Frequent Rework in Sealing Tests? The Root Cause Lies in the Testing System! WAFU Brothers Teach You How to Solve It Systematically

In the manufacturing industry, rework caused by sealing tests is like a stubborn “chronic illness”—not only eroding corporate profits but also damaging product reputation in the market. According to statistics from a certain auto parts manufacturer in Ningbo, in 2023, their sealing test rework rate reached 8.7%, directly increasing annual production costs by 4.2 million RMB, accounting for 35% of their total quality inspection expenses. However, most companies simply attribute the cause of rework to product process defects, overlooking potential problems within the testing system itself.

With 15 years of deep expertise in sealing testing, WAFU Brothers has analyzed over 300 real-world cases from companies such as Foxconn, Mindray, and CATL. Findings show that approximately 80% of frequent rework cases in sealing tests stem from inappropriate equipment selection, unreasonable process design, or gaps in data traceability. This article will dissect the core issues in the testing system that lead to rework and present WAFU Brothers' systematic solutions.

I. Equipment-Scenario Mismatch: The Hidden Trap of "False Failures"

1. Inadequate Environmental Adaptation: Misjudgments Caused by Temperature Fluctuations

The precision of traditional sealing test equipment is highly susceptible to environmental factors. In a smartphone OEM factory in Shenzhen, the workshop temperature can reach 38°C on summer afternoons, which is 13°C higher than the standard 25°C testing environment. Under these conditions, the error rate of ordinary direct-pressure testers increases by 22%, once resulting in 500 smartphone housings being wrongly reworked in a single day due to "false leakage" detection.

WAFU Brothers' intelligent testing devices, such as the DPS-9000 series, are equipped with environmental adaptation systems. With SHT30 temperature-humidity sensors and MPX5100 air pressure modules, the system collects 50 sets of environmental data per second and uses dynamic compensation algorithms to correct testing values in real time. After adopting this system, the OEM factory reduced environment-related rework rates from 12% to 1.5%.

2. Rigid Parameter Settings: The Dual Risks of "One-Size-Fits-All" Testing

Sealing requirements vary greatly between products. For example, new energy vehicle battery packs require a test pressure of 0.3 MPa, while smartwatches only need 0.02 MPa. A wearable device manufacturer in Huizhou once used the same parameters across products, resulting in 3,000 high-end models having deformed sealing rings (15% rework rate) and 2,000 entry-level models being under-tested (leading to 127 customer complaints).

WAFU Brothers' modular testing system includes a library of over 100 industry-specific parameters, allowing operators to scan a code to select the correct testing scheme. After implementation, the manufacturer's parameter-related rework rate dropped by 80%, and testing efficiency improved by 40%.

3. Equipment Aging: The Hidden Cost of Uncalibrated Devices

Core components of sealing test equipment lose about 2% of their accuracy annually. A medical device company in Suzhou used a flow-type tester for three years without calibration. As a result, infusion sets with a leakage rate of 0.0012 mL/min were mistakenly classified as "defective," causing 5,000 products to be reworked, resulting in losses exceeding 100,000 RMB.

WAFU Brothers' equipment management system automatically monitors component degradation and generates calibration work orders in advance. After adoption, the company reduced rework caused by accuracy issues by 90%, saving 680,000 RMB annually.

II. Process Breakpoints: The Vicious Cycle of "Unknown Rework Causes"

1. Lack of Data Traceability: The Inefficiency of Manual Recording

An automotive wire harness manufacturer in Changchun reworked 3,000 wire harnesses in October 2022 due to sealing failures. Because of missing data records, the quality control and production departments spent 3 days arguing before discovering that a 0.05mm deviation in seal ring size was the root cause. During this time, the products were reworked four times, resulting in losses of 280,000 RMB.

WAFU Brothers' digital system enables automatic full-process data collection, assigning each product a unique "testing ID." After adopting this system in 2023, the factory was able to identify the cause of similar issues within 20 minutes by scanning the code, preventing three rounds of unnecessary rework.

2. Ambiguous Judgment Standards: The Cost of Subjective Experience

A home appliance manufacturer in Qingdao reported a 35% dispute rate in water heater tank testing in 2022 due to a 30% variation in operators' judgment thresholds. This led to 400 products per month being delayed in delivery because of "secondary reviews."

WAFU Brothers introduced AI algorithms to build objective models that automatically distinguish between "real leaks" and "false alarms." As a result, consistency in judgment increased from 60% to 98%, and on-time delivery rates reached 95%.

III. Human Operation & System Coordination: Patching Human Error Loopholes

1. Inadequate Training: High Rework Rates Among New Employees

An automotive wire harness factory in Tianjin reported that in 2022, new employees who failed to master tooling cleanliness standards caused an 18% rework rate in certain batches of connectors, while the rate among experienced workers was only 3%.

WAFU Brothers implemented a "theory + practical + VR simulation" training system, replicating over 20 common mistake scenarios. After adoption, the new employee rework rate dropped to 6.3% in the first month, and training time was shortened by 5 days.

2. Undefined Responsibilities: The Time Cost of Departmental Buck-Passing

A new energy battery factory in Hefei experienced a sealing failure in battery packs in 2022. Production and quality control departments were deadlocked for 48 hours before discovering that the cause was worn tooling. The downtime cost them 500,000 RMB in just 2 hours.

WAFU Brothers' responsibility matrix system clearly defines accountability: If data is qualified but leakage occurs, it's the QC department's responsibility; if abnormal data is not handled, it’s the production department’s fault. After adoption, the factory's rework response time was reduced from 4 hours to just 1 hour.

3. Lack of Emergency Mechanisms: The Domino Effect of Unexpected Failures

A smartphone OEM factory in Zhengzhou switched to water testing due to equipment failure in 2022, resulting in 300 smartphone motherboards short-circuiting and losses of 210,000 RMB.

WAFU Brothers' "Sealing Test Emergency Manual" covers response processes for seven types of scenarios. After adopting the manual, similar incidents only affected 200 products, which were diverted to backup equipment without additional losses.

IV. WAFU Brothers’ Testing System Upgrade Solutions

Solution Level	Applicable Enterprise Size	Core Measures	Typical Results
Basic Version	Fewer than 100 employees	Equipment calibration + parameter standardization + operator training	A plastics factory in Zhongshan reduced its rework rate from 15% to 3%, saving 250,000 RMB annually
Advanced Version	100-500 employees	Digital traceability + rework cause analysis + continuous improvement mechanism	An auto parts company in Wuhan reduced batch rework by 65%, saving 4.2 million RMB annually
Premium Version	Over 500 employees	AI predictive maintenance + supply chain collaboration + intelligent alerts	An aerospace company in Shanghai maintained rework rates below 0.5%, securing an additional 12 million RMB in orders

Conclusion: Turn Testing Systems into Cost-Reduction Engines

The root cause of frequent sealing test rework lies in system loopholes. WAFU Brothers’ experience shows that through a three-dimensional approach—equipment upgrades, process optimization, and personnel empowerment—companies can reduce rework rates to below 1%.