1. Introduction
College–enterprise cooperative product development is mutually beneficial for the college and enterprise as it synergizes development of education and industry [
1,
2,
3]. This business model is developing rapidly in China, since product design plays an increasingly prominent role in enterprise competition [
4,
5]. To maximize the advantages of both sides, the college is generally entrusted to design the products, and the enterprise manufactures them. In the process of college–enterprise cooperative development, it is likely that the college’s design will be disconnected from the manufacturing conditions of the enterprise, especially in the first cooperative exercise. Unfortunately, this disconnection may lead to the need for many modifications or even redesign, which may greatly increase the cost of prototyping. To solve this problem, we carried out a case study of college–enterprise cooperative development to produce a carton-filling machine, and we proposed a green development method. This paper focuses on improving the management of the cooperative process by constructing a manufacturing knowledge functional (IDEF0) model to support the cooperative development process by integrating design for manufacturability (DFM) theory and IDEF0 methods.
Sustainable development is a long-term green development model that can be steadily improved. In the process of mechanical equipment development, the idea of sustainable development is widely used to guide design and manufacturing and continuously improve organizational performance. Rathi et al. [
6] identified 23 success factors of Green Lean Six Sigma (GLSS) from the literature pertaining to manufacturing and found that management and finance-related issues are the most significant critical success factors for improving organizational performance. The same conclusion was reached in their other research regarding a GLSS success factor analysis of Indian medical institutions [
7]. Recently, they established a framework for integrating GLSS and Industry 4.0 to improve the sustainability of an organization [
8]. The IDEF0 method is widely used for the process analysis and optimization of organizational activities. Gu [
9] used IDEF0 to improve the teaching process of information systems analysis and design. Li et al. [
10] used the IDEF0 model to optimize the collaborative distribution of agricultural products under cloud logistics. Lu [
11] used the IDEF0 method to direct the design and development of ship-loading fasteners. These researchers all achieved improved results.
Sun et al. [
12] emphasized the importance of manufacturing knowledge to the design process, analyzed the tasks and manufacturing knowledge required in each stage of product design, and built a manufacturing knowledge IDEF0 model for the product design process. In large-scale production or mature process conditions, the methods and technologies of design for manufacturing (DFM) or design for manufacture and assembly (DFMA) are widely used to reduce manufacturing costs and improve product performance by promoting the easy design and manufacturing of products [
13,
14,
15,
16]. While most of the literature describes successful application cases of DFM, Budinoff et al. [
17] used negative personal design experiences to emphasize the consideration of manufacturing constraints for hardware startups. In order to better support product design decision making and design innovation, many researchers continue to carry out research on manufacturing knowledge sharing [
18], manufacturing knowledge modeling [
19], manufacturing knowledge management [
20], and the system integration of manufacturing knowledge [
21]. The knowledge of different manufacturing processes refers to machine and process capabilities, and the latest technological developments are expressed through a reasonable structural model. Through the manufacturing knowledge retrieval system, the sharing of manufacturing knowledge is promoted, the knowledge transfer process is accelerated, and the overall manufacturing technology level is improved. Extensive integration of social technology systems is carried out in the manufacturing fields of aviation, shipbuilding, etc.
The above research conclusions regarding the key factors of organizational performance improvement as well as the application of DFM and IDEF0 methods in sustainable development are all based on the industry itself; colleges have not appeared as relevant parties, since they are not part of the manufacturing industry. When colleges directly participate in manufacturing activities, it is important to ensure that the cooperative parties communicate effectively and carry out cooperative activities smoothly, matching their design with manufacturing to improve the success of cooperative development. Building on the above research, this paper proposes a new, green method for cooperative development based on a case study of a carton-filling machine designed and engineered by a college team and a manufacturing team used to produce and build mechanical equipment.
4. Process Control Based on the IDEF0 Model of Manufacturing Knowledge
4.1. Building the College–Enterprise Development Team Based on the IDEF0 Model of Manufacturing Knowledge
According to the needs of manufacturing knowledge listed in the IDEF0 model, both sides of the cooperative development carried out an analysis of their advantages and limitations. The enterprise had experience in the development of products, such as a small cigarette box demolding machine, small cigarette box forming machine and single-opening strip box forming machine. The enterprise also had rich experience in robotics and visual inspection. The college team had outstanding advantages in the development of mechanical systems and paper packaging automation equipment but was relatively inexperienced in the programming and debugging of automatic control systems. Therefore, the participation of the relevant technical staff from the enterprise was needed for the effective promotion of the cooperative development process.
