To enhance the quality of box products, reduce costs, and minimize waste, companies should thoroughly research and optimize box part processing technology. They must make smart decisions about production type, blank processing, positioning references, process combinations, and machining allowances to ensure precision. Additionally, designing practical, high-performance fixtures is vital. This requires strictly following design specifications and continuously optimizing the design.
1 Machining Technology for Box Parts
Machining box parts is a demanding task. We’ll analyze this process using a specific example: a box part that houses a supporting transmission mechanism. This analysis will also include designing a specialized fixture for it.
1.1 Box Parts Production Types
When machining box parts, we determine the type of production. We do this by analyzing the average scrap and spare parts rates, which are based on planned output and production schedules. For this discussion, we’ll focus on a small-batch processing method.
1.2 Box Parts Blank Processing Method
For small-batch blank casting, metal mold casting is often the best choice among options like pressure casting or die forging. It’s preferred because it improves the internal structure’s density and increases output per unit area. This aligns well with the typical output and precision needs for box parts. We also need to carefully select the right blank material.
1.3 Selecting Workpiece Positioning References
Choosing the correct positioning datum is critical when machining box parts. Initially, we use the rough surface of the blank as the rough datum. This surface should be unprocessed, important, used only once, and easy to clamp with precise allowance control. The fine datum, on the other hand, must ensure consistency and alignment. This helps us effectively control positioning errors and improve the product’s qualification rate.
1.4 Machining Process of Box Parts
To boost efficiency, cut costs, and maintain processing accuracy, box part machining should follow the principle of process concentration. This means we combine operations scientifically to shorten the overall process route.
1.5 Optimizing the Machining Process Route for Box Parts
We need to select and optimize the process route for box parts based on the part’s size, shape, and precision requirements. This includes considering steps like blank casting, heat treatment, milling, turning, drilling, boring, tapping, deburring, and cleaning. We should also factor in machining accuracy, positioning references, ease of clamping, fixture reusability, the number of machine tools needed, and how often machines need to be changed. Our goal is to reduce clamping and machine changes, thereby improving production efficiency and machining quality.
1.6 Machining Allowance for Box Parts
Accurately determining the machining allowance is crucial for the precision of box parts. Therefore, we should calculate and analyze the machining allowance for each process according to technical specifications. We set these precisely to ensure quality and control costs.
1.7 Machine Tools for Box Parts Processing
When processing box parts, we should choose the appropriate machine tool. This decision depends on the part’s outer dimensions, desired accuracy, and production type. Drilling and boring usually require specialized machines, while tapping, milling, and chamfering can often be done with general-purpose machine tools.
1.8 Machining Fixtures for Box Parts
Choosing the right fixtures is essential for improving the accuracy and efficiency of cutting operations on box parts. Based on the production type and required processing accuracy, you’ll select between general-purpose fixtures (ideal for small batches or single pieces) and special-purpose fixtures (better for medium batches and larger).
1.9 Machining Tools for Box Parts
Different processing technologies, workpiece sizes, and required accuracies call for specific tools. For box part machining, we should select the appropriate standard tools according to the process manual’s guidelines.
2 Designing Fixtures for Box Part Machining
2.1 Designing Lathe Fixtures for Box Parts
A lathe fixture is a vital auxiliary tool for machining end faces and rotating surfaces. When designing it, we must ensure the machine tool spindle’s rotation axis aligns perfectly with the workpiece’s centerline.
2.1.1 Design Principles
When designing a lathe fixture for box-type parts, we must scientifically select the structural form of the positioning device. We also need to pay attention to the rationality of the layout position. Finally, we base the positioning element reference design on the fixture’s rotating axis.
2.1.2 Design Points
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2.2 Designing Drilling Machine Fixtures for Box Parts
2.2.1 Scientifically Selecting Positioning Benchmarks
When designing the drilling machine fixture, we only need drilling size accuracy for this process. Therefore, the center hole axis can serve as the positioning reference. The proposed design uses the mandrel, left end face, and bottom face to limit the workpiece’s movement.
2.2.2 Accurately Calculating Design Parameters
During fixture design, designers should scientifically calculate the clamping force. They do this using cutting force and clamping force formulas, considering processing parameters and safety factors. They must verify the reliability of the clamping mechanism. Finally, they optimize the fixture structure based on factors like fixture force, lever arm, and friction coefficient.
3 Conclusion
As China’s manufacturing industry grows, box part processing needs to actively adopt advanced technology and innovate. This will improve quality, efficiency, and qualification rates. It will also reduce costs and resource waste. Furthermore, designing and developing specialized fixtures based on actual needs will significantly boost the accuracy of box part processing, ultimately elevating the overall level of parts manufacturing.