Part One: Planning and Scheduling Concepts in Manufacturing :
Introduction:Any manufacturing activity is riddled with a lot of constraints, and even though the so-called "best enterprise" software companies in the world cannot solve them in their entirety, manufacturers can look for best-of-breed solutions to mitigate problems. Some common problems in manufacturing include long and erratic production lead times, irregular patterns of ordering, high setup and change over times, process bottlenecks, and excess inventory along the process route.
Master requirement planning (MRP) is important as it calculates the exact amounts of raw, sourced, and WIP materials to make exact amounts of finished products as per orders received. This will ensure that the manufacturer sources only required quantities of materials required, that he will be making only the required quantities of WIP and finished products, and that no inventories are created unnecessarily.
Master Production scheduling (MPS) is important because it calculates the time required to make finished products as per orders from raw, sourced, and WIP materials and so the delivery dates are determined from the lead times in processing materials on different work centers. In today's manufacturing both accurate delivery dates and optimizing resources are equally important. For this, good software which has excellent MRP and MPS capabilities is a must.
Concepts :# MRP and MPS software: Manufacturing software with any name like advanced planning and scheduling (APS), advanced planning and optimization, finite capacity planning, material requirement planning, or master production scheduling (MPS) mostly do the same thing. They first calculate the quantities of raw materials and intermediate materials (work in process materials) required to produce quantities of finished products as per your orders. Then they calculate the time and cost involved to produce these materials. The MRP part of the software calculates the quantities of the required WIP materials, and the MPS part of the software calculates time required to produce these materials and optionally the production costs involved. So it is obvious that the MPS part of the software needs quantities of material produced along with the rate at which they are produced (i.e., the production rate to calculate the time required for production). That means the MRP part of the software should be run first.
How come many vendors have software where the MPS part is run first then! Actually, in such software the capacity and production rate of the work center which makes the finished product is taken into consideration against the quantities of finished products required as per orders. Since they do not have information about the quantities of WIP required, they cannot calculate the time required for their production. If your production process is such that you make finished products directly from processing raw materials and that you do not have any WIP materials then it is alright. But in case you have WIP materials in your production process then this approach will not help you. Alas! Most of the vendors have software which falls in this category.
# Finite capacity planning software: If you are able to define your production facility's capacity in the software before you start doing any MRP or MPS exercise then most probably you are in safe hands. Because you are starting to do something that is going to be most probably a finite capacity planning and scheduling exercise.
# Advanced planning and scheduling (APS) software: To differentiate from MPS vendors, some vendors call their software an APS application and state that their software takes dynamic inputs for the planning and scheduling it does. They also state that their software does dynamic planning and scheduling as compared to the static planning and scheduling feature of MPS software. APS software adjusts the planning and scheduling dynamically on changes in the input parameters.
4. Bill of materials (BOM): BOM describes the relation of a finished or WIP product with the WIP or raw materials which go in making it. It will describe the ratio in which individual WIP or raw materials go in making one unit of finished or WIP product.
5. Multilevel BOM: When there is more than one level of BOM in a manufacturing process. In this case at least one WIP parent will consist of a WIP child.
6. Routing: Routing is the process of defining the route which a finished product and its WIP and raw materials will take through the work centers along the way. There could be many routings for the same finished product or it could be a unique path.
7. Advanced planning and optimization (APO) software: To differentiate from MPS and APS vendors, some vendors call their software an APO application and state that it takes dynamic inputs for the planning it does. They also state that their software does dynamic planning as compared to the static planning and scheduling feature of MPS software. APO software adjusts the planning and scheduling dynamically on changes in the input parameters. APO software is different from APS software in that it does not do scheduling.
8. MRP II software: In the late 1980s a new breed of software came in the market which improved on existing MRP software. In MRP, infinite capacity was assumed for any production facility and so requirement of raw material calculation was never right. In MRP II, finite capacity was taken for calculation of raw material requirements.
The bottom line is that whatever terminology used and claims made by vendors, you should be able to judge the merits of these statements and choose the software which will serve your purpose after careful evaluation. At the same time, you should be able to identify some minimum qualifications of the software which will guide you to make a cut mark which will identify whether software is totally useless or has some useful features for you.
This was the first part of a series of articles on manufacturing planning and scheduling software.
In the second part of this series of articles, we will discuss material requirement planning and master production scheduling software.
