Why can the POM release button always maintain precise size in a complex environment? ​

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POM, or polyoxymethylene, has a highly regular molecular structure. This regularity is not formed by chance, but is determined by its special polymerization method. In the molecular chain of POM, carbon atoms and oxygen atoms are arranged alternately in a specific pattern, forming a regular linear structure. Such a molecular structure enables the molecular chains of POM to be arranged and stacked in an orderly manner during the crystallization process, thereby obtaining a high degree of crystallinity. When the POM material is processed into a release button, these regularly arranged molecules are like well-trained soldiers, each in their place, forming a stable and tight structural system. Compared with the disordered arrangement of molecules in ordinary plastic materials, the regularity of the POM molecular structure gives it a stronger ability to resist external interference. Under different temperature and humidity environments, the molecules of ordinary materials are easily affected by external factors and move chaotically, resulting in changes in the molecular distance, and ultimately causing changes in the size of the material. However, due to its regular molecular structure and high crystallinity, POM materials have strong forces between molecules. This force is like an invisible rope that firmly binds the molecules in a fixed position, making it difficult for external environmental factors to easily destroy its stable structure, thereby ensuring that the medical injection molding pen POM release button can maintain precise dimensions in complex environments. ​
In high temperature environments, such as hot summer, the sharp increase in external temperature is a huge test for material performance. For parts made of ordinary plastic materials, high temperature will allow molecules to gain more energy, molecular motion will become extremely violent, the distance between molecules will also increase, and the material will inevitably expand and deform. Taking common polypropylene plastic as an example, its size may change significantly after being placed in a high temperature environment for a long time. When used for precision parts, this size change will seriously affect the normal operation of the equipment. However, POM release buttons show completely different characteristics in high temperature environments. Although high temperature will also enhance the thermal motion of POM molecules, the range of molecular activity is greatly limited due to the regularity and high crystallinity of its molecular structure. POM molecules can only vibrate and rotate slightly in a limited lattice space, and cannot diffuse and move freely like ordinary plastic molecules. This stable state at the molecular level makes the dimensional change of the POM release button in a high temperature environment almost negligible. In medical injection pens, precise dimensional matching is the key to ensure accurate drug injection. There is a precise matching relationship between the POM release button and the push rod, drug chamber and other components of the injection pen. If the release button expands in size at high temperature, it may generate excessive friction between it and the push rod, resulting in a stuck phenomenon when the button is pressed, making it impossible to accurately release the drug according to the set dose, or even completely unable to push, seriously affecting the patient's treatment process. The stable size of the POM release button ensures that it always maintains good matching accuracy with other components, and can still achieve smooth pressing and rebound operations in a high temperature environment, ensuring that the drug dose injected each time is accurate and correct, providing reliable protection for the patient's treatment. ​
The impact of a humid environment on material properties should not be underestimated. In a humid environment, water molecules will penetrate into the material in an all-pervasive manner. For some materials with poor water resistance, the intrusion of water will destroy the bonding force between molecules, causing the material to soften and deform, and then affect the dimensional accuracy of the component. For example, some nylon plastics with strong water absorption will expand and deform after being placed in a humid environment for a period of time due to the absorption of a large amount of water, causing the loosening of the fit with other parts. However, the POM release button has excellent moisture resistance. This is mainly due to the stability and chemical properties of its molecular structure. The lack of polar groups in the POM molecule that are easy to combine with water molecules makes it difficult for water to interact with the POM molecules. At the same time, the compact crystalline structure of the POM material is also like a solid barrier, effectively preventing the penetration of water. Even in a long-term humid environment, the POM release button can still maintain its original size and will not loosen with the pen body due to moisture. In the use of medical injection pens, sealing is crucial. Once the fit between the release button and the pen body is loosened due to moisture, impurities such as moisture and dust from the outside may take the opportunity to enter the pen. This will not only contaminate the drug, affecting the effectiveness and safety of the drug, but may also cause the mechanical parts inside the injection pen to rust and damage, reducing the service life of the injection pen. The stable size of the POM release button ensures the good sealing of the injection pen, avoids these potential risks, and ensures that patients can get safe and effective drug injection every time they use it. ​
In actual applications, the use scenarios of medical injection pens are extremely wide, and patients may carry injection pens in different environments. From warm indoors to cold outdoors, from dry and rainy north to humid and rainy south, the temperature and humidity of the environment vary greatly. The POM release button always maintains the characteristics of precise size, which is particularly important in such a complex and changeable environment. For patients who need long-term and regular injections of drugs, the performance stability of the injection pen is directly related to the control of the disease. Taking the use of insulin injection pens by diabetic patients as an example, the accuracy of insulin dosage plays a decisive role in controlling blood sugar levels. Even a very small dosage deviation, accumulated over a long period of time, may cause blood sugar fluctuations and cause a series of complications. With its stable size, the POM release button ensures that the insulin dosage released each time is accurate and consistent, helping patients maintain stable blood sugar levels, improve quality of life, and ensure physical health.​
From the perspective of manufacturing, the dimensional stability of the POM release button brings significant advantages to the production of medical injection pens. In the product design stage, since the size of the POM release button changes very little, designers can plan the size and shape of other parts of the injection pen more accurately to ensure the best matching accuracy between the various parts. In the mold manufacturing process, there is no need to reserve too large dimensional tolerances to cope with fluctuations in component size, thereby improving the manufacturing accuracy and production efficiency of the mold. In the batch production stage, stable dimensions make the production process more stable and controllable, reducing the number of production commissioning and process improvements caused by dimensional problems. This not only reduces production costs, but also shortens the production cycle of products and improves the market competitiveness of enterprises. At the same time, stable dimensions are also conducive to strict control of product quality, greatly reducing the scrap rate caused by unqualified dimensions, improving the overall quality and reliability of products, and laying the foundation for enterprises to establish a good brand image.