shifts worker responsibilities from watching a single machine, to managing multiple machines in a production cell. Equipment often must be modified to stop and signal when a cycle is complete or when problems occur, using a technique called autonomation (or jidoka). To make the cellular design work, an organization must often replace large, high volume production machines with small, flexible, "right-sized" machines to fit well in the cell. This one-piece flow method includes specific analytical techniques for assessing current operations and designing a new cell-based manufacturing layout that will shorten cycle times and changeover times. The approach seeks to minimize the time it takes for a single product to flow through the entire production process. Cellular manufacturing can also provide companies with the flexibility to vary product type or features on the production line in response to specific customer demands. Rather than processing multiple parts before sending them on to the next machine or process step (as is the case in batch-and-queue, or large-lot production), cellular manufacturing aims to move products through the manufacturing process one-piece at a time, at a rate determined by customers' needs. Implementation of this lean method often represents the first major shift in production activity, and it is the key enabler of increased production velocity and flexibility, as well as the reduction of capital requirements. In cellular manufacturing, production work stations and equipment are arranged in a sequence that supports a smooth flow of materials and components through the production process with minimal transport or delay. Implications for Environmental Performance.