What is process planning?

A process associated with product design consists of various planning stages to carry on the process of building a product. So, to obtain the physical entity (product), a manufacturing plan or a process plan is essential. The activity associated with such development of manufacturing plan is termed as process planning, which can also be termed as a relation between designing and manufacturing. The procedure employed in process planning requires the development of several steps involved in designing and manufacturing a product. The topic of process planning has been cross-referenced with production, planning, and control which is an important topic in industrial engineering.

Applications of process planning

Process planning has its application in all manufacturing industries that have various machinery and shop floors. It is carried out in various manufacturing processes on a single component. It is also implemented during the line balancing of the machinery.

A more detailed reading about the topic can be found in several books by various publishers, such as Butterworth-Heinemann.

Objectives of process planning

Process planning is a step-by-step plan to implement and renovate the design specifications into manufacturing instructions, which are required to manufacture products within the design constraints, with the least possible cost required to manufacture the product. The procedure of process planning can be compared to a digital thread, which is a communication network, that maintains the record of a product life cycle, from the beginning of its production to the finished product. The objective of process planning requires the construction of efficient manufacturing plans that deliver the high quality and functionality of the product. The process results in a reduced cost because of optimized work instructions, and less staff incorporated during the manufacturing process.

Process planning includes the selection of processes and estimating the conditions in the selection of the processes. The specifications and conditions are altogether included in the process plan. Both the engineering drawing and process planning form a vital document required by the manufacturing companies to begin the manufacturing process for the product.

Principles of process planning

The general principles involved in process planning are:

• Looking at the required outputs, then accordingly decide the resources to produce those outputs.
• Description of the goals of the operation needs to be incorporated for the manufacturing of a product. There should be frequent assessment of goals.
• After being decided and planned accurately, the process plan should follow a logical flow with optimized operation and material management.
• Any step or change in the management of material should reflect in the documentation.
• Consult the personnel involved in the process. He/she has the most recent updates about the resources and the ongoing operations of the activity.

Computer-aided process planning

With the fast-changing computer technology, the process and principles involved in process planning have been conquered by computers. This evolutionary step is known as computer-aided process planning (CAPP systems).

This process has five steps:

1. Manual classification, standardized process plans: On initiation of any new part plan, the process plan for that family is made, typed, and marked up. It improves the output of the process.
2. Computer maintained process plans: This includes table-driven costs and standard estimating systems.
3. Variant CAPP systems: The computer-aided approach of the variant CAPP systems is a group of technology, coding-based classification approach, to recognize the huge number of part resources and material management. These attributes and permits the system to choose an optimized activity plan and resource.
4. Generate CAPP: Here, the process planning decision rules are developed in the system. The decision rules will work based on the part group technology and feature-based technology. This will result in the creation of a process plan which requires minimum manual involvement and aids in maximum material management.

Advantages of CAPP systems

There are numerous advantages of this kind of process planning-

• Reduces the skill of a planner
• Reduces the process planning time
• Reduces the manufacturing cost
• Shortens the lead time by automating the processes
• Improves the feature recognition
• Results in a better surface finish to the parts produced by different manufacturing techniques

Generative and variant way of process planning

The subcategories of the CAPP systems are the generative and the variant way of process planning.

In generative systems, the system automatically synthesizes a process plan for a new part. The process information is synthesized automatically without human interference.

Some of the characteristics of the generative CAPP systems are,

• The ability to generate process plans for both new and existing components
• The process plans in the CAPP system are created using decision logic, formula, algorithms, geometry-based data, and technology-based coding schemes.

In the variant way of process planning, the process plan for the new component is produced by retrieving existing plan data for a similar existing component. Necessary modifications are carried out on that component. There are several steps involved in the variant CAPP. A coding system is initially defined, then the components/parts are grouped into part families. A standard process plan is then developed. The information related to that specific part is recalled and modified.

Feature recognition in the CAPP

The algorithms used in computer-aided design (CAD) and computer-aided manufacturing (CAM) are together integrated into the CAPP systems. The inclusion of a feature-based link to the system has improved the functionality and usage of the CAPP systems.

The algorithm in the feature-based system automatically detects any special features such as a hole, and an extrusion, present in the part component modeled as CAD. Along with it, the feature recognition has inbuilt automatic detection algorithms, which extract out additional features present in the CAD or CAM.  

Context and Applications

The topic of process planning is extensively taught in graduation and post-graduate curricula.

• Bachelors in Technology (Industrial Engineering and Management)
• Masters in Technology (Industrial Engineering and Management)

Practice Problems

1. Which of the following is the correct abbreviation for CAPP?

1. Computer-aided production planning
2. Computer-aided production plan
3. Computer-aided process plan
4. Computer-aided process planning

Correct option- d

Explanation- CAPP stands for computer-aided process planning.

2. Which of the following is the objective of process planning?

a) Process planning is a step by step plan for optimization of manufacturing processes

b) Process planning is simply a flow chart that is to be followed in manufacturing production lines

c) Process planning is a tool to select the right raw materials to create a product

d) None of these

Correct option: a

Explanation: Process planning is a step-by-step plan that recreates a product by optimized manufacturing procedures and material management procedures.

Q3) The process plan for a new component is created by retrieving the information of a previous component'. Which of the following subcategories of process planning justifies the statement?

a) Generative way of process planning

b) Variant way of process planning

c) CAPP systems

d) None of these

Correct option: b

Explanation: In the variant way of process planning, the existing information of a previous part or a component is recalled or retrieved. This information is then utilized for the new component for an efficient and optimized manufacturing process.

Q4) To which of the following areas in industrial engineering has the process planning a cross-reference?

a) Line balancing

b) Loading and scheduling

c) Production, planning, and control

d) Inventory management

Correct option: c

Explanation: The topic of process planning is a sub-category of production, planning, and control, which is generally studied in the area of industrial engineering.

Q5) Which of the following is an advantage of automating the process planning process?

a) Reduced labor cost

b) Reduced lead time of component

c) Requires less skillset

d) All of these

Correction option: d

Explanation: Automating the process planning procedure results in several advantages such as the requirement of the fewer skills to carry on the process, reduction of the lead time of the component, reduction in labor cost, and so on.