I. Numerous factors during the grinding of alloy circular saw blades cannot be overlooked.  
　　1. When the base material exhibits significant deformation, uneven thickness, and large tolerances in its internal bore—issues stemming from inherent defects in the base material—grinding errors will occur regardless of the type of equipment used. Large deformation of the base material causes deviations in the two-side angles; a large internal bore in the base material leads to deviations in the diameter runout. Uneven thickness of the base material results in deviations in both the back rake angle and the front cutting edge angle. If cumulative tolerances exceed acceptable limits, the quality and precision of the saw blade will be severely compromised.
　　2. The structure of the gear-grinding machine significantly affects the quality of gear grinding. The quality of grinding alloy circular saw blades largely depends on the machine’s structural design and assembly. Currently, there are roughly two main types of machines available on the market: The first type is the German Vollmer-style machine. This type of machine employs vertical grinding, with all movements driven by hydraulic stepless control. Its entire feed system utilizes V-shaped guide rails and ball screws for operation. The grinding head or large arm features a slow approach during feed and rapid retraction during withdrawal. The clamping cylinder precisely adjusts the center position, ensuring flexible and reliable support. Tooth-picking mechanisms provide accurate positioning, while the saw blade’s centering mechanism offers firm, automatic centering with adjustable angles to suit any requirement. The cooling and flushing systems are designed rationally, providing an intuitive human-machine interface. This type of machine boasts high grinding accuracy and a well-optimized, purely grinding-machine design. The second type is the currently popular horizontal-type machine, such as those from Taiwan and Japan. These machines rely on mechanical transmissions featuring gears and mechanical backlash, resulting in poor precision from their dovetail sliding guides. They also suffer from low stability in clamping, difficulty in adjusting the center position of supporting plates, and unreliable tooth-picking mechanisms. Moreover, the grinding of both side surfaces and the left and right rear angles fails to maintain a single central axis, leading to significant deviations, difficult angle control, and substantial mechanical wear, making it challenging to ensure consistent accuracy.
3. Welding factors: During welding, significant deviations in alloy alignment can affect grinding accuracy, causing one side of the grinding wheel to bear greater pressure while the other bears less. The same factors also apply to the back rake angle. Welding angle discrepancies and other unavoidable human-induced factors inevitably exert an impact on the grinding wheel and other related elements during the grinding process.
4. The quality and grit size of the grinding wheel significantly affect the grinding process. When selecting a grinding wheel for alloy blades, pay close attention to the wheel’s grit size. If the grit is too coarse, it may leave visible wheel marks on the workpiece. Conversely, if the grit is too fine, the wheel tends to clog easily, resulting in reduced material removal and increased risk of burning the blade. The diameter, width, and thickness of the grinding wheel should be determined based on the length, width, and shape of the alloy—whether it has teeth or not—and the specific characteristics of each surface of the alloy. It is crucial not to assume that a single wheel specification with a fixed back or front angle can handle all types of tooth profiles. Instead, you must carefully select a wheel specification that is specifically tailored to the particular tooth geometry and dimensions of the alloy being processed.
5. The feed rate of the grinding head—whether the alloy saw blade is ground well or poorly—is entirely determined by the feed rate of the grinding head. Generally, the feed rate for alloy circular saw blades should not exceed 6 millimeters per second; that is, the number of teeth ground per minute should remain within 20. If the feed rate exceeds 20 teeth per minute, it will lead to severe tool chatter or burning of the alloy grinding wheel, resulting in uneven surfaces that compromise the accuracy of tooth grinding and waste the grinding wheel.
6. The feed rate of the grinding wheel head—selecting an appropriate grit size for the grinding wheel is critically important to the depth of cut. As a general guideline, it is recommended to use grinding wheels with grit sizes ranging from 180# to 240#. At most, you may choose wheels with grit sizes from 240# to 280#, but avoid using wheels with grit sizes from 280# to 320#. Otherwise, you will need to adjust the feed rate accordingly.
