Introduction Operations Analysis and Improvement 2010 Spring Dr. Tai-Yue Wang Industrial and Information Management Department National Cheng Kung University
Presentation • Throughput or lead time are directly affected by the where and how the processing and storage resources are located in the factory. • Plant layout is an activity that all companies are forced to deal with sooner or later. • It is important to be familiar with the methodologies used to carry out these tasks.
Presentation • Cellular layouts - where labor and machines are grouped in cells - will be explained in depth in the following chapter.
HIGH FLEXIBILITY TRANSFER LINE PRODUCTION CAPACITY SPECIAL SYSTEM FLEXIBLE MANUFACTURING SYSTEM VOLUME MANUFACTURING CELLS STD. AND GEN. MACHINERY VARIETY LOW HIGH Production Systems Design
Introduction • Factory layout improvements typically occur more than one time during the factory’s life. • The study of plant layouts seeks the optimal location for all of the production resources. • Tries to ensure that the economic impact of the project on the enterprise will be as positive as possible. • New plant layout must be as safe as possible and satisfactory for the employees. • It seems obvious that the optimal solution will be unreachable or change routinely. • Commitment between all the aspects is achieved.
Signs and reasons for a new layout(1/8) • Location change. • Reasons to suggest a change of location of the factory. • Location has become inadequate or antiquated. • Factory expansion is impossible.
Signs and reasons for a new layout(2/8) • Location change. • Layout can be different if the company chooses a new location by constructing a new building, versus utilizing an existing facility. • New building construction can allow for an ideal layout because building functionality is the principle focus of the building design. • Use of the factory floor space should be better utilized.
Signs and reasons for a new layout(3/8) • Purchase new equipment • New needs as well as technology improvements form the basis of machinery purchase • Finding the best location for the purchased equipment can become a critical issue in making a “system” perform as intended.
Signs and reasons for a new layout(4/8) • Purchase new equipment • Newly purchased incremental equipment is generally placed in free space available. • In some cases it is necessary to move machines to create space. • In other cases the new machine is located in a place that promotes system efficiency.
Signs and reasons for a new layout(5/8) • Equipment set up is typically done once, while the materials flow is a continuing process. • The analysis of this material flow can in most cases be economically formulated.
Signs and reasons for a new layout(6/8) • Problems with materials flow • This problem is generally derived from a problem previously solved. • Placing new equipment in available space in the plant • The initial set-up costs decrease, but other problems arise. • Materials flow can be adversely affected by introducing additional equipment.
Signs and reasons for a new layout(7/8) • High work-in-process (WIP). • A good policy or layout in a given period of time may not always produce good results forever. • A measure of change in the company is the amount of partially completed products (work-in-process). • This should not be confused with a temporary situation caused by a momentary increase in demand or stock outages and/or surges.
Signs and reasons for a new layout(8/8) • Slow changes in product variability can hide the negative effects of the excessive work-in-process (WIP).
Thinking revolution The 5S Visual Control Workforce optimization Standard operations Poka-Yoke Jidoka TPM One-Piece flow Multi- functional workers Leveling Production Kanban SMED JUST IN TIME One-piece flow(1/7) • Before we begin exploring layout analysis tools, it is important to clarify the definition of production and transferbatch even though both sizes are normally the same.
Thinking revolution The 5S Visual Control Workforce optimization Standard operations Poka-Yoke Jidoka TPM One-Piece flow Multi- functional workers Leveling Production Kanban SMED JUST IN TIME One-piece flow(2/7) • Production batch. • Number of products included in the customer order. • Transfer batch (unit load). • Amount of units that flows from one machine to the next.
Thinking revolution The 5S Visual Control Workforce optimization Standard operations Poka-Yoke Jidoka TPM One-Piece flow Multi- functional workers Leveling Production Kanban SMED JUST IN TIME One-piece flow(3/7) • Work-in-process decreases with a reduction in the transfer batch size.
Thinking revolution The 5S Visual Control Workforce optimization Standard operations Poka-Yoke Jidoka TPM One-Piece flow Multi- functional workers Leveling Production Kanban SMED JUST IN TIME One-piece flow(4/7) • Advantages of reducing the transfer batch • Production feedback is faster. • Lead time decreases. • A reduction in the transfer batch increases the material handling between sections.
Thinking revolution The 5S Visual Control Workforce optimization Standard operations Poka-Yoke Jidoka TPM One-Piece flow Multi- functional workers Leveling Production Kanban SMED JUST IN TIME One-piece flow(5/7) • The ideal transfer lot size is called continuous one-piece flow. • Normally, a container size is considered unit load flow. • For example, a “1000-screws flow”, can be used as “unit load flow”.
Thinking revolution The 5S Visual Control Workforce optimization Standard operations Poka-Yoke Jidoka TPM One-Piece flow Multi- functional workers Leveling Production Kanban SMED JUST IN TIME One-piece flow(6/7) • One-piece-flow eliminates most of the causes and effects outlined in the previous section. • It is one of the Just-in-time tools. • To come closer to an ideal one-piece-flow, the material flow has to be minimized or eliminated. • If this is not possible, then the machines should be located as close together as possible.
Thinking revolution The 5S Visual Control Workforce optimization Standard operations Poka-Yoke Jidoka TPM One-Piece flow Multi- functional workers Leveling Production Kanban SMED JUST IN TIME One-piece flow(7/7) In order to improve the material flow, it is typically necessary to analyze and change the company’s layout.
