Milk Run Research Articles

Analysis of real-time tour building and scheduling strategies for in-plant milk-run systems with volatile transportation demand

In modern manufacturing systems, milk run (MR) systems represent route-based, cyclic material-handling systems that are used widely and enable frequent deliveries of containerized parts in small lot sizes from a central storage area to multiple points of use on the factory floor. Usually, deliveries take place at predetermined, constant time intervals. As in real-world MR systems, the number of containers to deliver in each interval varies in the short term, peaks in the number of deliveries may lead to capacity bottlenecks and late deliveries. In this paper, we develop three alternative strategies to determine starting times of MR cycles in real-time based on the current number of delivery orders in the system aiming to better handle variations in the number of orders. We evaluate the three strategies for different system load scenarios with respect to delivery service levels, order lead times, systems utilization and necessary number of MR trains using a discrete-event simulation model.

Marginalizing Last Mile Logistics Cost through 4th Party Milk Run

Marginalizing Last Mile Logistics Cost through 4th Party Milk Run

Intelligent cost optimized central warehouse and redistribution root plan with truck allocation system in Colombo region for Lion Brewery Ceylon PLC

This research is a case study based on Lion Brewery Ceylon PLC, Biyagama, which is a famous beer company and the market leader in Sri Lanka. Researcher identifies that, currently Company outbound logistics is consisted with a decentralized distribution and a redistribution process for bottles and cans in Colombo region, and an extra cost is being spent for that unnecessarily. The main objective of this research is to build a cost minimized model for distributing Bottles and Cans for the region. For that, all demand regions in Colombo region was divided in to main 6 sub clusters. Then a centralized Warehouse and an optimal path which joins each sub cluster has been determined. The gravity model (By using excel solver) was used to find a centralized warehouse that can easily be connected with each sub cluster. The optimal path was determined through Hamiltanian cycle by using the lingo software. Finally, the milk run was completed with determining a cost optimized truck allocation system through linear programming model. At the end result proved that, the proposed model saves the monthly cost of bottles distribution by 17.2% and monthly cost of cans distribution by 11.6%.

Optimizing Milk Run and Use of Bin-Packing in Waste Collection Problems

This paper uses the concepts of milk runs as well as bin packing in order to optimize collection and reduce cost. Using the concept of “milk run” and an approach of time minimization, we can optimize the number of trucks and other vehicles used for picking and transporting waste. The objective function involves cost of transportation and is linked to distance travelled to dispose wastes. The constraints are those of vehicle capacity. The profile of different types of trucks obtained from milk run is used to compute number of trucks as well as to allot them to different trips.

The Application of Simulation Model of a Milk Run to Identify the Occurrence of Failures

At present, AGV systems are an important part of numerous companies and their internal logistics systems. They are used to efficiently secure different types of transport processes in order to minimize operating costs. However, their reliable operation requires adequate setting and maintenance. Computer simulation is probably the most suitable option from a wide range of engineering methods with which to meet these requirements. This paper describes the development of a simulation model in the Tecnomatix Plant Simulation program to identify critical points of failure within a specific delivery process on the basis of a Milk Run system. Based on the results obtained, an appropriate solution was determined with which to make the whole process function more efficiently and reliably.

Electric vehicle handling routing and battery swap station location optimisation for automotive assembly lines

ABSTRACTAs electric vehicles (EVs) have been more and more widely used recently, in this paper, an electric vehicle handling routing and battery swap station location problem (EV–HR–BSSL) is presented to extend their range of application, which aims to determine the handling routing plan of a fleet of EVs and the location decisions of battery swap stations (BSSs) simultaneously under limited battery driving range. A mathematical problem is developed to illustrate the identified problem, where a fleet of identical EVs are assumed to fulfil the demand of stations for automotive assembly lines based on in-plant milk run handling strategy. Subsequently, several definitions and properties are proposed to solve this model more efficiently. A two-phase dynamic programming method is adopted to obtain the global optimum for small scale problems. For medium and large scale problems, an improved discrete cuckoo search algorithm is developed. The performances are evaluated in simulation and the results indicate that the proposed algorithm is valid and feasible.

