The development of modern medical technology has made plastics widely used in the medical field. From general pharmaceutical and pharmaceutical packaging, disposable medical instruments, to multiple precision and high-tech medical measuring instruments, surgical instruments, etc., medical plastics have played an important role in improving the level of medical technology. Because medical devices have special requirements for health, safety, surface smoothness, and corrosion resistance, the moulds of medical plastic products play an important role in the production process of their products. Mould is an important indicator to measure the level of a country's medical plastic product manufacturing level, to a large extent determines the product quality, efficiency and new product development capabilities. With the gradual improvement of China's medical care system, the demand for disposable medical device supplies has grown rapidly. Higher requirements have been placed on the manufacture of moulds, product production equipment and processes for medical devices, especially disposable medical devices.
(1) Strict selection of mould materials
Most disposable medical device products use medical grade polyvinyl chloride (PVC) and polycarbonate (PC). Because PVC has better corrosion resistance than steel, PC has higher hardness, so there are strict requirements for the selection of mould materials. It is recommended that domestic mould manufacturers choose Swedish-Shengbai S136H or Japan Datong NAR-80 steel, which have strong corrosion resistance and high polishing performance.
(2) Heat treatment process to adjust hardness
Due to the good fluidity of medical grade PVC materials, the parting surface is deformed due to the soft material of the mould during the use of the mould, which leads to flash burrs during the injection moulding process. Therefore, the hardness of such mould materials has high requirements. The heat treatment process used in the mould manufacturing process is that the template is tempered after rough machining, and the hardness is controlled at HRC32-36; after the mould trial sample is qualified, the hollow, moving mould, and core are vacuum-quenched and hardness controlled At HRC58-620.
(3) The structural design is reasonable and precise
For transparent products, try to choose hot runners to reduce the traces of the material; when using cold runners, soft PVC should try to shorten the size of the runners; because of the small volume and large batch of disposable medical devices, automatic unloading and shear pouring should be used. To ensure the production efficiency and quality; there are many transparent tubular parts for disposable medical equipment products. When designing, pay attention to the way of gate feeding position and dynamic model Z fixing, to avoid improper choice of gate position and core fixing method , Resulting in uneven flow of materials during injection moulding, resulting in elastic deformation of the core, uneven or incomplete filling of the product. Extended tube shape products should pay attention to the appropriate exhaust method, and the inlet runner should be opened according to the product moulding. Out of the overflow well to avoid the difficulty of product formation due to air shut-off; the mould cooling system should adopt multiple sets of separate cooling water channels to reasonably control the dynamic and fixed mould temperature to control product deformation.
(4) High precision in mould manufacturing
During the manufacturing process of medical plastic product moulds, the parting surface is required to be tight. As far as possible, the accuracy of the mould is ensured by equipment processing methods. The gap between the parting surfaces should be less than 0.01mm, and the clearance between the push rod and the push tube of the ejection system should be less than 0.01mm. The push plate is used to push out the structure, and the push plate should ensure a certain hardness.
The fixed and dynamic model cores of transparent products should be finely polished to ensure that the Ra value is above 0.20. If necessary, liquid polishing can be used.
(5) The injection moulding machine and parts are selected carefully
The injection moulding machine should use a small screw to ensure injection accuracy, and use an automatic discharge device. When the mould is ejected, gas-assisted discharge can be used; the machine tool is installed with a manipulator to realize the automatic process from product moulding to packaging to minimize pollution links; The feeding mechanism of the injection moulding machine should come from a closed vacuum feed, adopt a meticulous closed storage tank, arrange the feeding pipe to each injection moulding machine, and install an automatic metering vacuum feeding device at the inlet of the injection moulding machine to ensure that the raw materials are fed into the injection moulding machine No pollution before.
(6) The injection workshop should be clean and up to standard
The production workshop should be fully enclosed, install a high-power air conditioner ventilator, remove harmful gases in time, ensure the workshop's constant temperature and clean air; during the production process, it is strictly prohibited to use mould release agents and rust removers to ensure that the products are not contaminated by PVC products During the production process, the melting temperature should be strictly controlled to avoid excessive temperature of the material and long-term stay in the barrel to decompose the raw materials to produce harmful gases. When the machine is shut down, the screw and barrel should be cleaned immediately to avoid damage to the screw of the injection moulding machine by residual raw materials; Implement the GMP standard and strictly follow the IS0 9000 quality management system to ensure that there are no problems at all points in the production process.
Yuhuan Shengjiu Mould Co., Ltd. is a professional China manufacturer and supplier of Medical Mould . The main production and supply: medical mould products such as syringe moulds, safety needle moulds, oxygen mask moulds, needle-free injection takeovers, vaginal dilator moulds and so on. And provide customers with a complete mould configuration program to help and improve the production of disposable medical equipment. According to the requirements of the market and customers, Shengjiu has developed a new medical mould with a full hot runner system, and developed various new scientific medical equipment for customers. Welcome to consult and purchase: https://www.medicalmould.net/