Since the cost driving factor of integrated casting is casting, the rear frame needs to use a 7000t (70MN) die-casting machine. In this paper, the domestic 7000t die-casting machine is used for analysis. First of all, fixed costs: one-time investment in machines and installation costs. According to the general rules of the automobile industry, fixed costs are depreciated for 10 years; The maintenance cost is calculated at 2% of the original value of fixed assets. The second is the labor cost. Eight workers are allocated according to the standard, six are front-line workers, and the per capita wage is 80000 yuan/year; One is the team leader, and one is the mechanic. The cost of “five insurances and one fund” is included according to the per capita wage of 120000 yuan/year. Financial management expenses, such as office expenses, insurance premiums, consulting fees, and salaries of management and sales personnel during the operation of the project, are included in the management expenses; Financial expenses include long-term loan interest and working capital loan interest to be paid. See Table 1 for the annual fixed cost of the die-casting machine.
| Category | Cost |
| Depreciation of fixed assets | 638 |
| Maintenance costs | 11.6 |
| Workers’ wages | 72 |
| Total cost | 721.6 |
According to the guiding ideology of the activity-based costing method, “the cost object consumes the operation, and the operation consumes the resources”, so it is also necessary to calculate the consumed resources, such as water, electricity, gas, etc., that is, the energy consumption cost (variable cost). According to the above view, calculate the energy consumption cost. See Table 2 for energy consumption per minute of die-casting machine.
| Category | Energy cost |
| Compressed gas | 0.07 |
| Electricity | 31.54 |
| Water | 4.33 |
| Total cost | 35.94 |
Taking the fixed cost and the variable cost into consideration, we can get all the costs per minute of the die-casting machine. See Table 3 for the cost details of die casting.
| Category | Cost |
| Machine depreciation | 21.37 |
| Machine maintenance | 11.20 |
| Plant area | 4.36 |
| Energy consumption | 35.94 |
| Total cost | 72.87 |
It should be noted here that the depreciation of machines is based on 10 years of depreciation, with a residual value of 5%. It is calculated based on 250 working days per year, with 2 shifts per day and 10 hours per shift (operation time). The total production time of a year is 5000 hours. Generally, the production time required for casting a rear frame is 120s, and two workers are required to operate this die-casting machine, and the wage is 0.83 yuan/min. Assuming that this part is produced by a first-tier supplier, the supplier usually needs to add 10% of the management cost when quoting to the main engine factory (automobile company). The profit is usually 10%~15% according to the principles formulated by different suppliers. Assuming a profit rate of 15%, the cost of die casting can be obtained.
