China is one of the world's most important production bases for electrical-insulation laminates, including 3240 epoxy sheet, FR4 sheet, G10 sheet, G11 sheet, phenolic laminate, and related composite materials.

The country's advantage is not limited to price. China has mature upstream supply chains for epoxy resin, electronic-grade fiberglass cloth, hot-press lamination equipment, CNC machining, industrial packaging, and export logistics. Key manufacturing clusters are located in Guangdong, Jiangxi, Hebei, Jiangsu, Zhejiang, Henan, and Shandong.

For international buyers, Chinese manufacturers can provide standard sheets as well as customized insulation components for motors, transformers, switchgear, electronics, battery packs, tooling fixtures, molds, and industrial equipment.

However, purchasing 3240 epoxy sheet requires more than comparing prices. The same product name may refer to materials with different resin systems, fiberglass-cloth quality, thermal resistance, thickness tolerance, dielectric properties, and machining performance.

A reliable supplier should be able to explain exactly what material it is producing, which standard applies, how the board is inspected, and whether the final product is suitable for the buyer's operating environment.

The following companies are listed in no strict numerical order. They represent manufacturers and established suppliers with public product information, insulation-material experience, or production capabilities relevant to 3240 epoxy sheet sourcing.

China Epoxy Sheet Manufacturing Facility

Supplier Selection Criteria

The manufacturers in this article were evaluated according to the following practical sourcing factors:

- Product range covering 3240 epoxy sheet, FR4, G10, G11, or related electrical-insulation laminates

- Manufacturing or processing capability

- Technical documentation and material specifications

- Custom sheet-cutting and machining support

- Available capacity or production-scale information

- MOQ transparency

- Quality-management documentation

- Export communication and packaging capability

- Ability to support OEM and customized industrial projects

- Suitability for long-term supply cooperation

A supplier should not be selected based only on its website, product photos, or quoted price. Buyers should request samples, technical data sheets, recent inspection records, certificates, and application-specific test information before approving mass production.

Top 10 3240 Epoxy Sheet Manufacturers in China

1. Guangdong Weishi New Materials Co., Ltd.

Location: Guangdong, China

Established: 2007

Main products: 3240 epoxy sheet, FR4 sheet, G10 sheet, G11 sheet, anti-static epoxy sheet, copper-clad laminate, carbon fiber sheet, engineering plastic sheet, and customized insulation components.

Guangdong Weishi New Materials Co., Ltd. is a suitable option for buyers that require both standard epoxy sheets and customized insulation parts. The company focuses on composite materials, electrical-insulation boards, CNC processing, and flexible customer-oriented production support.

Its product range is suitable for electronics, electrical equipment, lithium battery packs, industrial machinery, mold fixtures, automation equipment, and machined insulation components.

Compared with suppliers that focus only on full-sheet sales, Weishi is particularly relevant for small and medium-sized OEM customers that need custom thicknesses, cut sizes, drilled holes, routed shapes, CNC-machined components, or application-based material recommendations.

The company's published production information indicates a facility area of more than 16,000 m², multiple production workshops, monthly production capability above 100 tonnes, and a technical team that supports material development and process control.

Core strengths:

- Flexible support for low-to-medium-volume customized projects

- 3240, FR4, G10, G11, anti-static, and composite-material options

- CNC cutting, drilling, routing, and custom-part processing

- Practical communication for export-oriented industrial buyers

- Suitable for buyers requiring sheet supply plus processed parts

- Support for customized thickness, color, dimensions, drawings, and packaging

Best suited for: Equipment manufacturers, battery-pack assemblers, electrical-component producers, automation companies, industrial-machinery factories, and overseas distributors requiring customization flexibility.

2. Hebei JingHong Electronic Technology Co., Ltd. / J&Q New Composite Materials

Location: Hebei, China

Established: 2018

Main products: 3240 epoxy sheet, FR4 sheet, bakelite sheet, phenolic cotton laminate, phenolic paper laminate, copper-clad laminate, and electrical-insulation materials.

