How to make diamond dry polishing pads

 

Keywords: Diamond resin dry polishing pads;  wet polishing pad; 

 

1 Preface

 

With the increasing development of the national economy, the awareness of resource conservation and environmental protection is gradually strengthening. In terms of polishing stone surfaces, we are committed to developing a product that can be used for grinding to solve the problems of energy conservation, environmental protection, and user safety. In foreign countries, new types of diamond dry polishing pads have gradually replaced the use of some diamond wet polishing pads. Some large stone processing bases in China, such as Yunfu and Foshan in Guangdong, Quanzhou and Xiamen in Fujian, and Laizhou in Shandong, have started to use dry polishing pads. With the continuous updating and improvement of diamond dry polishing pads products during use, completely replacing the use of wet polishing pads has become a trend.

 

 

2 Comparison of Manufacturing Methods and Appearance between Diamond Resin Dry polishing pads and wet polishing pads

2.1 Production and Manufacturing Method of Dry polishing pads

 

After mixing resin materials and adhesives, they exist in liquid form during production operations, unlike water mill powder, which is prone to flying. Pour the mixed powder into the molding mold, use a special fixture to remove the mold, and place it in an oven to bake for 20 minutes at a temperature of around 70 ℃ to solidify and form. Due to the fact that dry polishing pads were first developed, produced and applied abroad and are still in their infancy in China, there is not a deep understanding of the use of some raw materials, the characteristics of curing agents, and other factors. Some processing methods are limited, and now the production of dry polishing pads in China mainly relies on manual operation, which cannot be mass-produced in a short period of time, directly affecting the production efficiency of dry polishing pads and increasing their production costs.

 

 

2.2 Production and Manufacturing Method of Wet Polishing Pads

The main raw materials for producing wet polishing pads in China are melamine resin and phenolic resin, along with other auxiliary materials such as rosin modified resin and calcium sulfate dihydrate. The molding heating equipment is a flat vulcanizing machine. Pour the prepared powder into the mold, heat at a temperature below 200 ℃, and control the heating time between 9-10 minutes. The raw materials of wet polishing pads have certain toxicity, such as melamine resin powder, phenolic resin, etc., which are toxic substances. Long term exposure of workers and inadequate protective measures can easily cause harm to their health.

 

 

2.3 Appearance comparison between dry polishing pads and wet polishing pads,

as shown in Figure 1 and Figure 2

 

 

As shown in the figure, the dry Polishing pads is mixed and stirred with glue, baked and cured in an oven, with high bonding strength and smooth surface; The wet Polishing pads adopts a one-time molding process using a press mold. If the material is unevenly spread, it is easy to cause particle (tooth) dropping phenomenon

 

3 Raw materials and process flow for the production of diamond resin dry polishing pads

3.1 Raw material selection for the production of diamond resin dry polishing pads

3.1.1 Selection of Diamond

 

Resin and ceramic bond diamond grinding tools are suitable for RVD varieties. Diamond that belongs to the category of fine grinding and grinding in terms of particle size is an optional diamond

The particle size numbers are: 50/60, 60/70, 70/80, 80/100, 100/120, 120/140, 140/170, 170/230, 230/270, 270/325/400, 400/500.

 

Optional micro powder grade superhard abrasives belonging to the polishing category: W40, W28, W20, W14, W10, W7, W5, W3.5, W2.5, W1.5, W1.0, W0.5.

 

According to the requirements of users for processing stone, the grain size of diamond stone is mainly divided into: 30 #, 50 #, 100 #, 150 #, 300 #, 400 #, 600 #, 800 #, 1000 #, 1500 #, 2000 #, 3000 #, BUFF white, BUFF black, etc.

The comparison of diamond particle mesh numbers is shown in the table

 

3.1.2 Resin powder and auxiliary abrasives

Resin powder plays a role in polishing and coloring, and the main types of coloring agents are Cr2O3 and Fe2O3, which are basically the same as those of ordinary ceramic grinding tools. Cr2O3 and Fe2O3 are commonly referred to as chromium green (see Figure 3) and iron green (see Figure 4), combined with other zinc oxide, tin dioxide, etc. Abrasive is a component that plays a grinding role in grinding tools [3]. Adding auxiliary abrasives such as silicon carbide and white corundum can improve thermal conductivity and further improve the grinding efficiency of the grinding disc without causing scratches on the surface of the stone.

 

 

 

3.1.3 Mixing with AB glue

The use of AB glue for diamond resin dry grinding discs plays a significant role in the product manufacturing process. It can withstand high temperatures during the grinding process, form the abrasive during the casting process, and cure the product in a timely manner after being placed in an oven. The main components of adhesive A are epoxy resin adhesive (Figure 5a), and adhesive B is polyamide curing agent (Figure 5b). The usage ratio of the two is also important to meet the production requirements.

 

3.2 Production process of diamond resin dry Polishing pads

Ingredients → Mixing → Mixing and Mixing → Preparing Molds and Fixtures → Pouring → Unloading Molds → Shaping → Oven Baking → Post Processing → Finished Products (as shown in Figure 6)

 

4. Formula design and experimental comparison results of dry polishing pad

4.1 Formula design for dry polishing pad

Formula design principles: The model characteristics and ratio of the adhesive, the heat resistance of the raw materials, the heat transfer rate of the raw materials, and the selection of diamonds are all key considerations in our formula design. Next, we will take the design of the raw material formula for making a dry grinding disc with a particle size of 50 # as an example, and compare its performance with that of a water grinding disc, as shown in Table 2.

 

The amount of glue used accounts for one-third of the entire formula, with the aim of fully bonding and curing with other raw materials. Other auxiliary abrasives such as white corundum and silicon carbide can also accelerate the heat transfer speed to a certain extent and improve the sharpness of the tool

 

4.2 Comparison results of performance tests between dry polishing pads and wet polishing pads

In order to understand the performance of the two types of grinding discs, and based on the actual situation, a comparison of their service life and upper brightness is made. Test material: 635 granite; Test method: Grinding and polishing. The comparison results are shown in the table

The results showed that the thickness of the dry polishing pads is only half that of the wet polishing pads, but the service life is the same. In addition, the polishing degree of the dry polishing pads is higher than that of the wet polishing pads.

 

5. Conclusion

Through the production and comparative testing of diamond resin dry polishing pads, we have found that adding colorants to improve the finish of the abrasive tool and adding auxiliary abrasives to enhance its thermal conductivity can further enhance tool processing efficiency. Furthermore, using a judicious combination of epoxy resin glue and polyamide as a bonding agent, even without the addition of cooling water, both processing efficiency and quality are superior to those of wet polishing pads. However, the production cost is higher than that of wet polishing pads, and further research is needed to explore new materials and improve processing techniques to reduce production costs.

 

Our company produces and develops a variety of diamond flexible polishing pads for different users and specifications, which are widely used in the stone processing industry, construction engineering industry, home improvement hardware industry, and OEM for multiple offline and online platforms, as well as Amazon platforms.