The appearance of waste products is undoubtedly not a loss for enterprises. There are two types of waste products, one can be repaired, and the other is irreparable waste. In reality, any enterprise is striving to improve the quality of its products, thereby improving the market competitiveness of its products and making it invincible in the fierce market competition. Here are some reasons and solutions for resinoid grinding wheel waste:
1. Resinoid grinding wheel raw material particle size does not match, hardness does not match.
Method: Calculate the ingredients strictly according to the ingredient list, and review the key procedures.
2. Forming body cracks. The hot pressing temperature is too high, the product is rapidly cooled and heated, and the temperature is too low when the core is removed, the core should be removed in time, the raw materials are affected by moisture, or the compounding material is wrong.
a. End face cracks. The plasticity of the molding material is poor, and the method of unloading the mold and taking the blank is not appropriate. The bottom plate of the forming mold is not flat or the non-parallelism of the backing plate is too large.
b. Peripheral cracks. The mold sleeve is severely worn, and when the mold sleeve is removed, it is too skewed.
c. Aperture cracks. The strength of the blank is low, the oscillation is too large when the mold is unloaded, the mandrel is too worn or the taper is too small, and the unloading sequence does not conform to the technical rules.
d. Diagonal cracks. The selected spring horn has different elastic force, which causes the mold to be deflected and compressed to produce diagonal lines. The limit speed of the fine-grained abrasive tool is too fast, the pressure time is short, and the mold cooperation gap is too large.
e. Crack prevention measures on the resinoid grinding wheel: adjust the plasticity of the mixture well, the forming tools and molds must not exceed the regular wear standards, the template and the horn should maintain good flatness, the thickness of the horn should be consistent, and the elasticity of the spring horn should be Commonly, unload the mold in the order of technical rules.
3. Doping. Before mixing and beside the mixing process, arrange the tooling utensils along with it. Before ingredients, check whether there are impurities in various raw materials.
4. Mixing is uneven. Mixing materials according to technical requirements. Replace overly worn mixer parts at any time. The powdery resin material should be sieved according to the sieve number and number of times specified in the technical regulations.
5. Forming hardness does not match. The first piece must be inspected, no less than 30% of each batch of blanks are randomly inspected, the weighing unit is often checked, and the pressure is often changed.
6. The bridge is uneven. The cooling needs to be uniform; the surface of the workpiece "warped" without a flat plane is called a bridge. This is caused by uneven cooling and uneven shortening of the parts or unevenness of the backing plate of the furnace. Mostly from flake grinding wheels and fine-grained thin products. When the cooling speed of the flake grinding wheel is too fast, bridge corrugated waste easily occurs.
7. Uneven arrangement and uneven hardness. Adjust the dry humidity of the mixture to make it have excellent formability. Spreading and scraping operations are carried out according to technical requirements. According to the technical requirements, use the horn first to maintain the accuracy of the press; when feeding, the material is unevenly scraped, the mixture is wet, or the material is agglomerated, the feeding is uneven, the mold is worn, and the material leakage is severe, and the mold needs to be replaced.
8. The two ends are not parallel. Adhere to the accuracy of the limit table of the press and operate according to the technical rules.
9. Uneven appearance. Tooling equipment is protected within the required accuracy range.
10. Foaming. Control the temperature hardening according to the standard hardening curve of the product, and carry out strict quality control of the compounding process; the molding temperature is too high or too low, and the temperature needs to be adjusted. The curing temperature is too high, and the curing oven temperature is out of control. The contact agent is misfitted; part of the surface of the superhard abrasive tool is convex and deformed or the entire surface is swollen, and has a resinous luster, and some have tortoise-like cracks. Reason for happening:
a. If the heating rate is too fast or the temperature fluctuates too much, the parts with fine particle size, high hardness and tight arrangement may foam and swell. Because these products contain a lot of contact dose or small pores, if the temperature control is not accurate and the heating rate is too fast, the contact agent will react violently, the amount of volatile matter will increase rapidly, and the gas pressure inside the green body will be high, which will cause the product to foam and swell.
b. The mixing of the molding materials is uneven, and there are lumps of the contact agent in the material or more solvents with lower boiling points (such as ethanol, acetone).
c. The faults in the mixing and forming processes increase the contact dose of the parts, the unit weight increases, and the pressure increases.
