Progress Control of Key Nodes in the Entire Molding Trial Process for Plastic Parts: A Closed Loop o

Time：2026-04-28 08:13:13 / Popularity： / Source：

Mold trial molding is core link in a plastic parts project, connecting mold processing to mass production. It is also of paramount importance for mold development progress control. Industry clients generally recognize four key trial molding nodes: T0 trial molding, T1 mold repair, T2 mold repair, and Tf final acceptance mold repair. These four nodes are not only core anchor points of mold development progress but also a comprehensive test of mold factory's design, processing, trial molding, and testing capabilities. Any process deviation or quality oversight in any stage will lead to failure to meet node on time, resulting in repeated mold repairs, increased project costs, and delivery delays.

Progress control of key nodes in mold trial molding is not simply a matter of meeting deadlines; it is a systematic effort integrating injection molding process principles and quality management standards. Core lies in standardized pre-node preparation, quantitative control of execution process, and closed-loop problem rectification. This article combines injection molding process theory and quality management knowledge to break down definitions, control standards, pre-preparation requirements, and risk response strategies for four core nodes of mold trial molding. This forms a directly implementable guide for managing progress of each trial molding node, ensuring that each stage of trial molding process is controllable, traceable, and feasible.

I. Overall Control Logic of Core Nodes in Mold Trial Molding

From completion of DFM manufacturability review to final mass production acceptance of mold, four core nodes of mold trial molding are core of progress management throughout the entire mold development process. Their overall management should revolve around "process adaptation as foundation, quality compliance as core, and node achievement as goal," while clarifying three core control principles:
Prioritizing Pre-Preparation: Before starting any node, comprehensive preparation of injection molding equipment, raw materials, testing tools, and process plans must be completed to avoid unpreparedness.
Quantitative Process Control: Quantitative process and quality standards should be established for every action in mold trial molding and mold repair to avoid deviations caused by experience-based operations.
Rapid Problem Closure: Problems discovered at each node must be recorded promptly, root causes analyzed, and rectification plans developed. Effect should be verified simultaneously after mold repair to ensure that problems are not carried over to next node.
It is also important to clarify that managing trial molding stage is not work of a single department, but rather a cross-departmental collaborative effort involving design, manufacturing, injection molding, and quality teams. Rationality of mold design determines foundation for trial molding, machining accuracy determines starting point, ability to debug injection molding process determines trial molding effect, and accuracy of quality inspection determines effectiveness of problem identification. A weakness in any link will become an obstacle to achieving milestone.

II. Definition and Standardized Management Standards of Core Nodes

Four core nodes of trial molding process are interconnected. T0 is basic inspection for initial trial molding; T1 and T2 are targeted mold modification verifications; and Tf is final acceptance loop. Each node has clear core objectives, preparatory requirements, and execution management standards. Among them, T0, as initial trial molding node, is foundation for all subsequent nodes, and its management standards are core reference for the entire trial molding process.

(I) General Pre-Trial Preparation Requirements

Before initiating any trial molding stage, standardized pre-trial preparations must be completed, with a comprehensive verification performed 48 hours in advance to ensure smooth trial molding. Core pre-trial preparations are uniformly required as follows:
Injection Molding Machine Reservation and Verification: Match a suitable injection molding machine to mold clamping force requirements, with a tonnage ≥ 1.5 times mold clamping force. Simultaneously verify machine's ejection system, injection volume, mold temperature control module to ensure compatibility with mold and product process requirements.
Raw Material Drying and Inspection: Perform precise drying according to characteristics of plastic material. For example, ABS material requires drying at 80℃ for 4 hours. After drying, inspect material. Moisture content of raw materials must be ≤0.02% to avoid defects such as bubbles and silver streaks in injection molded products caused by moisture content.
Preparation of testing tools and documents: Prepare high-precision testing instruments (coordinate measuring machine, 2D measuring instrument, hardness tester, etc.) and a "Trial Molding Problem Record Sheet" (containing 50 core inspection items), covering four dimensions: size, appearance, structure, and process, ensuring no trial molding problems are missed.
Pre-setting of process plan: Based on material properties, product structure, and mold flow analysis results, pre-set trial molding process parameters, including mold temperature, injection pressure, holding time, and cooling time, while reserving parameter adjustment space to adapt to process optimization during trial molding process.