7. In blade grinding, the center of all saw blades must be aligned with the blade’s body rather than with the cutting edge. The center for surface grinding cannot be precisely determined. Even using a machining center, it’s difficult to achieve perfect grinding of both the back and front angles on a single blade. During the three-stage grinding process, the blade’s center must not be overlooked. When grinding the side angles, pay close attention to the alloy thickness—since the grinding center shifts accordingly depending on the thickness. Regardless of the alloy thickness, when grinding the sides, the center line of the grinding wheel should remain aligned with the weld joint; otherwise, an angular discrepancy will arise, adversely affecting the cutting performance.
8. The tooth-picking mechanism cannot be overlooked. Regardless of the structure of any gear-grinding machine, the accuracy of the tooth-picking seat design directly affects the quality of the grinding tool. During machine adjustment, it is crucial that the tooth-picking pin presses against the tooth surface at the proper position and remains stationary. Additionally, when retracting the teeth, the tooth-picking claws must operate flexibly and reliably.
9. Clamping Mechanism: The clamping mechanism must be robust, stable, and reliable—it is the key component determining the quality of sharpening. During any sharpening process, the clamping mechanism must remain absolutely tight; otherwise, tooth-shaping deviations could become severely uncontrolled.
10. The grinding stroke—regardless of which part of the grinding blade is being worked on—is crucial. Generally, it’s advisable for the grinding wheel to extend beyond the workpiece by 1 millimeter or recede by 1 millimeter; otherwise, it could affect other teeth.
11. Program Selection: Most sharpening machines offer three different program options—coarse, fine, and lapping—depending on the required precision of the product. When sharpening the front angle, it is recommended to use the fine-grinding program.
12. The quality of gear grinding with coolant depends critically on the grinding fluid. During grinding, large amounts of tungsten-cobalt and diamond-grinding-wheel dust are generated. If these particles are not promptly rinsed off the tool surface and the pores of the grinding wheel are not cleaned in a timely manner, the ground surface of the tool will fail to achieve the desired smoothness. Moreover, insufficient cooling can also cause the alloy to burn.
     II. Selection of Geometric Parameters for Alloy Circular Saw Blade Cutting Edges  
The geometric parameters of cutting tools encompass the following aspects: A. Side angles (or planes)—including the side rake angle, side relief angle, upper side angle, and lower side angle. B. Back angles—such as the back rake angle, chamfer, and for metal-cutting blades, also the single-bevel back chamfer. C. Front angles—including the front rake angle—each of which is specifically designed according to the type of workpiece being cut. The side angles actually serve as secondary cutting edges; the cutting edge band typically needs to balance straight cutting performance with effective heat dissipation, while also accounting for cutting corrections. Generally, these angles range from 0.75° to 1°—designing them too large is not advisable. The back angle is the primary cutting edge; if designed too large, although sharp, it will lack wear resistance and compromise tool rigidity and heat dissipation. The optimal back angle should be between 15° and 18°. If the back rake angle is excessively large, the cutting tip may easily break, reducing cutting strength; thus, a typical back rake angle is between 9° and 11°. As for the front angle, there are design differences between metal cutting, wood cutting, bar stock, and thin-sheet materials. However, a larger front angle plays a significant role in enhancing heat dissipation. The front rake angle is used for chip evacuation—the greater the angle, the better the chip removal—but during cutting, this results in point contact rather than continuous cutting, thereby diminishing its edge-smoothing function. In summary, cutting-tool design is intricate and complex, yet it remains the most effective approach for improving machining quality, increasing efficiency, and reducing costs.
     III. Types of Base Materials for Alloy Circular Saw Blades  
1. 65Mn spring steel boasts good elasticity and plasticity, is economically advantageous, and exhibits excellent hardenability through heat treatment. It has a low heating temperature and is prone to deformation, making it suitable for saw blades with relatively low cutting requirements. When heated to 150°C, the stress in this material rapidly recovers.
