FEP heat shrink tubing (Fluorinated Ethylene Propylene heat-shrink tubing) is widely utilized in high-tech fields such as semiconductors, renewable energy, and medical applications due to its resistance to high temperatures (-200°C to 200°C), chemical corrosion, and low dielectric loss. However, improper operation can lead to issues such as uneven shrinking, sealing failure, or even material damage.

Mochitek provides a step-by-step operational guide, an analysis of five common mistakes, and industry application scenarios to help you quickly advance from a novice to a professional user.

I.Core Characteristics of FEP Heat-Shrink Tubing (Why Proper Usage is Crucial)

  • Temperature Resistance: Continuous operating temperature of 200°C with short-term tolerance up to 300°C (superior to PVC and rubber).
  • Chemical Inertia: Resistant to strong acids (such as concentrated sulfuric acid, hydrofluoric acid), strong bases, and organic solvents.
  • Electrical Properties: Dielectric strength >20kV/mm, suitable for high-voltage insulation applications.
  • Shrinkage Ratio: 3:1,1.6:1or 2:1, accommodating various size requirements.

Consequences of Improper Usage:

  • Insufficient Temperature→ Incomplete Shrinkage → Seal Failure
  • Excessive Heating→ Material Decomposition → Release of Toxic Gases
  • Improper Cleaning→ Interface Contamination → Decreased Adhesion Strength

II.Six Steps for Proper Usage of FEP Heat-Shrink Tubing

Step 1: Selection – Matching Size and Performance

(1)Diameter Formula:

D1 = D2 × S

Where D1 represents the inner diameter before shrinking,D2 represents the outer diameter of the object to be covered,and S represents shrinkage ratio(such as 1.3,1.6,2,etc)

(2)Wall Thickness Selection:

Application Scenario Recommended Wall Thickness
General Insulation 0.3-0.5mm
Chemical Protection 0.5-1.0mm
High-Voltage Sealing ≥1.0mm

Step 2: Surface Pretreatment – Cleaning and Polishing

(1)Tools: Non-woven cloth + isopropanol (acetone is prohibited as it may corrode FEP).

(2)Key Points:

  • Remove burrs from metal surfaces to avoid puncturing the heat-shrink tubing.
  • Lightly polish plastic surfaces with 200-grit sandpaper to enhance adhesion.

Step 3: Cutting and Pre-installation

(1)Length Formula:

L1 = L2 + 2*a

Where L1 represents heat shrink tubing length,L2 represents length of the area to be covered,and a represents allowance on both ends.

(2)Tips:

  • Use a sharp blade for cutting to avoid compression deformation.
  • If it is difficult to slide the tubing onto the object, briefly heat the tube opening to soften it.

Step 4: Heating and Shrinkage – Precise Control of Temperature and Time

(1)Tool Selection:

Tool Application Scenario Temperature Setting
Temperature-controlled hot air gun Small batches/precision operations 280-320°C
Infrared tunnel furnace Mass production 290°C ± 5°C
Heat-shrink oven Complex geometries Segmented heating

(2)Operation Process:

  • Start from one end and move in a spiral pattern to evenly heat (speed: 5-10cm/s).
  • When the transparent FEP turns translucent, it indicates the start of shrinkage.
  • After shrinkage is complete, maintain heating for 2-3 seconds to eliminate internal stress.

Step 5: Cooling and Shaping

(1)Natural Cooling: Allow to cool naturally for 3-5 minutes. Avoid forced cooling to prevent thermal stress cracking.

(2)Acceptance Criteria:

  • Smooth surface with no bubbles, wrinkles, or burn marks.
  • Uniform wall thickness after shrinkage (tolerance ±5%).

Step 6: Performance Testing (Optional)

(1)Industrial-Grade Testing:

  • Withstand Voltage Test: Apply 2 times the rated voltage for 1 minute with no breakdown.
  • Airtightness Test: Maintain a pressure of 0.5MPa for 30 minutes with a leakage rate <1%.

III. Five Common Errors and Solutions

Error Phenomenon Cause Analysis Solution
Surface Bubbling After Shrinking The Coated Object Contains Volatile Substances Clean, Dry, and Then Apply
End Recoil Uneven Heating / Insufficient Allowance Leave an Additional 10mm on Both Ends and Heat Thoroughly
Partial Burning Excessively High Hot Air Gun Temperature Use PID Temperature Control Equipment
Poor Adhesion Surface Not Sanded or Cleaned Apply Fluorine-Based Primer After Pretreatment
Incomplete Shrinking Insufficient Temperature or Time Increase to 320°C and Extend Heating Time

IV.Industry Application Scenarios

1.Photovoltaic Inverters – UV Resistance and Weatherability

  • Problem: Outdoor photovoltaic junction boxes experience powdering of heat-shrinkable tubing due to UV exposure.
  • Solution: Use black FEP heat-shrinkable tubing (with carbon black UV inhibitor added).

2.Chemical Pipelines – HF Acid-Resistant Sealing

  • Problem: Corrosion and leakage at joints in HF acid transfer pipelines.
  • Solution: Dual-layer structure: Inner layer of PTFE lining + outer layer of FEP heat-shrinkable tubing.

3.High-Frequency Communications – Low Dielectric Loss Applications

  • Problem: Signal attenuation in 5G base station antennas due to dielectric loss.
  • Solution: Adopt FEP heat-shrinkable tubing with a dielectric constant (ε) of less than 2.1.

If you have any questions or needs regarding our FEP/PTFE/PVDF heat shrink tube, please feel free to contact us. Our contact information is as follows:

Phone: +86 15956561251
Email: ruby@mochi.org.cn

Looking forward to working with you to create a bright future!