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How to calculate the cost of the injection molding process?

Products are usually injection molded in two ways, rubber injection molding and plastic injection molding. Injection molding can also be divided into injection molding method and die-casting method. Injection molding machine (referred to as injection molding machine or injection molding machine) is the main molding equipment that makes thermoplastic or thermosetting materials into various plastic products using plastic molding molds. 


1. What is the general consumption coefficient?  

The consumption coefficient is divided into two cases.  

A. Can add water mouth material, 2%-5%.

B. Not allowed to add sprues, single mould sprues weight / (single mould sprues finished product) 2% to 5%.

Remark: Can the spout material be returned to the processing master? Otherwise, the spout material should be discounted. Also, refer to the order quantity. 

2. Different equipment, cargo, number of holes, and time. What is the formula?  

A. Different tonnage prices. Example 150 tons – 800 to 1000 yuan/day, 120 tons – 600 to 800 / day, the specific situation also depends on the number of operators (a machine how many people do).  

B. The number of beer modules per day (24 hours). Generally 20 to 22 hours (maybe machine failure)  

20(hours)*60(minutes)*60(seconds)/single mold cycle(seconds)=number of molds per day  

Unit price per beer = daily processing cost/number of moulds per day, the unit price per hole = unit price per beer/number of holes.

3. Where can I find the cost of different injection moulding machines? How to calculate the general machine wear and tear? 


The wear and tear of the injection molding machine is generally calculated in 8 years  

Example: 150 tons at $160,000 per unit  

160,000 / 8 years / 12 months = 0.1667 million / month  

The cost of plastic parts is related to many factors but mainly consists of the following.  

1. Raw material cost

This cost is better to calculate. Ask a raw material supplier how much 1 kg, the weight of the product multiplied by 3% of the loss and then multiplied by the price of raw materials, you can get the cost of raw materials. 


2. Machine cost

Ask the plastic factory how much is the processing cost per hour of different injection moulding machines. Assume that the hourly processing cost of a 100-ton injection moulding machine is 60 yuan per hour, then the processing cost per minute is 1 yuan.

At this time, how much time is the injection cycle of the plastic part to be calculated and what is the number of open cavities of the mould?

Assuming that the injection cycle of the plastic parts you want to estimate is 30 seconds, then 1 minute can be shot 60 seconds divided by 30 equals 2, which means that 1 minute can be shot out of two mould products. In addition, assuming that the mould is one out of two cavities, then the processing cost of the plastic parts is 1 yuan divided by the number of cavities in the mold in 1 minute and then divided by the number of cavities in the mold, to get the final processing cost of the machine that is 1 yuan divided by 2 mold and then divided by 2 cavities, and finally wait for 0.25 Yuan/pc.

3. Secondary processing cost  

Secondary processing costs include painting / silk-screening / electroplating, etc., which the respective processing plant can ask for. 

4. Packaging cost  

The size and volume of the plastic parts can be derived from the cost of packaging cartons/bags, etc.  

5. Transportation cost

According to the delivery location and how many goods can be loaded at a time, the cost of a container truck to divide by the total number of loaded trucks to get the cost of transportation per pc.

6. Other costs

Because the above cost does not include the cost of overhead personnel and related personnel, some costs should be added according to the different situations of each factory.  

7. Profit  

With the sum of the above 6 items multiplied by 10-30% profit, you can get the final cost of a plastic part. The profit depends on each factory’s situation and the order size to order.


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