Due Date Setting Procedures
OLD
CON: A constant time allowance for manufacturing all jobs; that is, the same lead time is added to all jobs at receipt date to calculate the due date.
SLK: A time allowance that provides an equal (constant) waiting time or slack for all job; that is, the due date is set equal to the receipt date plus the sum of all processing times, plus a fixed additional slack time.
TWK: A time for waiting that has slack proportional to a job's total work content; that is, lead time to be added to receipt date is a multiple of the sum of all processing times.
[Thomas E. Vollmann, William L. Berry, D. Clay Whybark, F. Robert Jacobs - Manufacturing Planning and Control for Supply Chain Management Pages: 545-546]
NEW/BETTER
The most common approach to the due date setting and sequencing problem is to minimize the average weighted due date lead time (the due date of a job minus its arrival time) while maintaining a certain level (e.g., an upper bpund on the proportion of tardy jobs or an upper bound based on average tardiness). The results in the above cited papers indicate that due dates based on estimates of shop congestion and the estimated duration of the processing time of jobs lead to significantly lower average due dates. Baker and Bertrand (1982) suggest three parametric due date setting rules. The three rules quote customers due date lead times of a constant, a constant plus the expected processing time of job and a constant times the expected processing time of job, none of which depend on the amount of cengestion in the system.
(Due Date setting and Sequencing in a Time Competitive Environment, Izak Duenyas, pg 1)
CPOF (Capacity Planning Using Overall Factors)
OLD/BETTER
CPOF method begins with the total sandard hours required to produce each item in the MPS, then multiplies those hours by the number of units planned for a production in a given week. The resulting total hours required are then broken down for individual machines or work centers using the historical percentage of total time accounted for by each opeartion.
CPOF only requires information about total standard hours (either labor or machine hours) per unit of each product and the historical percentage of those hours by operation. Such information is often available as accounting data. Because the CPOF method does not account for leadtime offset, it can be quite inaccurate if product mixes change frequently. However CPOF can provide good capacity estimates when the production plan and product mix remain fairly constant.
CPOF method begins with the total sandard hours required to produce each item in the MPS, then multiplies those hours by the number of units planned for a production in a given week. The resulting total hours required are then broken down for individual machines or work centers using the historical percentage of total time accounted for by each opeartion.
CPOF only requires information about total standard hours (either labor or machine hours) per unit of each product and the historical percentage of those hours by operation. Such information is often available as accounting data. Because the CPOF method does not account for leadtime offset, it can be quite inaccurate if product mixes change frequently. However CPOF can provide good capacity estimates when the production plan and product mix remain fairly constant.
(Paul M. Swamidass, Encyclopedia of Production and Manufacturing Manangement, pg:78-81)
NEW
The highest level of capacity planning is based on the long-range business plan that extends out as much as 5 years. This time period is necessary for planning cash requirements, additional plants, capital equipment, and, in some cases, a work force requiring specialized skills. The capacity management technique at this level is resource requirements planning and will be based on the analysis of total planned sales or broadly defined product groups. The projection of requirements at this level may be based on the proration and extention of critical resources. This proration technique is known as CPOF (Capacity Planning Using Overall Factors).
(MRP II: Planning for Manufacturing Excellence, John W. Toomey, pg. 95)
JSA (Joint Service Agreements)
OLD
The solution to reducing lead times and simplifying the planning process. After sharing the results with all of the companies in the supply chain, the sales company and finished goods company agreed to work jointly. They began by implementing a joint service agreement that outlined their mutual roles in managing the supply chain and specified the performance standards guiding each party.
(Bob Donath,The IOMA handbook of logistics and inventory management,p 481)
NEW/BETTER
A joint service agreement is defined as one which establishes a new and seperate line or service to be operated by the parties at a joint venture. The new and seperate service fixes its own reates, publishes its own tariffs, issues its own bills of lading, and acts generally as a single carrier.
(World Shipping Industry, Ernst G. Frankel, pg 63)
Benelex
OLD/BETTER
Type of common plastics.Its properties are high compressive strength, machinable,resists corrosion (alkalis or acids), good electrical insulation,high flexural, shear, and tensile strength. Typical uses are work surfaces, electrical panels and switch gear, bus braces (low voltage only), and neutron shielding.
(McGraw-Hill Machining and Metalworking Handbook-3rd Edition-McGraw Hill-Ronald A. Walsh-Chapter 4-P.263)
NEW
Benelex is an industrial product specifically designed for laboratory and factory work surfaces.. Its’s about twice as dense as rock maple –so dense in fact that it’s also used as a neutron shield when disposing of radioactive nuclear wastes. 5 sq. ft. (1,25 in. thick) of this material weighs about 45 lbs.
(Popular Mechanics – Oct. 1970, pg. 162)
Polyurethane
OLD
Polyurethanes (PUs) are prepared from polyols and isocyanates.24,25 The isocyanate groups react with the hydroxyl groups on the polyol to form a urethane bond. The polyol can be a low-molecular-weight polyether or polyester. The isocyanate can be aliphatic or aromatic and in the preparation of linear PU is typically difunctional. However, isocyanates with greater functionality are used in preparing rigid foam PUs. The family of PU resins is very complex because of the enormous variation in the compositional features of the polyols and isocyanates. This variety results in a large number of polymer structures and performance profiles. Indeed, PUs can be rigid solids or soft and elastomeric or a have a foam (cellular) structure.
Polyurethanes (PUs) are prepared from polyols and isocyanates.24,25 The isocyanate groups react with the hydroxyl groups on the polyol to form a urethane bond. The polyol can be a low-molecular-weight polyether or polyester. The isocyanate can be aliphatic or aromatic and in the preparation of linear PU is typically difunctional. However, isocyanates with greater functionality are used in preparing rigid foam PUs. The family of PU resins is very complex because of the enormous variation in the compositional features of the polyols and isocyanates. This variety results in a large number of polymer structures and performance profiles. Indeed, PUs can be rigid solids or soft and elastomeric or a have a foam (cellular) structure.
(Kutz M., Mechanical engineers' handbook: Materials and mechanical design, p. 350)
NEW/BETTER
50 years ago, the first polyurethane coatings were developed. Otto Bayer and his team discovered that the technical properties of alkyd resins could be improved through modification with diisocyanates. However, the real conquest of coatings sector by polyurethanes only began with the development and industrial use of low-monomer polyisocyanates. The first products were based on toluene diisocyanate. Because of the aromatic nature of the base isıcyanate, thse tend to yellow on exposure to light and can therefore only be used for interior applications or in primers.
The range of applications was broadened later with introduction of products bsed on aliphatic diisocyanates, initially hexametylene diisocyanates. Today, polyurethane raw materials are used in the manufacture of foams: rigid foams for insulation (Construction industry, refrigirators) or energy-absorbing components in automobile interiors (instrument panels), integral skin foams, e.g. for furniture and medical applications; flexible foams for upholstery, matresses and packaging materials. Other applications for polyurethanes are found in the manufacture of versatile elastomers for the footwear and electrical industries, thermoplastic urethanes, e.g. for sports and leisure equipment, and polyurethane elastic fibers for stretch fabrics.
(Polyurethanes: Coatings, Adhesives and Sealants; Ulrich Meier-Westhues; pg 16)
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