Introduction to Process Analysis
Process analysis of mold parts refers to the analysis of manufacturing feasibility and economy for designed parts under the premise of meeting usage requirements, aiming to minimize manufacturing costs while ensuring performance. This comprehensive analysis is crucial in various manufacturing sectors, particularly in plastics injection molding where precision and cost-efficiency are paramount.
It includes the analysis of properties related to mold part blank casting, forging, mechanical cutting processes, heat treatment, surface treatment, and more. When formulating the mechanical processing procedure for mold parts, the focus is primarily on the analysis of part cutting process performance. Process analysis of parts mainly consists of two key components: analysis of part technical requirements and analysis of part structural processability, both of which play vital roles in plastics injection molding operations.
"The goal of process analysis is to ensure that mold parts can be manufactured efficiently, accurately, and economically while meeting all design specifications and performance requirements, especially in high-precision applications like plastics injection molding."
Mold Manufacturing Workflow
Comprehensive process chain from design to finished product in plastics injection molding
Precision Machining Technology
Advanced equipment used for achieving tight tolerances in plastics injection molding components
Analysis of Part Technical Requirements
The analysis of technical requirements for mold parts is mainly based on the part drawing and is crucial for ensuring quality in plastics injection molding. This analysis focuses on two primary aspects:
Completeness and Accuracy Check
This involves analyzing whether the part drawing is complete and correct, if all projection views are accurate and clear, and if dimensions, tolerances, surface roughness, and related technical requirements are complete and unambiguous. In plastics injection molding, even minor drawing inaccuracies can lead to significant production issues and increased costs.
Engineers must verify that all views necessary to fully understand the part geometry are included and that there are no conflicting dimensions or specifications. This is especially critical in complex plastics injection molding components where precise visualization is essential.
Technical Requirement Evaluation
This includes analyzing whether the technical requirements for the part—such as dimensional accuracy, geometric tolerances, surface roughness, material specifications, and heat treatment requirements—are reasonable. In plastics injection molding, finding the right balance in these requirements is essential for both performance and cost control.
Excessively high requirements will increase processing difficulty and costs, while insufficient requirements may affect the working performance of the part. This balance is particularly delicate in plastics injection molding where material properties and processing parameters must align perfectly with design requirements.
Pre-Processing Considerations
Before formulating a process plan, it is necessary to carefully analyze and study the purpose, performance, and working conditions of the entire mold, including its role in plastics injection molding systems. Understanding the part's position within the mold, its assembly relationships, and its specific functions is essential for determining appropriate manufacturing processes.
It is crucial to clarify how various technical requirements affect assembly quality and service performance, and to identify the main and critical technical requirements. If errors, omissions, or doubts are found, communication with design personnel is necessary to ensure that the subsequently developed processing technology is accurate and appropriate for the intended plastics injection molding application.
Design Considerations for Manufacturing Economy
For mold designers, attention should be paid to the following points during mold part design to ensure manufacturing economy, especially in high-volume plastics injection molding production:
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1
Surfaces that do not require processing should not be designed as machined surfaces. This principle is particularly important in plastics injection molding where unnecessary processing steps can significantly increase production costs.
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2
Surfaces with low requirements should not be designed with high precision and low surface roughness, as this would increase costs unnecessarily. In plastics injection molding, specifying appropriate tolerances based on actual functional needs can result in substantial cost savings.
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3
Standardized parameters should be adopted as much as possible. For example, parameters such as part hole diameters, tapers, thread diameters and pitches, arc radii, and grooves should use values recommended in relevant standards. This allows for the convenient use of standard tools, fixtures, and measuring instruments, reducing the design and manufacturing cycle and costs of special tools and fixtures—particularly beneficial in plastics injection molding where standardization can streamline production.
Technical drawing review is a critical step in ensuring manufacturing feasibility in plastics injection molding processes
Analysis of Part Structural Processability
Good structural processability of mold parts means that, under the premise of ensuring the technical requirements of the parts, mold parts can be manufactured conveniently and at low cost using existing equipment conditions. This is a concrete manifestation of the mold designer's "design based on manufacturing thinking," which enables high-precision and low-cost mold manufacturing, particularly important in plastics injection molding where production volumes can be extremely high.
As mentioned in previous chapters, mold parts are composed of some basic surfaces and special surfaces in terms of shape. Basic surfaces include inner and outer cylindrical surfaces, conical surfaces, and planes, etc. Special surfaces mainly include spiral surfaces, parabolic surfaces, and other forming surfaces. Processors need to select reasonable processing equipment based on the characteristics of these surfaces and formulate processing procedures. Therefore, designers need to consider the processing technology of parts during the design phase, especially for complex plastics injection molding components.
Key Structural Considerations
- Simplicity of geometry for easier manufacturing
- Uniform wall thickness to prevent distortion
- Adequate draft angles for plastics injection molding
- Standardized features for cost reduction
- Accessibility for machining tools
- Material selection appropriate for manufacturing processes
Comparison of Structural Processability for Typical Mold Parts
Table 2-6 below presents several typical mold part structures and compares the advantages and disadvantages of their structural processability, with special consideration for plastics injection molding applications:
| Part Type | Poor Processability Design | Good Processability Design | Advantages in Plastics Injection Molding |
|---|---|---|---|
| Cylindrical Housing | Non-uniform wall thickness, complex internal features | Uniform wall thickness, simplified internal geometry | Reduced warpage, improved cooling, faster cycle times |
| Flanged Component | Thin, unsupported flanges with sharp corners | Reinforced flanges with radiused corners | Improved strength, reduced stress concentrations, better mold filling |
| Threaded Inserts | Non-standard thread forms, undercuts | Standard thread forms, no undercuts | Simplified mold design, reduced wear, easier maintenance |
| Deep Cavities | Straight walls without draft, narrow access | Proper draft angles, adequate access | Easier ejection, improved material flow, reduced cycle time |
| Ribbed Structures | Thick ribs, uneven spacing, sharp corners | Properly sized ribs, uniform spacing, radiused corners | Reduced sink marks, improved strength-to-weight ratio, better cooling |
Impact of Structural Design on Manufacturing Costs
In plastics injection molding and other manufacturing processes, the structural design of mold parts has a profound impact on production costs. A well-designed part can reduce manufacturing time by 30-50% compared to a poorly designed one with the same functionality. The key factors include:
Chart showing the relative cost impact of various design factors in plastics injection molding part production
Conclusion
Process analysis of mold parts is a critical step in the manufacturing process that ensures both functionality and经济性. By carefully analyzing technical requirements and structural processability, manufacturers can optimize production processes, reduce costs, and improve quality—particularly important in competitive fields like plastics injection molding.
The integration of design for manufacturability principles ensures that mold parts can be produced efficiently using existing equipment while meeting all performance requirements. This approach is essential for success in modern manufacturing environments, especially in high-volume production scenarios typical of plastics injection molding.
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