Quality is often touted and often referred to as a cliché, and even when it’s used as a buzzword, many engineers throw the idea out of the way before delving into the situation. Every company wants to use this word, but how many are willing to use it? Quality is an attitude and a way of life. Quality is easy to say, but in this case it’s also something that can be described at every step of the design. Quality, first and foremost, must be taken seriously from the top down. Qualified motor products require attention: quality, delivery, and cost (in the design state), and if you focus on cost, you’re better able to provide customers with the highest quality product without over-engineering. This means there is a simple solution that is easier to produce and deliver. All the pieces must be integrated and the motor supplier must understand the purpose and intent of the user’s design.
Motor suppliers’ internal quality control systems mostly use a 4.5 sigma approach, and 6 sigma is not a satisfactory approach to what customers experience from their products. Only through strict quality control can they ensure that the product is needed, not just for design purposes. With this system the user gets “a motor that consistently and reliably meets specific requirements over the life of the motor”. This goal is especially important in high-volume production, where entire assembly lines can easily come to a standstill due to product defects. To ensure the quality of the company’s stepper motors, they focus on three key areas, component quality, design quality and manufacturing quality.
The selection of suppliers plays an important role in the survival and development of the motor manufacturing industry and the manufacturing strategy, and is an important part of supply chain management. When considering component quality, the manufacturing process involves multiple sub-assemblies: stators, rotors, shafts, bearings, end caps, windings, leads, connectors, and more. Also, each sub-assembly can be divided into sub-assemblies such as wires, insulation, housings and seals, connectors, etc. No one is surprised when we propose that the quality of each component matters, from bottom to top, each Components must all be of the highest quality so that the final product will pass.
For motors, the dimensional accuracy and concentricity of the rotor, stator and end caps are particularly important, maximizing the flux path across the stator and rotor teeth while minimizing reluctance. For this, the air gap or gap between the rotor and stator must be minimal. The smaller the air gap, the smaller the component machining error space. This sounds easy to understand, but if either or both components are poorly concentric, resulting in uneven air gaps will result in inconsistent performance. In the worst case, if a contact occurs, the motor becomes useless.
Rotor inertia affects the overall performance of a stepper motor. Low inertia rotors can respond faster and provide users with higher speeds and higher dynamic torque. Proper end cap design ensures maximum internal volume inserted into a large rotor. The end caps are responsible for the correct alignment of the rotor. Misalignment can have a big impact on the quality of the final product, and rotor misalignment can cause uneven air gaps and lead to erratic performance.
This inconsistent concentricity is compensated for by increasing the size of the air gap between the rotor and stator, reducing the likelihood of their contact. This is only valid for eliminating faults. This approach severely hinders the performance of stepper motors, and the greater the variation between parts, the more inconsistent the performance will be. Even small changes can have huge effects on inertia, resistance, inductance, dynamic torque output and resonance (unwanted vibration). The design of the rotor is key to maximizing the performance of the motor, the rotor must exhibit sufficient magnetic surface while remaining as light as possible to minimize the inertia of the rotor.
The stator can be tuned according to the end goal of the design: high accuracy, smoothness or high torque output, and the design of the poles determines how much winding material can fit between the stator poles. Also, the number of poles typically 8, 12 or 16 correlates with the accuracy and torque output of the motor. The shaft must be strong enough to withstand repeated torque loads and axial forces without deformation or degradation over time. Likewise, bearings must match the performance and life expectancy of the final product. As a component that determines motor life, bearings often experience the most wear.
Other critical components include the end caps, which hold the bearings in place and ensure proper alignment between the stator and rotor. The bearings themselves also need to be of the highest quality to maintain and ensure the longevity of the stepper motor. Each pole is essentially an electromagnet, which necessitates a consistent winding of each pole using the highest grade wire available. Variations in wire diameter can cause per-pole winding consistency issues, which will result in poor torque specification, increased resonance or vibration, and poor resolution in the final product.
in conclusion
How to choose high-quality and win-win suppliers requires comprehensive assessment methods and optimized statistical analysis tools to improve supplier performance management capabilities and promote the development of the motor industry. To ensure the quality of the motors, each motor is tested before shipment to meet the required electrical specifications (resistance, inductance, leakage current), torque specifications (holding and stopping torque), mechanical specifications (front axle extension and body length) and other special features.
Post time: Aug-02-2022