The two sides agreed that the college would be responsible for the development of the mechanical system, and the enterprise would be responsible for the development of the control system. The enterprise provided one manufacturing engineer to join the design team and participate in the whole design process. This engineer was in charge of providing the enterprise’s manufacturing knowledge as required at every design stage. The enterprise also provided one control engineer to join in the detailed design stage.
One green aspect of the design of the college–enterprise cooperative was to realize sustainable fostering of applied technological talents. Therefore, the development team invited three graduate students to participate in the development of the project. Due to time constraints, the participating graduate students were selected according to their ability to undertake part of the project independently after simple training. The students participated in the visits and exchanges between the two sides from the beginning and undertook part of the drawing work after entering the detailed design stage. They also participated throughout the assembly and commissioning work, being responsible for the pre-assembly of simple parts and recording problems in the assembly and commissioning of parts.
4.2. Communication of Manufacturing Technologies and Conditions Based on the IDEF0 Model of Manufacturing Knowledge
According to the IDEF0 model of manufacturing knowledge, the enterprise gave a clear disclosure of their manufacturing technology and hardware and software capabilities, submitting the relevant technical documents simultaneously.
At the beginning of the project, key participants from both the college and manufacturer visited the production site of the tobacco enterprise that would use the machine and gained a detailed understanding of the user’s technical requirements. The enterprise then led the college designers to visit their own processing and assembly workshops. After detailed discussions about the site conditions, process and equipment, the designers gained a comprehensive understanding of the enterprise’s own processing capacity, processing accuracy, manufacturing cycle, and especially the constraints of hoisting conditions in the debugging workshop on the overall size of machinery. They also gained a basic understanding of the number, skill level and operational efficiency of the commissioning technicians.
After completing the conceptual design, the documents (including the application specifications of standard parts, the supplier’s list of outsourcing parts and the list of commonly used materials) were sorted by the enterprise and provided to the designers, so the designers could prioritize using the available resources as much as possible, without incurring additional costs of supplier expansion and parts stock. These documents also facilitated the rapid commissioning of replacement parts if modifications were needed.
Next, the two sides held an experience exchange meeting about common problems encountered in the past debugging of similar equipment assemblies. Many problem prevention methods and improvement measures were proposed to avoid repeating past mistakes and to reduce the time taken in the manufacturing and assembly cycle.
4.3. Design Process Control
Based on the historical experience of collaborative development, the designers estimated the development cycle of this project would be no less than 150 working days, exceeding the time frame requested by the client company. Therefore, we re-evaluated the entire project and planned the development process in detail using on the IDEF0 model. We were finally able to set the development cycle at 120 working days. The time allotted for tasks was planned in four stages: conceptual design stage, preliminary design stage, detailed design stage, and assembly and commissioning stage, with a basic time unit of six days per week, as shown in
Figure 8.
We focused on optimizing the project in periods of phased scheme design and detailed design as follows:
(1) Optimization of the phased scheme review activities: Many review activities concentrated on the late conceptual design stage and the late preliminary design stage. General technical discussions were held online. Only the reviews of the principle, technical proposal and the detailed design program were held face-to-face between the college and the enterprise (marked by ▲ in
Figure 8). In the first stage, there were three centralized activities carried out by technicians from both sides. The first activity was completely based on manufacturing technology exchange. The other two project reviews included as many enterprise engineers and technicians as possible, especially those who had experience in the development of relevant machines. The engineers and technicians fully critiqued the proposed design scheme from the manufacturing perspective. All useful opinions were widely accepted by the designer team to avoid manufacturing defects in the design scheme. This greatly improved the manufacturing friendliness of the design.
(2) Optimization of detailed design activities: Based on the knowledge of corporate manufacturing, we finished the engineering design of the components in groups according to the length of the processing cycle and procurement cycle at the detailed design stage. We abandoned the traditional engineering design approach of functional module by functional module. The whole detailed design process was divided into six sub-stages according to the length of the processing cycle. The parts with long machining cycles or long lead times were designed first—the longer the cycle, the earlier the design. For particularly long lead times and problem-prone parts, a buffer period was reserved. This ensured that the last batch of parts scheduled for production could be completed in almost the same time as the previously designed parts. At the stage of detailed design activities, the graduate students played a complete role, since they undertook much of the engineering drawing work. Because the graduate students had a complete grasp of relevant manufacturing knowledge in the early stage, the engineering drawings they produced were correct and in line with standards.
