Compared with traditional sand mold manufacturing technology, sand mold CNC milling technology has fast forming speed and high machining accuracy. It integrates the characteristics of digitization, precision, flexibility, and greenness. It is a brand-new method for manufacturing castings without manufacturing. The wooden mold breaks through many obstacles in the traditional mold manufacturing process, and is a major revolution in traditional sand casting.
As the focus of attention in the modern advanced manufacturing field, sand mold CNC milling technology has the characteristics of green, digital, precise, flexible and rapid manufacturing, which promotes the sustainable development of the foundry industry and enhances the competitiveness of the foundry industry. Market prospects will become the new development direction of casting technology. However, there are still many defects. In the milling process, chipping, jagged edges, cracks, concave and convex, rough and unequal defects on the surface of the sand mold directly affect the surface quality and dimensional accuracy of the mold, especially when milling sand molds with complex thin-walled structures. more difficult.
Therefore, how to effectively improve the processing accuracy and surface quality of sand molds, improve the defects such as chipping, jagged edges, and cracks in the processing of sand molds, and achieve high-efficiency, high-precision, and low-cost CNC machining of sand molds is the current sand mold CNC milling technology. Problems to be solved. Combining the characteristics of CNC milling technology and casting technology, the main research contents of this paper are as follows:
- For the preparation of sand blanks for milling, approximately spherical orb sand is used as raw sand, and resin sand uses “new generation” furan resin as binder, and the content of binder and curing agent of sand blanks is analyzed on the performance of sand blanks. The influence of the law; the coated sand uses phenolic resin as the binder, combined with the requirements of CNC milling and casting technology, optimizes the sand blank ratio, and compares the performance of the two sand blanks to obtain the sand blank formula and preparation suitable for CNC milling method.
- Focus on the influence of the particle characteristics (grain size, gradation and accumulation distribution) of Baozhu sand on the properties of sand blanks, and discuss the bonding mechanism of sand molds and the mechanism of milling fracture.
- Study the influence law of milling process parameters (spindle speed, feed speed, milling depth and milling width) on sand mold surface integrity, surface roughness and dimensional accuracy, and optimize milling process parameters.
- After determining the formula and preparation method of sand blanks that are more suitable for CNC milling and optimizing process parameters, CNC milling is performed on a complex sand core, and compared with the laser sintering forming technology, and the milling surface quality, Surface integrity, dimensional accuracy and milling time used.