Step 1: Sourcing High-Purity Kraft Pulp – The Insulation Starts Here、
Every high-quality pressboard starts with cellulose. Our factory uses unbleached, chemical-free kraft pulp as the main material. This helps keep low conductivity and high strength.
- IEC-grade input materials
- Moisture-controlled fiber storage areas
- Full traceability for every production batch ➡️ Only virgin pulp is used—no recycled fiber contaminants.
Step 2: Sheet Forming & Drying Line – Turning Pulp into Pressboard
Kraft pulp is hydraulically pressed into sheets and then sent through multi-zone drying lines.
- Thickness options: 0.3–8.0 mm
- Drying cycles matched to final use (standard vs. pre-compressed)
- Inline moisture sensors monitor each sheet ➡️ Consistent thermal profiles during drying ensure mechanical stability.
Step 3: Calendering and Density Control – Optimizing Strength and Finish
To achieve uniform density and surface texture, sheets are calendered between heated rollers under pressure.
- Final density: 1.0–1.2 g/cm³ (standard), up to 1.35 g/cm³ (pre-compressed)
- Surface finish: smooth (for lamination) or textured (for oil flow)
- Every 100m² goes through checks for density and thickness. This step makes sure the board meets IEC 60641 thickness and dielectric tolerance.
Step 4: Cutting, Slitting, and Pre-Processing – From Sheet to Part
Once formed and calendered, pressboard is processed into OEM-ready formats:
- Slotted ducts
- Axial spacers
- Pressboard end rings and structural profiles 📦 Output formats include:
- Full sheets or cut panels
- Pre-punched kits
- Laminated blocks ➡️ We accept DXF, DWG, PDF drawings for pre-cut kits.
Step 5: Quality Testing & Certifications – Guaranteed to Perform
All batches are lab-tested before shipment. Our internal QA lab performs:
- Dielectric testing (oil-immersed breakdown voltage)
- Moisture level testing (<7%)
- Dimensional tolerance and visual inspections
- SGS testing and RoHS declarations are available upon request.
- 📄 Compliance standards include IEC 60641, ISO 9001, and RoHS.
- ➡️ QA reports come with every bulk or custom order.
Step 6: Packing & Global Shipping – Ready for Delivery Worldwide
We export to over 30 countries using robust packaging to prevent transit damage.
- Vacuum sealed or foil wrapped to limit moisture re-absorption
- Labeled by transformer part number or kit ID
- Palletized for bulk orders or boxed for LCL shipments
- ➡️ Shipping available to Europe, Middle East, Southeast Asia, and North America.
Why Our Factory?
- 20+ years as a certified insulation pressboard manufacturer
- IEC 60641 & ISO certified production process
- Full in-house CNC machining for ducts, rings, and spacers
- SGS, RoHS, and moisture test reports available
- Trusted by OEM clients in ABB, Siemens supply chain
- ⚙️ Over 2 million transformer kits delivered with <1% quality return rate since 2020.
Contact Us for Factory Tour or Quotation
Want to see how we turn cellulose into certified insulation kits? 👉 Book a live video factory tour or get a quote for your next transformer 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
