scholarly journals Determination of lot size orders of furniture raw materials using dynamic lot sizing method

2019 ◽  
Vol 674 ◽  
pp. 012050 ◽  
Author(s):  
M Djunaidi ◽  
B A R Devy ◽  
E Setiawan ◽  
R Fitriadi
Keyword(s):  
Lot Sizing ◽  
Raw Materials ◽  
Lot Size ◽  
Dynamic Lot Sizing

scholarly journals MATERIAL REQUIREMENT PLANNING UNTUK MEMENUHI PRODUKSI PADA CV. BANGUN CIPTA ARTHA DI BADUNG

2020 ◽  
Vol 9 (2) ◽  
pp. 426
Author(s):  
I Made Sugita Yasa ◽  
Kastawan Mandala
Keyword(s):  
Inventory Management ◽  
Lot Sizing ◽  
Raw Materials ◽  
Raw Material ◽  
Exact Order ◽  
Lot Size ◽  
Inventory Costs ◽  
Material Requirement Planning ◽  
Material Requirement ◽  
Total Inventory

Inventory management without Material Requirement systems in CV. Bangun Cipta Artha resulted in the lot size for each order of raw materials not optimal. One concept that can be used to plan and control raw materials is the Material Requirement Planning. This study is to determine the number of sizes of raw material orders, the exact order time, the method that produces the lowest cost for each raw material, and the effect of using MRP on inventory costs. This research conducted on 160x200cm spring bed products. Data was analyzed by making production master schedules, determining net requirements, determining lot size, and making MRP tables. Based on the results, the determination the best lot sizing is the order quantiy period which results in a total inventory cost of Rp. 26,475,220 where the total cost is lower, compared to lot for lot method which Rp. 43,464,000. part period balancing Rp. 33,106,576, and conventional method Rp.49,472,912. Keywords: Material Requirement Planning (MRP), Sizing Lot, Lot For Lot, Balancing Part Period, Period Order Quantiy

scholarly journals Joint lot sizing and scheduling of a multi-product multi-period supply chain

2019 ◽  
Vol 10 (5) ◽  
pp. 1516
Author(s):  
Ahmed Othman El-meehy ◽  
Amin K. El-Kharbotly ◽  
Mohammed M. El-Beheiry
Keyword(s):  
Supply Chain ◽  
Lot Sizing ◽  
Raw Materials ◽  
Supply Chain Design ◽  
Raw Material ◽  
Design Parameters ◽  
Distribution Centers ◽  
Lot Size ◽  
Holding Cost ◽  
Lot Sizing And Scheduling

The joint lot sizing and scheduling problem can be considered as an evolvement of the joint economic lot size problem which has drawn researchers’ interests for decades. The objective of this paper is to find the effect of a capacitated multi-period supply chain design parameters on joint lot sizing and scheduling decisions for different holding and penalty costs. The supply chain deals with two raw materials suppliers. The production facility produces two products which are shipped to customers through distribution centers. A mathematical model is developed to determine optimum quantities of purchased raw materials, production schedule (MPS), delivered quantities and raw material and products inventory for predetermined number of periods. The model is solved to maximize total supply chain profits. Results showed that at high capacity and low holding cost, the supply chain tends to produce only one product each period, for limited capacity and high value of holding cost, the supply chain may produce the two products together each period.

scholarly journals Optimalisasi Sistem Persediaan Bahan Baku Karet Mentah (Lateks) dengan Metode Lot Sizing (Studi Kasus: PT Abaisiat Raya)

2016 ◽  
Vol 12 (1) ◽  
pp. 317 ◽  
Author(s):  
Dina Rahmayanti ◽  
Ahmad Fauzan
Keyword(s):  
Inventory Management ◽  
Lot Sizing ◽  
Demand Forecasting ◽  
Crumb Rubber ◽  
Optimal Size ◽  
Lot Size ◽  
Planning Period ◽  
Safety Stock ◽  
Reorder Point

