INDUSTRIAL & MANUFACTURING SYSTEMS ENGINEERING
Course Name - Production Systems Analysis
Course # 91-413
Pull and Push Systems: An In-depth Look
Jegapiragasam Jyapiraharan 100 799 376
Mohanty Abhishek 101 421 155
Farsed Ibrahim 100 646 715
Yan Zhang 100 995 363
This report examines the different production planning methods being used in the current manufacturing environment. The report focuses on Push and Pull systems. The report discusses the advantages and disadvantages of each method and also looks at JIT and MRP as examples of Pull and Push systems respectively. The report also discusses two real world scenarios where these systems have been implemented successfully. In conclusion this report discusses Hybrid systems that have been gaining popularity.
Table of Contents
Table of ContentsPage 3
Pull systemsPage 5
Advantages and DisadvantagesPage 8
JIT A case studyPage 10
Push SystemsPage 13
Advantages and DisadvantagesPage 17
MRP A case StudyPage 20
Hybrid SystemsPage 26
Push and pull systems determine when and where to move material in a production process. A push system is characterized by a make to stock environment and a pull system is characterized by a make to order. An appropriate system that would cater to the requirements of the company has to be selected. A distinction is made between push and pull production systems based on the trigger point. The push system is based on customer orders, while a pull system is based on forecasts. In short, push systems can be compared with MRP systems that utilize past information to forecast the future customer demands. In the case of a pull system the difference between the safety stock point and the state of current inventory is similar to just-in-time which controls the order quantities. The fluctuations in inventory levels in a push system are affected by forecasting errors, while the fluctuations in customer demand affect the pull system. Most of the production problems can be solved by using an appropriate push and or pull system. It is evident that neither one is always better than the other. In fact, a hybrid approach is more superior, depending upon the manufacturing system. The main objective of a hybrid system is to combine the best features of both worlds, rather than differentiating between the two.
Pull systems were pioneered by American grocery stores. Grocery Stores only replace their shelves with products that are demanded or consumed by their customers. To make this possible, the grocer used FIFO and just in time delivery. The grocer also had to engage in continuous communication with suppliers as well as customers. In simple terms, a pull system is a method of controlling the flow of resources by only replacing materials that have already been consumed. An easy way to visualise a pull system is to think of a vending machine. The vending machine company only replenishes the exact amount that has been consumed by the consumers. A key concept is the production of small lots in standard sizes to replenish only the consumed inventory. Forecasts are also a key aspect of Pull systems. In pull systems the forecast values are used to turn cycle time into a target inventory level. In pull systems buffer inventories are determined by multiplying cycle times by the daily forecasts. This ensures optimal level of buffer inventory. There are three distinctive types of pull systems. These can be categorised as 1.Supermarket Pull System In a supermarket pull system, each process simply produces to replenish what has been consumed. Each process has its own supermarket, as material is pulled from the supermarket by a downstream customer; information is...