JingHong is a large-scale insulation-material manufacturer and exporter with a broad product portfolio. Its 3240 epoxy sheet range includes different grades, thicknesses, dimensions, and performance levels for electrical and industrial applications.

The company publishes relatively detailed product information for its 3240 products, including material composition, thickness range, standard sheet sizes, mechanical performance, dielectric strength, water absorption, density, and flammability information.

JingHong is a practical choice for buyers that need regular-volume supply, standard sheet formats, technical documentation, and a relatively transparent MOQ structure.

Core strengths:

- Large-scale insulation-material production

- Published annual capacity information

- Standard and custom 3240 epoxy sheet options

- Grade A, Grade B, and related material variants

- Support for export packaging and industrial supply

- Suitable for buyers with stable recurring sheet demand

Best suited for: Motor manufacturers, transformer factories, switchgear producers, electrical-equipment assemblers, insulation-part converters, and large industrial distributors.

3. ZTelec Group

Location: Henan, China

Established: Long-standing electrical-insulation manufacturer; legal entity details should be verified during supplier onboarding.

Main products: 3240 epoxy sheet, epoxy glass-cloth laminate, insulation paper, insulation film, transformer insulation materials, rods, tubes, tapes, and electrical-insulation products.

ZTelec Group is a specialized electrical-insulation supplier with experience in laminated insulation materials. Its 3240 epoxy sheet is positioned as a glass-cloth laminate produced using epoxy and phenolic resin under hot pressing.

The company's product information references common electrical-insulation standards and describes conventional 3240 material as a Class B insulation product. Its broad product range can be useful for buyers sourcing multiple insulation components for transformers, motors, switchgear, and electrical assemblies.

Core strengths:

- Dedicated electrical-insulation product portfolio

- Sheet, rod, tube, paper, tape, and film product coverage

- Suitable for transformer and motor insulation applications

- Application-oriented material selection support

- Multiple insulation-material categories from one supplier

Best suited for: Transformer manufacturers, motor producers, electrical-maintenance contractors, switchgear factories, and industrial insulation distributors.

4. Jiujiang Xinxing Insulation Material Co., Ltd.

Location: Jiangxi, China

Established: 2003

Main products: 3240 epoxy phenolic fiberglass laminate sheet, FR4, G10, G11, electrical-insulation laminates, and processed insulation parts.

Jiujiang Xinxing Insulation Material is a focused manufacturer of rigid electrical-insulation laminates. The company's product offering includes glass-cloth epoxy laminates used in electrical and electronic applications.

Its public company information indicates an annual insulation-laminate capacity exceeding 4,000 tonnes. It also references ISO 9001:2015 quality management and RoHS-related compliance for relevant products.

The supplier is suitable for buyers looking for a dedicated laminate producer rather than a general engineering-plastic distributor.

Core strengths:

- Focused on rigid electrical-insulation laminates

- Established operating history

- Standard and customized sheet sizes

- Dedicated epoxy-glass laminate product range

- Suitable for electrical and electronic insulation applications

- Available special cutting support

Best suited for: Electrical-equipment manufacturers, machinery factories, insulation-part processors, industrial distributors, and electronics-component producers.

5. Shenzhen Xiongyihua Plastic Insulation Ltd.

Location: Shenzhen, Guangdong, China

Established: 2006

Main products: 3240 epoxy glass sheet, FR4 sheet, bakelite sheet, PTFE sheet, nylon sheet, POM sheet, PVC sheet, ABS sheet, acrylic sheet, and custom machined parts.

Shenzhen Xiongyihua Plastic Insulation Ltd. combines insulation-material supply with engineering-plastic processing. This makes it useful for buyers that need 3240 epoxy sheet together with other industrial plastics, fabricated components, or machine parts.

The company provides 3240 epoxy fiberglass sheets in multiple thicknesses and sizes and supports customized processing. It also serves customers requiring mixed-material orders, such as epoxy sheets, nylon, PTFE, POM, and acrylic components in one procurement project.