(II) Core Definitions and Execution Control Standards for Each Node

1. T0 Trial Molding: First trial molding, comprehensive basic inspection
Core objective: Verify rationality of basic mold structure, test adaptability of injection molding process, and comprehensively identify potential problems in mold design, processing, and injection molding processes, providing accurate basis for subsequent mold repair.
Key points of implementation and control: Conduct short-shot analysis of 5-level stepped injection molding to observe filling path and balance of molten plastic within mold cavity. Identify issues such as insufficient filling, unreasonable weld line positions, and poor venting, providing data for gating system optimization and venting channel rectification.
Complete 9-point mold temperature mapping detection in cavity to ensure that temperature difference between different areas of cavity is ≤3℃. Mold temperature uniformity directly affects product shrinkage, warpage, and dimensional stability. If temperature difference exceeds standard, cooling water circuit and mold temperature controller operation status must be checked promptly.
Conduct ejection stress testing, using strain gauges to monitor stress distribution during product ejection. Identify issues such as unreasonable ejector pin arrangement and ejection stroke deviation to prevent defects such as ejection whitening, deformation, and tearing.
Complete a full-dimensional inspection according to "Trial Mold Problem Record Form," recording in detail issues such as dimensional deviations, appearance defects, structural interference, and process anomalies. Simultaneously analyze root causes of problems and initially formulate mold repair directions.

2. T1 Mold Repair: Initial Mold Repair, Targeted Problem Rectification and Verification
Core Objective: To repair mold addressing core issues identified in T0 trial mold, verifying effectiveness of repair plan, and focusing on resolving issues affecting product functionality such as dimensional deviations, structural interference, and severe appearance defects.
Key Execution and Control Points: Before mold repair, conduct a cross-departmental review to confirm rationality of repair plan, avoiding new problems caused by improper repair, and accurately calculate repair time to ensure controllable progress.
After mold repair, conduct a verification trial mold according to original trial mold process parameters, focusing on testing effectiveness of rectified areas, such as restoration of accuracy in dimensional deviation areas and fit of structural interference areas.
Complete closed-loop confirmation of rectified issues, analyze causes of unresolved issues, adjust repair plan, and record newly discovered minor issues for inclusion in T2 mold repair plan.
3. T2 Mold Repair: Secondary mold repair for closed-loop process and quality optimization
Core Objective: To address issues not fully resolved in T1 trial molding and minor related problems; to verify stability of injection molding mass production process window; to ensure that product dimensions, appearance, performance basically meet customer acceptance standards.
Key Execution and Control Points: Focus on verifying injection molding process window, testing adjustable range of parameters such as mold temperature, injection pressure, and holding time to ensure that fluctuations in key process parameters do not lead to product quality exceeding standards, providing a basis for mass production process development;
Perform SPC statistical analysis on key product dimensions to ensure that critical dimension CPK ≥ 1.33, meeting dimensional stability requirements for mass production;
Complete final optimization of product appearance defects, compare with customer limit samples for acceptance, ensuring that appearance defects meet tolerance standards, verify smooth operation of mold ejection and mold opening/closing systems.
4. Tf Mold Repair: Final Acceptance and Verification for Mass Production
Core Objective: To complete final rectification of all remaining issues, pass customer's full-dimensional acceptance, and achieve mass production delivery of mold. This is final closed-loop step in the entire mold trial process.
Key Execution and Control Points: Complete full-dimensional FAI testing of product to ensure that all dimensions meet 100% of design requirements. Submit test report for customer confirmation.
Conduct continuous mold trial verification, with ≥50 continuous production runs to ensure consistent product quality and smooth mold operation, verifying mold's mass production stability.
Complete customer confirmation of trial mold parts and simultaneously submit mold acceptance documents (test report, process parameters, spare parts list, etc.). After customer signature confirmation, mold officially completes trial mold acceptance and enters mass production maintenance phase.

