What main
wire harness workshop can learn and adopt from the overall layout of
car assembly workshop?
We are no talking about
cable assembly, but car assembly. That’s funny, we are making
cable assembly and wiring harness for car. But I think we can learn something from car assembly for our
cable assembly and cable harness procession. Let’s check and see.
The layout of the automobile final assembly process should first follow the seven principles mentioned above and then make a reasonable plan based on the specific actual conditions of each company's site. At present, the standard assembly process layout types mainly include S-shape, T-shape and U-shape, as shown in Figure 5-1, 5-2, and 5-3. The final assembly lines of Shenlong Motor Company and Dongfeng Honda Motor Company adopt an S-shaped layout. In contrast, Shanghai General Motors' last assembly line adopts a T-shaped structure, and most truck and mini-vehicle final assembly lines assume a U-shaped configuration.
Modular production
To facilitate the quality control of the final automobile assembly and the standardized management of the final assembly process, the automobile final assembly process is often divided into several modules, such as interior assembly line 1, interior decoration assembly line, chassis sub-assembly line, door sub-assembly line, instrument panel Sub-assembly line, wheel sub-assembly line, body assembly line, final assembly line, performance testing line, etc.
The automobile final assembly process is very complicated and consists of hundreds of stations. Figure 5-4 is the main process flow of a particular automobile company's automobile final assembly process. In order to simplify the assembly process and improve assembly efficiency, automobile assembly has generally realized modular production, that is, multiple assembly parts are combined into assembly modules according to their assembly relationships or functional associations, such as the power system (including engine And the entire transmission system), the axle and the suspension are integrated into a chassis assembly module (see Figure 5-5), which combines all the car's instruments and air conditioning unit into a module (see Figure 5-6), and install the door on the vehicle door All the accessories are combined into a module (see Figure 5-7) and so on.
Automobile assembly production method
Automobile final assembly has generally adopted the just-in-time pull production method JIT, which uses Kanban management as a means and adopts the "reclaiming system", that is, the last process is produced according to market demand, and the shortage of products in this process is the same as the previous process. The amount of work in progress, thus forming a pull control system for the whole process. This "pull-type" reverse control method synchronizes the relatively isolated processes developed by the division of the enterprise into production, calmly and effectively prevents blind overproduction, dramatically reduces the number of products in progress, and improves production efficiency and flexibility of the production system. To this end, it is necessary to formulate annual, quarterly, and monthly plans based on the company's operating policies and market forecasts and then develop daily production plans accordingly. However, these plans are all dynamic plans with rolling adjustments, which only play the role of forecasting guidance and reference for production. In actual production, production is driven by product orders. The final production order, which is truly a production order, only reaches the last process, that is, the general assembly line (mixed-flow production line). The rest of the methods are traced back sequentially from the broad assembly line and carried out by means of Kanban or synchronous control information.
You see Kanban here? I told you that Kanban is also very popular use in our
wiring loom and
cable assembly workshop. It can increase the 6-sigma performance in our
cable harness assembly workshop.
1. Work station and section
The workstation is the basic unit of the final assembly production line. The address of the workstation provides the location of material transportation, arranges production personnel and completes assembly tasks. Each station on the last assembly line is equipped with special tools and equipment for assembly, which are used by production personnel for the group of various assembly components. The body to be assembled is used as the assembly base and moves at a certain speed on the assembly line, and the operators of each station complete the assembly work of the station during the movement.
In order to facilitate management and improve production efficiency, the assembly of large assembly systems and the assembly of similar parts are often combined for centralized mass. This is the work section of the final assembly line. As mentioned above, the first interior assembly line, the second interior assembly line, the chassis assembly line, the door subassembly line, the power assembly line, the powertrain assembly line, the instrument panel subassembly line, the final assembly line, and the performance testing line are all An independent section on the last assembly line.
subassembly and power assembly line is key structure in our main
wire harness assembly flows. We need them to ensure both productivity and quality.
2. Work station pitch
The station pitch is the distance between the start and end of the station and the distance between the previous car and the next car. The rise of different stations is often other.
3. Assembly line beat
The pipeline beat refers to the time it takes for the car body to move from the start point to the endpoint of a station. The moment of the assembly line determines the working hours of each station under mixed production conditions.
4. Equivalent working hours
Station time: the time required to complete the contents of the station operation. If only one type of vehicle is produced on an assembly line, the work content of each station should be balanced so that the operating time of each station is as equal as possible to the beat of the assembly line. However, for a flexible production line with multiple vehicle models, the parts assembled in the same station of each vehicle model may not be the same, and the assembly process may also be different. It is often difficult, or even not, to make the operation time close to the beat of the assembly line. May. Therefore, in the process design, the equivalent station working hours should be calculated according to the production ratio of each vehicle model to make it as close to the assembly line beat as possible.
5. Work elements
Work elements, also known as processes, are part of the entire work content in the assembly process and are the smallest unit of work to complete a particular operation.
6. Work station quality control
According to the concept of lean production, the parts that flow from the front process to the back process must have a 100% pass rate, and no unqualified products are allowed to flow from the front process to the back process.
The so-called 100% pass rate not only means that the processing quality of the finished parts and products should be all qualified but also includes whether all the parts and products have been completed in accordance with the requirements of the production process. If the operator fails to meet the assembly work in the work area of this station, the product is regarded as an unqualified product and is not allowed to flow to the work area of the next station. If a particular station fails to complete its work in its work area, the worker in that work position must pull down the switch or button marked Andon (see Figure 5-8), stop the movement of the assembly line, and continue the work. The completed assembly work (the team leader will come to assist in the assembly at this time). After knowing that the work is completed, pull down the Andon switch here to restart the movement of the assembly line.
Once an employee in a particular station pulls down the Andon rope or presses the Andon button to stop the movement of the assembly line, employees in other positions are also forced to stop the assembly and remain idle. This not only affects the work efficiency of the entire assembly line but also affects the operating rate of the assembly line. In addition, if the assembly line is frequently stopped and started, it will also adversely affect the service life of the assembly line. This is why it is necessary to balance the working hours of the workstations.