Download
1 / 47
480 likes | 490 Views
Product and Equipment Analysis. Chapter 2 S.S. Heragu, Facilities Design , 4 th Edition, CRC Press. Data required for developing good layouts. Product Analysis Process Analysis. Input Data and Activities. What data are critical to the facility plan? Muther categorizes the information as:
E N D
Product and Equipment Analysis Chapter 2 S.S. Heragu, Facilities Design, 4th Edition, CRC Press
Data required for developing good layouts • Product Analysis • Process Analysis
Input Data and Activities • What data are critical to the facility plan? • Muther categorizes the information as: P – Product (what?) Q – Quantity (how much?) R – Routing (where?) S – Support (with what?) T – Timing (when?)
Product Analysis • Bill of Materials • Assembly Charts • Engineering Drawing • Operation Process Chart • Route Sheet
Input Data and Activities • Tompkins, White, et. al., categorize it as: Product Design – what is to be produced? Process Design – how is it to be produced? Schedule Design – when and how much? Product Facility Schedule Process
Product Design • Based on • Function • Aesthetics • Costs • Materials • Manufacturing Methods • Key point • The product design MUST be finalized before designing the facility. Otherwise a flexible facility is needed. Driven by market demand
Tools Used in Product Design • Product/Part Drawings • 2-D, 3-D visualization • Exploded Assembly Diagrams
Tools Used in Process Design A partial list (dependent on product and service): • Process Flowcharts and Process Maps • Make vs. Buy • Parts Lists • Bill of Materials • Route Sheets • Assembly Charts • Operations Process Charts • Precedence Diagrams
UPS Active Bins Parcel Post Picking Packing Receiving Shipping Reserve Storage Mono-gramming Next-Day UPS Embroid-ering Quality Assurance Back to Vendor Hemming Gift Boxing Process Flowcharts
Is order complete? Prepare soup or salad order Give order to waiter Process Maps Customer Waiter Salad Chef Dinner Chef N Place order Y Give soup or salad order to chef Prepare dinner order Give dinner order to chef Drink Get drinks for customer Eat salad or soup Deliver salad or soup order to customer Give order to waiter Deliver dinner to customer Eat dinner Receives check Deliver check to customer Gives payment to waiter Receive payment for meal Credit Cash or Credit? Cash Collect change, leave tip Bring change to customer Run credit card through Fill in tip amount Return credit slip to customer Collect tip
Make vs. Buy? BUY No Is it cheaper for us to make? Yes Can we make the item? Yes Yes Can item be purchased? Is the capital available? No No Yes No MAKE BUY BUY MAKE
Parts List • A listing of component parts.
Bill of Materials • Many different types of “structured parts lists”
Route Sheet Company: ARC Inc. Produce: Air Flow Regulator Part: Plunger Housing Part No. 3254 Prepared by: JSU Part No. 6/6/03
4150 3250 2200 3254 3253 3251 A-4 3252 4250 A-1 SA-1 A-2 A-3 3255 Assembly Chart • Analog model of the assembly process. • Circles denote components • Links denote operations/subassemblies • Squares represent inspections operation • Begin with the original product and to trace the product disassembly back to its basic components. I-1 1050 Pack
９ ３ ５ ６ ７ 1０ ８ 1２ 1１ Assembly Charts 1 ４ ２
Found by superimposing the route sheets and the assembly chart, a chart results that gives an overview of the flow within the facility. Operations Process Chart
Equipment Selection • Traditional Model • Queuing Model
Production Requirements – Yield Loss Pi – Production input to operation i si – Fraction of Pi lost (scrap) Oi– output of process i i Pi Oi Pisi
Production Requirements – Series Systems . . . 1 2 n P1 On Pnsn P1s1 P2s2
Example • 5 processes in series • Need 2000 units out
3 M2 M1 M4 M3 s5=4% s1=1% s3=2% s4=1% 1 M2 s2=2% 2 4 5 Production Requirements – Non Series Part B Part A Work backward from end of the line. 100,000 units
Traditional equipment selection model • P desired prod rate • t time (in hours) to process one part • m/c avail time (in hours) • m/c efficiency
Traditional equipment selection model • Nol Number of good units at output of stage l • Nil Number of units reqd at input of stage l • Sl Scrap at stage l
