Mold is widely used in industrial manufacturing, different from the traditional mass mold, precision mold is in high-end industrial manufacturing to support more refined needs, and medical mold is the highest representative of high-end manufacturing. As a part of the core process of manufacturing, medical injection molding play a decisive role in patient safety and treatment. From daily syringes, infusion sets, and even to implant human organs, joints and other molds determine the perfect formation of medical products.
what is medical injection molding
Medical injection molding is a high-precision processing technology specially used for the production of medical injection equipment, by injecting medical grade polymer materials into precision molds in a controlled environment, molding the melted material into a specific shape of medical devices, and finally producing parts that meet the strict national medical standards.
The production method of this process accounts for more than 1/3 of the global medical device manufacturing market and is the core manufacturing technology for key medical products such as orthopedic implants and drug delivery systems. The development trend in advanced industries is toward intelligent, miniaturized and environmentally friendly development, which promotes medical machinery to serve patients more accurately, safer and more intelligently. The service life of medical injection molding produced by high-end medical molds can be as high as 2 million times or even more.
material of medical injection molding
Different materials will produce different application range of medical injection supplies, usually need to be selected according to the requirements of the specific product, such as physical and chemical characteristics, medical standards, product costs and so on. At present, the medical injection molding materials used by enterprises in the mass market are basically divided into three kinds
Thermoplastic engineering plastics: Generally can be heated to a melting state and solidified when cooled. And can be recycled, more widely used people, and strong plasticity, can create a more complex shape. The plastic material is generally the following four kinds according to its advantages and disadvantages
Thermoplastic engineering plastics
PEEK: has excellent bio-compatibility, mechanical properties are very close to bone, can withstand gamma radiation, long-term implantation stability is high, but it is determined that due to high processing temperature and energy consumption is 300% higher than that of general plastics, the overall material cost is 15-20 times that of general medical.
PEI: Light transmittance up to 88%, steam sterilization resistance, flame retardant, but also strong moisture absorption, chemical resistance is relatively poor, relatively easy to be eroded by strong alkali.
PP: Medical grade PP has a very large cost advantage, the price is only 1/20 of PEEK, with acid and alkali resistance, alcohol resistance and gamma radiation chemical stability, and can be welded linear, suitable for different circumstances to increase or reduce the assembly process, and the cost advantage brings disadvantages are also more obvious, low light transmission and heat resistance and low temperature brittleness. Not too high temperature and not too low temperature,
PC: has higher light transmittance than PEI, excellent dimensional stability, and excellent impact strength. However, the resistance to stress cracking is poor, gamma radiation is easy to cause yellowing, and it is easy to hydrolysis at high temperature
Special functional materials
COC/COP: Ultra-low dissolution, extremely high water vapor barrier and excellent optical properties, but the price is very expensive, and the processing requirements are complex and demanding.
TPU: Very excellent fatigue resistance, and blood compatibility can be less than 2%, but it should be noted that its additives are prone to migration, requiring a special stabilization system
Other categories such as rubber materials, degradable materials, etc., are also commonly used materials for medical injection molds. Depends on the best fit for the desired scenario.
application of medical injection molding
The application areas of medical injection molding can generally be divided into several categories: diagnostic testing equipment, drug delivery systems, surgical instruments, disposable surgical tools, implanted interventional instruments, and in vitro support systems.
Medical injection molding is responsible for different key technologies and part of the product assistance in each scenario. Application scenarios largely affect the material selection and process of medical injection molding. For example, in the case of long-term implantation in the body, it is more inclined to choose the medical PEEK material for high temperature precision forming process against the corresponding verification standards. Other scenarios of product functional requirements such as mechanical properties, three-dimensional characteristics, etc., should be combined with the corresponding regulatory requirements for system design. Precision mold is the first step to make all these concrete landing.
process of medical injection molding
The medical injection molding process is one of the most rigorous manufacturing processes and is a source of quality assurance for both the application of materials and the high standards of regulations. Subdivision to each step of the process is strictly required.
Early preparation of the space environment: temperature and moderate requirements, decontamination treatment in the production process.
Mold treatment: whether the fineness roughness meets the standard, and whether the mold surface is qualified
Processing and shaping stage: melt temperature control, injection speed and pressure control, temperature change adjustment, intelligent pressure holding algorithm technology and sealing control, dynamic temperature regional temperature regulation and finally through the robot ultra-low error accurate removal, visual detection integration, through anti-pollution measures under the transmission and packaging.
Post-treatment stage: Precision finishing through laser and plasma treatment, cleaning and entering the package to verify parameters and functions.
Special process variations: Different process characteristics are changed for different needs, generally micro-injection molding and multi-material molding.
