Custom Heavy Duty Chair Caster Wheels Manufacturers

What process is used to connect the wheel body and axle of Nylon Heavy Duty Casters to ensure high strength and stability? ​

Embedded injection molding connection: building a precise physical and mechanical connection system​
Embedded injection molding connection is one of the core processes for achieving a firm connection between the wheel body and the axle in the production of nylon heavy duty casters. Before this process is implemented, the pretreatment of the axle is crucial. Zhejiang Lubote Plastic Technology Co. , Ltd. will carefully select axles made of high-strength alloy steel or stainless steel according to different usage scenarios and load-bearing requirements. In warehousing and logistics scenarios where heavy objects need to be frequently moved and corrosion resistance is required, stainless steel axles are usually selected; in ordinary industrial production environments, high-strength alloy steel axles are the first choice due to their excellent strength performance. ​
After the axle is selected, special structures such as threads, grooves or knurling are machined on the surface of the axle through high-precision CNC machining equipment. Taking the knurling process as an example, the fine pattern formed on the surface of the axle can increase the contact area between the axle and the nylon material. This structural design is not a simple change of shape. From the perspective of material mechanics, the increased contact area can effectively disperse the pressure and reduce local stress concentration, thereby significantly improving the friction and bonding strength between the two. ​
In the injection molding process, the advanced injection molding equipment used by the company shows strong process control capabilities. Environmentally friendly and biodegradable PA and PP nylon materials melt into a fluid state at a precisely controlled temperature. At this time, the temperature control accuracy reaches ±2℃, ensuring that the fluidity of the material is in the best state. During the injection molding process, the molten nylon material can evenly and fully wrap the axle by accurately setting the pressure and time parameters. When the temperature gradually decreases, the nylon material undergoes a phase change, and the polymer chains inside it are like countless tiny ropes, tightly wrapped around the special structure on the surface of the axle. This dual effect of physical bite and mechanical interlocking forms a tight connection between the wheel body and the axle similar to a "mortise and tenon structure", which greatly enhances the overall connection strength and can easily cope with various stress challenges under complex working conditions.​
Press-fit connection process: precise process to achieve a stable fit
The press-fit connection process also plays an important role in the production of heavy-duty nylon wheels. When implementing this process, Lubote Plastic Technology has almost strict requirements on the machining accuracy of the wheel body shaft hole. Using high-precision CNC machining equipment, the dimensional tolerance of the shaft hole is strictly controlled within a very small range, usually the diameter tolerance does not exceed ±0.05mm, and the shape and position tolerances such as roundness and cylindricity of the shaft hole are also precisely controlled. The inner wall of the shaft hole is processed by special grinding or rolling process to form a suitable roughness, which can form a tight bite with the surface of the wheel shaft at the microscopic level, effectively preventing relative sliding between the two. ​
In the process of pressing the wheel shaft, the intelligent press-fitting equipment plays a key role. The equipment is equipped with high-precision pressure sensors and displacement sensors, which can monitor and feedback various parameters in the press-fitting process in real time. The technicians will pre-set the best press-fitting parameters, including press-fitting speed, pressure peak, etc. according to the material, size and design requirements of the wheel body and the wheel shaft. During press-fitting, the axle slowly enters the wheel body shaft hole with a constant and appropriate pressure. The whole process is like inserting a key into a lock core accurately, which not only ensures the tightness of the connection, but also avoids the problem of wheel body rupture due to excessive pressure or loose connection due to insufficient pressure. ​
In order to further improve the reliability of the connection, the company's independently developed and formulated special adhesive has become the "secret weapon" of the press-fit connection process. This adhesive uses a special polymer material formula and has excellent bonding properties and weather resistance. After being applied to the contact surface of the shaft hole and the axle, it can quickly fill the tiny gap between the two and form a tough and elastic film during the curing process. This film not only enhances the tightness of the connection, but also effectively buffers vibration and impact, just like putting on a layer of protective armor for the connection between the wheel body and the axle, ensuring that the caster can still operate stably under complex working conditions. ​
Multiple testing and verification: building a solid defense line for process quality​
No matter how good the process is, it needs strict testing to verify and ensure quality. Lubote Plastic Technology has established a comprehensive and multi-level testing system that runs through the entire process of nylon heavy-duty caster production. In terms of quality inspection of the wheel body and axle connection process, detailed and strict inspection standards and processes have been formulated. ​
After each batch of casters is produced, sampling inspection will be carried out first. In the mechanical performance test, the load-bearing, steering and movement conditions in the actual use scenario are simulated to perform fatigue tests on the casters. The test equipment will subject the casters to repeated load changes and directional rotations within a specified time. For example, for 8 consecutive hours, the steering operation is performed at a frequency of 30 times per minute, while applying loads of different gradients. The inspectors use high-precision displacement sensors and strain gauges to monitor the deformation and stress of the connection between the wheel body and the axle in real time. Once signs of looseness, deformation or damage are found, they will be analyzed and improved immediately. ​
Static load-bearing tests are also indispensable. Heavy objects that far exceed the rated load capacity of the casters are placed on the casters for several hours or even longer to observe the bearing capacity of the connection parts. The company has also introduced advanced testing equipment such as electron microscopes to perform microstructural analysis of the connection parts. By magnifying the image hundreds or even thousands of times, we can detect microscopic details such as the bonding state between the nylon material and the axle surface, the uniformity of adhesive distribution, etc., to ensure that the connection process of each caster reaches the optimal level.