[Discussion on assembly line of sheet metal spraying] Sheet metal spraying

With the continuous development of maintenance stations in recent years, the business of sheet metal spraying in maintenance stations has become more and more busy. Many maintenance station managers are considering how to upgrade hardware (i.e., through equipment and tools) or software (i.e., through management level and skills) to improve the efficiency and profit of the sheet metal painting workshop. And "assembly line" is a very popular practice now. In this paper, the theme of "assembly line operation" of body panel and spraying workshop in maintenance station is discussed in depth.

Process background

The idea of assembly line comes from the assembly line of automobile factory.

On the assembly line of automobile factory, vehicles are placed on moving tracks to install various components. Different processes are designed at different positions on the assembly line, such as installing tires and doors, and each process is operated by professionally trained workers. The premise of assembly line operation is that the workers in each position must complete the specified work within the specified time. For example, the process of installing car tires must be completed within 10 minutes, that is, whether it is completed or not, the car will be automatically taken to the next process by the track after 10 minutes. Due to such division of labor and cooperation, the production efficiency has been greatly improved.

The first automobile factory to use this method was Ford Motor Company. At the beginning of the 20th century, the founder of Henry Ford? Ford used this to make Model T popular in the whole American market. It is Japan's Toyota Motor Corporation that carries this forward. Through in-depth research and bold innovation, they developed a set of assembly line system called TPS (Toyota Production System). Toyota in the 1980s. This system has been introduced into the improvement of after-sales service and has been tried in some countries in Southeast Asia.

Brief introduction of flow shop

Flow process refers to the re-planning of the sheet metal painting workshop, transforming the workshop into different functional areas by specific methods, and the specific tasks are completed by specific operators. Because the different processes of the vehicle to be repaired are completed in different areas and operated by different technicians, it is similar to the "assembly line" of the automobile factory in form, so it is called "assembly line".

Flow shop classification

Flow shop can be divided into hardware flow shop and process flow shop according to its realization form, and can be divided into non-beat flow shop and beat flow shop according to the connection mode of each process. We will explain them one by one below.

Hardware running water (figure 1) refers to the running water form formed after the maintenance station has carried out large-scale renovation of the sheet metal painting workshop and installed ground rails, specially designed curing barn and primer room. The implementation of hardware pipelining requires extremely high factory buildings and investment. Depending on whether the vehicles on the ground track are arranged vertically or horizontally, the paint workshop of the maintenance station must be 30-80m long to accommodate the whole line. In addition, due to the need to increase the ground track, rebuild or increase the curing barn and primer room, the overall investment will be quite huge.

Because the hardware pipes are mostly straight rails in form, rhythmic connection is generally adopted. Generally, it is divided into parts disassembly-sheet metal-putty-polishing/masking-primer/polishing-masking-topcoat-baking-polishing-installing parts and other processes, and the time of each process is fixed and straight, which is called the beat, such as 1 hour. Only in this way can the assembly line run.

The advantages of hardware pipelining include: compared with the traditional car body and painting workshop, the efficiency is greatly improved; Well equipped; Good working environment for employees; Fixed beat, easy to manage; The vehicle is parked on a trolley on the ground rail and pushed forward by technicians, so in general, the vehicle does not need to be started from beginning to end.

On the other hand, the hardware pipeline also has its disadvantages, including:

First, the investment is huge and the requirements for the factory building are high;

Secondly, it is difficult to determine the time of each jump. In most cases, the time of the beat is imagined by people.

Third. Lack of flexibility, because as long as the time per beat is fixed, how many cars can be calculated theoretically every day, such as per beat 1 hour, and theoretically 8 cars can be exported online every day. However, it is difficult for the maintenance station to guarantee such a fixed vehicle source every day, which may sometimes be 10 and sometimes 6 vehicles, which will affect the flow of hardware.

