1. Local modulus extraction of 3D model
In the production process, the riser design of steel castings conforms to the principle of sequential solidification. The main design methods include modulus method, hot nodal circle proportion method, feeding liquid method, cubic equation method of steel castings riser, hyperbolic equation graphic method, perimeter quotient method, etc.
The module method is used to design the riser system of steel castings. Based on the modulus method theory, when designing the riser of steel castings, it is necessary to calculate the local modulus of castings. The definition of the local modulus is as follows:
Where, V is the volume of the intercepted body; SW is the surface area of the interceptor; SP is the area of invalid heat dissipation surface in the intercepted body surface area.
When calculating the local modulus of steel castings, different types of cutting tools can be selected and set according to the type of steel castings, and then the local modulus of steel castings can be obtained.
Among them, the types of interceptor tools are: cubic interceptor, cylindrical interceptor, sector interceptor and user-defined interceptor.
The table shows the influence of the type of interceptor tool on the local modulus of steel castings by taking rectangular interceptors and cylindrical interceptors as examples.
|Interceptor||Length / mm||Width / mm||Height / mm||Radius / mm||Intercepted volume / mm3||Non radiating surface area ／ mm2||Local modulus of casting||Riser modulus range|
|Cubic shape||40||20||30||117 628.41||333.84||44.64||49.10-58.03|
2. Parameter setting riser design of steel castings
According to the principle of modulus method for riser design of steel castings, the formula for the relationship between local modulus MC of castings and riser modulus MR of steel castings is:
Where, FR is the coefficient. When fr = (1.1 ~ 1.3), the molten metal in the riser of the steel casting can achieve better feeding effect on the casting.
Given the local modulus of the casting, the range of the riser of the steel casting corresponding to the local modulus can be obtained. Because the same riser module may correspond to different riser types and riser parameters of steel castings, it is necessary to search a large number of data in the database that meet this range and screen the appropriate riser types of steel castings before completing the riser design of steel castings. The process is cumbersome. Reduce the workload and narrow the search scope of information in the steel castings riser database. In the design, the type required for the design of the steel castings riser system will be selected from the existing steel castings riser types in the database, and then according to the calculated steel castings riser modulus range, the system can automatically search the appropriate riser type parameters from the steel castings riser system database for selection. Through the operation of this process, the type of steel casting riser, the parameter values of each length and the position of steel casting riser can be located. This process closely matches the data of steel casting riser database, reduces the interference in the search and reduces the data search range. The numerical value is accurate, and finally realizes the parametric operation.