How to evaluate the manufacturing cost of preform molds
一. Material cost evaluation
1. Mold steel cost
2. Auxiliary material cost
二 .Processing cost evaluation
1. Machining cost
2. EDM cost
3. Heat treatment and surface treatment costs
三. Assembly cost evaluation
1. Labor assembly cost
2. Debugging cost
四. Indirect cost assessment
1. Design cost
2. Management costs and profits
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一. Material cost evaluation
1. Mold steel cost
The core and cavity of the preform mold are the key parts, and their material cost accounts for a large proportion. Choose the appropriate mold steel according to the size of the preform, precision requirements, and production batch. For example, for high-precision, long-life preform molds, H13 steel may be selected, which is relatively expensive but has excellent performance. Its price is usually around 20-30 yuan per kilogram, and the specific price will fluctuate depending on factors such as the origin and quality grade of the steel.
To calculate the weight of the steel required for the core and cavity, consider its shape and size. The volume can be estimated through 3D modeling software or geometric formulas, and then multiplied by the density of the steel (generally, the density of mold steel is about 7.8-7.9g/cm³) to get the weight. For example, the size of a core is 30cm long, 20cm wide, and 15cm high. By calculating its volume to 9000cm³, its weight is about 70.2-71.1kg. Then multiply it by the unit price of steel to get the cost of this part of the steel.
In addition to the core and cavity, other parts of the mold such as templates, guide columns, etc. also require steel. The steel cost of these parts can be calculated based on their size and quantity. For example, the template generally uses ordinary carbon steel, which is relatively cheap, and may be around 10-15 yuan per kilogram.
2. Auxiliary material cost
Cooling system materials are an important part of the preform mold. Cooling pipes usually use copper pipes or stainless steel pipes. The price of copper pipes is relatively low, and the price per meter may be around 20-50 yuan, while the price of stainless steel pipes is slightly higher, about 50-100 yuan per meter. According to the design of the cooling system, the length of the required pipe is calculated to get the cost of the cooling pipe.
Auxiliary materials such as release agents and lubricants are also needed in the mold manufacturing process. The price of mold release agent varies according to brand and performance, and is generally around 50-200 yuan per kilogram. The price of lubricant is about 30-100 yuan per kilogram. Estimate the amount and cost of these auxiliary materials according to the size of the mold and the production frequency. For example, a medium-sized preform mold uses about 0.5kg of mold release agent and about 0.3kg of lubricant each time. According to the corresponding unit price, the cost of using these auxiliary materials each time is about 45-130 yuan.
二 .Processing cost evaluation
1. Machining cost
In the roughing stage, the loss of cutting tools and processing time are mainly considered. For the roughing of preform molds, a larger cutting amount is generally used, and the tool wear is relatively fast. For example, when ordinary carbide tools are roughing mold steel, the tool loss cost per hour may be around 10-20 yuan. The roughing time can be estimated based on the size and machining allowance of the part. If a core roughing allowance is 5mm, the machining time may take 5-10 hours with appropriate cutting parameters, then the tool loss cost is about 50-200 yuan.
At the same time, the cost of using the machine tools for rough machining should also be calculated. The cost of using the CNC machining center per hour includes equipment depreciation, electricity costs, maintenance costs, etc., which may be around 80-150 yuan. According to the above processing time, the cost of using the machine tools for rough machining a core is about 400-1500 yuan.
In the finishing stage, the machining accuracy requirements are higher, the cutting amount is small, and the tool cost and processing time are also different. The price of finishing tools is higher, and the tool loss cost per hour may be around 20-30 yuan. Since the finishing speed is relatively slow, it may take 10-20 hours, and the tool loss cost is about 200-600 yuan. The cost of using finishing machine tools may be around 100-200 yuan per hour, and the processing cost is about 1000-4000 yuan.
2. EDM cost
When there are some complex shapes in the preform mold, such as deep grooves, narrow slits, etc., EDM is required. The cost of EDM mainly includes the cost of electrode production and the cost of using the EDM machine tool. The electrode material is usually copper or graphite, with copper electrodes costing about 80-120 yuan per kilogram and graphite electrodes costing about 40-60 yuan per kilogram.
