Facilities Planning and Design Course code: 1704031511 Spring 2017-2018 Required Text: Tompkins et al., (2003). Facilities Planning, 3rd or later Edition, John Wiley and Sons Inc. Students are encouraged to refer to the text book, and to take notes during the lectures.

Facilities Planning and Design Course code: 1704031511 Spring 2017-2018 Required Text: Tompkins et al., (2003). Facilities Planning, 3rd or later Edition, John Wiley and Sons Inc. Students are encouraged to refer to the text book, and to take notes during the lectures.

Chapter 2: Product, Process and Schedule Design Chapter Topics: PART I Facilities Planning Process for Manufacturing and Assembly Facilities. Relationship between PP&S design and Facilities Planning. Product Design PART II Process Design Process identification Process selection Process sequencing PART III Schedule Design Quantity of the product Equipment requirements Operator requirements PART IV Facilities Design

Facilities Planning Process for Manufacturing and Assembly Facilities. 1. Define the products to be manufactured and /or assembled. 2. Specify the required manufacturing process and/or assembly processes and related activities. 3. determine the interrelationships among the activities. 4. Determine the space requirements for all the activities. 5.Generate alternative facilities plans. 6. Evaluate the alternative facilities plans. 7. Select the preferred facilities plan. 8. Implement the facilities plan. 9. Maintain and adapt the facilities plan. 10. Update the products to be manufactured and/or to be assembled and redefine the objective of the facility.

Relationship between PP&S design and Facilities Planning. Before we start developing alternative facility plans, we should have answers for the following questions: What is to be produced? How are the products to be produced? When are the products to be produced? How much of each product will be produced? For how long will the product be produced? Where will the products be produced?

Schedule design Schedule design provides answers to questions involving: Production quantity - lot size decisions When to produce - production scheduling How long to produce – marketing forecasts Schedule design decisions impact machine selection, number of machines, number of shifts, number of employees, space requirements, storage equipment, material handling equipment, personnel requirements, storage policies, unit load design, building size, etc. We design facilities for major parts and operations What do we need to know to start designing our facilities Number of products demanded by the market Number of products to be produced Number of machines required Number of employees required Sequence of operations Relationships between departments

Schedule design - Marketing information Objective – market estimate Data from marketing: Production volumes Trends Future demands Min information provided by marketing is shown in Table 2.2 Detailed information by marketing is shown in Table 2.3:

Volume-variety chart – Pareto law More general items produced everyday: Mass production area (High volume) Items that are produced maybe by special orders: Job shop area (Low volume) 85% of the production volume is attributed to 15% of the product mix Therefore when facilities are designed, top 15% of the items that are produced should be considered the most. If no products dominate the production flow, a general job shop facility is suggested

Schedule design – Process requirements Specification of process requirements has three phases: Determination of the quantity to be manufactured for each component Identification of each equipment required by each operation Overall equipment requirements Scrap Estimates (Examples solved during the class) Determination of the quantity to be manufactured for each component For high volume production The estimation of scrap

Schedule design – Process requirements Specification of process requirements has three phases: Determination of the quantity to be manufactured for each component Identification of each equipment required by each operation Overall equipment requirements Reject Allowance Problem Determination the number of additional units to allow when the number of items to produce are very few and rejects randomly occur For low volume production The cost of scrap is very high

Reject allowance problem X: Number of good units, random variable p(x): Probability of producing exactly x good units Q: Quantity of production C(Q, x): Cost of producing Q units, with x good units R(Q, x): Revenue from producing Q units, with x good units P(Q, x): Profit from producing Q units, with x good units P(Q, x) = R(Q, x) - C(Q, x) E[P(Q)]: Expected profit when Q units are produced X and Q are discrete variables, therefore p(X) is a discrete probability function Objective: Determine production quantity Q that has exactly x good units and maximize the expected profit: E[P(Q)] Other useful information is what is the probability of loosing money if Q is produced.

Reject allowance problem Example A foundry produces castings to order. An order for 20 custom-designed castings has been received. The casting process costs $1,100 per unit scheduled. If a casting is not sold, it has a recycle value of $200. The customer has indicated a willingness to pay $2,500 per casting for 20 acceptable castings – no more, no less! • Based on historical records, the probability distributions given in Table 2.6 have been estimated. • How many castings should be scheduled for production to maximize the expected profit? • What is the probability of losing money at this production level? Example Summary 20 castings are needed (no more, no less)  C = $1100/unit  Price = $2500 Recycling Value = $200 Determine Q that max. E (Profit)

Table 2.6 Probability Distribution for Number of Good Castings (x) out of Q

Revenue, cost and profit functions for the reject allowance problem

Profit for producing Q and having different x good units among them Expected Profit for producing Q and having different x good units among them

Equipment fractions The quantity of equipment required for an operation Most of the time facilities need fraction of machines How can we determine the number of machines we need in order to produce Q items? F: the required number of machines per shift S: the standard time per unit produced [min] Q: the number of units to be produced per shift E: actual performance (as % of standard time) H: amount of time available per machine [min] R: reliability of machine (as % “uptime”)

Machine assignment problem Operator Requirements Machine assignment problem

Machine assignment problem If we know the activities needed and the time required to complete each activity, we can determine the ideal number of machines per operator n’ (for identical machines) If found n’ is not an integer value (it will not be in most cases), how do we determine the number of machine for each person (m)? If m < n’ then operator will be idle If m > n’ then machines will be idle This question can be answered more accurately if we know the cost of machining and of the operator

b : Independent operator activities (walking, inspecting, packing) Human-Machine chart or Multiple Activity chart a : Concurrent activity (both machine and operator work together: load, unload machines) b : Independent operator activities (walking, inspecting, packing) t : Independent machine activities (automatic machining) (a+b): Operator time per machine: time an operator devotes to each machine (a+t): Machine cycle time (repeating time): time it takes to complete a cycle L: Loading T: Walking U: Unloading I&P: Inspection & Packing Ideal worker-machine assignment:

Cost per unit produced during a repeating cycle of a combination of m machines and an operator. If <1 then TC(n)<TC(n+1), n machines should be assigned If >1 then TC(n)>TC(n+1), n+1 machines should be assigned