How to calculate the production cost of powder metallurgy parts?
Dec 11, 2022
How to calculate the production cost of powder metallurgy parts?
The direct production cost of powder metallurgy parts can be divided into five aspects: material, mold, pressing, sintering and subsequent treatment. The cost of metal powder is generally higher than the casting cost of corresponding metal, which is caused by factors such as energy consumption when metal ingots are made into powder. Of course, the material utilization rate of powder metallurgy process is very high, so the total material cost after product manufacturing is not necessarily higher than that of parts manufactured by casting and forging process.
The material utilization rate of powder metallurgy parts is generally 95% - 98%. The raw material cost of metal parts is roughly calculated as follows:
1. Material cost of powder metallurgy parts: cost of metal material per gram × Part volume × Part density
The material cost shall also include the actual cost of raw materials such as lubricants and alloy additives.
2. Mold cost
The cost of the mould includes the price of the mould plus the cost of maintenance and replacement. The original price of the mold depends on the complexity of the mold, which is directly related to the complexity of the parts. Therefore, the cost should be related to the complexity of the part. As a set of powder metallurgy molds often produce a large number of parts, the mold materials should be materials that can withstand high pressure and powder friction.
3. Cost containment
Containment costs include machine costs and labor costs. With the increase of the press tonnage, the investment cost of the press increases, but the productivity decreases. The selection of the press size is based on the product of the cross sectional area perpendicular to the pressing direction and the unit pressing pressure. The unit pressing pressure is related to the pressing density of the part. The unit pressing pressure of low-density iron base parts is generally 400 MPa, and that of medium and high density parts is 600-700 mpa. Printing costs are also related to printing automation and printing rates. Although the working cycle of the powder metallurgy press is slower than that of the stamping parts, it is faster than that of the plastic forming press and requires less equipment.
4. Sintering cost
Sintering cost includes equipment cost, energy consumption, shielding gas and labor cost. Due to different sintering processes, the fusion cost also includes the fusion cost (additional costs such as pressing and placing of the fused metal). Since sintering does not require heating the base metal to the melting point, the energy consumption is lower than that of the casting process.
5. Subsequent processing cost
The cost of subsequent treatment includes the cost of all possible subsequent treatment processes, such as finishing, immersion, small metal cutting, heat treatment or surface treatment (steam treatment, grinding, deburring, shot peening, etc.).
In addition to the direct production cost, the production cost should also include the administrative expenses and auxiliary expenses. Management costs include design, technology, sales and other major projects, while auxiliary costs include power management, equipment maintenance, transportation and other costs. Generally speaking, these costs can be calculated according to the proportion of long-term accumulated data in the direct production costs.
