QLT Factory Reveals: How to Effectively Avoid Glass Bottle Neck Cracks? Control Quality from the Source of Production

In the production of glass bottles, “neck cracks” (commonly known as “炸脖” in Chinese) are a common problem that troubles many manufacturers. The so-called “neck cracks” refer to the occurrence of cracks on the neck of glass bottles. Mild cases affect the appearance, while severe cases lead to leakage – deep cracks will cause direct liquid leakage, and shallow cracks are also prone to liquid seepage. If an automatic aluminum cap sealing machine is used for sealing, the neck may even break from the cracked area, causing economic losses to customers. As QLT Glass Products Manufacturing Co., Ltd., which focuses on the production of high-quality glass bottles, we are well aware of the impact of “neck cracks” on product quality. Through years of practice, we have formed a full-process control system covering “molds, feeders, bottle-making machines and operations” to avoid “neck cracks” from the source. Below, we will detail how QLT specifically addresses hidden risks in each link.

1. Mold Control: Eliminate Causes of Neck Cracks from “Basic Hardware”

Molds are the “framework” for glass bottle forming, and the condition of molds directly determines whether neck cracks are likely to occur on the bottle neck. Based on production experience, the main mold-related issues leading to “neck cracks” are burrs on the initial mold or mold mouth, and wear of the quick clamps for the mold mouth and forming mold. Burrs can cause surface scratches during the forming of the bottle neck, which in turn lead to cracks; worn quick clamps cannot stably fix the mold, resulting in uneven stress during the forming of the bottle neck and the formation of hidden cracks.

In mold management, QLT has established a full-life-cycle control mechanism of “daily inspection + regular maintenance + scrap and replacement”, with significant advantages. On the one hand, we assign full-time mold inspectors to check the initial molds, mold mouths and quick clamps in production every 2 hours: high-precision vernier calipers are used to measure the flatness of the mold mouth to eliminate residual burrs; visual inspection combined with tactile touch is used to check whether the quick clamps are worn or loose – once burrs are found, a special polishing tool is immediately used for mold mouth polishing to ensure the mold mouth is smooth and flawless; if the quick clamps are worn, new clamps are replaced on the same day, and we never leave hidden dangers due to “making do with it”. On the other hand, we establish a “file” for each set of molds, recording the number of uses, maintenance records and wear conditions. When the number of uses of a mold reaches 80% of the industry’s average service life, even if there are no obvious problems in appearance, we will arrange for a backup mold to replace it in advance to avoid “neck cracks” caused by mold aging. This “prevention-oriented and timely handling” model keeps QLT’s molds in the best working condition at all times, reducing the possibility of “neck cracks” from the hardware source.

2. Feeder Regulation: Precisely Control the Key Link of “Raw Material Forming”

The feeder is responsible for delivering the glass melt to the mold in an appropriate state. Improper dropping temperature, excessive scissor marks or skewed material dropping will directly lead to uneven distribution of the glass melt during the forming of the bottle neck, thereby causing cracks. If the dropping temperature is too high, the fluidity of the glass melt is too strong, and the “too thin” area is prone to appear on the bottle neck, which is easy to crack under stress; if the temperature is too low, the melt is easy to solidify and cannot fit tightly with the mold, forming gap-like cracks; excessive scissor marks or skewed material dropping will cause material accumulation or shortage on the bottle neck, laying hidden dangers for cracks.

In feeder regulation, QLT realizes precise control of the feeding link by virtue of the dual guarantee of “intelligent monitoring + manual calibration”. Firstly, we install intelligent temperature sensors on the feeder to monitor the dropping temperature in real time, and the data is synchronously transmitted to the central control system. When the temperature deviates from the standard range (±2℃), the system automatically alarms and adjusts the heating device to ensure that the dropping temperature fully meets the forming requirements – for example, when producing red wine bottles, the dropping temperature needs to be stably maintained at around 1150℃, and the sensor will accurately lock this value to avoid temperature fluctuations. Secondly, to address the problems of excessive scissor marks and skewed material dropping, we check the scissors before the start of each shift every day and replace the worn scissor blades to reduce scissor marks; at the same time, we adjust the guiding device of the material dropping channel and use a laser calibrator to ensure that the center of the dropped material is completely aligned with the center of the mold, eliminating skewed material dropping. In addition, 3-5 initially formed bottle bodies are sampled and inspected every hour to observe whether there are residual scissor marks or uneven material distribution on the bottle neck. Once a problem is found, the machine is immediately shut down for adjustment. This process keeps QLT’s feeding link stable and controllable at all times, avoiding the risk of “neck cracks” from the raw material delivery level.

3. Bottle-Making Machine and Operation Management: Standardize Processes to Avoid Human and Equipment Errors

The operating status of the bottle-making machine and the standardization of the operator’s operations are also important factors affecting “neck cracks”. Improper coordination between the opening/closing time of the mold mouth and the closing time of the forming mold, too rapid or unstable opening of the forming mold, excessively high mold bottom, skewed positive air-blowing head, too fast bottle taking by the bottle clamp, or abnormal bottle clamp will all cause external impact or uneven stress during the forming or bottle-taking process of the bottle neck, leading to cracks. For example, if the opening/closing time of the mold mouth is not synchronized with the closing time of the forming mold, the glass melt will be “stuck in the mold” at the bottle neck, forming cracks; if the bottle clamp takes the bottle too fast, it will exert a pulling force on the bottle neck, resulting in hidden cracks.

QLT minimizes the hidden dangers in the bottle-making machine and operation links through “equipment optimization + standardized operation”. At the equipment level, we lock the key parameters of the bottle-making machine: the PLC control system is used to precisely adjust the coordination between the opening/closing time of the mold mouth and the closing time of the forming mold, ensuring that the coordination error does not exceed 0.1 seconds; the mold release speed of the forming mold is set to the “uniform and slow” mode to avoid impact caused by too rapid opening; at the same time, the height of the mold bottom is regularly calibrated with a height gauge, and the positive air-blowing head is calibrated with a level to ensure uniform air blowing and balanced stress on the bottle bottom. At the operation level, we have formulated the “Standardized Operation Manual for Bottle-Making Machines”, requiring operators to undergo 3 months of training and pass the assessment before taking up their posts – for example, when taking bottles, the speed of the bottle clamp should be controlled at 5cm/s, and the angle should be kept perpendicular to the bottle body to avoid pulling; if the bottle clamp is stained with oil or bent, the machine should be shut down immediately for cleaning or replacement, and the size of the shaft should also be measured regularly to ensure it matches the bottle body. In addition, skill assessments for operators are organized every month to strengthen the awareness of standardized operations and avoid “neck cracks” caused by human errors.

Choose QLT: Say Goodbye to “Neck Cracks” and Obtain High-Quality Glass Bottles

Although “neck cracks” seem minor, they are directly related to the use safety of glass bottles and customer reputation. Starting from the three core links of molds, feeders, bottle-making machines and operations, QLT Glass Products Manufacturing Co., Ltd. controls the “neck crack” rate below 0.01% through strict control mechanisms, advanced equipment guarantees and standardized operation processes, which is far lower than the industry average. Whether it is food packaging bottles, wine packaging bottles or pharmaceutical packaging bottles, when you choose QLT, you not only get high-quality products without the hidden danger of “neck cracks”, but also our ultimate control over every production detail. If you have a demand for glass bottle procurement, you may wish to choose QLT, and let us protect the quality of your products with our professional strength.