Resin grinding wheel production process will produce many quality problems, because resin grinding wheel manufacturing is a multidisciplinary synthesis of composite materials, so the causes are complicated.
01
Raw material problem
Resin grinding wheel is a complex system composed of a variety of main and auxiliary raw materials, as long as the material is abrasive and bonding, auxiliary materials include fillers, reinforcing materials, colorants and so on.
1. Issues that should be concerned about abrasives
At present, the quality of abrasives on the market is uneven, mainly as follows:
(1) The chemical composition of abrasive is often qualified, but the physical properties are poor; The main performance is that there is a gap between the accumulation density of abrasive and that of foreign countries.
(2) The particle size composition of the abrasive is confused, and the provisions of the standard are greatly different; The main performance is that the basic particle content of the same particle size abrasive is different from that of foreign countries.
2. In terms of bonding agents, mainly phenolic resin:
(1) The quality stability of the resin, especially the content of free phenol in the resin. Excessive free phenol content will accelerate the resin cracking after hardening of resin grinding wheel and affect the strength of grinding wheel.
(2) Mixing uniformity of resin powder and Ulotropine, Ulotropine as a resin hardener, the amount of Ulotropine added is insufficient, the resin hardening is incomplete, affecting the strength and hardness of the grinding wheel; If the content is too high, the excessive ulotropine will not combine with the resin, decompose and volatilize in the hardening process, increase the porosity of the grinding wheel, and reduce its strength and hardness.
(3) The binder size is too coarse or too fine:
It is generally believed that the size of the binder should be fine, which is conducive to the uniform distribution of the binder. If the particle size is too coarse, the forming material is not easy to mix evenly, which affects the hardness and strength of the grinding wheel. Even for the coarse-grained resin flake cutting wheel and cymbal grinding wheel, the selected bond (resin powder) particle size should also be finer
However, if the particle size of phenolic resin powder is too fine, it will bring difficulties to the mixing, it is difficult to achieve the uniformity of the mixture, and then affect the cutting performance of the resin grinding wheel.
02
Resin grinding wheel manufacturing process problems
The manufacture of resin grinding wheel is an industrial product with strong processability. There are many problems in the process of mixing, forming, hardening and processing.
(1) Mixing process: the key to mixing is uniformity, forming material should be achieved: the components are evenly distributed, maintain loose, but should not appear obvious powder leakage, must ensure uniform spread, with good forming performance.
(2) Molding process: At present, most of the domestic rotary amortizing mechanism, but due to the limitations of the rotary amortizing mechanism, resulting in a large number of manufacturing enterprises some employees do not operate the key, uneven distribution of mixed materials, line tolerance and static balance.
(3) hardening process: this is the most critical production process, easy to cause quality problems there are two factors, one is the curing oven or burning kiln temperature difference is too large; The second is the improper way of loading the furnace. The temperature difference of the hardening furnace is too large, which causes the hardening of the resin grinding wheel to deviate from the set hardening specification (hardening curve), so that the curing (hardening) quality of the grinding wheel can not be fully guaranteed.
(4) Processing process (mainly large diameter and high thickness resin grinding wheel) : resin grinding wheel, especially large diameter and high thickness, or the grinding wheel requiring strict dimensional tolerance, should be processed after hardening to ensure the geometric size and shape tolerance of the grinding wheel.
(5) The production formula and process parameters are rote.
03
Tooling problem
(1) Equipment problems: production equipment is an important material condition for the production of grinding wheels, some enterprises are insufficient equipment, such as no lack of a good mixer, hydraulic press tonnage specifications are small; At the same time, the equipment maintenance is poor, and the product quality is not easy to guarantee.
(2) Tooling problems: Some of the smaller resin grinding wheel enterprises have weak tooling management, no good storage places, and disorderly storage on the production site.
04
Check equipment problem
(1) Raw material inspection, process inspection, factory inspection, is an important content of resin grinding wheel manufacturers to implement effective inspection control, but there are fewer production enterprises that truly achieve standardized management and standardized management. The main problems are incomplete system, the function is not implemented, the management is not strict, the shortage of inspection equipment is out of control, and the professional quality of inspection personnel is poor.
(2) The inspection equipment is not fully set
The inspection equipment is not complete, and the inspection equipment of resin grinding wheel has 3 large parts: namely, rotary strength testing machine; Sandblast hardness machine (or Rockwell hardness machine) - except resin slicing and grinding; Static balancer (diamond grinding wheel also needs a dynamic balancer), others should also have wafer grinding wheel end face, radial runout tester, inner diameter gauge, vernier caliper, grinding wheel cutting performance tester, etc.
Inspection equipment lacks proper maintenance and maintenance