Simulation model generation for warehouse management: case study to test different storage strategies

A simulation model generator was developed to help a company of the Bosch Group to reduce costs in time and space with its warehouse. The simulation models are automatically created in Simio and can simulate pickers riding milk runs to collect containers from the warehouse, to satisfy the needs of production lines, assisting warehouse management by testing different storage strategies. Thus, the purpose of this paper is to present the developed generator and to use it in a case study, to test different storage policies for the company. The generator was validated, as was the simulation model automatically created. With this tool, some suggestions could be made to the company in question. Namely, it was shown that it would not be possible to maintain the FIFO rule and, at the same time, eliminate the upper floor of all racks for ergonomic reasons. To allow this, the rate of replacing containers should be synchronised with the needs of production lines. Alternatively, it was also shown that the performance of the warehouse would improve by dividing it into zones allocated to each milk run.

Design of Mixed Truck System with Milk Run Pick Up And Single Hub Cross Docking Distribution-A Case Study

Logistics is a fundamental component in any automotive industry. The study involves the delivery system that consists of milk run pick up with the single hub cross-docking system. It was identified that there is no direct shipment of goods from supplier to the customer; a company is experiencing lower service quality of the delivery system. After adapting third-party logistics partner also there is a lower delivery rate of products. This study develops a model for the mixed truck delivery system that allows both single hub cross-docking with milk run and direct shipment. A mathematical model was developed to determine the total transportation cost and shows the 12% cost saving achieved by providing flexibility in transportation by efficiently using services provided by third party logistics.

Simulation model generation for warehouse management: case study to test different storage strategies

A simulation model generator was developed to help a company of the Bosch Group to reduce costs in time and space with its warehouse. The simulation models are automatically created in Simio and can simulate pickers riding milk runs to collect containers from the warehouse, to satisfy the needs of production lines, assisting warehouse management by testing different storage strategies. Thus, the purpose of this paper is to present the developed generator and to use it in a case study, to test different storage policies for the company. The generator was validated, as was the simulation model automatically created. With this tool, some suggestions could be made to the company in question. Namely, it was shown that it would not be possible to maintain the FIFO rule and, at the same time, eliminate the upper floor of all racks for ergonomic reasons. To allow this, the rate of replacing containers should be synchronised with the needs of production lines. Alternatively, it was also shown that the performance of the warehouse would improve by dividing it into zones allocated to each milk run.

Optimization of In-Plant Production Supply with Black Hole Algorithm

Logistic process is a basic factor in the success of manufacturing plants’ operation and has a direct impact on its efficiency, flexibility and reliability. Today’s successful operation of manufacturing processes views logistics as a high priority to ensure maximum utilization of resources. The material supply of manufacturing processes in the automotive industry is usually based on supermarkets and milk runs. This paper proposes an integrated supply model of manufacturing processes, which includes facility location and assignment. After a careful literature review, this paper introduces a mathematical model to formulate the problem of supermarkets and milk run based supply of machines. The model seeks the optimal location of buffers as well as the optimal assignment of buffers and machines so as to minimize the material handling costs while taking into account order limits of machines and capacities of resources. Next, we demonstrate an enhanced black hole algorithm dealing with multi-objective supply chain model to find the optimal structure of the system. Numerical results demonstrate how the proposed model supports the efficiency, flexibility and reliability of the manufacturing process.

DELIVERY AND PICK-UP PROBLEM TRANSPORTATION - MILK RUN AND CONVENTIONAL SYSTEMS

This paper examines the role of inventory and transportation in the supply system of parts adopted by most of the Brazilian automotive companies to feed their assembly lines. It is a system for programmed collection of pieces called Milk Run that aims, within a window of time, to collect parts from suppliers, fulfilling established routes in order to minimize the cost of transport operations and reducing inventory in the supply chain. Milk Run, a scheduled collection system of parts can be carried out by automotive industry itself: the automaker manage the best route for its collector vehicle, determining the quantity of parts required to collect at each supplier within a given route, aiming to best utilize the capacity of the vehicle. Another way to work within the Milk Run system is the automaker to find the best routing and determines the amount of parts needed to be collected from each supplier on each trip. The collection, however, is held by a third carrier. As a third way of working, the assembler can determine the quantity of parts to collect and when it will require them. A logistics carrier determines the best routing for the collection of pieces in order to meet the production plan so that there is not a lack of parts or components on the assembly line, which would lead to a stop. In this case, the logistics carrier transports parts on its own fleet of vehicles or transfer the transport operation to a carrier.