Last but not least, because the damage of each vehicle to be repaired is different, for example, car A damaged five workpieces and car B damaged 1 workpiece. Does it take the same time to polish them with putty? The inconsistent maintenance time of each car has caused that if you run according to the beat, it is likely that some cars will have to wait, and some cars will not finish running within the stipulated beat. Therefore, it is easy to cause paralysis of running water. At this time, it is necessary to rely on the superb scheduling and coordination of workshop managers.

Generally speaking, hardware pipelining is a pipelining method with large investment and good effect. So far, some large 4S maintenance stations in the coastal areas of China have realized the hardware assembly line.

Another way of process production is "process flow". The process flow refers to the process form of dividing the car body and painting workshop into different functional areas, and Figure 2 is the schematic diagram of the workshop process flow. It can be seen that according to the time-consuming degree of each process, how much their work station occupies is different. The two processes of "putty/polishing" are the most time-consuming in the painting process, so there are more stations assigned to them. There are six stations in the picture.

Moreover, because the whole running water is not a straight line strictly, the form of "non-rhythmic running water" is adopted more in the connection mode. Therefore, there is no strict time limit for each process. If the damaged area of the vehicle to be repaired is large, it can stay in the putty process for a period of time, and if the damaged area is small, it can quickly enter the next process.

The biggest advantage of the process is that there is basically no hardware investment, which is less investment and quick effect for the maintenance station. At the same time, because there is no beat. Therefore, the maintenance station is more flexible. No matter how many cars are picked up, this process line can still operate normally.

The disadvantage of the process flow is that the connection time between each process is completely "fuzzy", so a supervisor who is quite proficient in sheet metal spraying is needed to manage this line, otherwise it may cause inefficiency.

The key of sheet metal spraying

Sheet metal spraying is a big project, involving all aspects of the maintenance station. To complete this project, the work to be done includes the improvement or transformation of workshop layout, the improvement of technical personnel's skill level, the division of technical personnel's functions and the improvement of workshop manager's management ability.

Taking the division of technicians' functions as an example, the sheet metal and painting workshops in existing maintenance stations are mostly managed according to the following modes: sheet metal technicians and painting technicians are divided into several teams, each team consists of a master, several middle-class workers and several apprentices, and each team is assigned to several fixed stations. When the vehicle to be repaired enters the workshop, the workshop director will send workers to a certain team to complete the repair. In this mode, due to the management ability of each team leader and the coordination between teams, it is difficult to finish paint repair efficiently.

The implementation of assembly line must break the above model. All paint technicians and sheet metal technicians must be divided into different types of work, including professional preparation technicians, professional covering technicians and professional painting technicians. Different jobs will be assigned to different stations, which are organically linked according to the sheet metal spraying process. Form running water. Therefore, theoretically speaking, the implementation of "assembly line" can give full play to the working ability of the body panel and painting technicians, improve the working efficiency of the body panel and painting workshop and increase the number of trains.

The key point of sheet metal spraying is internal communication. The objects of communication include front desk staff (SA), service manager, workshop supervisor, body panel and painting technician, etc. Only by full communication can we ensure the reasonable and correct sequencing of vehicles and personnel. Let the "running water" run normally.

Kanban is a good way of communication. Through Kanban, everyone knows what they are doing and what others are doing. What you want to do, what others want to do; Workshop managers can also better adjust and plan their present and future work through kanban, reduce time waste and maximize efficiency. Of course, it is also a good method to use professional sheet metal spraying management software. A good software can help the maintenance station manager manage the assembly line more effectively and efficiently.

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At present, the maintenance stations that implement assembly line operation in China have different operation and management methods. This also reminds us that the situation of each maintenance station is different, and the implementation of assembly line operation is closely related to the actual situation of each maintenance station, which also means that there can be no "one size fits all" criterion for assembly line operation, and each maintenance station needs to explore its own scheme through the actual situation. In the process of implementing assembly line operation, the maintenance station must follow the principles of comprehensive demonstration, full preparation, cautious implementation, continuous summary and timely improvement to ensure the effective implementation of assembly line operation.