5. Results and Discussion
By utilizing the IDEF0 model of manufacturing knowledge, the college and the enterprise strengthened their communication. By clearly understanding the interrelationships in each design stage, the three stages of the design process were completed on schedule. The overall structure of the box filling machine is shown in
Figure 9. According to the workshop conditions and hoisting and transportation capacity of the enterprise, the main body of the machine was divided into three sections. This greatly sped up the assembly process, since the three groups carried out assembly operations at the same time, and the final machine assembly was completed 2 days in advance. The main body of the machine had 256 machined parts in total. The structures and dimensions were each carefully designed according to the manufacturing capacity of the enterprise, and only six parts (2.3%) were redesigned for being beyond the processing capacity of the enterprise. In comparison, the previous similar machine that the enterprise and another college developed in cooperation had 20 redesigned parts, accounting for 9.5% of the total 210 machined parts. Moreover, compared with the addition of two suppliers in the previous similar machine development, no suppliers were added in this case. Reasonable selection of part materials, purchasing parts according to the common suppliers list of the enterprise, and utilizing a large number of purchased parts in stock accounted for 20% of the total purchased parts in this case, which helped the enterprise to effectively reduce their inventory. The surface treatment of parts was handled, together with other product parts, by adopting the same treatment process of the enterprise, which also reduced the environmental pollution and manufacturing costs.
In the testing stage of the materials, some functional problems were discovered, and the functional units were modified. The modifications involved multiple core functional components. A total of 12 parts were modified and processed into a total of 26 pieces. Since all parts could be modified by the enterprise on site, the enterprise arranged processing and production immediately after the college team submitted the modified drawings. The modification project was rapidly advanced, and after several days of material commissioning, the machine met the user’s requirements.
Figure 10 shows the local prototype of the carton-filling machine and the filled carton. It took 135 days to complete all the development tasks, saving 10% of the time compared to the traditional timeline of 150 days. The manufacturing cost was RMB 176,000, a savings of 12% of the manufacturing budget of RMB 200,000. A comprehensive comparison of the benefits of the new method is shown in
Table 1.
In addition to the benefits directly related to the design and manufacturing process, subsequent transportation and delivery operations were also easier and cheaper, due to giving full consideration to lifting and transportation requirements. The machine needed to be transported more than 1100 kilometers from Wuhan to Chengdu, where it was installed for production. The reasonable segmented structure design enabled the equipment to be disassembled into three parts and rearranged accordingly on the back of an open truck, so that transportation could be successfully completed with only one truck. If the machine had been transported as a whole, it would have needed to be transported by a flatbed truck because the overall width of the machine exceeded the width of the ordinary truck, which would greatly increase the cost of long-distance transportation. After arriving at the destination, only the forklifts owned by the customer’s enterprise were used to complete the unloading and moving of the machine parts, without the need to hire a large crane, which was also more cost-effective.
6. Conclusions
This paper describes a green design method for a carton-filling machine. Two partners adopted the ideas of the DFM and IDEF0 methods to establish the IDEF0 model, which defined the manufacturing knowledge required at each stage of the product design. The enterprise provided the necessary manufacturing knowledge to the college in a timely manner through a variety of appropriate methods, so the design plan and decision making were always based on the enterprise’s manufacturing capacity.
This case shows that the IDEF0 model of manufacturing knowledge can play a vital role in the communication and process management of cooperative development between college and enterprise. The model ensures that the design is well matched with the manufacturing capability of the enterprise, improves the development success rate, shortens the cooperative development cycle, and reduces waste and loss caused by redesign and remanufacture. It is a green design method for improving the cooperative performance of mechanical development between colleges and enterprises, especially for a designer who emphasizes theory.
Because contradiction between design and manufacturing teams is common in all cooperative development processes (not only between colleges and enterprises), it is necessary to find a universal method to solve this problem. The method proposed in this paper shows promising results in the case described and needs to be verified by more applications. The process should be continuously improved to be more widely adaptable to guide various cooperative developments in the field of manufacturing.