1. Introduction
Diamond has excellent properties such as extremely high hardness, wear resistance and thermal conductivity, and is widely used in many industrial fields such as mechanical processing, stone cutting, geological drilling,
etc. Resin-bonded diamond tools use resin as a binder to consolidate diamond abrasives together to form cutting and grinding tools with specific shapes and functions. Compared with other binders (such as metal binders and ceramic binders),
resin-bonded diamond tools have the advantages of good self-sharpening, high processing surface quality, and low grinding force, and occupy an important position in the field of precision and ultra-precision processing.
This research report aims to conduct a comprehensive and in-depth discussion on the performance, preparation process, application status and development trend of resin-bonded diamond.
2. Performance characteristics of resin-bonded diamond
(I) Hardness and wear resistance
Although the hardness of the resin bond itself is relatively low, through reasonable formula design and the synergistic effect of diamond abrasives, it can achieve effective processing of hard materials to a certain extent.
Diamond abrasive provides a high-hardness cutting edge, while the resin binder supports and maintains the distribution of the abrasive. During the processing, as the abrasive wears, the resin binder gradually falls off, allowing new abrasives to continuously expose, ensuring the tool's continuous cutting ability and good wear resistance.
(ii) Self-sharpening
This is one of the significant advantages of resin-bonded diamond tools. During the grinding or cutting process, when the diamond abrasive grains gradually become blunt, due to the relatively low strength of the resin binder,
the blunt abrasive grains are easily detached from the binder, and new sharp abrasive grains are able to participate in the cutting, thereby always maintaining a high cutting efficiency of the tool, reducing energy consumption and heat accumulation during the processing process, and helping to improve processing accuracy and surface quality.
(iii) Processing surface quality
The resin binder has a low elastic modulus and has a certain buffering effect during the processing process, which can reduce the impact and scratches on the surface of the workpiece, thereby obtaining a better surface finish.
It is especially suitable for processing materials with high surface quality requirements, such as optical glass, ceramics, gemstones, etc.
(IV) Grinding force
Compared with metal bond tools, resin bond diamond tools generate less grinding force during processing. This helps to reduce the load and wear of processing equipment and extend the service life of equipment.
It is also beneficial to improve the stability and processing accuracy of the processing process, and is more beneficial for the processing of some thin-walled and brittle materials.
III. Preparation process of resin bond diamond
(I) Raw material selection
1. Resin bond
Common resins include phenolic resin, epoxy resin, polyimide resin, etc. Phenolic resin has the advantages of good heat resistance, wear resistance and low cost, and is a widely used resin bond; epoxy resin has high bonding strength and good chemical stability,
but relatively poor heat resistance; polyimide resin has excellent high temperature performance, but the price is relatively high. In practical applications, a single resin or a combination of multiple resins is often selected based on specific processing requirements and cost considerations.
2. Diamond abrasive
The quality of diamond abrasive has a great influence on tool performance. Including indicators such as diamond particle size, strength, and purity. The particle size determines the cutting ability of the tool and the roughness of the machining surface.
Generally, the appropriate particle size range is selected according to the machining accuracy requirements; high-strength diamond abrasives can withstand greater cutting forces and ensure the service life of the tool; high-purity diamonds reduce the adverse effects of impurities on the machining process.
(ii) Mixing
The selected resin binder, diamond abrasive and an appropriate amount of filler (such as silicon carbide, aluminum oxide, etc., used to improve the performance of the binder and adjust the hardness of the tool, etc.) are fully mixed in a mixing device in a certain proportion.
During the mixing process, attention should be paid to controlling the mixing time and speed to ensure that the components are evenly dispersed and avoid agglomeration, otherwise it will affect the performance consistency of the tool.
(iii) Molding
The mixed materials are made into the tool blank of the desired shape by cold pressing or hot pressing. The cold pressing pressure is generally between tens of MPa and hundreds of MPa,
while hot pressing is carried out at a certain temperature (usually within the resin curing temperature range) and pressure, which helps to improve the curing degree of the binder and the density of the tool.
The design of the molding mold should take into account factors such as the shape of the tool, dimensional accuracy requirements and demolding convenience.
(IV) Curing
The formed blank needs to be cured to make the resin binder undergo a cross-linking reaction to form a stable three-dimensional network structure, thereby firmly bonding the diamond abrasive together.
Process parameters such as curing temperature, time and curing atmosphere have an important influence on the performance of the binder. Different resin systems have different curing conditions.
For example, phenolic resin is generally cured at 150-200°C for several hours, while the curing temperature of epoxy resin is relatively low, at around 80-150°C. The process parameters need to be strictly controlled during the curing process to ensure the quality and performance stability of the tool.
IV. Application Status of Resin-bonded Diamond
(I) Mechanical Processing
In the grinding of metal materials, resin-bonded diamond grinding wheels can be used to grind carbide tools, high-speed steel tools, etc., which can obtain high-precision tool edges and good surface quality, and improve the cutting performance and service life of the tools.
In the manufacturing of automotive parts, such as the grinding of engine cylinders and crankshafts, resin-bonded diamond tools also play an important role, helping to improve processing efficiency and ensure product quality.
