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Tips for Manufacturers
. . Response to circumstances makes the difference!
To Help You Succeed!
To Maximizing the
of Manufacturing Cells
Achieving the full benefits of cells -- grouping unlike machine or assembly stations to complete a part or sub-assembly -- requires a plan.
As with all improvement efforts, success is related to commitment, care and capability. Cells require your employees to work as a team, and fostering an attitude of caring for customer needs and other team members is vital.
The principles of cells differ from traditional manufacturing and involve
significant education and training. Successful companies that use cells spend an average
of 80 hours per year per employee to train, retrain and refresh employees on pertinent
business issues, team building and problem solving skills.
Include People in Your Plan
Before you implement cells or expand your use of cells in the plant, remember that your people are vital to the process. Consider this five-step plan to maximize the full benefits of manufacturing cells.
Step 1. Choose from several methods to select the parts to be produced in each cell. For best results, conduct a production-flow analysis to determine the best group for each part. Systematically review each part's machine tool routing, part rates and volumes. Categorize parts into compatible groups accordingly.
Step 2. Consider processing options. Remember that the direction of cells is away from batch processing and toward continuous or synchronous-flow manufacturing. The degree to which you phase out batch processing depends on the best level of automation for the parts produced. Consider system up-time and flexibility, integration costs and support requirements. Common examples of factory automation range from roller conveyors and carts to automated guided vehicle systems (AGVSs), flexible machine tools and robots.
Step 3. Material-handling considerations often contain many opportunities for improving your current processes. At present, producing parts in your plant may involve materials traveling considerable distances and increased "piles" of work-in-process parts. A major objective of cells is to consider the optimal location of work cells within the plant. Strive for one-directional flows. Minimize backtracking, "crisscrossed" paths and stop-and-go action of parts is they travel from beginning to end.
Consider whether any of these material-handling opportunities exist:
Step 4. Select the appropriate equipment for the process you've defined for each cell's assigned parts.
Avoid surprises by reviewing machine footprints and the compatibility of cell machines, machine controls and communication systems. Save time and money by detecting problems before equipment is in place. Double-check each machine's footprint for adequate clearance for work-handling and part-transfer and plan for adequate chip control along the pallet or machining axis.
Be aware of and manage differences between machines in each cell. Critical differences include:
Recognizing and minimizing these differences reduces process lead times and rework. As you increase the level of automation in a cell, the compatibility of machine controls and communication systems becomes more important. Neglecting these incompatibilities can result in costly corrections on the floor.
For instance, you'll need to consider sensitivities to electrical and electromagnetic interference. Also, make sure that each machine or cell controller can talk to the host controller. And, make sure machine offsets and movements at optimum feeds and speeds are within cycle-time requirements.
Step 5. Develop a cell layout. Floor plans are influenced by the number of different part types, their sizes and work content, number of operations, work flow and available space.
"Do you occasionally
Let's look at how successful manufacturers improve on-time customer delivery performance, and apply those strategies to your own business.
First, measure your delivery performance. The best measures reflect your customers' perspectives. Survey your customers on how they record and monitor your delivery "window" that defines on-time receipt, or do they consider any day other than the required receipt day a "non conforming" shipment?
Periodically compare internal delivery performance to your customers' data to make sure you're measuring performance the same way.
Some manufacturers track on-time delivery performance as early/late parts per million shipped. For example, 400 late parts per million equals an on-time delivery performance of 99.96%. This performance may seem "pie-in-the-sky," but many manufacturers haven't had a single late shipment during the past year.
Looking at Internal Data
Supplement information on extended performance with internal delivery performance data. Superior delivery performance begins with managing, internal delivery performance. Track internal schedule attainment each day.
Other data that will help you diagnose delivery performance include:
By analyzing this information, you can determine whether your business's delivery problems are capacity or priority related.
Capacity or Priority
Capacity problems are characterized by inadequate total resources to meet customers' delivery dates. With a priority problem, the company has adequate total resources but lacks the working hours necessary for on-time delivery. Priority problems are usually less costly and easier to fix than capacity problems.
Plant A vs. Plant B
Plant A machines valves. Pant-wide capacity utilization averages 64%, Individual work center utilization ranges from 52% to 82%.
The plant has operated at 95.5% of its production standard for the past six months, with a work center range from 88% to 110%. Work center queues vary from 1.1 to 2.4 days. Internal schedule attainment averages 97.8%. On-time delivery performance averages 92.4%. Stockroom inventory levels of semi-finished parts and subassemblies increased approximately 40% during the past several months.
Plant A has a priority problem. The manufacturer should commit more resources to meeting near-term customer order requirements and less to building inventories.
Plant B manufactures headrest assemblies for the automobile industry. Plant-wide capacity utilization averages around 55%. Work center queues average 1.7 days. For the last six months, the plant has averaged 96.8% of standard output with work centers ranging from 92.2% to 102.7%. Internal schedule attainment averages 94.5%.
Work centers 105 and 118 have queues of seven and four days, respectively. Work center utilization approaches 90% (six days per week, two-shift operation) for work centers 105 and 118.
Stockroom inventory levels have increased 4% during the last six months. Internal schedule attainment averages 97.2%. Customer on-time delivery performance averages 93.1 %.
For Plant B, work centers 105 and 118 appear to have inadequate capacity to consistently meet customer shipment deadlines.
Solutions to Capacity and Priority Problems
Pinpointing the Cause
You can usually identify the cause of late customer shipments as either inadequate capacity or poor scheduling priority. Before tackling a problem, make sure you have the right data and have analyzed it property.