Core strengths:

- Broad engineering-plastic and insulation-material range

- Flexible custom cutting and CNC-machining support

- Suitable for mixed-material procurement

- Product options for electronic, mechanical, and industrial applications

- Export-oriented sales experience

- Useful for low-volume customized parts and prototype projects

Best suited for: Automation-equipment manufacturers, jig-and-fixture producers, machine builders, electronics factories, prototype developers, and industrial-component distributors.

6. Shenzhen Xionghua Plastic Insulation Material Co., Ltd.

Location: Shenzhen, Guangdong, China

Established: 1993

Main products: Electrical-insulation materials, engineering plastics, epoxy sheets, phenolic sheets, acrylic sheets, nylon sheets, POM sheets, PTFE sheets, and custom industrial parts.

Shenzhen Xionghua Plastic Insulation Material has a long operating history in Shenzhen's industrial-material market. The company supplies electrical-insulation products and engineering plastics for machinery, electronics, automation, and industrial processing.

For buyers that need standard sheets, cut parts, and multiple industrial material categories, Xionghua can be considered as a comparison supplier. Its long market presence may be useful for projects requiring responsive stock supply and conventional machining support.

Core strengths:

- Long operating history in industrial materials

- Broad insulation and engineering-plastic product range

- Support for standard sheets and fabricated components

- Suitable for industrial parts and machining applications

- Convenient sourcing option for mixed material categories

Best suited for: Machinery manufacturers, repair and maintenance companies, industrial-part fabricators, electronics factories, and trading companies.

7. Huai'an Jianlong Electrical Technology Co., Ltd.

Location: Jiangsu, China

Established: To be verified during supplier qualification

Main products: 3240 epoxy sheet, FR4 sheet, insulation tubes, insulation rods, electrical-insulation boards, composite materials, and custom insulation components.

Huai'an Jianlong Electrical Technology focuses on electrical-insulation materials and related composite products. The company offers 3240 epoxy resin fiberglass plates, insulation boards, rods, tubes, and converted components for electrical applications.

Its public information highlights research, production, processing, and technical support for insulation materials. The company is particularly relevant to buyers that require both standard sheets and fabricated insulation components for motors, generators, transformers, and electrical assemblies.

Core strengths:

- Electrical-insulation material specialization

- Sheet, tube, rod, and custom component supply

- Suitable for motor and transformer applications

- Technical support for electrical-insulation projects

- Ability to supply converted insulation parts

Best suited for: Motor manufacturers, generator factories, transformer producers, electrical-equipment assemblers, and insulation-component processors.

8. SIDA Insulation Material

Location: To be verified during supplier qualification

Established: To be verified during supplier qualification

Main products: 3240 epoxy glass sheet, epoxy fiberglass tubes, rods, laminated insulation materials, and power-equipment insulation products.

SIDA supplies 3240 epoxy glass sheet and related fiberglass insulation products. Its product descriptions focus on the material's mechanical strength, electrical-insulation performance, and suitability for industrial electrical applications.

The company can be considered for buyers seeking sheet, tube, and rod formats from one supplier. However, buyers should conduct full factory verification before approving long-term supply, particularly where supplier registration details, production scale, and certification information are not publicly available.

Core strengths:

- 3240 epoxy sheet, tube, and rod product coverage

- Electrical-insulation application focus

- Suitable for industrial maintenance and component supply

- Can support multiple insulation product formats

Best suited for: Electrical-maintenance companies, industrial distributors, equipment manufacturers, and buyers requiring insulation sheets together with tubes or rods.

9. Quanda Plastic / Ketonolic®

Location: To be verified during supplier qualification

Established: To be verified during supplier qualification

Main products: 3240 epoxy fiberglass sheet, epoxy rods, epoxy tubes, engineering plastics, and machined insulation components.

Quanda Plastic markets 3240 epoxy fiberglass products under the Ketonolic brand. Its product range includes sheets, rods, tubes, and related insulation parts.

