Complete Guide to Dispensing Needle Specifications and Models

Overview

Dispensing needles are critical components in precision dispensing processes, with their specifications and materials directly affecting dispensing accuracy, efficiency, and cost. This article provides a comprehensive guide to various dispensing needle specifications, material properties, applications, and selection criteria.

Stainless Steel Dispensing Needle Specifications

Stainless steel dispensing needles offer high precision, corrosion resistance, and reusability, making them the preferred choice for high-end dispensing applications.

Specification (G)	Outer Diameter (mm)	Inner Diameter (mm)	Wall Thickness (mm)	Material	Suitable Adhesives	Applications
14G	2.11	1.60	0.26	304/316L	High viscosity adhesives	High-flow dispensing
16G	1.65	1.19	0.23	304/316L	Medium-high viscosity	Fast dispensing
18G	1.27	0.84	0.22	304/316L	Medium viscosity	Standard dispensing
20G	0.91	0.60	0.16	304/316L	Medium viscosity	Precision dispensing
22G	0.72	0.41	0.16	304/316L	Low viscosity	Fine dispensing
25G	0.51	0.26	0.13	304/316L	Low viscosity	Ultra-fine dispensing
27G	0.41	0.20	0.11	304/316L	Very low viscosity	Micro dispensing
30G	0.31	0.16	0.08	304/316L	Very low viscosity	Nano dispensing

Stainless Steel Needle Features

• High Precision: Dimensional tolerance ±0.02mm
• Corrosion Resistance: Suitable for various chemical adhesives
• Reusable: Can be cleaned and reused multiple times
• Long Life: Service life up to tens of thousands of cycles

Plastic Dispensing Needle Specifications

Plastic dispensing needles are low-cost, disposable, and suitable for mass production.

Specification	Outer Diameter (mm)	Inner Diameter (mm)	Material	Color	Suitable Adhesives	Features
Coarse Needle	2.0-3.0	1.5-2.5	PP/PE	Transparent/White	High viscosity	Disposable, low cost
Medium Needle	1.5-2.0	1.0-1.5	PP/PE	Transparent/Blue	Medium viscosity	General purpose
Fine Needle	1.0-1.5	0.6-1.0	PP/PE	Transparent/Green	Low viscosity	Precision dispensing
Ultra-fine Needle	0.8-1.0	0.4-0.6	PP/PE	Transparent/Yellow	Very low viscosity	Micro dispensing
Tapered Needle	Variable	Variable	PP/PE	Transparent	Various viscosities	Adjustable flow

Plastic Needle Features

• Low Cost: Price only 1/10 of stainless steel
• Disposable: Avoid cross-contamination
• Color Coded: Easy specification identification
• Lightweight: Reduce equipment load

Special Material Dispensing Needles

PEEK Material Needles

• Specification Range: 18G-30G
• Features: High temperature resistance (260°C), corrosion resistance
• Applications: High-temperature dispensing, chemical adhesives

Ceramic Material Needles

• Specification Range: 20G-27G
• Features: Ultra-hard, wear-resistant, insulating
• Applications: High precision, long-term use

Titanium Alloy Needles

• Specification Range: 18G-25G
• Features: Lightweight, corrosion-resistant, biocompatible
• Applications: Aerospace, special environments

Gold-plated Needles

• Specification Range: 20G-30G
• Features: Good conductivity, oxidation resistance
• Applications: Electronic packaging, conductive adhesives

Needle Shape Classification

Straight Needles

• Standard Straight: Consistent inner and outer diameter, stable flow
• Tapered: Gradual inner diameter change, adjustable flow
• Stepped: Multi-stage inner diameter, precise control

Bent Needles

• 90° Bent: Right-angle turn, space-constrained applications
• 45° Bent: Angled turn, special angle dispensing
• Adjustable Bent: Adjustable angle, flexible applications

Special Needles

• Dual-tube: Dual channels, adhesive mixing
• Heated: Built-in heating, hot-melt applications
• Vibrating: High-frequency vibration, anti-clogging

Dispensing Needle Selection Guide

Selection by Adhesive Viscosity

Adhesive Viscosity	Recommended Spec	Material Suggestion	Features
>10000cP	14G-18G	Stainless steel/Coarse plastic	High flow, fast dispensing
1000-10000cP	18G-22G	Stainless steel/Medium plastic	Balanced speed and precision
100-1000cP	22G-25G	Stainless steel/Fine plastic	High precision, medium speed
<100cP	25G-30G	Stainless steel/Ultra-fine plastic	Highest precision, slow speed

Selection by Dispensing Precision

Precision Requirement	Recommended Spec	Features	Applications
Coarse Dispensing	14G-18G	High flow, fast	Encapsulation, filling
Standard Dispensing	18G-22G	Balanced speed and precision	General electronic packaging
Precision Dispensing	22G-25G	High precision, medium speed	Precision electronics
Ultra-precision Dispensing	25G-30G	Highest precision, slow speed	Microelectronics, optics

Selection by Application Scenario

Application Scenario	Recommended Spec	Material Suggestion	Special Requirements
Electronic Packaging	20G-27G	Stainless steel/PEEK	High precision, corrosion resistance
LED Packaging	25G-30G	Stainless steel/Ceramic	Ultra-precision, insulation
PCB Dispensing	22G-27G	Stainless steel	Conductivity, precision
Automotive Electronics	18G-25G	Stainless steel	Reliability, durability
Medical Devices	25G-30G	Stainless steel/Titanium alloy	Biocompatibility, sterility

Needle Maintenance and Care

Stainless Steel Needle Maintenance

• Cleaning: Use specialized cleaning agents, ultrasonic cleaning
• Sterilization: High-temperature or chemical sterilization
• Storage: Anti-rust treatment, dry environment
• Lifespan: Reusable, regular wear inspection

Plastic Needle Maintenance

• Cleaning: Solvent cleaning, avoid strong acids and bases
• Sterilization: UV or chemical sterilization
• Storage: Sealed packaging, light-proof and moisture-proof
• Lifespan: Disposable or limited use

Common Problems and Solutions

Problem	Cause	Solution	Prevention
Clogging	Adhesive curing, impurities	Replace needle, clean	Regular cleaning, filter adhesive
Uneven Flow	Needle wear, deformation	Replace needle	Regular inspection, proper use
Precision Decline	Needle wear, vibration	Replace needle, adjust parameters	Optimize process parameters
Adhesive Splashing	Needle too large, high pressure	Replace with finer needle, adjust pressure	Proper selection, parameter optimization

Selection Recommendations

Cost Considerations

• Mass Production: Choose plastic needles to reduce costs
• Small Batch High Precision: Choose stainless steel needles to ensure quality
• Special Applications: Choose special materials to meet requirements

Precision Requirements

• General Precision: 18G-22G, balance cost and precision
• High Precision: 22G-25G, ensure quality
• Ultra-high Precision: 25G-30G, special applications

Production Efficiency

• Fast Production: Choose coarse needles to increase speed
• Precision Production: Choose fine needles to ensure precision
• Automation: Consider needle replacement convenience

Summary

Choosing the right dispensing needle is key to ensuring dispensing quality and efficiency. It's necessary to comprehensively consider adhesive properties, precision requirements, cost factors, and production efficiency. Through proper selection and maintenance, the stability and reliability of dispensing processes can be significantly improved.

Remember: Larger specifications mean finer needles, higher precision, but smaller flow rates. In practical applications, it's necessary to find the optimal balance point based on specific requirements.