Simple example 1. Consider a simple jobshop manufacturing system that makes three major “Class A” products requiring five types of machines. The three products include seven parts shown in Table 2.1. Table 2.1 also shows the time standards in units per hour. 2. Assume we an hour has only 55 minutes of productive time and that 5 minutes are lost due to operator or machine unavailability and machine downtime. 3. Dividing the value 55 by the values in Table 2.1, we get the as well as time per unit. 4. Determine the quantities of machines of each type required to make the standard time per unit. 5. Assuming 12000 “representative” parts are to be made and that only 440 minutes of productive time is available per shift, we can find that we need 4.9 units of machine A, 5.85 units of machine B, and 4.3 units of machine C. 6. Rounding up these numbers gives us 5, 6, and 5 units of machine types A, B, and C, respectively.
Calculating Equipment Requirements How many pieces of equipment do we need? Pi Production rate for operation i (pcs/period) Ti Time per piece for operation i (time/pc) Ci Time available to run operation i (time/period) Ei Efficiency of machine while running Ri Reliability of machine Mj Number of type j machines required xj Set of operations run on machine j
Example • Consider Machine 2 • x2={2,3} • Do similar calculation for other machines • Other factors to consider • Number of shifts • Setup times • Customer lot sizes (smaller require more setups) • Layout type • Maintenance activities
Operator-Machine Charts • Tool for showing activity of both operator and machine along a time line • Also called “multiple activity chart” Example: 1 minute to load 1 minute to unload 6 minute run cycle 0.5 minute to inspect and pack 0.5 minute to travel to another machine
Queuing Model Manufacturing engineers at the Widget Manufacturing Company recently convinced their manger to purchase a more expensive, but flexible machine that can do multiple operations simultaneously. The rate at which parts arrived at the old machine followed a Poisson process with a mean of 10 parts per hour. The service rate of the flexible machine is 15 units parts per hour compared with the 12 units per hour service rate of the machine it replaced. (All service times follow an exponential distribution.)
Queuing Model The engineers and manager were convinced that the company would have sufficient capacity to meet higher levels of demand, but just after a two months of purchasing the machines it turned out that the input queue to the flexible machine was excessively long and part flow times at this station were so long, that the flexible machine became a severe bottleneck. The engineers noticed that more parts were routed through this machine, and that the parts arrival rate to the flexible machines had increased from 10 per hour to about 14 per hour, but were puzzled why the part flow time at this station doubled from 30 minutes to one hour and the work-n-process (WIP) inventory increased nearly threefold from 5 o 14 when the arrival rte only increased 40%. Use a queuing model to justify the results observed at Widget Manufacturing Company.
Personnel requirements analysis • n number of types of operations • Oi aggregate number of operation type i required on all the pseudo (or real) products manufactured per day • Ti standard time required for an average operation Oi • H total production time available per day • η assumed production efficiency of the plant
Queuing Model The American Automobile Drivers’ Association (AADA) is the only office serving customers in New York’s greater capital district area. Ahead of the busy summer season, the office manager wants to hire additional staff members to help provide these services to members effectively - summer travel planning, membership renewal, disbursing traveler’s checks, airline, hotel, and cruise booking, and other travel related services. It is anticipated that each customer typically requires 10 minutes of service time and customers arrive at the rate of one customer every three minutes. The arrival process is Poisson and the service times are exponentially distributed. Determine how many staff members are required if the average wages and benefits per staff member are $20 per hour and the “cost” to AADA for every hour that a customer waits to be served is $40.
