Precision Copper Capillary Tube (Cu-OF / Cu-ETP / Cu-DHP)
Precision copper capillary tubes are small-diameter copper tubes designed for applications requiring controlled flow of liquids or gases through a precise internal passage. By controlling the tube's internal diameter, wall thickness, length, and dimensional consistency, copper capillary tubes can provide stable flow resistance and controlled pressure drop.
Our copper capillary tubes are available in Cu-OF (CW008A), Cu-ETP (CW004A), and Cu-DHP (CW024A) copper alloys. Depending on the application, they can be supplied for refrigeration flow control, heat pipe evacuation and charging, precision fluid transfer, instrumentation, and other small-bore tubing applications.
For refrigeration applications, Cu-DHP / CW024A / C12200 is a commonly selected copper grade for capillary tubing because of its formability and suitability for brazed copper tube systems. For heat pipe manufacturing, Cu-OF / CW008A / C10200 is suitable for applications where low oxygen content, material purity, vacuum processing, and subsequent sealing are important
Capillary Tube Sizes We offer:
Copper Grades: Cu-OF (CW008A), Cu-ETP (CW004A), Cu-DHP (CW024A)
Coil Tube OD: 0.5–10 mm
Wall thickness:0.05-1.2mm
Straight Tube OD: 0.5–40 mm
Wall Thickness: 0.05–2.00 mm
Straight lengths or tube coils
Custom profiles and precision tolerances
Technical support, competitive pricing, and worldwide shipping
Precision Copper Capillary Tube Manufacturing Advantages
Outside Diameter: From 0.5 mm with ±0.01 mm tolerance
Wall Thickness: From 0.05 mm with ±0.005 mm tolerance
Length Accuracy: Up to ±0.05 mm
Excellent straightness and concentricity
Smooth inner and outer surface finish
Suitable for automated assembly and high-precision manufacturing
Custom dimensions and tolerances available upon request
Processing Services We provide:
Precision cutting
Tube bending
Tube expansion
End forming
CNC machining
Cleaning and degreasing
Coil winding
Custom profile manufacturing
Copper Grades for Different Applications
The appropriate copper grade depends on how the capillary tube will be used. Rather than treating all copper grades as interchangeable, we select the material according to the application's flow, forming, joining, vacuum, cleanliness, and processing requirements.
Cu-DHP / CW024A / C12200 — For Refrigeration Capillary Tubes
Cu-DHP / CW024A / C12200 is a phosphorous-deoxidized copper grade commonly used for copper tubing applications requiring good formability and brazing suitability.
For refrigeration capillary tubes, the material works together with the tube's internal diameter and effective length to provide the required flow resistance and refrigerant metering characteristics.
This copper grade is suitable for applications such as:
Refrigeration capillary tubes
Refrigerators and freezers
Small refrigeration systems
Air-conditioning equipment
Dehumidifiers
Small heat pump systems
For customers who specify different material designation systems, Cu-DHP, CW024A, and C12200 identify the material through commonly used copper designation systems in different markets.
Cu-OF / CW008A / C10200 — For Heat Pipe Manufacturing
Cu-OF / CW008A / C10200 is an oxygen-free copper grade suitable for applications where low oxygen content and material purity are important.
For heat pipe and vapor chamber manufacturing, small copper tubes can be used as evacuation tubes, charging tubes, fill tubes, or degassing tubes. They provide a connection for removing air and other non-condensable gases, introducing the working fluid, and completing the sealing process.
Typical applications include:
Heat pipe evacuation tubes
Heat pipe charging tubes
Heat pipe fill tubes
Heat pipe degassing tubes
Vapor chamber manufacturing
Electronics thermal management
CPU and GPU cooling assemblies
For customers using different international designation systems, Cu-OF, CW008A, and C10200 refer to the corresponding material designation used in different markets.
Cu-ETP / CW004A
Cu-ETP / CW004A is an electrolytic tough-pitch copper grade known for its high electrical and thermal conductivity. It can be supplied for selected precision tube applications where high conductivity is an important requirement.
The suitability of Cu-ETP depends on the customer's tube manufacturing process, joining method, service environment, and dimensional requirements. Please contact us with your application details so we can confirm whether Cu-ETP is appropriate for your specific capillary tube requirements.
Applications of Precision Copper Capillary Tubes
Copper capillary tubes are used in different industries because their small internal passages allow controlled movement of liquids or gases. The required material and dimensions vary according to the application.
Refrigeration Capillary Tubes
In refrigeration systems, the capillary tube acts as a throttling and flow-control device between the condenser and evaporator.
A typical refrigeration cycle is:
Compressor → Condenser → Capillary Tube → Evaporator → Compressor
The refrigerant leaves the compressor as a high-temperature, high-pressure gas. After releasing heat in the condenser, it becomes a high-pressure liquid or liquid-dominant refrigerant stream. When the refrigerant passes through the small internal passage of the capillary tube, the flow resistance produces a pressure drop and limits the refrigerant flow into the evaporator.
Typical applications include:
Refrigerators
Freezers
Small refrigeration units
Beverage coolers
Dehumidifiers
Small air-conditioning systems
Small heat pump systems
Heat Pipe Evacuation and Charging Tubes
Copper capillary tubes can also be used during the manufacture of heat pipes and vapor chambers.
In this application, the tube does not primarily function as a refrigeration throttling device. Instead, it serves as a manufacturing connection for:
Vacuum evacuation
Degassing
Removal of non-condensable gases
Working-fluid charging
Filling
Final sealing
A typical process is:
Heat Pipe Fabrication → Cleaning → Evacuation → Degassing → Working-Fluid Charging → Sealing
The small copper tube is connected to the heat pipe during manufacturing. After the required vacuum level and working-fluid charge are achieved, the tube is sealed, crimped, cut, or otherwise closed according to the manufacturer's process.
Typical applications include:
Heat pipes
Vapor chambers
CPU cooling systems
GPU cooling systems
Laptop cooling modules
Server thermal management
Communication equipment cooling
Power electronics cooling
For these applications, material cleanliness, tube dimensions, compatibility with the heat pipe body, working fluid, evacuation process, and final sealing method should all be considered.
Precision Fluid and Instrumentation Tubes
Beyond refrigeration and heat pipe manufacturing, small-diameter copper tubes can be used in applications requiring controlled transfer of liquids or gases.
Potential applications include:
Precision instrumentation
Laboratory equipment
Fluid transfer systems
Gas distribution systems
Metering systems
Specialized industrial equipment
Small-bore fluid circuits
Material selection and tube dimensions can be adjusted according to the pressure, temperature, fluid, cleanliness, joining method, and dimensional requirements of the application.
Why Choose Our Capillary Copper Tubes?
Premium Cu-OF (CW008A), Cu-ETP (CW004A), and Cu-DHP (CW024A) materials
Outside diameters from 0.5 mm
Wall thicknesses as thin as 0.05 mm
Straight tubes and continuous coils available
Round, oval, square, rectangular, hexagonal, and custom profiles
Tight dimensional tolerances for precision applications
OEM manufacturing and custom processing
Worldwide export experience with fast delivery
Request a Quote
Please provide the following information when requesting a quotation:
Application + Copper Grade + OD/ID or Wall Thickness + Length + Tube Form + Quantity + Processing Requirements
For refrigeration applications, please also provide the refrigerant type and available system parameters.
For heat pipe applications, please provide the heat pipe material, working fluid, evacuation/charging process, and sealing requirements.
We can then confirm the suitable copper grade, dimensions, processing requirements, and supply option for your application.
