In the plastic packaging manufacturing industry, controlling specific technical parameters is key to ensuring functionality, efficiency in use, and the acceptance of the final product. One such parameter, often overlooked at first glance, is the ovality of cylindrical containers.
But what is ovality, and why is it so important?
In this article, we will explore the concept of ovality, its impact, and how it influences the design, production, and performance of cylindrical plastic containers throughout their lifespan.
We will talk about...
- What is ovality?
- The impact of ovality on plastic containers
- How to control ovality in production
What is ovality?
Ovality is defined as the deviation from a perfect cylindrical shape. In other words, it measures how close a cylindrical container is to being perfectly round. In the plastic industry, deviations in this parameter can arise from various factors, such as the manufacturing process, material behavior during processing, and even storage or transportation conditions.
Ovality is typically measured by calculating the difference between a containers’ maximum and minimum diameters. It is expressed as a percentage, obtained by dividing this difference by the nominal diameter. High ovality values indicate significant deformation, whereas low values signify a more uniform product. Each container has a defined tolerance limit based on its technical specifications.
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The impact of ovality on plastic containers
1. Compatibility with filling and sealing equipment
Excessive ovality can hinder the automatic filling processes, as containers may not fit correctly into the machine holders. Additionally, improper shape can cause sealing defects, leading to leaks and product contamination.
2. Structural stability and stackability
Containers with high ovality are less stable, particularly when stacked. This increases the risk of tipping over and sustaining damage during transportation and storage, ultimately affecting customer perception of quality.
3. Aesthetics and consumer perception
In today’s highly competitive market, packaging appearance is crucial. Containers with visible deformations may be perceived as defective or of lower quality, negatively impacting brand image and consumer trust.
4. Efficiency in material usage
Controlling ovality allows for optimized wall thickness, reducing production costs and, consequently, minimising environmental impact by using only the necessary amount of material.
5. Labeling issues
Ovality deviations beyond acceptable limits can hinder proper label application. Labels may wrinkle, shift, or fail to adhere uniformly, affecting product presentation and making critical information, such as ingredients, barcodes, or usage instructions, difficult to read.
How to control ovality in production
Ensuring that ovality remains within acceptable limits requires several key considerations :
- Proper mold design: An optimally designed mold help containers maintain their shape during manufacturing and cooling
- Material selection: Using polymers with good mechanical and thermal properties reduce the risk of deformation.
- Continuous monitoring and measurement: Implementing regular quality controls help verify compliance with ovality standards.
- Storage and transportation conditions: Proper storage prevents excessive pressure that could deform them.
- In-line control: Optical inspection systems and measurement devices integrated into production lines continuously monitor diameters and calculate ovality in real time. These systems enable immediate adjustments when deviations exceed tolerance limits, ensuring consistent quality without disrupting production flow.
In summary, ovality is a critical factor that influences the functionality, aesthetics and efficiency of cylindrical rigid plastic containers. Proper control of this parameter enhances performance across packaging production and distribution processes while reinforcing consumers’ perception of quality. In a highly technical industry, attention to details like ovality can determine or failure a container.
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It is essential to remember that a plastic container’s structural integrity is influenced throughout the whole production process, especially as it exists the blow molding station at high temperatures.
At APS, we maintain strict compliance with the ovality parameters defined in our production technical specifications, conducting in-lie checks to detect and correct any deviations. Contact us! Our team will help you find the perfect container for your product!