III. Key Points for Integrating Injection Molding Process and Quality in Trial Molding Node Control

Control of each node in trial molding process is essentially a deep integration of injection molding process requirements and quality management standards. Each implementation point must align with process principles of injection molding, identification and rectification of each problem must be based on quantifiable quality standards. Two complement each other and are indispensable.
(I) Injection Molding Process Provides Technical Support for Achieving Key Milestones
Core of trial molding is verifying compatibility between mold and injection molding process. Accuracy of process debugging directly determines effectiveness of key milestone achievement:
Short-shot analysis and mold temperature mapping are based on process rules of injection molten plastic filling, cooling, and shrinkage. Process testing identifies defects in mold design and processing, making mold repair more targeted.
Process parameter debugging for each milestone requires consideration of material's physical properties. For example, for crystalline materials (PA66, POM), mold temperature and cooling time need to be carefully controlled; for non-crystalline materials (PC, ABS), injection pressure and shear heat need to be carefully controlled to ensure that process parameters are compatible with material and product.
Mass production process window verification for milestone T2 is crucial in connecting trial molding and mass production. Through gradient testing of process parameters, process range for mass production is determined, avoiding product quality problems caused by minor process fluctuations during mass production.
(II) Quality Management Provides Standards for Milestone Achievement
Quantified quality standards are core basis for identifying, rectifying, and verifying trial molding problems, ensuring that achievements of each milestone are measurable and acceptable:
50 inspection items in "Trial Molding Problem Record Form" all have quantified quality standards, such as dimensional tolerances, appearance defect tolerance, and mold temperature difference range, leaving no room for ambiguity in identifying trial molding problems;
Rectification verification at each milestone requires confirmation through precise quality testing, such as coordinate measuring machine (CMM) dimensional inspection, two-dimensional measuring machine (MM) appearance inspection, and strain gauge testing of ejection stress, using data to verify rectification effect and avoid subjective judgment;
FAI full-size inspection and continuous trial molding verification at Tf milestone are core means of quality management, ensuring that mass production quality after mold delivery meets customer requirements and achieving a quality closed loop from trial molding to mass production.

IV. Core Risk Management Strategies for Trial Molding Milestone Progress Control

During trial molding milestone management process, risks such as trial molding process abnormalities, incomplete mold repair and rectification, milestone delays are prone to occur. Risk identification must be prioritized, targeted response strategies must be developed for core risks of each milestone to ensure that milestone progress is controllable and losses are minimized.
(I) Core Risks and Countermeasures of T0 Trial Molding
Core Risks: Poor melt filling, uneven mold temperature, and ejection deformation, leading to an inability to fully identify problems during trial molding.
Countermeasures: Review mold flow analysis report before trial molding, optimize gating system and venting channel design; conduct pressure holding tests on mold cooling water circuit before trial molding, calibrate mold temperature controller to ensure no water leakage in water circuit and normal operation of mold temperature controller; optimize ejector pin arrangement according to product structure, and check ejection stroke in advance to ensure uniform force on ejection system.
(II) Core Risks and Countermeasures for T1/T2 Mold Repair
Core Risk: An unreasonable mold repair plan may lead to incomplete rectification, or new problems may arise after mold repair, resulting in delays in project milestones.
Countermeasures: Before mold repair, organize design, machining, and injection molding engineers to jointly review mold repair plan, combining mold machining technology and injection molding process requirements to ensure plan's feasibility; strictly control machining accuracy during mold repair, and conduct a full mold accuracy inspection after completion to avoid mold repair deviations; during trial molding verification, conduct small-batch injection first to quickly verify rectification effect, promptly identify new problems, and make adjustments.

