Six steps approach for identifying and creating manufacturing cells

manufacturing work cells

Step 1 – Determine Product Volume and Mix These categories represent marketing’s definition of product groupings and correspond roughly to divisions in the company’s product catalog.Within each product category, representative parts were identified.

For example, the shelving product category includes shelving units that vary by depth, width, height, number of shelves, back panel configuration, and end panel configuration.  A single shelf unit – 18 inches deep, 36 inches wide, and 7 feet high with six shelves and no back or side panel – was selected to represent all shelf units.Then, the complete bill of materials was exploded for each product, and process data was gathered for each part.

Step 2 – VSM Generated & Time study for Process Times of Representative PartsProcess flow mapping with all options (80/20 rules)Process times (run time and setup time) for each part are identified.

Step 3 – Identify Product / Part FamiliesThe purpose of Step 3 is to group the product categories identified in Step 1 so that a manufacturing cell can be created for each part or product family. After extensive analysis, the company decided that product-focused (rather than part-family-focused) cells were appropriate.  The deciding factor was process technology.With the soft-tooled technologies, there were no clear differences in the types of equipment required to produce different parts or products.  However, almost all of the hard-tooled applications were product-oriented.

For example, separate roll forming equipment and tooling had been established for the uprights associated with each type of pallet rack and shelving.  The decision to retain certain hard-tooled processes in the cells drove the product focus.In other applications, it may not be most appropriate to create product focused cells.  Other bases for grouping parts or products into families include factors such as material type and thickness; common routings; and part size, configuration, and geometry.

Example at this stage, the company also decided to create a punching cell that would deliver punched parts in the flat to each of the product specific cells.  Although two product cells contained dedicated CNC turret punches, none of the other cells had enough volume to fully load a turret punch.Because this punching technology represented a significant investment for the company, it sacrificed a little on the ideal of producing a product from start to finish within the cell in favor of some practical economic considerations.

Step 4 – Identify Alternative Process TechnologiesThe left column lists the hard-tooled process technologies it employed in the past.  The right column lists the new, more flexible process technologies integrated into the cellular operations.Note that hard-tooled technologies were retained in several instances.  Over time, the company had engineered some creative and effective tooling approaches. With these approaches, certain high-volume products (standard shelf sizes, for example) could be produced effectively on a hard-tooled line retained in the cell.To truly integrate these operations into a cellular manufacturing environment, later setup reduction efforts (encompassing both hard- and soft-tooled processes) were added to the overall implementation plan.

Step 5 – Develop Conceptual Manufacturing CellsThis cell is typical of most other cells created by the company.Parts enter the cell either directly from raw materials or from the punching cell.  They are punched, formed, and welded within the cell.  They exit the cell for paint and then return to the same cell for final assembly.To determine the equipment requirements in each cell, overall process time was calculated from projected volumes and expected lot sizes.

This step required considerable application of engineering experience to determine setup and run times for operations transferred from the hard-tooled to the computer numerically controlled (CNC) equipment.The conceptual cells roughly approximate the physical size of the cell and equipment items in it to facilitate the plant layout process in Step 6.  The intent of creating a conceptual cell layout is to test the feasibility of the cell concept and to take a quick cut at the space and configuration requirements of the cell.

Step 6 – Create Layout for Manufacturing Cells and PlantA layout is created in two steps.  First, a macro layout planning process optimizes the location of each cell with respect to the other functional activity areas in the plant.  This is done by carefully considering all material flow and other nonflow relationships between the different areas.