Strain Analysis in Molded Plastics Using Polariscope Strain Viewers
Stress and strain analysis hold a huge importance in quality control processes in the mold plastics and resins industries. The strain on such plastics could happen due to injection molding where the molten polymers are poured into the mold, allowed to cool, and reform. Detecting such stains is crucial to avoid deformities, product recalls, and other damages. Polariscope strain viewers are used to identify and analyze strains in mold plastics across industries ranging from consumer electronics to automotive. This post offers information on the use and benefits of using polariscope strain viewers for strain analysis in mold plastics.
Overcoming the Challenge of Detecting Strain in Molded Plastics
Accurately identifying internal strains visually, especially in complex shapes or opaque materials, is next to impossible. With a polariscope, identifying stress patterns at a micro level is manageable. A polariscope works on the principle of optical birefringence, wherein polarized light is passed through stressed plastic to determine the magnitude and direction of residual stresses in a plastic piece. This is also called photoelastic effect and is a very effective and accurate way to measure stress patterns in translucent or transparent materials. Also, this process is fast, non-destructive, and does not require a highly trained operator.
How Polariscope Strain Viewers Enhance the Accuracy of Strain Analysis
Polariscopes are used as strain viewers for analyzing stress patterns in molded plastics and identify warping, cracking, and other deformities. Here are some pointers regarding the accuracy these instruments offer, and help enhance the strength and integrity of the plastic product.
- Polariscope strain viewers offer non-destructive testing (NDT), which means there is no physical contact and hence the integrity of the molded plastic is maintained.
- They help assess the internal stresses within plastic components in detail, ensuring quality control in manufacturing processes and enhancing the reliability of plastic products.
- Polariscopes evaluate 2D distribution map of colored resin products up to 175 mm. Most of these instruments are partially or fully automatic, and hence reduce measurement errors. They can measure colored resin products, residual stress, and cracks that are impossible to measure with conventional instruments.
- It enables quantitative stress measurement by analyzing the number and orientation of fringes as well as calculating the magnitude and direction of internal stresses.
- Polariscopes offer a clear and direct view of the internal stresses, which helps reduce errors.
- It is effective for various types of plastics, regardless of color or state, such as opacity, translucency, or transparency.
- It reveals hidden stress patterns, allowing for corrective actions before production issues arise.
- It promotes consistent product quality and reduces the risk of failures and product recalls.
Importance of Quality in Molded Plastics
Any amount of strain in molded plastics leads to warping, cracking, and reduced strength. This may happen due any of the to the forming process steps such as uneven cooling, injection pressure variations, mold design, and more. Plastics with such stress patterns cannot be taken as is in making any parts or components. They are used across industries such as automotive, electronics, consumer goods, and so on in making significant parts. Hence, a thorough inspection of molded plastics is crucial to ensure quality. These plastics are used in making various parts across industries such as dashboards in cars, enclosures or covering parts in electronics, and more. Hence, they must have a high impact resistance and no deformities. Molded plastics must maintain both structural integrity and aesthetics, which reflects the features and functionality of the final product.
How Types of Plastics and Their Opacity Influence the Functioning of Polariscopes?
Material properties including the level of opacity, translucency, and transparency are reflected in the polarized light transmitted through a sample. In addition, materials such as acrylic and polycarbonate are prone to stress marking and exhibit a high coefficient of thermal expansion. This leads to internal stresses that build up during cooling and impacts the level of opacity. To view opaque plastics, the source light needs to be beyond the visible spectrum (>700nm). This near-IR light penetrates visibly opaque materials, which allows a near-IR polariscope to identify internal stresses. Combining these three aspects enables a polariscope strain viewer to identify stress patterns in a wide range of opaque plastics.
Applications of Polariscope Strain Viewers in the Plastics Industry
Molded plastics are used in many important industries such as automotive, electronics, and so on. Hence, polariscopes find use in all these industries to study the strain applied on plastics. Here are some application areas of polariscopes in the plastics industry.
- Polariscopes are primarily used in quality control inspections of molded parts for internal stress patterns.
- They identify stress caused by specific mold features or processing parameters.
- They help optimize mold design and injection molding processes to minimize strain.
- Using a polariscope ensures structural integrity for applications requiring high strength and reliable performance.
If you have any questions about using polariscope strain viewers in the molded plastics segment or need to discuss your requirements or custom options, feel free to contact the team at Barnett Technical Services. The company is an authorized distributor for various brands of spectroscopy instruments such as polariscope strain viewers and more.
Related Products:
LSM-9002LE: Strain measurement in the visible across a 175×175 mm area
LSM-9002S: Strain measurement in the visible with a variable field of view for 10-10 to 60×60 mm
LSM-9001NIR: Near-IR system to measure strain in semiconductors
LSM-9100WNIR: Near-IR system to measure strain in resins and other plastics