Common problems in the manufacturing of resin bonded grinding wheels
Resin abrasives is an important part of abrasives and one of the important common and important grinding tools in industrial production. In order to promote technical exchanges in the industry and help customers to solve common problems in the manufacturing process of resin grinding wheels, this article mainly introduces common problems in the manufacturing of resin bonded grinding wheels.
I. Analysis of the causes of unstable quality of resin grinding wheel
There are many quality problems in the production process of resin grinding wheels.
Raw material problem
The Resin Abrasive Wheels are complex product made from a variety of main and auxiliary raw materials including filler, reinforcing material, coloring agent etc.
1. about abrasives At present, the quality of abrasives on the market is uneven, mainly as follows:
(1). The chemical specification of abrasives is often qualified, but also with poor physical properties. It is mainly shown that there is still a gap between bulk density of China and international quality material. (2). The particle distribution of some abrasives is disordered, which is quite different from the standard specification.
2. In terms of binder, mainly about phenolic resin:
(1). Resin quality stability problems, especially the level of free phenol in the resin. Excessive free phenol content will accelerate the cracking of the Resin Cutting Disc after heating and hardening of the resin wheel and affect the strength of the grinding wheel;
(2). The binder’s particle is too thick or too fine: It is generally believed that the fine grain is benefitial to uniform distribution of the binder. If the grain is too coarse, the molding material is not easily mixed uniformly, which affects the hardness and strength of the grinding wheel. Even for the coarse-grained resin sheet cutting wheel and the cymbal grinding wheel, the size of the binder (resin powder) selected should be finer than 320#.
Manufacturing process of resin grinding wheel
The manufacturing of Resin Grinding Disc is a highly technical industrial process. There are many problems in the processes of materials mixing, molding, hardening, and processing.
(1). Mixing process: The key of mixing is uniformity.
(2). Molding process: At present, rotating material distribution mechanism is widely applied in domestic market. But due to the limitations of the rotating material distribution mechanism, the employees of some large manufacturing enterprises have no way to operate, which causes the distribution of mixed materials uneven.
(3). Hardening process: This is the most critical production process. There are two factors that easily cause quality problems. One is the temperature difference among the curing oven or the firing kiln is too large. The other is improperly installed furnace.
(4). Manufacture procedure (mainly large-diameter and high-thickness resin grinding wheels): Resin grinding wheels, especially with large diameters and high thicknesses, or with strict dimensional tolerance must be processed after hardening to ensure the geometric size and tolerance.
(5). Apply the production formula and process parameters mechanically.
Equipment tooling problem
(1). Equipment problems: Production equipment is very important for grinding wheel production. Some enterprises lack equipment.
(2). Tooling problems: Some of the smaller resin grinding wheel companies have weak tooling management.
II. How to maintain the quality stability of resin grinding wheel
This paper mainly analyzes how the raw materials with phenolic resin and glass fiber mesh affect the quality stability of the resin grinding wheel.
The quality stability of the Steel Wheel is most prominent in the following two aspects:
(1). The change of strength and cutting performance of resin grinding wheel within a certain period (under normal temperature and humidity conditions);
(2). The variation of the strength and cutting performance of every batch of grinding wheel in the production cycle (such as different seasons in a year). The influence of raw materials on the quality stability of resin grinding wheels is mainly reflected in:
a. Liquid phenolic resin. The fluctuation range of solid content, viscosity, gel time and water solubility of liquid phenolic resin has different degrees of influence on grinding wheels. Therefore, the factories must combine the product performance requirements and its own mixing, forming and hardening process to make a suitable technical index.
b. Powder phenolic resin. For powder phenolic resin, the fluctuations of its flow length (fluidity), particle size (grain size, fineness), urotropine (six times) content and gelation time all will affect the quality of the grinding wheel.
(3). Stability of the technical indicators of the mesh The mesh was originally applied to the resin wheel to increase the strength of the wheel. As the performance of the resin grinding wheel continues to increase, the mesh plays a very important role in the resin grinding wheel, which is mainly manifested in fluctuations in the strength of the grinding wheel, deformation of cutting Flap Disc (mainly double-wire grinding wheel), stratification of abrasive disc etc.
The glue content of the mesh has an influence on the strength, viscosity and grinding performance of grinding wheel. In theory, when the production process is stable and the mesh with the higher amount of glue, the grinding wheel will be with the higher strength, the better bonding performance and the more stable cutting performance.
III. The deformation of resin cutting wheel occurs frequently
The deformation of the resin grinding wheel has long troubled the manufacturers. The root of the deformation is the uneven organization in the effective area of the grinding wheel, which in turn causes uneven stress in the hardening process of the product.
Resin grinding wheel manufacturers should focus on solving the uniformity of the mixture, the uniformity of the molding and the stability of the mesh. Only the above three problems can be solved, the deformation problem of the resin grinding wheel (mainly the cutting wheel) will be solved.