(III) Core Risks and Countermeasures for Tf Final Acceptance
Core Risk: Unqualified dimensions found in FAI full-dimensional inspection, or customer dissatisfaction with trial mold parts, leading to failure to pass final acceptance;
Countermeasures: After T2 milestone is completed, conduct pre-FAI inspection in advance to rectify potential dimensional problems in advance; during trial molding process, keep customer informed of trial molding progress and product status, focusing on verifying customer's core requirements to ensure trial mold parts meet customer expectations; develop precise FAI unqualified dimension repair plans to quickly complete final mold repair verification.
(IV) General Schedule Delay Risks and Countermeasures
Core Risk: Untimely handling of issues at each stage, leading to overall schedule delays;
Countermeasures: Establish a tiered problem-solving mechanism for trial molding stages, classifying issues into three levels: critical, serious, and minor. Prioritize handling critical and serious issues that affect product functionality and milestone achievement; accurately calculate processing time for each stage, rationally allocate human and equipment resources to ensure efficient problem handling; develop a schedule early warning mechanism, take timely remedial measures if schedule deviations occur, while simultaneously updating progress with customer.

V. Practical Requirements for Trial Molding Node Management: Comprehensive Capabilities of Forging Mold Manufacturers

Whether four key trial molding nodes can be achieved on time and to required standards ultimately tests comprehensive capabilities of mold manufacturer, rather than technical level of a single link. To achieve standardized and efficient node management, four key requirements must be implemented in practice:
Cross-departmental Collaboration: Establish a dedicated trial molding project team, with designated personnel from design, processing, injection molding, and quality departments to coordinate. Clearly define responsibilities and node tasks for each position, ensure timely communication of issues during trial molding process to avoid inter-departmental buck-passing and ensure efficient problem-solving.
Data-Driven Full-Process Recording: Record all data during trial molding process, including process parameters, test results, and problem logs. Records, mold repair plans, rectification results are all digitally recorded and archived, forming a complete data archive of mold trial process. This provides a basis for subsequent mold repairs and accumulates experience for development of similar molds.
Resource Priority Allocation Mechanism: A priority allocation mechanism for equipment, manpower, materials is established for mold trial and mold repair work. For example, processing equipment and testing instruments required for mold repair are given priority use to ensure that mold repair work can be carried out quickly and without delaying schedule.
Real-time Customer Communication: Progress of each stage of mold trial, problems found, mold repair plan, and rectification results are communicated to customer in a timely manner. Customer is invited to participate in important plans and acceptance stages to ensure that both parties have a consistent understanding, avoid failure to pass acceptance due to discrepancies in customer requirements.

Core Summary

Progress control of four core stages of mold trial (T0, T1, T2, Tf) is core lever for plastic part mold development from processing to mass production. Its essence is precise implementation of injection molding process rules and quality management standards throughout the entire mold trial process, rather than simply meeting deadlines. Effective milestone management hinges on adhering to principles of "standardized pre-development preparation, quantified control during execution, and closed-loop problem rectification." This involves cross-departmental collaboration among design, manufacturing, injection molding, and quality teams, incorporating preparation, execution, and verification of each milestone into a standardized management system.
Achievement of trial molding milestone not only reflects mold development progress but also demonstrates mold factory's comprehensive capabilities. By scientifically managing key milestones, we can reduce cost of repeated mold repairs, shorten project delivery cycles, ensure a high degree of compatibility between mold and injection molding process. This lays a solid foundation for stable processes and high-quality standards in subsequent mass production. Ultimately, we achieve a seamless transition from trial molding to mass production, making plastic parts projects fully controllable in terms of cost, schedule, and quality.

Gud Mould Industry Co., Ltd