What are the main costs of injection molds and plastic products?
The main cost components of injection molds and plastic products include raw material costs, mold expenses, labor and manufacturing costs, energy consumption and indirect costs, etc.
1.Raw Material Cost
This is the most fundamental part of plastic product costs, primarily determined by the purchase price of plastic pellets (such as PP, ABS, PC, etc.). Material prices are significantly affected by fluctuations in international oil prices, and different performance grades (e.g., general-purpose, engineering-grade, specialty modified materials) vary widely in cost. Additionally, material loss rate (typically 5%–15%) and the proportion of recycled material usage also impact actual costs.
2.Mold Development and Amortization Cost
The mold is the core of injection molding production. Its cost depends on product structural complexity, steel grade, number of cavities, and surface treatment processes. A precision mold can cost anywhere from tens of thousands to hundreds of thousands of yuan. This is a one-time investment that must be amortized over the expected production volume. For example, a USD200,00-yuan mold used to produce 500,000 units results in a per-unit amortization of USD0.04.
3.Labor and Manufacturing Costs
Labor Cost: Includes operator wages, social insurance, and training expenses. While automation has reduced labor’s share, human involvement remains necessary in debugging, trimming, and quality inspection.
Equipment Depreciation: Injection molding machines are expensive (e.g., a 150-ton clamping force machine costs about 800,000 yuan); annual depreciation is approximately 80,000 yuan over a 10-year period.
Auxiliary Equipment Expenses: Maintenance and operation costs for robotic arms, dryers, cooling systems, etc.
4.Energy Consumption Cost
Injection molding consumes large amounts of electrical energy, with equipment power typically ranging from 20kW to 100kW. At an average power of 50kW and electricity cost of 0.8 yuan/kWh, hourly electricity cost is about 40 yuan. Cooling water and compressed air also add to energy expenses.
5.Quality and Defect Loss
Includes prevention costs (e.g., process optimization), appraisal costs (quality inspection labor and equipment), and internal failure costs (scrap, rework). High defect rates significantly increase unit costs. Establishing a quality management system can effectively control these hidden expenditures.
6.Logistics, Warehousing, and Management Fees
Logistics and Packaging: Transportation, handling, and packaging material costs—especially impactful for large or high-value products.
Warehousing Costs: Inventory of raw materials and finished goods ties up capital; poor management can lead to overstocking or damage.
Management Fees: ERP system usage, administrative operations, supply chain coordination, and other indirect expenses.
7.R&D and Design Costs
Upfront investments include mold design, prototype production, and DFM (Design for Manufacturability) analysis. While not directly included in per-unit cost, they are crucial for long-term cost optimization.
