The service life and improvement methods of metal stamping parts

Analysis of the causes of metal stamping mold cracking:

1. Inappropriate material dropping

No demagnetization treatment before production, no material return tips; During production, there are stuck materials such as broken needles and springs; When assembling the mold, there is no leakage of feces, or rolling blockage of feces, or foot blockage of feces. This is common. If the assembly master does not pay attention, such as when there are many drop holes or when the mold has cushion blocks, this situation is prone to occur.

2. Design process

The mold strength is insufficient, the blade spacing is too close, the mold structure is unreasonable, and there are not enough template blocks without cushion pads.

3. Heat treatment: deformation caused by improper quenching and tempering process

Practice has proven that the thermal processing quality of molds has a significant impact on their performance and service life. According to the analysis and statistics of the causes of mold failure, accidents caused by improper heat treatment account for more than 40% of mold failure.

4. Improper wire cutting processing

The ground wire was cut, and the gap between the lines was not properly treated. The metamorphic layer was affected by the lack of corner cleaning and line cutting. The cutting edge of the punching die is mostly processed by wire cutting. Due to the thermal and electrolytic effects of wire cutting processing, a thick deteriorated layer is formed on the surface of the mold, resulting in a decrease in surface hardness and the appearance of microcracks. This makes the wire cutting die prone to early wear, directly affecting the maintenance of the punching gap and the susceptibility of the cutting edge to breakage, shortening the service life of the mold. Therefore, in online cutting processing, reasonable electrical standards should be selected to minimize the occurrence of deteriorated layers.

5. Selection of punching equipment

The punching tonnage and cutting force are insufficient, and the adjustment of the mold is too deep. The accuracy and rigidity of stamping equipment (such as press machines) have a crucial impact on the lifespan of stamping dies. The stamping equipment has good rigidity and greatly improves the service life of the stamping die. For example, the material of the complex silicon steel sheet stamping die is Crl2MoV, which is used on ordinary open press machines and has an average regrinding life of 10000-30000 times; When used on modern press machines, the regrinding life of the die can reach 60000-120000 times.

The braking performance of a vehicle is an important evaluation indicator of its driving performance, and the pedal feel of a sedan is one of the important evaluation directions in the evaluation of vehicle braking performance. According to relevant research, the reflection of pedal feel in cars mainly focuses on issues such as insufficient braking force, soft braking, and insufficient brake sensitivity. To improve the pedal feel of cars, it is necessary to summarize and analyze the various factors that affect the pedal feel of cars, and through detailed theoretical analysis and data comparison, find reasonable methods.

1. What is the feeling of a car brake pedal

In the hydraulic braking system of a sedan, the brake pedal is connected to the vacuum booster and brake master cylinder through a lever mechanism to form the sedan braking system. When braking a sedan, the driver overcomes the clearance and resistance of the brake pedal mechanism while driving the vacuum booster to control the brake master cylinder. This increases the oil pressure in the pipeline and drives the brake cylinder, resulting in a braking torque between the friction plate and the brake disc. This increases the friction between the tire and the road surface, thereby achieving deceleration of the sedan. In this complete set of brake control, the feeling of the car brake pedal displacement and pedal force obtained by the driver when stepping on the car brake pedal, combined with the vehicle's braking deceleration and dynamic operation during the braking process, constitute the car brake pedal sensation.

2. Analysis of Factors Affecting the Brake Pedal Feeling of Sedans

There are several factors that affect the feeling of the car brake pedal in the hydraulic brake system of a sedan, including:

(1) The efficiency of the car braking system should be well matched in the design process of the car braking system. Only when the overall braking efficiency of the car meets the braking needs of the vehicle can it have a good brake pedal feel. To achieve good braking performance of sedans, it is necessary to design a matching system for the overall braking system of the vehicle. (2) The vacuum degree has an important impact on the feel of the car brake pedal in the car brake system. The vacuum degree of the vacuum booster can only exert good braking performance under the condition of good vacuum degree. Currently, some engines cannot provide the vacuum source required by the car brake system due to design defects or other reasons, which affects the feel of the car brake pedal. In addition, some key parameters of the vacuum booster are also important factors affecting the feel of the car brake pedal. (3) The longer braking stroke and variable displacement in the car braking system can also have an impact on the feel of the car brake pedal.