Jili Company Sheet Metal Fabrication Case: Custom – Made Gold – Colored Metal Bracket
1. Project Background
In the manufacturing industry, with the increasing demand for miniaturization and integration of equipment in various sectors, the demand for all kinds of precision sheet metal parts is also growing day by day. Relying on its professional capabilities in CNC machining and sheet metal fabrication, Jili Company undertook a custom sheet metal fabrication project for a gold – colored metal bracket. This bracket is used for the internal structural support of high – end electronic devices, and the customer has strict requirements on its dimensional accuracy, surface quality, and mechanical properties.
2. Part Analysis
（1）Structural Features
The gold – colored metal bracket in the figure is composed of multiple flat plate parts through the bending process, presenting a unique “Z” – shaped structure. The bracket is provided with two round holes for installation and fixation, and the positional accuracy of the holes directly affects the assembly effect of the bracket with other components. In addition, the bending angles and side lengths of the bracket also have strict tolerance requirements to ensure that it can be accurately positioned in the electronic device and provide stable support.
（2）Material Properties
High – quality brass material is selected. Brass has good electrical conductivity, thermal conductivity, as well as relatively high strength and hardness, which can meet the requirements for signal transmission and mechanical support inside the electronic device. At the same time, the surface of brass is easy to be electroplated to achieve the gold appearance required by the customer, enhancing the aesthetics and anti – corrosion performance of the product.
3. Jili Company’s Sheet Metal Fabrication Process
（1）Pre – production Preparation
- Design Communication and Confirmation
- Conduct in – depth technical exchanges with the customer to obtain detailed design drawings and technical requirements for the metal bracket, including dimensional tolerances (±0.1mm), surface roughness (Ra3.2μm), and electroplated layer thickness (8 – 12μm).
- Organize the internal design and process teams to conduct a detailed analysis of the drawings, formulate a preliminary sheet metal fabrication process plan, and communicate and confirm it with the customer repeatedly to ensure that the plan can meet all the customer’s requirements.
- Material Procurement and Inspection
- Purchase brass sheets that meet the standards according to the design requirements. Conduct strict quality inspections on the purchased sheets, including chemical composition analysis, mechanical performance tests (tensile strength, yield strength, etc.), and thickness uniformity detection of the sheets. Only materials that pass the inspection can enter the subsequent processing links.
（2）Sheet Metal Processing
- Laser Cutting
- Use a high – precision laser cutting machine to cut the brass sheet into the required shape and size according to the design drawings.
- During the cutting process, optimize the laser cutting parameters, such as laser power, cutting speed, and auxiliary gas pressure, to ensure that the cutting edge is smooth and burr – free, and at the same time, ensure the accuracy of the cutting dimensions. For the round holes on the bracket, the method of cutting the outer shape first and then processing the round holes is adopted to reduce the deformation effect during the processing.
- Bending and Forming
- Place the cut plate on a CNC bending machine for bending operations.
- According to the pre – set bending program, accurately control the bending angle and bending position to ensure that the tolerance of the bending angle of the bracket is controlled within ±0.5°.
- During the bending process, use appropriate bending dies and take necessary anti – deformation measures, such as adding support blocks and arranging the bending sequence reasonably, to ensure the shape and dimensional accuracy of the bracket.
- Deburring and Surface Treatment
- Deburr the bent bracket using grinding tools to remove the burrs on the cutting edges and bending parts to avoid damaging other components during the subsequent assembly process.
- Then, clean the surface of the bracket to remove oil, impurities, etc. on the surface, preparing for the subsequent electroplating process.
（3）Electroplating Process
- Pre – electroplating Treatment
- Perform special pre – electroplating treatment on the cleaned bracket, including chemical degreasing, pickling activation, and other steps.
- Chemical degreasing is to completely remove the oil on the surface, and pickling activation is to remove the oxide film on the surface, exposing the fresh metal substrate on the brass surface and enhancing the bonding force between the electroplated layer and the substrate.
- Electroplating Operation
- Adopt the gold electroplating process, immerse the bracket in the electroplating solution, and form a uniform and dense gold electroplated layer on the surface of the bracket by controlling parameters such as electroplating time and current density.
- During the electroplating process, monitor the composition and temperature of the electroplating solution in real – time to ensure that the thickness and quality of the electroplated layer meet the requirements.
- After electroplating, wash and dry the bracket to remove the residual electroplating solution on the surface.
（4）Quality Inspection
- Dimensional Inspection
- Use a high – precision coordinate measuring machine to comprehensively inspect the key dimensions of the bracket, including side lengths, bending angles, diameters, and positions of round holes.
- Compare the measurement results with the design drawings to ensure that the dimensional tolerances are controlled within the specified range.
- Appearance Inspection
- Carefully inspect the appearance of the bracket under sufficient natural light to observe whether the surface of the electroplated layer is flat and smooth, and whether there are defects such as bubbles, pockmarks, and missing plating.
- The color of the electroplated layer is required to be uniform without obvious color difference.
- Performance Testing
- Conduct mechanical performance tests on the bracket, such as tensile tests and bending tests, to verify whether its strength and toughness meet the design requirements.
- At the same time, conduct a salt spray test to detect the anti – corrosion performance of the electroplated layer. It is required that there is no obvious corrosion phenomenon on the electroplated layer within the specified salt spray test time (such as 48 hours).
4. Project Challenges and Solutions
（1）Dimensional Accuracy Control Problem
Due to the small size and complex structure of the bracket, it is easy to deform during laser cutting and bending, making it difficult to control the dimensional accuracy. The solution is to properly pre – treat the sheet before laser cutting, such as leveling treatment, to reduce the internal stress of the sheet. During the bending process, by optimizing the design of the bending die and the bending process parameters and increasing auxiliary supports, the deformation amount is effectively controlled, ensuring that the dimensional accuracy meets the design requirements.
（2）Electroplated Layer Quality Problem
During the electroplating process, problems such as uneven electroplated layer and poor bonding force are prone to occur. By strictly controlling the process parameters of pre – electroplating treatment, ensure that the bracket surface is clean and fully activated. At the same time, optimize the electroplating process parameters, such as reasonably adjusting the current density, electroplating time, and composition of the electroplating solution, and adopt advanced stirring and circulation systems to ensure the uniformity of the electroplating solution, thereby effectively solving the problem of electroplated layer quality and obtaining a uniform, dense, and well – bonded gold electroplated layer.
5. Project Outcomes
（1）Customer Feedback
Jili Company completed the custom – made processing task of the gold – colored metal bracket on time and with high quality according to the contract requirements. The delivered products were highly praised by the customer, who said that the dimensional accuracy, appearance quality, and mechanical properties of the bracket fully met the design requirements. In the subsequent actual assembly and use process, the bracket performed stably, providing reliable support for the normal operation of high – end electronic devices.
（2）Company Gains
Through this project, Jili Company has accumulated valuable experience in sheet metal fabrication processes, especially in the processing of small precision sheet metal parts and electroplating processes. It has further improved the whole – process management system from design, material procurement, processing and manufacturing to quality inspection, enhanced the company’s technical level and market competitiveness in the field of high – end sheet metal fabrication, and laid a solid foundation for undertaking more similar high – requirement projects.
