Cots and aprons are one of the most important spinning equipment that directly affects spinning quality. Companies also attach great importance to the use of cots and aprons. However, with the rapid development of new technologies, new processes, new equipment, and new equipment, as well as the limitations of understanding new technologies for rubber roller and apron manufacturing, there are often many misunderstandings in actual use, resulting in many unnecessary quality problems.
Selection of rubber roller types
Try to use treatment-free cots for pure cotton varieties; use treatment-free and micro-processing cots for polyester-cotton varieties depending on the number of blends; generally use treated cots for pure polyester varieties, but Enterprises with good temperature and humidity control can choose micro-processing; users with high quality requirements generally choose treatment-free; low quality requirements generally choose treated rubber rollers.
Selection of rubber roller diameter
When choosing the diameter of rubber roller, it is often too large to control, even reaching About 36 mm, it has good elasticity and can be regrinded frequently, which not only saves costs but also improves quality. A large diameter of the rubber roller is beneficial to the extension of the drafting force boundary, but the rubber roller is deformed and pressed into an ellipse to generate mechanical waves, which seriously increases the CVb value.
Countermeasures: Reasonably select the diameter of the rubber roller according to your actual situation. If you need to increase the size, you must also consider the process matching and regrinding cycles to avoid waste and quality deterioration.
Selection of rubber roller structure
The aluminum-lined rubber roller has good pressure resistance and stability. But the price is expensive; double-layer rubber rollers have a long maturation period, large sleeve differences, internal stress, and are prone to aging and denting, but the price is relatively cheap.
Countermeasures: Take what you need. If the quality requirements are high, use aluminum lining. If the quality requirements are low, use double layers.
Selection of rear area rubber rollers
The selection of rear area rubber rollers mainly considers the matching principle and hardness It is generally 5 to 10 degrees higher than the front rubber roller, and the diameter is generally 0.5 mm to 1.5 mm smaller than the front rubber roller. But for V-type drafting, the diameter is preferably larger than the front rubber roller. If old rubber rollers are used, the degree of rubber aging is different, resulting in inconsistent hardness of the rear rubber rollers. As a result, the uneven weight of the yarn and the spindle difference increase. At the same time, changes in the friction boundary are also prone to hidden hard heads and hidden mechanical waves. .
Countermeasures: The grade of the rear rubber roller is slightly lower. You can choose a rubber roller with a slightly higher hardness and a slightly smaller diameter, except for V-shaped drafting.
Apron selection
The general principles for selecting apron are soft on the top and hard on the outside. The principle of soft inside and hard on the inside, loose on the top and tight on the bottom, is used in order to reduce the maturation period and adopt the method of matching old and new. There is a one-sided emphasis on cycle time and wear resistance, so the apron is often selected based on the principle of thickness and hardness, resulting in the upper and lower aprons running out of sync and causing sluggishness.
Countermeasures: Select the apron specifications according to the type of yarn being spun, the type of top pin, the form of pressurization and the amount of pressurization. Pure cotton is generally thinner and softer, while chemical fiber is generally thicker and harder, but you must pay attention to the top and bottom matching, and the total thickness should not exceed 2 mm. Special attention should be paid to pressurizing the leaf spring. Due to the lack of elasticity and hard pressurization, the circumference of the rubber ring should be appropriately larger.
Grease selection
Grease problem is the most easily ignored issue by enterprises. In fact, many companies use grease improperly. According to the requirements, extreme pressure lithium-based grease should be used, but many companies choose ordinary lithium-based grease. The main reason is that ordinary lithium-based grease is not resistant to high temperatures and melts easily. Due to the extremely strong permeability of oil stains in the rubber, the molecular movement on the surface of the rubber roller is also accelerated, the heat resistance of the rubber roller is weakened, and a large amount of static electricity is generated on the surface, resulting in the problem of tangled flowers and rubber rollers. The key is that many companies are not aware of this and adopt other methods to solve the problem of bypassing. The effect is not obvious and it is a waste of manpower and material resources.
Countermeasures: Use No. 3 extreme pressure lithium-based grease, add it frequently and sparingly. Enterprises with conditions can add imported grease.
Selection of rubber roller bearings
Many companies use the same bearings when using aluminum linings and double-layer rubber rollers. In fact, This is completely wrong. Since the inner lining of the aluminum-lined rubber roller is metallic aluminum, it is easy to be damaged by friction and requires more lubrication than the double-layer, so the gap should be larger than the double-layer. In this way, the generation of mechanical waves and eccentricity can be avoided.
Countermeasures: Have a correct understanding of aluminum-lined bearings and double-layer bearings, and eliminate the one-sided view that the smaller the gap, the better the quality. Use different types of upper bearings for aluminum-lined and double-layered bearings. Roller bearings.
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