One notable advantage is its stated ability to provide a broad thickness range, which may be useful for buyers of heavy-duty insulation structures, thick-machined components, electrical supports, and industrial fixture parts.

For thick sheets or complex machined components, buyers should request internal-quality inspection requirements. Thick laminates may require greater attention to curing consistency, resin distribution, void control, flatness, and machining behavior.

Core strengths:

- Wide thickness options

- Sheet, rod, tube, and component formats

- Suitable for thick insulation structures

- Useful for custom-machined industrial components

- Product range beyond conventional full-sheet supply

Best suited for: Electrical-support component manufacturers, tooling companies, machinery builders, fixture producers, and industrial equipment factories.

10. Zhongcheng Insulation

Location: To be verified during supplier qualification

Established: To be verified during supplier qualification

Main products: 3240 epoxy sheet, transformer insulation materials, electrical-insulation components, and related industrial insulation products.

Zhongcheng Insulation provides 3240 epoxy glass-cloth laminate materials for electrical applications. Its product descriptions emphasize mechanical strength, insulation performance, moisture resistance, and industrial use.

The supplier may be suitable for buyers sourcing transformer-related insulation materials, electrical support components, and conventional epoxy-glass laminates. However, buyers should carefully clarify the exact thermal grade, resin formulation, test standard, and application limitations before final approval.

Core strengths:

- Electrical-insulation application focus

- Suitable for transformer and electrical-equipment projects

- Product positioning for industrial insulation components

- Potential support for application-specific material selection

Best suited for: Transformer manufacturers, electrical-panel builders, switchgear suppliers, motor repair companies, and industrial insulation distributors.

Custom CNC Machined Insulation Components

Manufacturer Comparison Table

Manufacturer	Main Focus	Capacity / Scale	MOQ	Certifications / Standards	Customization Capability
Guangdong Weishi New Materials	Epoxy sheets, FR4, G10/G11, machining	100+ tonnes/month disclosed	Quote required	Product-specific documents available upon request	Strong support for cut-to-size and CNC parts
JingHong / J&Q	3240, FR4, phenolic laminates	Large-scale production disclosed	500 kg published for selected products	ISO management systems and material test data	Standard and customized sheets
ZTelec Group	Electrical insulation materials	Not publicly quantified	Quote required	IEC and GB/T references	Sheets, tapes, rods, tubes, insulation materials
Jiujiang Xinxing	Rigid insulation laminates	4,000+ tonnes/year disclosed	Quote required	ISO 9001:2015 and RoHS references	Custom sizes and processed parts
Shenzhen Xiongyihua	Insulation sheets and engineering plastics	100 tonnes/month claim	Quote required	ISO, RoHS, and SGS references	Strong mixed-material and machining support
Shenzhen Xionghua	Industrial plastics and insulation	Not publicly quantified	Quote required	Quality-system documentation should be confirmed	Sheet cutting and custom industrial parts
Huai'an Jianlong	Electrical insulation boards and components	100+ tonnes/month claim	Quote required	GB/T and IEC references	Sheets, tubes, rods, and custom components
SIDA Insulation Material	Epoxy sheet, tube, and rod	Not publicly quantified	Quote required	Standards should be confirmed	Sheet, tube, and rod formats
Quanda / Ketonolic	Thick epoxy laminates and components	Not publicly quantified	Quote required	Documentation should be confirmed	Thick sheets, tubes, rods, and parts
Zhongcheng Insulation	Electrical and transformer insulation	Not publicly quantified	Quote required	Documentation should be confirmed	Application-oriented insulation supply

What Buyers Should Know Before Ordering

3240, FR4, G10, and G11 Are Not the Same Material

Many suppliers use these product names together in one product listing. This can be convenient for marketing, but it can create technical risks for buyers.

3240 epoxy sheet is generally an epoxy-phenolic glass-cloth laminate. It is commonly used as a Class B electrical-insulation material.

FR4 is generally a flame-retardant epoxy-glass laminate and is often required for electrical applications where flame resistance matters.

