PRODUCT LIFE CYCLE (PLM)

Audio: Product life cycle (PLM)

Mechanical design engineers are primarily involved in developing new products, but one must understand all the stages a product goes through to develop a successful product. In this article, we will learn what the product life cycle is and which stages products go through during their life cycle. Furthermore, we will look into the design requirements that mechanical design engineers could receive from different sources.

Introduction

Developing a new product is challenging, complex, and a long process, and once the product is introduced to the market, success is not guaranteed. Multiple departments must synchronize and work as one to deliver the product that will help targeted customers and that they will be willing to pay for. Usually, people from different departments look at their part of the job in the product development process as the main and most important one. However, that is rarely the case.

In reality, every department is equally important for the product’s success. Every department has a puzzle that must come in place to get the whole picture. For example, without marketing, there are no customer relationships and knowing what customers need; without manufacturing, there is no ramping up production to satisfy the market requirements; without the quality department, there is no way to ensure that the product’s quality is satisfactory to the customers, etc.

As a mechanical design engineer, the better you understand how all these different departments work together and their requirements and needs for the product, the better your design will be. For example, if you design the product without taking into account service, there is a high possibility that the service will be unnecessarily expensive, which could result in customer dissatisfaction. A dissatisfied customer will look for a similar alternative product, and they will not recommend your product to others.

As a mechanical design engineer, you should understand the complete product development process from beginning to end. Invest time in understanding which department is responsible for what and how they are involved in the new product development. Learn who is a responsible person in each department for what and communicate with them during the development process as often as possible. Make sure you get as much relevant information from each department as possible to ensure that your design will meet all the criteria for success.

In order to do so, you need to understand the product life cycle and stages that each product goes through. So let us dive into it!

The product life cycle (PLC)

Every commercially available product has a life cycle on the market. The product life cycle starts with the development of a product, introduction to the market, growth, maturity, decline, and ends with the product’s retirement. Therefore, it is crucial to understand in which stage of the life cycle the product is to timely react and adjust it to the current market or to start developing a new product.

Depending on the size and structure of the company, mechanical design engineers usually are not tracking the product’s revenue and how the market is reacting to it. This is more a business side of product development. However, mechanical design engineers need to understand the product life cycle to predict essential features that could, in later stages, be too expensive to add or change (the further in the product life cycle we are, the more costly changes are).

Usually, the product life cycle is visualized in the literature and in the industry, as shown in the diagram below.

Development

The development phase happens before a product is introduced to the market. In this phase, companies are investing in new product development, there is no revenue, and the costs are high. In this phase, we are going through the new product development process from product discovery to ramp-up.

Introduction

In the introduction phase, the product is launched on the market. The marketing department promotes the product to the target market, building the product’s demand. Due to the small sales at the beginning of the introduction phase (smaller manufacturing quantities), the product’s manufacturing cost is high, and it could happen that some companies in this stage operate with negative profits. The primary goal is to establish a market for the product.

Growth

In the growth phase, there is an established demand for the new companies, and sales start to rapidly grow. With the higher demand for the product, the price/piece is reducing, and the profit is growing. In this phase, the competitors might come into the market with their products and try to direct the customer’s attention to them. Some of the earnings in this phase could be spent on additional product promotion or developing new product families to cover more customer demands.

Maturity

In the maturity phase, the product is stable on the market. This is the most profitable stage in the product’s life cycle. While the sales growth is not steep, sales are steady, the costs are optimized, and the income stream is secure. Usually, in this phase, the companies are at the breakeven point, and they can start to plan a new product development or update the existing one to extend its life cycle.

Decline

In the decline phase, the market becomes saturated, the product is technologically obsolete, or the customer’s trends have changed, and sales begin to decline. If the company has decided to update the product based on the current situation in the market, the product cycle life cycle could be extended. However, if the product (technology) is too outdated and there is no real need for the product, the product is retired.

While the product life cycle is helpful for understanding in which stage our product is and how it is performing on the market, this overview involves everyone who is included in the process. I find it useful to know the product life cycle, but more important is to understand the stages from a mechanical design engineering perspective. When designing a new product, we must consider all the later stages and start designing for them at the beginning of the product life cycle.

Let us now focus on mechanical design engineering relevant stages of a product.

The stages of a product

For mechanical design engineers, the most important thing is customer requirements. A customer is always at the center of everything done during the product development process. But, in addition to the customer requirements, we must consider other requirements from different departments to develop, produce and deliver a reliable, reasonably priced product to our customers. Therefore, all departments should always work together with the customer in mind.