PT Abaisiat Raya is one of the manufacturers of rubber crumb (crumb rubber) in the city of Padang. Latex inventory management system at PT Abaisiat Kingdom basically signinfikan still need improvement. It is based on the planning activities in the warehouse inventory of raw materials firms irregular, thus causing excess stock (over stock) at a time and shortage of stock (stock out) at other times. Process optimization is done with latex inventory system involving factors such as demand forecasting production planning or latex needs during the period of next 12 (in 2012), the costs involved, the waiting time (lead time), the implementation of forecasting methods, determination of size lots (lot sizing), the determination of safety stock (safety stock), and re-ordering time (reorder point), so the output will get a number of requests are for 12 periods ahead, the size of each reservation period, the total cost is required, when re-ordering will be done , as well as how much inventory to latex in the warehouse. Based on these results, it was found that the optimal size of the book is the same as the demand for each period (reservation is made each period) due to a cyclical pattern of demand and decreases throughout the planning period. Value of the stock or safety stock is located in Kg 114,282.20, and re-ordering time (reorder point) to cope with fluctuations do when the stock has reached a level of 333,130.95 kg.Keywords: Forecasting, Time Wait, Lot Size, Safety Supplies, Reorder

scholarly journals Optimal pricing and lot-sizing decisions under Weibull distribution deterioration and trade credit policy

2008 ◽  
Vol 18 (2) ◽  
pp. 221-234
Author(s):  
S.K. Manna ◽  
K.S. Chaudhuri ◽  
C. Chiang
Keyword(s):  
Weibull Distribution ◽  
Trade Credit ◽  
Lot Sizing ◽  
Retail Price ◽  
Lot Size ◽  
Credit Period ◽  
Two Parameter ◽  
Weibull Distribution Deterioration ◽  
Dependent Demand

In this paper, we consider the problem of simultaneous determination of retail price and lot-size (RPLS) under the assumption that the supplier offers a fixed credit period to the retailer. It is assumed that the item in stock deteriorates over time at a rate that follows a two-parameter Weibull distribution and that the price-dependent demand is represented by a constant-price-elasticity function of retail price. The RPLS decision model is developed and solved analytically. Results are illustrated with the help of a base example. Computational results show that the supplier earns more profits when the credit period is greater than the replenishment cycle length. Sensitivity analysis of the solution to changes in the value of input parameters of the base example is also discussed.

Polynomial-Time Solvability of Dynamic Lot Size Problems

2016 ◽  
Vol 33 (03) ◽  
pp. 1650018
Author(s):  
Chung-Lun Li ◽  
Qingying Li
Keyword(s):  
Polynomial Time ◽  
Lot Sizing ◽  
Sufficient Conditions ◽  
Quantity Discounts ◽  
Lot Size ◽  
Minimum Order ◽  
Cost Structures ◽  
Minimum Order Quantity ◽  
Dynamic Lot Sizing ◽  
Dynamic Lot Size

There has been a lot of research on dynamic lot sizing problems with different nonlinear cost structures due to capacitated production, minimum order quantity requirements, availability of quantity discounts, etc. Developing optimal solutions efficiently for dynamic lot sizing models with nonlinear cost functions is a challenging topic. In this paper, we present a set of sufficient conditions such that if a single-item dynamic lot sizing problem satisfies these conditions, then the existence of a polynomial-time solution method for the problem is guaranteed. Several examples are presented to demonstrate the use of these sufficient conditions.

Risk analysis for lot-sizing and maintenance optimization problem under energy constraint with subcontractor solution

2020 ◽  
Vol 37 (6/7) ◽  
pp. 873-904
Author(s):  
Mohamed Ali Kammoun ◽  
Zied Hajej ◽  
Nidhal Rezg
Keyword(s):  
Risk Analysis ◽  
Preventive Maintenance ◽  
Lot Sizing ◽  
Maintenance Cost ◽  
Lot Size ◽  
Content Type ◽  
Analysis Study ◽  
Dynamic Lot Sizing ◽  
Maintenance Plan ◽  
Maintenance Problem

