One of the most important tasks of Industry 4.0 is to realize a highly flexible production system. The heat development depends on the physical properties of the workpiece and the tool [23].
Literature review
30] studied the mechanical properties and failure mechanisms of AA 6061-T4 aluminum alloy plates in friction stir spot welding. 13], the mechanical and metallurgical properties of various friction-welded aluminum alloys 2024 and 7075 were analyzed.
Conclusions
Friction stir welding of aluminum alloys: A review of experimental findings - process, variables, development and applications. Effects of vibration on microstructure and thermal properties of friction stir welded (FSSW) aluminum alloy (Al5083).
TOP 1%
Introduction
The first machines for mass production were developed in Britain in the mid-eighteenth century. The term "mass customization" was introduced as "companies try to reach the same large segment of customers in the market, but treating them individually as a personalized market" [3]. The main characteristics of mass customization are variety that meets customer needs at prices comparable to mass production [4, 5].
However, mass customization comes with additional costs and end-of-life issues when compared to mass production. The use of DDM for mass production or mass customization is just beginning to be explored [8]. This chapter links Industry 4.0 innovations with mass production, mass customization and DDM to optimize their sustainability in environmental, social and economic dimensions.
A literature review of mass production, mass customization and DDM is followed by analysis of Industry 4.0 innovations using manufacturer sustainability needs hierarchies.
Mass production characteristics 1 Economics
- Workforce
- Environment
Mass production uses special machines for efficient high volume production at the expense of flexibility [2]. Work in progress (WIP) queues and inventory levels can be high and long delays often occur as this approach does not account for the workload of the next work center. Taylor's work focused on the needs of the process as opposed to the needs of the individual worker, leading to worker unrest, turnover and social conflict.
As a result of the different characteristics of the technical systems of process and discrete production, there are different requirements for operators [14]. Mass production workers are motivated to focus on functional performance to ensure reliability and efficiency. Mass production uses fewer resources than mass customization, but can contribute to more waste as consumer needs may not be fully met.
End-of-life (EOL) strategies for products that are recycled are likely to be easier to apply due to the uniformity of the products.
Mass customization characteristics 1 Economics
- Workforce
- Environment
Depending on the tasks, workers can still develop RSI, but the cause is more difficult to identify. However, it is likely that more material resources will be required to produce mass-customized products compared to mass-produced products, as modular products cannot be optimized for weight and thus material consumption [32]. At the product level, mass-customized products may not be as easy to optimize for energy use as mass-produced products.
However, end-of-life mass-customized products may not fit the requirements of another consumer, making them more difficult to reuse in the original form, unless the product is designed to be reconfigured or re-customized [ 34 ]. It can be more difficult to determine whether mass-customized products, or which of their ingredients, have negative environmental or health consequences. Modular mass-customized products can be easier to disassemble than mass-produced products that are not modular.
If a modular design is adopted but cannot be standardized across multiple products, the most pressing environmental consideration for the manufacturer of mass-customized products is probably process efficiency.
Direct digital manufacturing characteristics 1 Economics
- Workforce
- Environment
The focus of the research was on sustainable development through additive manufacturing through (1) improved resource efficiency enabled through redesign of both products and processes for internal waste minimization; (2) extending the life of the product through the use of technical approaches and a stronger relationship between person and product; and (3) simplified value chains by reducing logistical complexity and bringing production closer to the consumer [60]. A lot of energy can be required in the production of the necessary raw materials (feedstock), but considerable savings can be achieved if recycling is possible [47]. There is a significant risk of additive manufacturing causing a rebound effect from an increase in total consumption, especially in fashion products [69].
The ecodesign concept enabled by additive manufacturing has the greatest potential to provide sustainability improvements [58]. Additive manufacturing has the potential to provide spare parts and influence the modularity of products relevant to circular economy efforts [70]. Since additive manufacturing can be used to repair or remanufacture damaged components, savings of up to 50% can be achieved [47].
More efficient designs may be possible with additive manufacturing as well as integration of additional engineering functionality [47].
Smart production innovations
Symbiotic connections, life cycle connections and closed loops could significantly reduce or eliminate the negative impacts of additive manufacturing. Improved design can increase market acceptance, which can lead to reduced waste. Pull production means that raw materials or semi-finished products are automatically requested on demand.
