Design of Disposable Medical Syringe Injection Mold

Disposable syringes are commonly used medical devices in clinical practice, with a huge market demand. Due to the extremely stringent production requirements for disposable medical syringes, including multiple professional tests such as sliding performance, body sealing, and cone tip sealing, the requirements for disposable medical syringe injection molds are correspondingly higher. KRMOLD is a supplier with extensive experience in medical device injection mold manufacturing, dedicated to helping medical product companies increase production capacity and stabilize product quality through efficient, stable, and precise medical plastic syringe injection molds.

1.Five Core Principles of Medical Plastic Syringe Injection Mold Design

1.1 Functional Principle

The primary task of the disposable medical syringe injection mold is to produce plastic parts that meet the requirements. For disposable medical syringes, it is critical to guarantee that the dimensional accuracy of the plastic components fulfills the standards, often with tolerances between IT11 and IT13. Furthermore, the syringe's appearance should be free of defects such as shrinkage marks, bubbles, and flash, as well as meeting the structural strength requirements of the plastic part to guarantee safety and effectiveness during use.

1.2 Process Principle

The medical plastic syringe injection mold design must be adapted to the parameters of the injection molding machine, such as clamping force, injection volume, and tie rod spacing. Meanwhile, disposable medical syringe injection mold design should also facilitate subsequent processing (such as CNC, EDM, wire cutting, etc.) and assembly debugging. Complex structures not only increase costs but also reduce production efficiency and affect the syringe production cycle.

1.3 Economic Principle

While meeting performance requirements, medical plastic syringe injection mold design should simplify the structure and reduce the number of complex parts to lower manufacturing costs. Furthermore, disposable medical syringe injection mold lifespan is extremely important, typically requiring 50,000 cycles to effectively reduce unit production costs.

1.4 Safety Principle

To stop component interference during disposable medical syringe injection mold closing, the medical plastic syringe injection mold must have dependable guiding, positioning, and protective elements. The ejection mechanism must be steady to prevent plastic components from adhering to the medical plastic syringe injection mold or deforming or being damaged during demolding, thereby guaranteeing the syringe's safety and dependability.

1.5 Maintainability Principle

Vulnerable components for disposable medical syringe injection molds include ejector pins, slides, and sprue sleeves should be made to be simple to remove and replace. To minimize medical plastic syringe injection mold downtime for maintenance and guarantee continuous and consistent production, cooling and venting systems should also be simple to maintain and clean.

2.Essential Preparatory Work Before Medical Plastic Syringe Injection Mold Design

Before officially starting the disposable medical syringe injection mold design, thorough preparation can prevent extensive rework later. This step is crucial, and the main preparatory work is as follows:

2.1 Product Structure and Processability Analysis

After receiving the product model of the disposable syringe, a comprehensive analysis must be conducted first:

-Dimensional and Precision Analysis: Clarify the tolerance requirements for critical dimensions of the plastic part. For critical dimensions, consider achieving them through high-precision mold processing (such as insert fitting); while non-critical dimensions can be marked with looser tolerances to reduce medical plastic syringe injection mold costs.

-Wall Thickness Analysis: Check whether the wall thickness of the syringe plastic part is uniform. Ideally, the wall thickness deviation should be ≤10%. Excessive wall thickness can easily lead to shrinkage marks and bubbles, while insufficient thickness will cause filling difficulties. For areas with uneven wall thickness, optimization can be achieved by adding ribs, reducing material, or adjusting the structure.

-Draft Angle Confirmation: Draft angles must be designed for all molding surfaces. The draft angle for the appearance surface should be ≥3°, and for non-appearance surfaces ≥1°. This can prevent damage to the plastic part during demolding. The "Draft Analysis" tool in CAD software can be used to check and mark the undercut areas that require core pulling or angled ejector treatment.

-Rounded Corners and Transition Design: Rounded corners (R≥0.5mm) should be designed at the corners of the plastic part to avoid stress concentration and cracking. Rounded corners should also be designed at corresponding locations in the mold cavity to extend disposable medical syringe injection mold life.

2.2 Material Property Compatibility

Different plastic materials have significantly different molding characteristics; therefore, the medical plastic syringe injection mold design must be compatible with the material used:

-Material Type: PP (polypropylene) is a commonly used material for syringes. Its flowability, shrinkage rate, and other characteristics must be considered in the disposable medical syringe injection mold design.

-Shrinkage Rate Range: Understand the shrinkage rate of the material used and make corresponding adjustments in the medical plastic syringe injection mold design to ensure that the dimensions of the syringe after molding meet the requirements.

-Flowability: The disposable medical syringe injection mold design should consider the flowability of the plastic to ensure that the material can smoothly fill the mold cavity during injection molding.

3.Features of Disposable Medical Syringe Injection Mold

KRMOLD specializes in the design and manufacture of medical plastic syringe injection molds, boasting several unique disposable medical syringe injection mold features:

-Flexible Production Capacity: Medical plastic syringe injection mold designs ranging from 16 to 64 cavities can be selected to meet different production scales.

-High Surface Quality: The core and cavity undergo special polishing, resulting in a highly transparent and dent-free surface, enhancing the appearance of the syringes.

-High Precision Control: High precision control over the parallelism of the template machining and the concentricity of the inserts ensures consistent production quality for each syringe.

-Optimized Structure: A single-cavity self-locking structure prevents product eccentricity, improving production consistency.

-Easy Maintenance: A single-insert structure allows for interchangeable standard components within the mold, facilitating maintenance and reducing long-term operating costs.

-Balanced Cooling Design: The template's water channels employ a unique balanced design, ensuring consistent water flow and pressure in each cavity, resulting in more stable molding quality.

-Rapid Cooling System: All water channels in the mold cavities utilize a spiral unidirectional circulation mechanism, enabling rapid cooling, shortening the molding cycle, and improving production efficiency.

4.Disposable Medical Syringe Injection Mold Solutions

Disposable medical syringes include body, plunger, piston, plug, needle cap, and needle tip among several other components. PP (polypropylene) makes up the main material of common syringe sizes, which range from 1ml, 5ml, 10ml, 20ml to 25ml. Including mold design, mold manufacturing, and mold testing—a full service package—KRMOLD professionally offers high-precision medical plastic syringe injection mold solutions.

KRMOLD is committed to providing users with an integrated pre-sales, sales, and after-sales service model, ensuring customers receive high-quality support and service at every stage. KRMOLD warmly welcomes customers to visit its factory, where you can gain a deeper understanding of the manufacturing process of disposable medical syringe injection molds and evaluate the quality and performance of KRMOLD medical plastic syringe injection molds.