Main types of industrial companies • In an open-market, there exists a multitude of different products. • food, cars, computers, bricks, cement, ships,... • Each product has a specific manufacturing process. • Analysis is conducted based on similarities • Cars and washing machines? yogurt and soap?
Main types of industrial companies • The grouping is based on the type of production facilities that the companies uses. • Industrial companies can be grouped into four sectors. • Primary, Secondary, Tertiary and Service Sector. • Secondary Sector (Process Industry and Consumption Industry). • Tertiary Sector (Production and Assembly factories).
Process industry(1/4) • Process focused industries • The manufacture of the product dictates the equipment and product flow. • Paper, wood, cement, painting and fabrics manufacturers,...
Process industry(2/4) • Consumer goods will also be grouped into this type • Quality or purity measures will be much higher. • Yogurts, ice creams, drinks,… • Pharmaceutical and cleaning products.
Process industry(3/4) • Four main steps • Raw materials preparation • Received in bulk and storage in large warehouses or silos. • Product mixing is carried out in hoppers or in smaller drums. • Treatment • filter, dry, separate,...
Process industry(4/4) • Finishing • Restore some properties (Metals). • Superficial treatments. • Polishing or painting. • Bottling or packaging • Bottling or packing lines.
Assembly companies • Companies that exclusively assemble final products. • Cars, televisions, microwaves. • Their components are purchased from external companies.
Assembly companies • Some processing operations are also carried out internal to the factory. • They are not profitable to subcontract. • Sheet cutting. • Welding. • Plastic injection molding. • Painting.
Manufacturing companies • Companies that manufacture component parts do not belong to any of the previous groups • Forges • Plastic injection machines • Presses • CNC machines.
Manufacturing companies • Factory layout depends on the product type and volume to be manufactured • Later this will be analyzed in more detail
Layout types • There are numerous classifications of industry according to their layout. • We will use four basic layout groupings or classifications. • The grouping is primarily the result of the material flow in the production plant • Fixed position layout • Process layout • Product layout • Cellular or combination layout
Fixed position layout • The product does not move throughout the production process, the needed resources do. • Ships, buildings, trains,… • Products with short or immediate needs • Milling center, presses,... • Historically this layout was also used for custom car production
Process layout • Machines are grouped into departments or stations according to the operation that they perform. • Presses -> pressing department • Lathes -> lathes department
Process layout • Used in companies that manufacture by orders. • Specialty parts or components. • A small job shop that makes unique dies or fixtures • Products that are made in very small batches
Process layout. Advantages • The flexibility of products (almost any part that fits within the volumetric boundaries of the machines) is possible. • An in depth understanding of a specific process can be obtained. • Some tooling and fixtures can be shared.
Process layout. Disadvantages • The spaghetti flow is difficult to manage and control. • There is usually a lot of inventory in front of each machine.
Process layout. Disadvantages • Set up is usually expensive and time consuming. • Material handling times are large. • It is difficult to automate these types of systems.
Product layout • Machines are grouped according to the product manufacturing sequence. • These layouts are called manufacturing or assembly lines. • High volume component parts are normally produced using a product layout.
Product layout • Assembly companies normally use this type of layout, especially in the automotive sector.
Product layout • The layout change carried out by Henry Ford drastically reduced the car production lead time. • Some companies are able to manufacture an automobile every 40 seconds.
Product layout. Advantages • Large batches can be produced inexpensively • Material handling is minimal • In-process materials are minimized • It is easy to control these systems • Automation is more achievable and justifiable
Product layout. Disadvantages • They are inflexible, in that only one or very few products can be produced on them. • Set-up time for these systems is very large. • Duplicate tooling is required to replace worn tooling so that maintenance can be minimized.
Cellular or combination layouts • Some companies can not be classified exclusively by one of the previous layout types. • Large product manufacturing industries (airplanes or presses) have opted for modularization. • Different modules are produced in different lines and assembled as subsets.
Cellular or combination layouts • Dismantling sections and creating manufacturing cells to accommodate demand. • Special screws manufactures. • Cellular layout. • Share the critical resource. • High cost of the resources. • Combination layout between product and process layouts.
Cellular or combination layouts • Common first phase and different assembly lines to elaborate the final product. • Appliances manufactures. • Plastic injection and presses sections, combined with assembly lines grouped by product families.
Layout design methodology(1/11) • These next steps are applicable to most of the possible layout problems, they are oriented mainly for a general layout analysis. • Step 1. Formulate the problem. • Define what is the main objective of the study. • Including a new machine? • Modifying the existing building?
Layout design methodology(2/11) • Step 2. Analysis of the problem. • Can be carried out in a systematic way. • Richard Muther in his now classic book " Practical Plant Layout " presented 8 factors to consider for facilities layout. • These factors will be described in the tools section.
Layout design methodology(3/11) • Step 3. Search for alternatives. • The analysis of the 8 Muther’s factors enables engineers to define the problem and properly align the solution to the problem. • It is important to take into account three practical principles. • First the whole and then the details. • First the ideal solution and then the practical one. • Brainstorming.
Layout design methodology(4/11) • Step 3. Search for alternatives. • First the whole and then the details. • Giving priority to the general area or total space shared and then to each one of the specific areas. • Layered planes are developed to characterize the situation.