Sheet metal fabrication is a critical sector in modern manufacturing. Sheet metal enclosures and fabricated components are widely used in chassis cabinets, electronic device housings, automotive parts, and other fields. To meet the needs of different products across various industries, custom sheet metal fabrication has gradually become a key means for enterprises to enhance product competitiveness and user experience. Hongfa Shunda is an OEM/ODM factory with 20 years of focus on custom sheet metal fabrication. This article will systematically introduce the process flow, key technical points, and practical production considerations of sheet metal fabrication, helping readers gain a comprehensive understanding of this precision manufacturing process.
Overview of Sheet Metal Fabrication & Engineer Workflow
Sheet metal fabrication refers to the process of cutting, stamping, bending, welding, and other operations on metal sheets to produce parts or products of the required shape and size. Its processing objects mainly include steel plates, aluminum plates, copper plates, and other materials, which are characterized by light weight, high strength, and relatively low cost.
In a sheet metal fabrication project, an engineer's workflow typically includes the following key steps:
Assembly Drawing Review: Ensure reasonable assembly dimensions, proper fitting relationships, and reliability of parts and accessories.
Process Feasibility Review: Propose solutions for difficult-to-process components and confirm them in writing with the customer.
Material & BOM Creation: Classify and count materials by model and thickness, and clarify information on purchased parts.
Sheet Metal Part Unfolding: Expand 3D models into 2D processing drawings using professional software or manual methods.
Process Flow Design & On-Site Tracking: Arrange processes reasonably, formulate work instructions, and track production progress in real
time.
The rigorous execution of this workflow is the foundation for the smooth completion of custom sheet metal enclosure projects.
Core Points of Sheet Metal Part Drawing Unfolding
Drawing unfolding is a critical link in sheet metal fabrication, directly affecting the quality and efficiency of subsequent processing. The preparation of unfolded drawings must follow these steps:
Review Drawing → Establish Document → Determine Drawing Frame → Unfold Drawing → Adjust Scale → Print Drawing → Inspect → Add Notes → Dimension Marking
There are various unfolding methods, with common ones including:
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PRO/E Automatic Unfolding: Suitable for regular sheet metal parts, offering high efficiency.
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Neutral Layer Method: Considers the position of the neutral layer during material bending, ensuring good precision.
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Feature Point Method: Positions via feature points, suitable for complex structures.
During the unfolding process, special attention should be paid to the following:
- Adopt a reasonable drawing unfolding method to reduce unnecessary processes.
- Select tolerances appropriately and reserve space for powder coating and baking paint film thickness.
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Clarify the positions and directions of processes such as threading, riveting, and embossing.
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For door panels, boxes, and similar parts, design reasonable hemming relationships and gaps.
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Ensure complete dimension marking without omitting key inspection dimensions.
The rigorous execution of this workflow is the foundation for the smooth completion of custom sheet metal enclosure projects.
Sheet Metal Modeling & Process Design
When conducting 3D modeling of sheet metal parts, full consideration should be given to their unfoldability, bending processability, and assemblability. The following points are particularly important:
Unified Internal Radius Design:
- T=0.8~1.5mm → R0.3
- T=1.5~2mm → R0.5
- T=2~3.2mm → R0.8
The internal radius is generally not zero (except for special cases such as dead edges), as this affects unfolding precision.
Process Notch Design:
Reasonable bending notches can improve product appearance and strength.
Material & Weld Optimization:
Save materials, reduce welds, and lower costs.
Comprehensive Manufacturability Evaluation:
Assess feasibility across all links, including stamping, bending, riveting, welding, and spraying.
For example, when designing a four-sided closed structure, its unfoldability must be considered:
For small material pieces, the width should be no less than 1.5 times the material thickness to ensure stamping quality:
Detailed Explanation of Key Processing Procedures
Sheet metal fabrication involves multiple processes, each influencing the final product quality.
1. Blanking Process
NC Punch Press: High precision, suitable for small-batch processing of stainless steel and other materials.
Laser Cutting: High flexibility, suitable for small-to-medium batch parts, with wide material adaptability.
Conventional Punch Press: High mold cost, suitable for mass production with good consistency.
Shearing Machine: High efficiency, suitable for large-size cutting of blank materials.
2. Bending Process
Bending is the core link of sheet metal forming. Key considerations include:
Replace the lower V-groove die according to sheet thickness.
Control the minimum distance from bending holes to edges to prevent hole deformation.
Master special bending processes such as step bending and dead edge pressing.
Understand equipment stroke and processing range limitations.
3. Forming Process
Forming processes include ribbing, embossing, louvering, etc., used to enhance structural rigidity or achieve specific functions:
Reinforcing Ribs: Improve panel rigidity and prevent deformation.
Louvers: Used for ventilation and heat dissipation, with dimensions meeting process requirements (e.g., a≥4t, h≤5t).
The reasonable arrangement of these processes is crucial for realizing structural optimization and functional integration in custom sheet metal fabrication.
Process Flow Design & Work Instructions
The process flow is an important basis for guiding production. Reasonable process arrangement can improve efficiency and reduce costs. A typical sheet metal fabrication flow includes:
Blanking → Deburring → Leveling → Wire Drawing → Fitting → Bending → Stamping → Riveting → Welding → Surface Treatment → Assembly
When formulating work instructions, note the following:
Arrange processes in a logical order, with clear key dimensions and inspection methods.
Combine text and images for easy understanding by operators.
Specify details such as inspection tool codes and process datum conversion.
Practical Applications of Custom Sheet Metal Enclosures
With the increasing market demand for personalized and functional products, custom sheet metal fabrication has become the preferred choice for many enterprises. Whether it's cabinets, control boxes, instrument enclosures, or smart device exterior parts, custom sheet metal not only meets structural needs but also enhances brand recognition and user experience.
In practical customization projects, special attention should be paid to:
- Fully communicate with customers in the early stage to clarify functional and aesthetic requirements.
- Optimize design based on process feasibility.
- Select appropriate surface treatment processes (e.g., spraying, electroplating, wire drawing).
- Strictly control tolerances and assembly gaps to ensure finished product quality.
Sheet metal fabrication is a comprehensive discipline integrating design, technology, and manufacturing. From drawing unfolding to finished product delivery, every link requires a rigorous attitude and professional technical support. Upholding the concept of continuous innovation and quality first, Hongfa Shunda aims to provide high-quality, flexible metal structure solutions and various custom sheet metal enclosures for customers in various industries. If you want to learn more, please contact us for product details.
