Arsenievskaya Aviation Company "Progress" has optimized the technology of production of casting "Rama"

2021: Optimization of "Frame" casting technology

Arsenievskaya Aviation Company Progress has improved the technology for the production of Rama casting. This was announced on September 2, 2021 by CSoft.

The use of the Polygon Soft LP SCM when optimizing the technology for casting the Frame made it possible to reduce the weight of the casting unit by 57%. The ratio of the weight of the finished cast to the weight of the entire block is raised to 31.5%. The labour input of the mold assembly was reduced by 45%.

Castings of the "Frame" type are made of ML5ph alloy according to the casting technology in the form of ChTS. As a rule, they are a thin-walled structure with an average wall thickness of 8-10 mm and numerous stiffeners. To feed heat units formed at joints of frame flanges and stiffening ribs, profits are installed along perimeter of casting. To extend the power effect, each profit is insulated by a heat insulating insert. In some cases, refrigerators are installed between profits.

An inconvenience of this runner-feed system (LPS) design is that the profits are mounted on a surface that is not machined according to the drawing. Despite this, the foundries agree to an additional operation of cleaning the remaining profits, since the technology allows you to obtain castings without shrinkage porosity and successfully undergo radiographic control. In addition, it should be noted that the yield ratio of the castings is low (the ratio of the cast weight to the cast block weight is only 18-20%), the labor intensity of the mold assembly. High cost and expensive heat insulation inserts, as well as the use of refrigerators.

In order to obtain a defective, stable, and most importantly economical design of the block for one of the castings of the "Frame" type, the concept of the runner system was completely changed. Instead of vertical insulated cylindrical profits, one annular side is developed without insulation with a section in the form of a trapezoid. The profit passes the casting heat units through the slot feeders. The size of the profits and feeders, as well as their number, were selected using technology modeling at the Polygon Soft LP. In the course of solving the problems, it was decided to leave the concept of the central supply of melt unchanged.

Analysis of the technology in SKM LP Polygon Soft showed that with such a power system, there should be no macro and micro porosity in the casting, so it was decided to transfer the technology to the enterprise for the manufacture of an experimental batch of castings.

The experimental batch successfully passed radiographic control, but at the same time cracks were found at the places where the manifold feeders passed to the frame body. The reasons for their formation with the help of the "Hook" stress solver determined additional modeling in SKM LP "Polygon Soft." Due to uneven cooling of the casting block and difficult shrinkage in the form of ChTS, plastic deformations accumulated at the places of crack formation.

As a result of additional refinement of the design of the casting unit, the profile of the manifolds for supplying the melt, width, thickness and number of feeders were changed. In the final version, the 3D model of the foundry block is shown in Figure 5a. For comparison, a serial version of the LPS design is shown nearby.

File:Рис 5а.jpg

Not always the casting technology used in mass production can be called optimal. The very first technology is often introduced into production, which allows you to get suitable castings, and then it scales. This fact is primarily associated with temporary restrictions. The Polygon Soft product, developed by CSoft Group of Companies, is essentially a simulation of the foundry, with its help you can get a bunch of different options in a short time and find the best in quality and cost. Polygon Soft allows you to choose the best technological parameters and the design of the runner-feed system, which helps reduce the cost of production of the final product, "said Alexey Monastyrsky, deputy head of the mechanical engineering department, candidate of technical sciences.