Selecting the correct pressboard insulation material is critical to transformer performance, safety, and long-term reliability. Whether you are a procurement engineer or an OEM project lead, making the right choice means knowing how pressboard properties fit your needs.
In this guide, we will show you five important steps. These steps will help you choose the right electrical insulation pressboard. We will cover material selection based on your needs and how to check supplier capabilities.
Step 1: Define Your Application Clearly
The first step in material selection is to clarify how the pressboard will be used inside your transformer. Properties like rigidity, oil absorption, and dielectric strength vary significantly by application.
Common Applications Include:
- 🌀 Winding layer insulation – requires flexibility and uniform thickness
- 🔩 Structural coil spacers – must support compression and stress
- 🧱 Cylinder sleeves, duct strips, end rings – demand thermal endurance and dimensional integrity
➡️ Application clarity allows you to specify the right shape (e.g., CNC-cut blocks, rolls, or laminated sheets).
Step 2: Understand the Types of Insulation Pressboard
Different grades of pressboard are designed for different structural or insulation roles. Below is a quick overview:
| Type | Description | Thermal Class |
|---|---|---|
| Standard Pressboard | Pure kraft cellulose, general insulation use | A / E |
| Pre-Compressed Pressboard | High-density board for load-bearing insulation | F+ |
| Formable Pressboard | Can be bent into 3D shapes; used in corners/barriers | Varies |
✅ Choose based on mechanical needs and whether shaping, bending, or CNC machining is required.
Step 3: Select the Right Thickness & Format
Thickness and format influence how the pressboard performs and how it integrates with your production process.
Standard Thickness Ranges:
- 0.3 – 8.0 mm for standard insulation use
- 8 – 60 mm for pre-compressed and structural boards
Available Formats:
- Sheets and rolls
- Blocks for CNC shaping
- Die-punched or slotted profiles
📏 Tip: For tight tolerances (±0.1 mm), always confirm batch specs with your supplier.
Step 4: Verify Key Electrical & Mechanical Specs
Transformer-grade pressboard must meet strict performance requirements. Confirm the following before purchase:
PropertyTypical ValueStandardDielectric Strength≥60 kV in oilIEC 60641Density1.0–1.2 g/cm³ (standard)SGS/IECThermal ClassificationA–F depending on gradeIEC 60085
✅ Ask for IEC test certificates and SGS batch reports for transformer OEM projects.
Step 5: Evaluate Supplier’s Processing Capabilities
Even the best pressboard material fails if it’s not properly processed. Your supplier should provide value-added services:
- CNC machining, slotting, and shaping
- Oil impregnation or pre-drying (for oil-filled designs)
- CAD-based custom insulation kits
➡️ Work with a certified pressboard insulation material factory that understands transformer specs and supports end-to-end customization.
✅ Conclusion: Don’t Leave Insulation to Guesswork
The right custom pressboard insulation material is the foundation of reliable transformer performance. Define your needs clearly, match thermal and dielectric specs, and verify supplier capabilities.
👉 Contact us for technical support, datasheets, or sourcing transformer insulation boards tailored to your project.
🔘 Request a Quote Now
🔘 Download Technical Datasheet
✅ Response within 24 hours. Pre-cut shapes and samples available on request.
📲 WhatsApp: +86 180 6910 1930
