Comparison of door hinge processing methods and quality control methods at home and abroad_Industry

Overseas Processing Methods and Quality Control for Door Hinges

Foreign manufacturers have adopted more advanced methods for producing door hinges, particularly for the traditional design shown in Figure 1. These manufacturers utilize door hinge production machines, which are combined machine tools that enable the manufacturing of spare parts such as body and door components. The process involves placing the material (up to 46 meters long) in a trough, where the machine tool automatically cuts it and positions the parts for milling, drilling, and other necessary procedures. The finished parts are then assembled once all machining processes are complete. This method reduces errors caused by repeated positioning, ensuring dimensional accuracy. Additionally, the machine tool is equipped with an equipment status monitoring device that monitors product quality parameters in real time. Any issues are promptly reported and adjusted.

To maintain quality control during hinge assembly, a full opening torque tester is utilized. This tester conducts torque and opening angle tests on the assembled hinges and records all the data. This ensures 100% torque and angle control, and only those parts that pass the torque test proceed to the pin spinning process for the final assembly. During the swing riveting process, multiple position sensors detect parameters such as the diameter of the riveting shaft head and the height of the washer, guaranteeing the torque meets the requirements.

Domestic Processing Methods and Quality Control for Door Hinges

Currently, the general production process for similar door hinge parts involves purchasing cold-drawn plow steel and subjecting it to multiple machining processes such as cutting, polishing, deburring, flaw detection, milling, drilling, etc. Once the body parts and door parts are processed, they are assembled by pressing the bushing and pin. Equipment used includes sawing machines, finishing machines, magnetic particle inspection machines, punching machines, high-speed drilling machines, powerful milling machines, and more.

In terms of quality control methods, a combination of process sampling inspection and operator self-inspection is adopted. Various routine inspection methods, including clamps, go-no-go gauges, calipers, micrometers, and torque wrenches, are utilized. However, the inspection workload is heavy, and most inspections are performed after production, limiting the ability to detect any potential issues during the process. This has resulted in frequent batch quality accidents. Table 1 provides quality feedback from the OEM for the last three batches of door hinges, highlighting the inefficiency of the current quality control system, leading to low user satisfaction.

To address the high scrap rate issue, it is planned to analyze and improve the production process and quality control of door hinges through the following steps:

1. Analyze the machining process for the door hinge body parts, door parts, and assembly process, evaluating the current process and quality control methods.

2. Apply statistical process control theory to identify quality bottleneck processes in the door hinge production process and propose corrective measures.

3. Enhance the current quality control system through re-planning.

4. Utilize mathematical models to predict size by modeling the process parameters of the door hinge.

By focusing on these aspects, the aim is to improve the efficiency of quality control and provide valuable insights for similar enterprises. AOSITE Hardware, which prides itself on offering excellent customer service, has been specialized in producing high-quality door hinges for many years. Its commitment to providing the finest hardware products has gained recognition from customers worldwide and various international institutions.