Automobile front bumper products

2 month ago

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Horizon Mold Chain Co., Ltd

7 month

Product details

Injection mold for the bumper of a Mercedes-Benz car 2

Injection mold for the bumper of a Mercedes-Benz car 1

Injection molds for BMW and Audi automobiles4

Large mold for car bumper 2

As a crucial exterior component of a vehicle, the front bumper of a Mercedes Benz car has stringent requirements for both aesthetics and functionality. The manufacturing process of its injection mould demands high precision and complex structural design to ensure the quality and performance of the bumper. Below is an introduction to the manufacturing process and complex structural technology of the Mercedes Benz front bumper mould:

I. Mold Design and Development

1. Product Design Analysis

The shape of the Mercedes Benz front bumper is complex, resembling a saddle. It features numerous bosses, penetrations, and ribs, resulting in significant flow resistance for the injection melt. The design must consider the coordination with the vehicle body shape, achieving a harmonious integration of aesthetics and functionality. Additionally, the bumper must possess sufficient strength and rigidity to provide cushioning during collisions and protect the vehicle body.

2. Mold Material Selection

High quality mold steel is typically chosen for the Mercedes Benz front bumper mold, such as pre hardened injection mold steel P20 or 718. These materials offer excellent strength, toughness, and wear resistance, ensuring the mold’s durability and longevity during the production process. For components requiring higher hardness and wear resistance, heat treatment processes such as quenching and tempering are applied to enhance material performance.

3. Mold Structural Design

Cavity and Core Design: Based on the shape and dimensions of the front bumper, the cavity and core are precisely designed. High precision CNC machining centers are used to machine these components, ensuring their dimensional accuracy and surface roughness meet requirements. To improve mold release performance, the cavity surface undergoes special treatments such as polishing and texturing.

Parting Line Design: Advanced internal parting surface technology is adopted. The parting clamp line is hidden on the non appearance surface of the bumper, ensuring no visible parting lines affect the appearance after assembly on the vehicle.

Venting System Design: A venting system is designed to promptly exhaust air and gases released from the plastic melt during injection. This prevents defects such as burn marks and voids in the molded part. Thin vent slots are machined on the parting surface of the mold, and vent plugs or other specialized venting components are installed.

II. Mold Manufacturing Process

1. Machining of Mold Components

CNC Machining: The majority of mold components, including the cavity, core, and mold base plates, are processed using CNC machining centers. These machines utilize CAD/CAM technology to convert design models into machining programs, enabling automated machining of complex shapes and precise dimensions. CNC machining ensures high precision and surface quality while improving production efficiency.

Electrical Discharge Machining (EDM): For complex cavities and ribs in the mold, EDM is employed. This process uses an electrode to erode the mold material, achieving the desired shape and size. EDM excels at machining complex contours and small, intricate structures that are challenging to machine with traditional cutting tools, but it has drawbacks such as low efficiency and potential electrode wear. During EDM, parameters like discharge energy, frequency, and pulse width must be carefully controlled to ensure machining accuracy and surface quality.

Wire Electrical Discharge Machining (WEDM): WEDM is primarily used for machining slit shaped cavities, cooling channels, and other components. A moving wire electrode erodes the mold material along a predetermined path to form the desired shape. WEDM offers high machining accuracy and surface quality, with tolerances typically ranging from ±0.01 mm to ±0.02 mm. It also avoids mechanical machining stresses, preventing deformation of the workpiece.

2. Heat Treatment of Mold

Heat treatment is a critical process in mold manufacturing. For the Mercedes Benz front bumper mold, key components like the cavity and core undergo quenching and tempering to increase hardness and wear resistance. During quenching, the mold material is heated to a suitable temperature, held for a specific duration, and then rapidly cooled. Tempering involves reheating the quenched mold to a predetermined temperature and cooling it again. This process eliminates quenching stresses and further enhances material properties. Strict control of heat treatment processes is essential to ensure the mold achieves the desired hardness and mechanical properties.

3. Mold Assembly

After machining and heat treatment, the mold components undergo meticulous assembly. The cavity and core are installed into the mold base, and guidance components like guide pins and bushes are mounted to ensure precise alignment and smooth movement of the mold during operation. The ejection mechanism, cooling system, and other components are also assembled. During assembly, precise measuring tools like dial indicators and micrometers are used to check the fit and positional accuracy of mold parts. Any deviations are promptly corrected to ensure the mold operates reliably and produces high quality bumper components.