PurposeThe main contribution of this manuscript is to suggest new approaches in order to deal with dynamic lot-sizing and maintenance problem under aspect energetic and risk analysis. The authors introduce a new maintenance strategy based on the centroid approach to determine a common preventive maintenance plan for all machines to minimize the total maintenance cost. Thereafter, the authors suggest a risk analysis study further to unforeseen disruption of availability machines with the aim of helping the production stakeholders to achieve the obtained forecasting lot-size plan.Design/methodology/approachThe authors tackle the dynamic lot-sizing problem using an efficient hybrid approach based on random exploration and branch and bound method to generate possible solutions. Indeed, the feasible solutions of random exploration method are used as input for branch and bound to determine the near-optimal solution of lot-size plan. In addition, our contribution to the maintenance part is to determine the optimal common maintenance plan for M machines based on a new algorithm called preventive maintenance (PM) periods means.FindingsFirst, the authors have funded the optimal lot-size plan that should satisfy the random demand under service level requirement and energy constraint while minimizing the costs of production and inventory. Indeed, establishing a best lot-size plan is to determine the appropriate number of available machines and manufactured units per period. Second, for risk analysis study, the solution of subcontracting is proposed by specifying a maximum cost of subcontractor in the context of a calling of tenders.Originality/valueFor maintenance problem, the originality consists in regrouping the maintenance plans of M machines into only one plan. This approach lets us to minimize the total maintenance cost and reduces the frequent breaks of production. As a second part, this paper contributed to the development of a new risk analysis study further to unforeseen disruption of availability machines. This risk analysis developed a decision-making system, for production stakeholders, in order to achieve the forecasting lot-size plan and keeps its profitability, by specifying the unit cost threshold of subcontractor in the context of a calling of tender.

scholarly journals A heuristic solution of multi-item single level capacitated dynamic lot-sizing problem

1970 ◽  
Vol 38 ◽  
pp. 1-7 ◽  
Author(s):  
Sultana Parveen ◽  
AFM Anwarul Haque
Keyword(s):  
Lot Sizing ◽  
Research Work ◽  
Optimal Solution ◽  
Point Of View ◽  
Lot Size ◽  
Heuristic Solution ◽  
Single Level ◽  
Solution Algorithms ◽  
Lot Sizing Problem ◽  
Dynamic Lot Sizing

The multi-item single level capacitated dynamic lot-sizing problem consists of scheduling N items over a horizon of T periods. The objective is to minimize the sum of setup and inventory holding costs over the horizon subject to a constraint on total capacity in each period. No backlogging is allowed. Only one machine is available with a fixed capacity in each period. In case of a single item production, an optimal solution algorithm exists. But for multi-item problems, optimal solution algorithms are not available. It has been proved that even the two-item problem with constant capacity is NP (nondeterministic polynomial)-hard. That is, it is in a class of problems that are extremely difficult to solve in a reasonable amount of time. This has called for searching good heuristic solutions. For a multi-item problem, it would be more realistic to consider an upper limit on the lot-size per setup for each item and this could be a very important parameter from practical point of view. The current research work has been directed toward the development of a model for multi-item problem considering this parameter. Based on the model a program has been executed and feasible solutions have been obtained. Keywords: Heuristics, inventory, lot-sizing, multi-item, scheduling.DOI: 10.3329/jme.v38i0.893 Journal of Mechanical Engineering Vol.38 Dec. 2007 pp.1-7

scholarly journals The Maximum Setup Time and Setup Cost of Achieving Just-in-Time System

2016 ◽  
Vol 4 (1) ◽  
pp. 75
Author(s):  
Fu C. Chyr ◽  
Shan Y. Huang
Keyword(s):  
Cost Reduction ◽  
Necessary Conditions ◽  
Lot Sizing ◽  
Setup Time ◽  
Just In Time ◽  
Lot Size ◽  
Setup Cost ◽  
Policy Variable ◽  
Dynamic Lot Sizing ◽  
Setup Cost Reduction

<p><em>The primary topic of operation management has turned to setup cost reduction because of the success of Just-in-</em><em>T</em><em>ime (JIT) system. Setup cost is treated as a policy variable that can be reduced. A few papers prove that setup cost reduction will increase the number of setups and approach to JIT. However, those papers do not discuss the maximum setup time allowed that will successfully achieve to JIT. The Wagner-Whitin (WW) algorithm is known to produce optimal lot size for T-period dynamic lot-sizing problems. This paper develops an extension of the WW algorithm to establish a recursive model and find the sufficient</em><em> </em><em>and necessary conditions of yielding JIT. Furthermore, the limited</em><em> </em><em>maximum setup time that will yield JIT system is discussed. The maximum setup time of achieving JIT can be easily computed and understood in practice. The formula and table of the setup time allowed are obtained to act as a goal of reducing setup time in JIT system.</em></p>

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