Improving the logistics of a constant order-cycle kanban system

Kanban systems are simple, effective means of improving production that are widely applied in practice. Based on the logistic process involved, kanban systems can be divided into constant order-quantity and constant order-cycle systems. The former has received much research attention, but the latter, also known as a milk run, has been relatively neglected. Further, most prior work has been based on deterministic data, which is an assumption often violated in practice. We present the case of a manufacturer of domestic water heating equipment where a constant order-cycle kanban implementation initially failed. A structured Define–Measure–Analyse–Improve–Control approach is adopted to improve the process. It was revealed that the failure was due to high variability in the logistic processes involved. Decreasing this variability resulted in a reduction of tardy replenishment routes from 50 to 3%; a reduction in the route time coefficient of variation from 40 to 16%; and a reduction in the mean route time from 31 to 25 min. These improvements allowed one of three existing routes to be eliminated without any negative impact on replenishment. This led to financial savings through the elimination of two operators. The logistic process appears to have a significant impact on kanban performance. Consequently, kanban implementations should not only focus on the kanban system itself but also on the other processes involved. Future research should therefore explore how resources can best be allocated between the different aspects required for a successful kanban implementation.

IMPLEMENTATION OF MILK RUN LOGISTICS IN VEHICLE COOLING SYSTEM OF PRIDE KIA PARTS

A good and efficient production process is valuable while all the parts and materials are accessible when needed at the exact time. Otherwise, the lack of inventory required at that moment causes the stop line and imposition of heavy penalties. Likewise, its earlier presence ahead of the production planning makes the capital dull, which results in damages and scrapes. Milk-run logistics project, in the category of strategic improvement was held in Pars Khodro Automobile Manufacturing Company (SAIPA Group) known as the oldest car manufacturer whose joint with General Motor is recorded previously. Pars Khodro has the experience of producing more than 250 000 vehicles annually in various diversities including Renault and NISSAN Products such as Logan, Megan, Maxima Sundero, Brilliance, and Pick Up. In this article, due to the problems regarding the feeding of parts C, milk-run logistics has been proposed with the aim of balanced development and use of modern logistical systems attempting to improve the logistic processes and reduce unnecessary costs relevant to the production and logistic processes. The purpose of this paper is to review the milk-run logistics and to present an overview of its implementation practices adopted by the manufacturing organizations. The paper discusses milk run logistics in the line feeding system with a special emphasis on the automobile industry, which leads to the enhancement of logistics indices.

Study on Multi-Depot Collaborative Transportation Problem of Milk-Run Pattern

Analyze the relevance between Milk Run mode and collaborative transportation problem, put forward collaborative transportation problem of multiple-depot on Milk Run mode under the supply and demand separate nodes, consider the value of transport and transport costs, introduce the concept of node - arc flow, by comparing the size of traffic flow determine nodes collection, and then constructed multi-transport model of the problem. Considering one-way pickup and delivery closed, construct two-stage algorithm model, use dynamic programming recursive solution to determine the best route to pick up, and then solving delivery routing problem with different start and return point based on geometric method of Cosine. Finally use a numerical example illustrates the effectiveness of the algorithm and reasonable model.

육군 야전군수활동의 통합운영방안에 관한 연구-군수지원사령부 기능별 지원과 통합운영 성과 비교를 중심으로-

Developing aspects have been noticed in the area of supply, maintenance and transportation through the activities of Army field logistics legacy systems. The combat troops, however, have recognized relatively low grade regarding effectiveness of logistics support. We assume that positive impact on the effectiveness and efficiency of logistics support could come true by integrating logistics activities at the contact area. New policy and guidelines were sat up for integrating activities and pilot test was began below corps level. Small warehouses were merged into mid and big size warehouse with priority of demand. Quantity oriented inventory management was replaced by quantity and location basis. Using multi-story loading, equipment and machine for handling were utilized. Weekly supply was changed into daily supply directed to the end user. Transportation was upgraded from back and forth to the milk run. We have proposed the input, process and output key performance indicators for the measurement of the logistics activities. Comparison between the functional support based upon the legacy system and integration support was expected that clear answer for the future direction of Army logistics development. Input indicators showed declining trend of engaged personnel and facilities while process indicators explained steady growth of efficiency. Futhermore, the output indicators represented growing curves of effectiveness and efficiency at the same time. Integrating options have been evaluated for cutting off input activities with growing the effectiveness and efficiency at the field level logistics support area. Both policy making level and field support level can get some lessons and insights with this thesis.