The weight of the electrode is calculated based on its shape and size, thereby obtaining the electrode production cost. For example, an electrode with a complex shape weighs 2kg and uses copper electrode material, which costs about 160-240 yuan. The cost of using an EDM machine tool per hour is about 120-200 yuan. The processing time may take 3-8 hours depending on the complexity of the part, and the processing cost is about 360-1600 yuan.
3. Heat treatment and surface treatment costs
The heat treatment cost mainly includes quenching, tempering and nitriding treatment. The cost of quenching and tempering treatment per kilogram of mold steel is about 10-20 yuan. If the total weight of the core and cavity is 100kg, the heat treatment cost is about 1000-200 yuan. The cost of nitriding treatment is relatively high, with a cost of about 100-200 yuan per square meter of treatment area. Calculate the cost of nitriding treatment based on the surface area of the core and cavity.
Surface treatment such as polishing and coating also has a certain cost. The polishing cost is calculated based on the surface roughness requirements and the area of the part. For example, fine polishing with a surface roughness of Ra0.4 - Ra0.8μm is required, and the cost per square meter is about 200-500 yuan. The coating treatment cost varies depending on the coating material and process, such as the cost of titanium nitride coating per square meter is about 300-800 yuan.
三. Assembly cost evaluation
1. Labor assembly cost
The assembly of bottle preform molds requires skilled technical workers. The salary level of assembly workers varies depending on the region and skill level. Generally speaking, the hourly wage of assembly workers is around 30-80 yuan. The time required to assemble a bottle preform mold depends on its complexity and may take 10-30 hours. For example, a bottle preform mold with medium complexity has an assembly time of 20 hours and an assembly worker salary of 50 yuan per hour, so the labor assembly cost is about 1,000 yuan.
During the assembly process, some auxiliary tools and equipment may also be required, such as assembly fixtures, torque wrenches, etc. The cost of these tools and equipment should also be allocated to the assembly cost. For example, the price of a set of assembly fixtures is about 2,000-5,000 yuan. Depending on its service life and frequency of use, the cost allocated for each assembly may be around 50-200 yuan.
2. Debugging cost
After the mold assembly is completed, debugging is required. The debugging process includes checking the opening and closing action of the mold, whether the demolding mechanism is normal, whether the cooling system and the gate system are unobstructed, etc. The time required for debugging may take 3-8 hours, the salary of the debugging staff is about 40-80 yuan per hour, and the debugging cost is about 120-640 yuan.
Some test materials may also be required during the debugging process, such as plastic raw materials for trial molds. The cost of plastic raw materials is calculated based on the material and amount of the bottle embryo. For example, the price of PET plastic raw materials is about 10-15 yuan per kilogram, and a trial mold may require 1-2kg, with a cost of about 10-30 yuan.
四. Indirect cost assessment
1. Design cost
The design cost of preform molds is part of the manufacturing cost. Design costs include the salary of designers, the cost of using design software, etc. The salary of designers varies according to their experience and skill level, and is generally around 8,000-15,000 yuan per month. It may take 1-2 weeks to design a preform mold. Based on 20 working days per month and 8 hours per day, the design cost is about 4,000-12,000 yuan.
The license fee for design software such as CAD/CAM software is also high. For example, the annual license fee for a well-known CAD software may be around 20,000-50,000 yuan. According to the use time of mold design, the software cost allocated to each mold design is about 1,000-3,000 yuan.
2. Management costs and profits
The management costs of mold manufacturing companies include management staff salaries, office space rental, utilities, etc. These costs need to be allocated to the manufacturing cost of each mold. General management costs account for about 10-20% of the total mold cost. For example, the total cost of a mold is estimated to be 100,000 yuan, and the management cost may be 10,000 to 20,000 yuan.
Enterprises also need to consider profits. Profit margins vary depending on the company's market positioning and competition. The profit margin of a general mold manufacturing company is around 20-30%. According to the above example, a mold with a cost of 100,000 yuan may have a profit of 20,000 to 30,000 yuan.
Foshan Heyan Precision Mold Technology Co., Ltd.'s main business is bottle preform molds, bottle blowing molds, bottle cap molds and other products. It has a strong engineering, R&D, technology, and sales team, advanced processing equipment and rich project experience. If you want to know more or have special needs, please call 13318345050, WeChat at the same number.