The technology can be used to enable hybrid push-pull manufacturing based on customer order decoupling point (COPD) [73]. The following section will introduce sustainability hierarchies and apply them to mass production, mass consumption and DDM to determine which of the above Industry 4.0 innovations would be of greatest benefit in relation to the financial, environmental and social needs of producers.
Hierarchies of sustainability dimensions
- Extension of the hierarchies to mass production, mass customization and DDM
- Integrating manufacturer needs with industry 4.0 innovations
Using Table 2 of the needs with the greatest impact on the production method, it is now possible to use the descriptions of Industry 4.0 innovations and adapt them to these needs to show where the greatest sustainability benefit can be achieved.
Value analysis
It is assumed that the use phase at mid-life is the same for all production processes. It is also assumed that the modular product is suitable for disassembly into modules for end-of-life treatment such as remanufacturing, refurbishment or recycling. Tables 4–6 describe value captured and value uncaptured for each production system based on the literature.
The value opportunities for mass production include incorporating 'pull' into the production system, finding an activity or relationship to utilize overproduction, entering into relationships to better enable product recycling as well as improvement. Value Missed Need for new supply chains, limited material options, expensive input materials, resource and process inefficiencies, slow production, small batches, quality issues. The value opportunities for mass customization include improving resource efficiency, establishing relationships to take full advantage of product distribution and collection, and providing appropriate information to those involved in end-of-life treatment of products.
The value opportunities for DDM focus on relationships with designers for improvements in all life cycle stages.
Conclusion
- Calculating initial installed capacity and OEE (overall equipment effectiveness)
- Identification of causes that lead to low productivity in the manufacturing process of the M300 wheel hub
The first step was to conduct a general analysis of the manufacturing process, identifying each of the activities and operations used to create the product. The critical path with critical activities has been identified and shortcomings have been identified in the implementation of the activities along these critical paths. These strategies must be used in the manufacture of the front and rear M300 wheel hub supplied to General Motors.
The inventory of performance failures showed that there was no record of machine stoppages or other deficiencies in the process, and no standardized time tests to identify the plant's maximum installed capacity along with bottlenecks. A high loss occurs due to movement of materials and people due to poor distribution of the machines in the plant. Material: There is a large accumulation of inventory at the bottleneck of the process, there is an imbalance in the line and a lack of order to place material.
Management: Quality inspections are carried out on 100% of the finished products leading to a huge waste of time for the operator.
Materials and methods
Implementing improvements through the strategic use of lean manufacturing tools
Method: The problem central to the critical activity was solved by using a human-machine diagram [15] to create a balanced lathe cell. The goal was to have data that can be used in the ongoing calculation of the OEE. A visual management strategy was used for continuous display of OEE and other vital production performance indicators.
Standardized work at workstations became the norm through the use of documentation designed by each of the Kaizen teams. Material: Manipulation of material was particularly improved by the new arrangement of the plant plus the application of the 5S together with standards for material control and trained personnel. Management: Statistical control of the process at the bottleneck was introduced, along with training and increased lighting.
Quality: Kaizen teams performed root cause analysis using Ishikawa diagram and implemented corrections.
Results
Results for the quality level: The amount of non-conforming product since July 2017 to September 2018 can be seen in figure 4. A decrease in the number is seen and during the last 4 months the internal target of no more than 15,000 PPM has been exceeded. Results for labor productivity [19] (relationship between the value of sales and the cost of labor required to produce the said quantity).
This contributed to improvements in labor productivity from February to September 2018 as demonstrated in Figure 5. Standardized documents: The OEE has become the standardized indicator for measuring the performance of the productive process. The discipline to collect the necessary date for the calculation of the OEE is established: machine availability, efficiency and quality.
Finally, phase 7 was officially closed with the Kaizen teams presenting the goals that were achieved using the data illustrated above and the new projects drawn up by each composite team.
Conclusions
As the improvements were implemented, but especially as the standards were met in Phase 6, a factory administration was established that embraced the lean manufacturing philosophy. Better workplace safety and higher quality and productivity levels were seen in the results achieved as a result of implementing the standardized work strategy via the respective documents. Safe, clean and organized workstations were the result of applying the 5S method to the various operations in the production process.
The round tables for standardized work achieved a higher level of organization of workplaces, thus avoiding unnecessary travel to look for things. Finally, the results obtained also led to higher labor productivity due to the reduction of the number of operators and the gradual increase of the number of pieces.
Recommendations
Establishment of standard methodologies to improve production speed of assembly lines used for low value added products.