2. Carbon tool steels have high carbon content and high thermal conductivity; however, their hardness and wear resistance drop sharply when exposed to temperatures between 200° and 250°. They also exhibit significant distortion during heat treatment, poor hardenability, and require long tempering times, making them prone to cracking. These steels are economical materials for tool manufacturing, such as T8A, T10A, and T12A.
3. Compared with carbon tool steels, alloy tool steels exhibit superior heat resistance, wear resistance, and machinability. Their hot deformation temperature ranges from 300° to 400°, making them well-suited for manufacturing high-grade alloy circular saw blades.
4. High-speed tool steel boasts excellent hardenability, high hardness and strength, minimal thermal deformation, and is classified as an ultra-high-strength steel. It exhibits stable thermoplasticity, making it ideal for manufacturing high-end, ultra-thin saw blades.
     4. How can the Chinese sawing industry currently enhance the wear resistance and precision of alloy circular saw blades, thereby boosting their market competitiveness?  
It is an undisputed fact that China’s sawing industry has rapidly expanded onto the global stage over the past decade. The main factors are:
1. China has cheap labor and a low-cost commodity market.
2. Chinese power tools have experienced rapid development over the past decade or so.
3. Over the past two decades since China’s opening up, various industries—including furniture, aluminum profiles, building materials, plastics, and electronics—have simultaneously risen to the forefront of the global market. The industrial revolution has brought us limitless opportunities. In the sawing industry, China primarily focuses on producing and exporting to overseas consumer markets as well as markets for power tools. Chinese saw manufacturers currently account for over 80% of the global market, with annual sales exceeding 100 million RMB. However, due to the relatively low quality of our products, foreign buyers tend to drive down prices, resulting in high sales volumes but meager profits for the industry. Moreover, the absence of a unified industry association has led to fierce competition among individual companies, causing market price chaos. As a result, many enterprises have neglected to invest in upgrading their equipment, enhancing their technology and processes, and developing products toward higher-end, more sophisticated segments. Of course, in recent years, some saw manufacturers have become increasingly aware of this trend and have made significant progress in shifting toward mid-to-high-end products. Starting last year, foreign brands have gradually begun placing orders with these Chinese manufacturers for OEM production. It is only a matter of time before certain Chinese companies emerge as leading players, boasting superior product quality, established brands, and renowned reputations.
For a long time, China has relied heavily on imports for industrial alloy circular saw blades. Each year, the Chinese market generates sales revenue approaching 3 billion RMB, with nearly 90% of the market share held by dozens of imported brands—including Ruide Wuyi, Blue Star, Lekke, Yuhong, Israel, Jianfang, and Xiaochilang. These brands have recognized the enormous demand in the Chinese market, and some have already set up factories and made investments in China. Although companies in Guangdong and other domestic enterprises have long been aware of this trend and began production and R&D several years ago, some of these domestic firms have now achieved product quality comparable to that of foreign brands. As someone who has been involved in the import and sale of alloy blades into China for over two decades—and who has spent more than ten years researching and developing alloy saw blades domestically—I’ve witnessed firsthand how companies across various sectors—such as woodworking machinery, metalworking, construction materials, electronics, furniture, and plastics—have consistently favored imported brand products. It’s truly heartbreaking to see how our own sawing industry has been left behind. Recently, while attending the 2008 Woodworking Machinery Exhibition and the 2008 National Hardware Fair, I conducted an in-depth investigation and found that the development of China’s sawing industry is indeed full of promise. Domestic enterprises are steadily improving their equipment and hardware, expanding their product lines, and enhancing their awareness of advanced saw-making technologies and processes. Despite the challenges ahead, I firmly believe that, thanks to the ingenuity and determination of the Chinese people, and through our collective efforts, the quality of China’s sawing industry will continue to rise steadily.