Introduction:Any manufacturing activity is riddled with a lot of constraints, and even though the so-called "best enterprise" software companies in the world cannot solve them in their entirety, manufacturers can look for best-of-breed solutions to mitigate problems. Some common problems in manufacturing include long and erratic production lead times, irregular patterns of ordering, high setup and change over times, process bottlenecks, and excess inventory along the process route.
Master requirement planning (MRP) is important as it calculates the exact amounts of raw, sourced, and WIP materials to make exact amounts of finished products as per orders received. This will ensure that the manufacturer sources only required quantities of materials required, that he will be making only the required quantities of WIP and finished products, and that no inventories are created unnecessarily.
Master Production scheduling (MPS) is important because it calculates the time required to make finished products as per orders from raw, sourced, and WIP materials and so the delivery dates are determined from the lead times in processing materials on different work centers. In today's manufacturing both accurate delivery dates and optimizing resources are equally important. For this, good software which has excellent MRP and MPS capabilities is a must.
Concepts :# MRP and MPS software: Manufacturing software with any name like advanced planning and scheduling (APS), advanced planning and optimization, finite capacity planning, material requirement planning, or master production scheduling (MPS) mostly do the same thing. They first calculate the quantities of raw materials and intermediate materials (work in process materials) required to produce quantities of finished products as per your orders. Then they calculate the time and cost involved to produce these materials. The MRP part of the software calculates the quantities of the required WIP materials, and the MPS part of the software calculates time required to produce these materials and optionally the production costs involved. So it is obvious that the MPS part of the software needs quantities of material produced along with the rate at which they are produced (i.e., the production rate to calculate the time required for production). That means the MRP part of the software should be run first.
How come many vendors have software where the MPS part is run first then! Actually, in such software the capacity and production rate of the work center which makes the finished product is taken into consideration against the quantities of finished products required as per orders. Since they do not have information about the quantities of WIP required, they cannot calculate the time required for their production. If your production process is such that you make finished products directly from processing raw materials and that you do not have any WIP materials then it is alright. But in case you have WIP materials in your production process then this approach will not help you. Alas! Most of the vendors have software which falls in this category.
# Finite capacity planning software: If you are able to define your production facility's capacity in the software before you start doing any MRP or MPS exercise then most probably you are in safe hands. Because you are starting to do something that is going to be most probably a finite capacity planning and scheduling exercise.
# Advanced planning and scheduling (APS) software: To differentiate from MPS vendors, some vendors call their software an APS application and state that their software takes dynamic inputs for the planning and scheduling it does. They also state that their software does dynamic planning and scheduling as compared to the static planning and scheduling feature of MPS software. APS software adjusts the planning and scheduling dynamically on changes in the input parameters.
4. Bill of materials (BOM): BOM describes the relation of a finished or WIP product with the WIP or raw materials which go in making it. It will describe the ratio in which individual WIP or raw materials go in making one unit of finished or WIP product.
5. Multilevel BOM: When there is more than one level of BOM in a manufacturing process. In this case at least one WIP parent will consist of a WIP child.
6. Routing: Routing is the process of defining the route which a finished product and its WIP and raw materials will take through the work centers along the way. There could be many routings for the same finished product or it could be a unique path.
7. Advanced planning and optimization (APO) software: To differentiate from MPS and APS vendors, some vendors call their software an APO application and state that it takes dynamic inputs for the planning it does. They also state that their software does dynamic planning as compared to the static planning and scheduling feature of MPS software. APO software adjusts the planning and scheduling dynamically on changes in the input parameters. APO software is different from APS software in that it does not do scheduling.
8. MRP II software: In the late 1980s a new breed of software came in the market which improved on existing MRP software. In MRP, infinite capacity was assumed for any production facility and so requirement of raw material calculation was never right. In MRP II, finite capacity was taken for calculation of raw material requirements.
The bottom line is that whatever terminology used and claims made by vendors, you should be able to judge the merits of these statements and choose the software which will serve your purpose after careful evaluation. At the same time, you should be able to identify some minimum qualifications of the software which will guide you to make a cut mark which will identify whether software is totally useless or has some useful features for you.
This was the first part of a series of articles on manufacturing planning and scheduling software.
In the second part of this series of articles, we will discuss material requirement planning and master production scheduling software.
