Scheduling in Production Units

There are several types of modem manufacturing systems including intermittent, continuous and flexible production systems. Intermittent production is where more than one of the same product is being made in a short amount of time. There are stmctures of intermittent systems including batch production, jobbing production. 

In project production a complex sets of interrelated activities (project) are performed within a given period of time and estimated budget to make a product characterized by its immobility during production. Examples of such products are ships, locomotive, aircrafts buildings and bridges. The product is located in a fixed position where production resources are moved to it. 

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As companies rely more on their business partners or suppliers, scheduling within production units has to be extended to coordinate between members in the supply chain. 

The material balances ensure the conservation of mass around each unit and concerning each state involved in production scheduling. 

We define the following parameters for the example process B0 = Bi = B2 = B3 = B4 = 20 d = d2 = 3 d3 = 2 b = 10 b2 = bz = 4. The initial amount of Si is 20 units and the goal of the production is to produce 8 units of S3 and 12 units of S4. The optimal schedule with respect to the makespan (the overall production time) is shown in Figure 10.2. Each occurrence of a task in the schedule is called an operation and the number of operations must be determined by the scheduler. The schedule in Figure 10.2 is obviously valid because it satisfies the requirements from Section 10.1.3. It is also optimal, because none of the operations can be shifted to the left to reduce the makespan which is determined by the last operation of T3. In the optimal schedule, 2 operations of both, T1 and T2, as well as 3 operations of T3 are necessary to meet the market demand. The optimal makespan is 10 and all raw and intermediate materials have been processed without overproduction of final products. 

Suppose you are a chemical distributor who wishes to optimize the inventory of a specialty chemical. You expect to sell Q barrels of this chemical over a given year at a fixed price with demand spread evenly over the year. If Q = 100,000 barrels (units) per year, you must decide on a production schedule. Unsold production is kept in inventory. To determine the optimal production schedule you must quantify those aspects of the problem that are important from a cost viewpoint [Baumol (1972)]. 

Reactor systems that can be described by a yield matrix are potential candidates for the application of linear programming. In these situations, each reactant is known to produce a certain distribution of products. When multiple reactants are employed, it is desirable to optimize the amounts of each reactant so that the products satisfy flow and demand constraints. Linear programming has become widely adopted in scheduling production in olefin units and catalytic crackers. In this example, we illustrate the use of linear programming to optimize the operation of a thermal cracker sketched in Figure E 14.1. 

If the product is to be marketed in the United States, the plant must meet the FDA s good manufacturing practices (GMP) requirements (which now apply in most of the developed countries). If other products are being manufactured in a given plant for sale in the United States, it is not a certainty that the FDA will inspect the plant for the production of each new compound fhaf is to be produced therein. It is virtually certain that the plant will be inspected, however, if the company has not been previously cleared by the FDA for manufacturing or sale in the United States. Inspection is also likely if the new process represents a significant deviation from the processes that have been carried out in the plant in the past. Requests to the FDA for plant inspection should be made as early in the NDA cycle as the law permits as scheduling the actual date for inspection can be a problem. 

Section 8(2) of the Medicines Act 1968 requires those involved in the manufacture or assembly of a medicinal product to hold a manufacturer s licence. In fact. Schedule 1 to 1994 Regulations requires the manufacturer/assembler in the United Kingdom of an unlicensed product for particular patient supply to hold a particular type of manufacturer s licence (a manufacturer s special licence). It should also be noted that Section 23 of the act prohibits the manufacture of a medicinal product unless that product has a marketing authorisation, or is exempt from the marketing authorisation requirement. 

Technology Production Schedule in Weeks Mobilization Costs in Unit Costs in /yd ... 

In summary, the aquisition of a laboratory robotics unit allows unattended 24 hour a day operation allowing an increase in productivity by permitting scheduling of sample preparation and final instrumental analysis. It also serves to increase accuracy and precision by eliminating human sources of error. 

By 1972, luding out —taking methaqualone with wine—was popular on college campuses. Excessive use of the drug leads to tolerance, dependence, and withdrawal symptoms similar to those of barbiturates. Overdose by methaqualone is more difficult to treat than barbiturate overdose, and deaths have frequently occurred. In the United States, the marketing of methaqualone pharmaceutical products was discontinued in 1984, and the drug became a Schedule I controlled substance. However, some level of occasional abuse has continued. 

The majority of thermoforming production is by roll fed machines. Sheet fed machines are used for the smaller volume applications. Larger production units have in house sheet extrusion equipment. Because of the complexities in synchronising sheet extrusion equipment and the thermoforming machines, the two processes can be carried out independently of each other, the extruded sheet being produced in advance of production schedules. 

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