III. Complex Structural Technology of the Mold

1. Hot Runner System

The Mercedes Benz front bumper mold employs a fully hot runner system with an 8 point sequential valve controlled hot runner gate. This technology uses cylinder driven sequential valve systems to control the opening and closing of eight hot nozzles, achieving an ideal weld free surface on the plastic part. The hot runner system offers numerous advantages, including stable melt flow, uniform holding pressure, significant feeding effectiveness, consistent plastic part shrinkage, improved dimensional accuracy, and reduced mold clamping force and residual stress in plastic parts. It also minimizes weld marks or positions them on non appearance surfaces, shortens molding cycles, and enhances mold productivity.

2. Lateral Core Pulling Mechanism

Due to the internal parting surface design of the front bumper mold, the parting line at the fixed mold plate’s rear buckle is located under the inclined top of the moving mold side. To prevent mold damage during operation, the core pulling sequence must be strictly controlled during mold opening. The mold features a compound inclined roof structure, combining straight roofs, transverse inclined roofs, and large inclined roofs. To ensure smooth core pulling, adequate space must be maintained between the inclined and straight roofs, with a 3°–5° slope designed at their contact surfaces. Cooling water channels are designed for the large inclined and straight roofs on both sides of the internal parting bumper injection mold. Additionally, a fixed mold needle structure is designed for core pulling in the side holes of the internal parting bumper’s fixed mold.

3. Cooling System

The mold temperature control system adopts a “straight cooling water pipe + inclined cooling water pipe + cooling water well” configuration. Key design considerations for the cooling channels include focusing cooling on the more complex and heat concentrated moving mold structure while maintaining a minimum distance of 8 mm between cooling channels and pushrod, straight top, and inclined top holes. The spacing between water channels is set at 50–60 mm, and the distance between water channels and the cavity surface is 20–25 mm. Straight cooling holes are preferred over inclined holes where possible. For inclined holes with slopes of less than 3 degrees, square holes are used instead. The length of cooling channels should not vary excessively to ensure balanced mold temperature.

4. Guidance and Positioning System

As a large thin walled injection mold, the guidance and positioning system directly impacts the accuracy of plastic parts and the mold’s lifespan. The mold uses square guide pins and 1° precision positioning guides. Four 80 × 60 × 700 mm square guide pins are installed on the moving mold side, and four 180 × 80 × 580 mm square guide pins are placed between the moving and fixed molds. For parting surface positioning, two cone positioning structures (also known as inner die tube positions) are adopted at both ends of the mold, with a cone slope of 5°.

5. Ejection System

The plastic parts of the front bumper are large thin walled components, requiring stable and safe ejection. The center of the mold uses a straight top and ejector pins with a diameter of 12 mm. However, due to the small contact area and difficulty in resetting, ejector pin collisions with the fixed mold cavity surface are common. Therefore, the internal parting bumper should be designed as straight as possible, with minimal use of ejector pins. Given the large number of pushers and the resulting high ejection and reset forces, the ejection system employs two hydraulic cylinders as power sources. All thimble and driver cylinder fixed ends on the moving core’s uneven surface are designed with stop structures.

IV. Mold Testing and Quality Control

After assembly, the Mercedes Benz front bumper mold undergoes rigorous testing and quality control to ensure its performance and product quality meet requirements. Testing includes try out molding to inspect the appearance, dimensions, and performance of the bumper components. Any defects, such as warpage, shrinkage, or flash, are analyzed and addressed by adjusting mold parameters or modifying the mold structure. Additionally, precision measuring instruments and testing equipment are used to evaluate the mold’s dimensional accuracy, surface roughness, and other parameters. Only molds that pass testing and quality inspection are approved for mass production. During production, continuous monitoring and quality control of the mold and its output ensure stable production of high quality front bumper components.

In summary, the manufacturing process and complex structural technology of the Mercedes Benz front bumper mold demonstrate extremely high professionalism and precision. From mold design and development to machining, assembly, and quality control, every step requires advanced technology and rigorous management. These efforts ensure the mold produces high quality front bumper components that meet Mercedes Benz’s stringent standards, contributing to the brand’s reputation for excellence in automotive manufacturing.