Dynamic material flow control in mixed model assembly lines

This study investigates the control of material flow in mixed model assembly lines. It focuses on the use of tugger trains to feed stations in assembly lines by materials and parts from a warehouse or a supermarket. The movement of tugger trains is based on the principle of in-plant milk run. The study considers a strategy to deal with disturbances such as machine breakdown, line stoppage, defective parts, and resequencing of product models. These disturbances lead to unexpected fluctuations in stations demand for parts. The strategy is applied using a mix between the demand-oriented and e-kanban systems to facilitate the planning of three problems, namely, train routing, scheduling, and loading. The information obtained using e-kanban is combined with the information about the expected stations demand based on previously known sequence of product models and the materials needed for each model. Routing was investigated analytically while scheduling and loading problems were investigated using integer programming. Results showed that the method proposed outperforms the traditional methods of material flow planning.

순회배송 물류전략에서 탄소배출 비용의 효과 분석

This paper develops an analytic model for minimizing the cost of distributing items by truck from one supplier to many customers under Milk run logistics strategy. The model derives formulas for not only inventory and transportation costs but also costs associated with carbon emission trading scheme. In addition, monetary investment for reducing carbon emissions is considered. We analyze how to determine optimal shipment size and carbon emission reduction investment. The purpose of this work is to evaluate the effects of carbon emission trading scheme on the Milk run logistics strategy in terms of how much to reduce carbon emissions and/or inventory and transportation costs. We analytically show that it is possible to reduce carbon emissions while reducing inventory and transportation costs by introducing cap-and-trade carbon emission trading scheme under certain conditions.

A Two-Phase Heuristic Algorithm for the Common Frequency Routing Problem with Vehicle Type Choice in the Milk Run

High frequency and small lot size are characteristics of milk runs and are often used to implement the just-in-time (JIT) strategy in logistical systems. The common frequency problem, which simultaneously involves planning of the route and frequency, has been extensively researched in milk run systems. In addition, vehicle type choice in the milk run system also has a significant influence on the operating cost. Therefore, in this paper, we simultaneously consider vehicle routing planning, frequency planning, and vehicle type choice in order to optimize the sum of the cost of transportation, inventory, and dispatch. To this end, we develop a mathematical model to describe the common frequency problem with vehicle type choice. Since the problem is NP hard, we develop a two-phase heuristic algorithm to solve the model. More specifically, an initial satisfactory solution is first generated through a greedy heuristic algorithm to maximize the ratio of the superior arc frequency to the inferior arc frequency. Following this, a tabu search (TS) with limited search scope is used to improve the initial satisfactory solution. Numerical examples with different sizes establish the efficacy of our model and our proposed algorithm.

Using Simio to automatically create 3D warehouses and compare different storage strategies

This paper focuses on a simulation based approach to reduce warehouse costs. At an early stage, the tool needs to be able to generate different types of warehouses. To accomplish this, a Simio add-in was built in C#, using the Simio API, where the user only needs to insert the layout data on an excel spreadsheet. Afterwards, the created warehouse is capable of modelling different storage strategies and compare them. The obtained results indicate that the proposed strategy is able to reduce the picking time in about 15% and the number of stops per milk run in 50%. Moreover, it was found that the strategy currently in use needs 35% more space than the proposed one.

Cross-docking and milk run logistics in a consolidation network: A hybrid of harmony search and simulated annealing approach

In this paper, we develop a novel integer programming model for the transportation problem of a consolidation network where a set of vehicles are used to transport goods from suppliers to their corresponding customers via three transportation systems: direct shipment, shipment through cross-dock (indirect shipment) and milk run. Since the proposed problem formulation is NP-hard, we offer a hybrid of harmony search (HS) and simulated annealing (SA) based heuristics (HS-SA algorithm) in order to solve the problem. The objective of this problem is to minimize the total shipping cost in the network, so it is tried to reduce the number of required vehicles using an efficient vehicle routing strategy in the algorithm. Solving several numerical examples demonstrates that our solving approach performs much better than GAMS/CPLEX in reducing both the shipping cost in the network and computational time requirement, especially for large size problem instances.