(II) Stone processing industry
Stone cutting and grinding are one of the important application areas of resin-bonded diamond tools. Tools such as saw blades and grinding discs used for cutting natural stones such as marble and granite can quickly and efficiently complete the processing of stones, and the surface of the processed stones is smooth,
reducing the workload of subsequent polishing processes. With the continuous expansion of the artificial stone market, the demand for resin-bonded diamond tools is also growing continuously. They also show good performance in the processing of artificial quartz stone, granite and other materials.
(III) Electronic information industry
In the electronic information industry, resin-bonded diamond tools are used for cutting, grinding and polishing of electronic materials such as silicon wafers, sapphire and ceramics. For example, in the process of semiconductor chip manufacturing,
the cutting and polishing of silicon wafers require high-precision and low-damage processing tools. Resin-bonded diamond wire saws and polishing pads can meet these requirements and ensure the manufacturing quality and performance of chips.
Sapphire is a common material for mobile phone screens, camera protective glass, etc. Its processing is also inseparable from resin-bonded diamond tools, which can achieve precision molding and surface finishing of sapphire.
(IV) Jewelry Processing
For the cutting and polishing of various gemstones such as diamonds, rubies, emeralds, etc., resin-bonded diamond tools have become the preferred tools in the jewelry processing industry with their good self-sharpening and processing surface quality.
Gems can be processed into various exquisite shapes and styles, showing the brilliant brilliance of gemstones.
V. Challenges and development trends faced by resin-bonded diamonds
(I) Challenges faced
1. Heat resistance problem
The heat resistance of resin bonds is relatively poor. They are easy to soften and decompose under high-temperature processing conditions, which limits their application in high-speed and high-efficiency processing. For example, in some high-speed grinding processes, the service life and processing accuracy of resin-bonded diamond tools will be greatly affected due to the large amount of grinding heat generated.
2. Insufficient wear resistance
Although resin-bonded diamond tools have certain wear resistance, compared with metal-bonded tools, resin bonds wear faster during long-term and high-intensity processing, resulting in premature shedding of diamond abrasives, large tool loss, and frequent tool replacement, which increases processing costs.
3. Bonding strength needs to be improved
In some special processing applications, such as the processing of high-hardness and high-strength materials, higher bonding strength is required to ensure the stability of diamond abrasives during processing. At present, the bonding strength between resin binders and diamond abrasives cannot fully meet the requirements of all harsh processing conditions, and it is easy to cause problems such as abrasive shedding and tool breakage.
(II) Development trend
1. Improvement and innovation of resin system
The development of new high-performance resin binders is the key to improving the performance of resin-bonded diamond tools. Researchers are exploring ways to improve the heat resistance, wear resistance and bonding strength of resins by modifying the molecular structure of resins and adding special functional additives. For example, the addition of nanomaterials can significantly improve the comprehensive properties of resins, improve their wear resistance and adhesion to diamond abrasives; the development of organic-inorganic hybrid resins combines the advantages of organic resins and inorganic materials, and is expected to improve heat resistance while maintaining good processing performance.
2. Application of micro-nano diamonds
With the development of micro-nano manufacturing technology, the application of micro-nano diamonds in resin-bonded diamond tools has gradually attracted attention. Micro-nano diamonds have the characteristics of large specific surface area and high surface activity. They can better interact with resin binders and improve the holding force of binders on diamond abrasives. At the same time, their small size effect helps to achieve ultra-precision machining and obtain lower surface roughness. The combination of micro-nano diamonds and conventional diamonds is expected to develop resin-bonded diamond tools with higher performance.
3. Intelligent and green manufacturing
In the future, the manufacturing of resin-bonded diamond tools will develop in the direction of intelligence and greening. Intelligent manufacturing technology can achieve precise control of the production process, including precise proportioning of raw materials, automatic monitoring of the mixing process, real-time adjustment of molding and curing process parameters, etc., to improve product quality and production efficiency and reduce the impact of human factors on product quality. Green manufacturing focuses on reducing environmental pollution and resource waste in the production process, developing environmentally friendly resin materials, and optimizing production processes to reduce energy consumption and waste emissions, in line with the requirements of sustainable development.
4. Development of multifunctional integrated tools
In order to meet complex processing needs, multifunctional integrated resin-bonded diamond tools will become a development trend. For example, developing tools that integrate cutting, grinding, polishing and other functions, and realizing one-time efficient processing of workpieces by rationally designing the structure and distribution of abrasives of the tools, reducing processing procedures and costs, and improving processing accuracy and consistency of surface quality. At the same time, more adaptive tools for different materials and processing technologies will be developed, such as special resin-bonded diamond tools suitable for composite material processing, which can effectively solve the processing problems of different components in composite materials.
In summary, resin-bonded diamond, as an important superhard material tool, has a wide range of applications in multiple industrial fields. Although it is currently facing some challenges, with the continuous advancement of materials science and technology and the continuous innovation of manufacturing processes, its performance will continue to improve, and its application scope will be further expanded, and it is expected to play a more important role in the future high-end manufacturing field.
