https://pmc.ncbi.nlm.nih.gov/articles/PMC11507497/

The end of the user information briefly summarizes "The manufacturing process of Bloodletting Needles involves several steps." Although the description still retains traces of historical tools, this precisely provides us with a starting point for comparing ancient and modern techniques. The manufacturing of "bloodletting needles" in the modern sense (mainly referring to disposable sterile blood collection needles) is a highly automated, precise, and strictly controlled industrial process, completely overturning the traditional manual forging model. Next, we will elaborate on this modern manufacturing process by combining the clues in the user information.

Step 1: Preparation of Raw Materials and Wire

The needle barrel part of modern blood collection needles usually uses medical-grade stainless steel, as mentioned in the user information, such as AISI 304 or 316L. These materials have excellent corrosion resistance, appropriate hardness and toughness, as well as good biocompatibility. The raw materials are extremely fine stainless steel tubes (hollow needles) or solid steel wires (for some special needles). The diameter of the wire has initially approached the outer diameter of the final needle barrel. The incoming raw materials need to undergo strict chemical composition and physical property tests to meet the relevant standards for medical device materials.

Step 2: Needle Tube Molding and Cutting

For hollow blood collection needles, the coiled stainless steel tubes are straightened and then cut by precise equipment to the specified "length." This length is an important parameter for modern blood collection needles, typically ranging from 25mm to 40mm, which is long enough to penetrate the skin and the walls of blood vessels, but not so long as to increase patients' fear and operational inconvenience. The cutting surface must be smooth and free of burrs.

Step 3: Pointed Tip Grinding Forming

This is the core manufacturing process, directly determining the puncture pain sensation and success rate. The traditional manual "sharpen and refine the tip" has been replaced by fully automatic multi-station grinding machines. The syringe is fixed, and it is ground by a precision grinding wheel at a specific angle to form two symmetrical cutting planes, forming an extremely sharp "injection molding" needle tip. The angle of the needle tip's cutting surface, symmetry, and burr control are key quality indicators. Advanced techniques can produce "triple cutting planes" or "five-cutting planes" needle tips, making the puncture smoother and reducing the pain. After grinding, the needle tip needs to be inspected 100% under a microscope or undergo sampling statistical inspection to ensure sharpness, no hooks, and no burrs.

Step 4: Heat Treatment and Polishing

The needle tubes after grinding may require appropriate heat treatment (such as bright annealing) to relieve stress and maintain the flexibility of the material. Subsequently, the outer surface and inner cavity of the needle tubes will undergo electrolytic polishing or mechanical polishing. Polishing not only removes microscopic burrs, achieving a mirror-like smoothness on the surface, reducing the puncture resistance, but also enhances the corrosion resistance of stainless steel. The smoothness of the inner cavity is crucial for the smooth flow of blood.

Step 5: Component Injection Molding and Assembly

The modern blood collection needle is a system consisting of a needle holder (usually made of medical plastic such as polypropylene or ABS), a sheath, and possibly a needle holder. The needle holder is formed through precise injection molding. In a clean workshop, the needle tube is automatically inserted into the needle holder and securely fastened by means of adhesive, hot melting, or mechanical clamping. The "diameter" (gauge) information of the needle will be marked on the needle holder or the packaging. The needle tip will immediately be fitted with a safety sheath to prevent needle punctures and contamination.

Step 6: Cleaning, Sterilization and Packaging

The assembled needles will undergo multiple cleaning processes to remove contaminants such as oils and metal particles from the processing. After cleaning, the products are sent to the sterilization stage. The most common methods are ethylene oxide (EO) sterilization or gamma-ray irradiation sterilization to ensure the elimination of all microorganisms. The sterilization process has strict parameter control and biological indicator verification. After sterilization, in a clean environment, the blood collection needles are placed in specially designed packaging bags or blister packs that can maintain a sterile state. The packaging must have a microbial barrier function and clearly indicate product information, sterilization method, expiration date, etc.

Step 7: Full-process Quality Control and Certification

Just as the user profile emphasizes, "Certification: ISO9001:2015, ISO13485," quality is consistently maintained throughout the process. From the warehousing of raw materials to online size inspection (needle length, outer diameter, slope angle), to performance testing of finished products (penetration force, connection firmness, leakage test), and to sterility testing and biocompatibility testing (cell toxicity, sensitization, etc.), each step has strict control points and records. The final product must meet the medical device regulations of the registration location (such as China's NMPA, the US FDA, and the European CE).