It is not an easy task for a mechanical design engineer to incorporate all of the requirements into the product. There will always be tradeoffs between a few different options. However, that does not mean that it is not possible. The first step is to understand through which stages the product will go through. The better you understand the process in your company, the better your design will be.

Each product during the life cycle goes through the following stages: product development, production and delivery, use, and end of life.

Let’s take a general look into each stage and then see which requirements could come from it.

Product development

New product development is a set of activities, from identifying customer problems or needs and developing solutions to production, sales, delivery, and retirement of the product; you can read more about it here, introduction to the new product development (NPD).

In this stage, all the activities are conducted from the product discovery to the ramp-up phase, and the mechanical design engineers go through the product development process addressing all the requirements for all the following stages.

Ideally, all customers, different departments, government requirements, etc., will be defined in the product definition phase. However, realistically, that is rarely the case. Requirements could change due to the change in the market, new standard release, or what is usually the case due to the poorly defined requirements during the product definition phase.

Production and delivery

This stage includes manufacturing, assembling, distribution, and installation of the product. In this stage, mechanical design engineers must pay attention to DFM (design for manufacturing), DFA (design for assembly), design for cost (DFC), etc. Furthermore, the mechanical design engineer must ensure that the product he is designing can be distributed in a costly and effective manner and that the product (if required) can be installed at the customer’s location.

Use

This stage includes the operation, cleaning, and maintenance of the product. The mechanical design engineer must ensure that the product is fulfilling its intended purpose, that it can be cleaned if needed, and that it can be appropriately maintained.

End of life

This stage includes retiring, disassembling, and reusing or recycling the product. At the end of the product’s life, the product must be disassembled and reused or recycled. This is called design for the environment (DFE).

Design requirements

We understand now which stages products go through during their life cycle, and it is time to round up all this in the list of the requirements that mechanical design engineers could encounter. This list is not definite; it is hard to write down each requirement that could pop out in mechanical engineering.

User requirements are, of course, the most important of all. Usually, based on the user requirements, the other requirements will be derived.

User requirements:

service life – time duration under certain conditions, load cycles, one-time use, etc.
environmental requirements – weather conditions, chemicals, radiation, etc.,
product function,
product aesthetics – if not specifically defined by a customer, it could be a marketing requirement – color, surface finish, size, etc.
product performance
usability,
durability,
serviceability,
reliability,
price,
quality,
governmental regulations or certification,
safety,
specific testing requirements, etc.

Manufacturing requirements:

manufacturing cost,
optimizing part design for different manufacturing techniques (DFM) and optimized assembly process (DFA),
fully defined part and assembly drawings,
fully defined assembly instructions,
design of different machines, tooling, or fixtures for components manufacturing or assembling,
product packaging – sometimes could be specified by the mechanical design engineer or marketing, etc.

Quality requirements

governmental regulations or certification – often customers are not aware of these requirements,
different testing requirements (design for testing – DFT),
Product performance, usability, durability, serviceability, reliability (design for quality), etc.

Service requirement:

access to the serviceable parts,
cleaning,
maintenance instructions (design for maintenance), etc.

Design for environment

product disassembling,
product’s parts reuse or recycling (design for environment – DFE), etc.

As you can see from the list above, there are numerous requirements that you will have to take care of when you are developing a new product. However, this list only includes what needs to be done, not how. The “how” is your responsibility to figure out as a mechanical design engineer.

Closing words

Every product has a life cycle and different stages it goes through. Understanding this is crucial to any mechanical design engineer working on new product development. The more requirement you have, and the sooner you get them, it is easier for you to incorporate them in the early stages of design. The later in the design process you make a change, the changes will be more expensive.

I would like to finish by pointing out the design for the environment. You, as a mechanical design engineer, have the power to influence what types of materials will be used, how they will be manufactured and assembled, and in the end, how the product will be retired. I would appeal to all of you to always keep this in mind and give your best to design the products with as minimal environmental impact as possible. If enough of us do it, we could seriously impact our environment positively.

Now you have an excellent overview of the product life cycle, stages of a product, and some of the requirements you could encounter as a mechanical design engineer. However, I suggest you go through the text once more and identify areas you think need more understanding and clarity. Then, once you have identified those areas, start building up your knowledge in those areas.

To make it easier for you to find related posts, check the “Further reading” chapter below. Do you have any questions or need something to be clarified better? Leave a comment below, and I will give my best to adjust the post accordingly.

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