Chapter 3

1. Chapter 3 Planning for Production

2. Objectives • Product oriented manufacturing systems versus people oriented manufacturing systems. • Manufacturing smaller lot sizes with less lead time. • Push, pull, and Kanban manufacturing systems.

3. The unskilled factory system • Fredrick Taylor (1856-1915) believed that complicated jobs can be broken down into a series of simple tasks. • An inexperienced person could quickly learn how to do a simple task, which eliminated the need for skilled workers. • Once a process was defined and the worker was following the correct procedure, Taylor timed each task – time and motion study. • Knowing the time it takes to do a task enabled managers to predict how many parts could be made in a time period and how many people would be needed to make the products at the rate required.

4. The Production Line Manufacturing System • Henry Ford developed a manufacturing approach known as vertical integration, where Ford created the parts instead of relying on outside suppliers. • The Ford Company made everything from the steel to the paint used in their automobiles. • Ford’ engineers used Taylor’s approach to define an individual’s work . They also used a conveyor to move the car from task to task (supposedly Ford adapted this idea from a meat packing plant he visited). • Ford’s production system produced the Model-T automobile – the first affordable mass produced automobile.

5. People Oriented versus Product Oriented Manufacturing Systems • Keeping workers busy was the focus of management. • This created a build up of materials on the factory floor – called Work in Progress (WIP). • Incentive systems paid workers on the amount they produced (piece rate) or bonus proportional to amount over a base level – created excess WIP.

6. Product Flow Manufacturing Systems • A manufacturing system that is operating just in time (JIT) will not have any work in progress. • Increase in excess WIP is a symptom that a problem exists. • Problems can be one or more of the following 5 categories: quality, machine breakdown, setup or change over downtime, operator problems or unplanned absenteeism, or materials availability. • Qualityproblem – 5 % of the parts made by the stamping operation are defective. Symptom – 105 parts are made for every 100 parts needed. Solution – institute a quality improvement process to eliminate quality problem. • Machine breakdown – establish a preventive or predictive maintenance program to eliminate the breakdown problem. • Setup or changeover downtime – establish a single minute changeover of dies (SMED) program. This is a team approach to reduce die changeover times. • Operator Problem – Provide the operator with knowledge, support, authority, and responsibility to produce good parts. • Delivery of required materials is late – choose suppliers on their ability to respond on time and provide quality materials.

7. The Basis for Lean Manufacturing • 1. Quality • Quality programs in lean manufacturing eliminate and prevent waste (non value added activities) in the production of a product. • Inspection of parts and products is a non value added activity. • Three steps used to ensure replication of characteristics in Statistical Process Control (SPC): • a. Establish Control: make the process or activity capable of replicating a product or task. • b. Monitor the Activity: visual method to track performance of activity to recognize when the activity is not performing normally. • Designers usually provide for some variation – tolerance. • Process variation is normally considered to be 6 standard deviations. • Run charts (fig 3-5, page 63) incorporate a centerline and control limits to enable the operator to monitor and interpret if the process is in control. • c. Problem Solving: train personnel to be problem solvers to bring activity back in control. • Cause and Effect Diagram: Breaks down main cause into smaller sub causes to discover the root cause and not just the symptoms of a problem or condition. • The 5 Why’s: Ask the question “why” 5 times to get to the root cause of a problem. • Pareto Analysis: A bar chart displaying in descending order the most frequent to the least frequent problems. 80 % of defects are produced by 20% of problems.

8. The Basis for Lean Manufacturing • 2. Reliability • Institute a maintenance program based on following the manufacturer’s recommendation about the care that should be given to production equipment known as preventive maintenance . • It requires operators to be trained in maintaining their equipment. • The objective of all maintenance programs is to reduce waste caused by interruptions to product flow.

9. The Basis for Lean Manufacturing • 3. Setup Reduction • The setup time should be small enough to enable the manufacturing lot size to equal the quantity the customer wants shipped as an order. • Successful companies approach setup reduction time the same way a NASCAR team views the time it takes to do a pit stop. • Involve a setup reduction team in developing an innovative solution to achieve the target setup time.

10. The Basis for Lean Manufacturing • 4. Operator Ability • To carry out the tasks assigned each person must possess the knowledge/skill to: do the task correctly, obtain help to solve the problem if they are not able to do it, and never let a problem/defect move on in the manufacturing process.

11. Manufacturing System • Materials Requirement Planning (MRP) is computer based scheduling that minimizes raw material inventory and excess WIP. • For critical orders production control managers, manufacturing department supervisors, and sales managers rely on a group of people (expeditors) to track, confirm, and work out problems. • Delays due to breakdowns, absences, and unforeseen setups cannot be forecast by the computer system.

12. Push and Pull Systems • Push system: When an order is received a push system begins by ordering materials and then establishes a start date to begin production based on when the materials will be available. Push systems push the product through the factory. • Pull systems: try to respond immediately by shipping the order when it is received. Shipping the order then creates a demand that moves up the production line to replace what has just been shipped. • Pull systems are considered to be more responsive to customers than a push system.

13. Kanbans • The triggers used to start production in a pull system are called Kanbans. • The Kanban signal to initiate production consists of a card and a container (tote pan). • The Toyota system used a specific size container for each part. • This container cycles back and forth between the producing department and the using department. • Producing departments may not make parts unless there is an empty Kanban container and a card (Kanban) authorizing production. • The number of containers is controlled by manufacturing management and is kept to the smallest possible quantity.

14. Bringing Vendors into the Manufacturing System • Typically, the date that a company said it would ship an order had to include the time it took to procure needed materials from a supplier. • Buffer stocks allow lean manufacturing systems to deal effectively with distant vendors, complex product mixes, and fluctuating demand loads.

15. Summary • Fredrick Taylor (1856-1915) believed that complicated jobs can be broken down into a series of simple tasks. • An inexperienced person could quickly learn how to do a simple task, which eliminated the need for skilled workers. • Once a process was defined and the worker was following the correct procedure, Taylor timed each task – time and motion study. • Knowing the time it takes to do a task enabled managers to predict how many parts could be made in a time period and how many people would be needed to make the products at the rate required. • Problems can be one or more of the following 5 categories: quality, machine breakdown, setup or change over downtime, operator problems or unplanned absenteeism, or materials availability. • Process variation is normally considered to be 6 standard deviations. • Run charts incorporate a centerline and control limits to enable the operator to monitor and interpret if the process is in control. • Cause and Effect Diagram: Breaks down main cause into smaller sub causes to discover the root cause and not just the symptoms of a problem or condition. • The 5 Why’s: Ask the question “why” 5 times to get to the root cause of a problem. • Pareto Analysis: A bar chart displaying in descending order the most frequent to the least frequent problems. 80 % of defects are produced by 20% of problems.

16. Home Work • 1. What is Taylor’s time and motion study, and what is its advantage? • 2. Name the 5 categories of product flow problems in a manufacturing system? • 3. What is the acceptable normal process variation? • 4. What are run charts?