**3. Lean manufacturing challenges**

The fourth industrial revolution or revolution 4.0 is the product of the innovative efforts of the previous revolutions. Without a doubt, this phenomenon not only generated industrial improvements but also changes in the way of interacting with each other. Series production, electricity, transportation, are just a few examples of progress. In the current revolution, digital changes arise that cause ruptures in social, economic and political aspects, and in this sense, the administrative process is part of it.

In light of the technological developments associated with the revolution 4.0, the relationship between lean manufacturing and technology has once again become an area of research interest [7, 8].

The fourth industrial revolution promises to change the manufacturing landscape, and those who cannot take advantage of new technology-induced opportunities are destined to lag behind their competitors. An important area to investigate is the role that lean manufacturing will play in this new industrial age [7].

Lean manufacturing as a system is possible with various subsystems (tools), which are used to reduce and eliminate waste in companies. The right tools that help to eliminate all the waste and all the operations that do not add value to the product or to the processes, is the last aim of this system.

The challenges of lean manufacturing, especially in small and medium-sized companies have to influence the integration of the lean culture within their vision, develop leadership based on that culture. It is necessary to deploy that culture to everyone in the organization; involve the entire management team; have welldefined plans; know very well what processes contribute and which ones do not add value; and finally make this culture your day to day.

Below we give an account of the identification tools used in this system and we delve into the innovation of manufacturing, ending our analysis with the culture of quality.

The production systems related to a product or service must be analyzed under the approach of a value chain, which implies showing all the related activities to identify those activities that do not add value and that are classified as waste according to the manufacturing philosophy. Lean, which provides us with a series of tools that must be carefully selected to apply the most appropriate to eliminate waste and improve flow, as well as productivity in these production systems [9].
