Foundry is an industrial basic industry and has an irreplaceable position. At present, there are about 26,000 foundry enterprises in my country, and the annual output of castings accounts for about half of the world's total output. Among many casting methods, sand casting is the most common production method, and the products produced by sand casting account for more than 90% of the total castings. But in the traditional sand casting method, there are the following problems:
●High labor intensity, poor labor environment, shortage of employees, difficulty in recruiting, and difficulty in retaining people are common;
●Molding cost is high, the cycle is long, and it is difficult to meet the production needs of multi-variety and small batches;
●When manufacturing molds with complex geometric shapes, the density, and precision are low, which increases the difficulty of subsequent processing;
Additive manufacturing technology (3D printing) breaks the shackles of traditional preparation processes. With the help of computer-aided design, based on digital models, the three-dimensional model of parts is divided into multiple two-dimensional sections by the principle of discrete/stacking, and the sections are stacked by stacking. into a three-dimensional entity. At present, this technology is used in the field of sand casting, just to meet the needs of the industry:
●Instead of manual operation, all molding processes are carried out in a relatively closed box, and there will be no dust phenomenon during the printing process, greatly improving the working environment and reducing heavy physical labor;
●Omit the process of making molds, which not only saves production costs but also improves the speed and flexibility of product trial production;
●Improve the dimensional accuracy of products, enhance the ability to control the size of sand molds, reduce the dependence of enterprises on high-skilled workers, and enhance product quality, which not only reduces the subsequent scrap rate of products caused by size problems but also improves the processing efficiency of subsequent casting products;
With the continuous development of aviation, aerospace, ships, new energy vehicles, and other fields towards high performance, high reliability, and low cost, more and more parts, and components tend to be high-strength, light-weight, and complex, thus promoting additive materials. The application of manufacturing technology in many fields.
Casting 3D printing case
Engine flywheel housing
Product weight: 50-100kg
Product difficulty: The main structure is a large plane and thin wall (7mm), and the local thickness is large, which is prone to defects such as air bubbles and cold insulation.
Solution: adopt inclined casting process, large plane, and multi-point exhaust to ensure good filling
3D printing lead time: 15 days
screw compressor housing
Product weight: about 1 ton
Product difficulty: complex cavity structure; thick local structure, easy to shrink and loosen; many drilling parts
Solution: Isolate thick and large parts, and use strong cooling measures; adopt a special melting process (CE4.4 ~ 4.5, △ T≤3) to achieve simultaneous solidification
Mold cost: 700,000 yuan for wood mold
Mold opening cycle: 50 days
3D printing lead time: 25 days
Multi-way valve
Product weight: 15-400kg
Product Difficulty: The internal flow channel has high dimensional accuracy requirements, and no defects such as slashes can appear; the body sampling (close to the heart) is required to measure the metallographic phase, and the spheroidization rate is required to be ≥90%, and the number of graphite balls is ≥100
Solution: The runner core is made into a whole core to ensure dimensional accuracy and avoid defects such as core splaying; use a long-acting inoculant and special modularizing agent to achieve metallographic requirements
Mold opening cost: 500,000 yuan for metal mold
Mold opening cycle: 90 days
3D printing lead time: 15 days
internal combustion engine
Product weight: 30-2000kg
Product Difficulty: The product structure is particularly complex, and any form of welding repair is not allowed. The cost of opening the mold is high and difficult, and the size of the sand core is large.
Solution: The overall modeling in the form of 3D printing can solve problems such as double-layer tubes, inner cavity cores, and complex inner cavity structures. The most complex products only need to be divided into 5 sand cores
Cost saving: 20%-60% of mold cost
Mold opening cycle: 3-6 months
3D printing lead time: 25-30 days for the first piece
Aluminum alloy casting
Product weight: 2-60kg
Product Difficulty: The internal flow channel has high dimensional accuracy requirements, and defects such as seams cannot appear; the structure is complex, and the mold forming is difficult
Solution: Simplify the complexity, connect multiple cores together, reduce the number of cores, ensure dimensional accuracy and avoid defects such as cores and seams
Cost saving: 20%-60% of mold cost
Mold opening cycle: 20-90 days
3D printing lead time: 15-25 days delivery
The integration of 3D printing technology and traditional industries has become an inevitable trend. In the field of sand casting, 3D printing technology has also opened up a new way for the development and production of rapid, green, multi-functional, large-scale complex, and high-demand parts. Sharing will not forget the original intention, continue to focus on promoting the industrial application of casting 3D printing technology, and promote the transformation and upgrading of the foundry industry.