G10 is an epoxy-glass laminate grade that may not include the same flame-retardant requirements as FR4.

G11 is generally selected for higher-temperature applications than conventional 3240 material.

Before placing an order, buyers should clearly state the required grade instead of writing only "epoxy sheet" or "FR4 3240 sheet."

Important Material Parameters to Confirm

Ask suppliers to provide the following information for the exact material grade:

- Resin system

- Fiberglass-cloth type

- Thermal class

- Thickness tolerance

- Density

- Flexural strength

- Tensile strength

- Water absorption

- Dielectric breakdown strength

- Insulation resistance

- Flammability performance

- Applicable test standard

- Test sample thickness

- Test-condition details

- Batch number and inspection date

Common Sourcing Risks

The most common problems in 3240 epoxy sheet procurement are not always visible when inspecting a sheet surface.

Buyers may receive material with:

- Lower-grade fiberglass cloth

- High filler content

- Inconsistent resin distribution

- Internal voids

- Poor curing

- Weak interlayer bonding

- Excessive thickness variation

- Low dielectric strength

- Surface cracking after machining

- Delamination around drilled holes

- Material substitution between sample and mass production

A sheet may look smooth and acceptable before machining but fail after drilling, routing, heat exposure, humidity exposure, or electrical loading.

A Less Discussed Quality Check

For machined insulation parts, full-sheet inspection is not enough.

Buyers should request a sample in the same thickness and grade intended for production. Then the buyer should machine the sample using the same drilling, milling, routing, and fastening process planned for the final part.

This process can reveal:

- Edge cracking

- Delamination

- Burr formation

- Hole-wall damage

- Warpage

- Uneven hardness

- Surface peeling

- Internal voids

- Dimensional instability

This is especially important for battery-pack insulation parts, high-voltage components, transformer supports, electrical fixtures, and CNC-machined industrial components.

3240 Epoxy Sheet Material Comparison

Sample and Qualification Process

A structured sample process helps reduce production risks.

1. Send a clear drawing and technical specification to three to five shortlisted suppliers.

2. Request the material data sheet, safety data sheet, quality certificate, RoHS declaration, and current management-system certificates.

3. Confirm the required grade, thickness, tolerance, surface condition, color, and sheet dimensions.

4. Order samples using the final production thickness rather than a convenient stock thickness.

5. Test the sample under real working conditions, including machining, temperature, humidity, electrical load, and assembly.

6. Approve a signed reference sample before mass production.

7. Include the approved grade, inspection requirements, packaging method, and labeling standard in the purchase order.

8. Arrange pre-shipment inspection for the first order or for high-value projects.

Epoxy Sheet Quality Inspection Process

Packaging and Shipping Considerations

3240 epoxy sheets are rigid but can still be damaged during domestic transportation, container loading, sea freight, and unloading.

Buyers should specify:

- Export-grade pallet requirements

- Fumigated or non-fumigated pallets

- Moisture-proof wrapping

- Corner protection

- Edge protection

- Sheet interleaving paper or protective film

- Maximum pallet height

- Thickness separation

- Carton and pallet labeling

- Batch number identification

- Purchase-order number

- Country-of-origin information

- Destination-port requirements

For CNC-machined components, buyers should also specify whether each part requires individual protection, foam separation, vacuum packaging, or moisture barriers.

Conclusion

China offers a broad range of 3240 epoxy sheet manufacturers, from large-scale laminate producers to flexible custom-processing factories. The right supplier depends on whether the project requires standard sheets, high-volume supply, customized dimensions, CNC machining, mixed-material procurement, thermal performance, or electrical-insulation reliability.

Guangdong Weishi New Materials Co., Ltd. is a practical option for buyers that value flexible customization, responsive communication, controlled processing, and support for both standard epoxy sheets and custom insulation components.

For long-term purchasing, the most reliable approach is to compare suppliers using the same technical specification, validate samples under real operating conditions, confirm documentation, and establish clear inspection requirements before mass production.