Views: 0 Author: Site Editor Publish Time: 2026-09-15 Origin: Site
Custom SMC should be specified according to the final component, molding process and performance requirements—not simply by resin type, color or glass fiber content. A complete RFQ allows the SMC supplier to evaluate formulation, molding behavior, compliance requirements and commercial feasibility before recommending a suitable material.
JLON supplies custom Sheet Molding Compound for electrical insulation, automotive components, utility enclosures, sanitary products, transportation parts and other compression-molded applications. Working with qualified manufacturing partners, JLON can adjust the resin system, glass fiber content, fillers, additives, color and molding characteristics to meet different component requirements.
This guide explains the technical and commercial information buyers should provide when requesting a custom SMC formulation or quotation.
Sheet Molding Compound, commonly known as SMC, is a ready-to-mold thermoset composite supplied in sheet or roll form. A typical SMC formulation contains unsaturated polyester or vinyl ester resin, chopped glass fiber reinforcement, mineral fillers, low-shrink or low-profile additives, initiators, mold-release agents, thickeners and pigments. Flame-retardant additives and other functional materials may be added when required.
The complete formulation determines the material’s strength, stiffness, flow, shrinkage, surface quality, electrical insulation, flame resistance, heat resistance, weatherability and molding performance.
A standard SMC grade may be suitable for common industrial parts, but many components require a customized formulation. For example, an outdoor electrical enclosure may require high CTI, low water absorption, flame resistance, UV stability and a specific color. An automotive exterior panel may instead prioritize low density, Class A surface quality, dimensional stability and low-profile performance.
Custom SMC development should therefore begin with the finished component and its operating conditions—not with a generic technical datasheet.
A request such as “Please quote flame-retardant SMC” does not provide enough information for accurate material selection.
Different flame-retardant SMC grades may have different UL 94 classifications, glass fiber contents, tracking resistance, mechanical properties, density, surface quality, shrinkage, molding flow, color limitations, regulatory status and material costs.
The correct Sheet Molding Compound also depends on part geometry, mold design, press capacity and processing conditions. Two customers manufacturing similar parts may need different SMC formulations because their equipment, molds and quality requirements are different.
A detailed custom SMC RFQ helps JLON and its manufacturing partners match the project with an existing SMC grade, determine whether formulation modification is necessary and identify technical risks before sampling.
Complete information also allows the supplier to recommend realistic performance values, estimate material consumption, evaluate production cost and prepare samples that are closer to the customer’s actual application. This can reduce repeated molding trials, shorten qualification time and improve the accuracy of the price, MOQ and lead time.
The first requirement is a clear description of the molded component and its end-use environment.
JLON supplies custom SMC materials for electrical meter boxes, water meter boxes, distribution boxes, switchgear components, EV battery enclosures, energy-storage enclosures, automotive body panels, automotive underbody panels, manhole covers, drainage covers, railway components, commercial-vehicle parts, shower trays, bathtubs, bathroom wall panels, seats, equipment housings and other structural industrial components.
The final application determines which material properties deserve the highest priority.
Final product: State the name and function of the finished molded component.
Installation location: Explain where the component will be installed and whether it will be used indoors or outdoors.
Operating environment: Identify exposure to electricity, heat, moisture, chemicals, salt water, wastewater, sunlight or mechanical impact.
Structural requirement: Confirm whether the component will carry a continuous, temporary or impact load.
Appearance requirement: State whether the molded surface will be visible, painted, coated or hidden during final assembly.
Current material: Identify the existing SMC, BMC, metal, thermoplastic or other material currently used.
Reason for material change: Explain whether the project aims to reduce cost, improve strength, solve molding defects, reduce weight, improve fire performance or meet a new standard.
Information about the current material and its limitations is especially valuable when JLON is asked to recommend a replacement grade.
A two-dimensional drawing, three-dimensional model or clear component photograph should be provided whenever possible.
The SMC supplier needs to understand the overall dimensions, nominal wall thickness, thick and thin sections, ribs, bosses, metal inserts, holes, openings, material flow distance, surface area, expected component weight, critical tolerances and visible surfaces.
Large, thin components generally require better material flow than small, thick components. Deep ribs, narrow corners and long flow distances can affect mold filling, glass fiber distribution and required molding pressure.
Engineering drawing: A PDF drawing should show dimensions, tolerances, wall thicknesses and important component features.
Three-dimensional file: STEP, STP or another suitable CAD format can help the technical team evaluate geometry and flow distance.
Component photograph: Clear photographs can show the surface, inserts, ribs, openings and assembly position.
Existing material data: A current technical datasheet or test report can provide a useful performance benchmark.
Failure information: Photographs or reports showing cracks, warpage, incomplete filling, poor surface appearance or other defects can help identify the correct improvement direction.
Existing samples: A physical component or material sample may be useful when drawings and technical specifications are incomplete.
JLON uses these documents to evaluate material suitability, customization requirements and quotation conditions.
Most SMC materials are processed by compression molding in a heated metal mold. However, molding equipment and processing conditions vary significantly between manufacturers.
The customer should provide the molding process, press type, press tonnage, platen dimensions, mold dimensions, mold temperature, molding pressure, curing time, material-loading method, charge position and planned production cycle.
The press capacity must be suitable for the projected component area and required molding pressure. A formulation with excellent mechanical properties may still perform poorly if its flow behavior does not match the mold, press or charge pattern.
Material flow: The formulation can be adjusted to improve filling of large areas, deep ribs and complicated features.
Curing behavior: Faster or slower curing may be required according to the mold temperature, component thickness and production cycle.
Fiber distribution: Formulation and processing adjustments can help reduce glass fiber separation during long-distance flow.
Mold release: The internal release system can influence demolding efficiency and surface condition.
Surface appearance: Resin, filler and additive selection can affect gloss, fiber read-through, waviness and porosity.
Dimensional stability: A suitable low-shrink or low-profile system can help reduce warpage and dimensional variation.
Whenever possible, customers should provide the processing conditions used with their current SMC material.
Mechanical requirements should be defined according to the finished component and relevant testing standards.
A custom SMC specification may include tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, compressive strength, shear strength, screw-holding performance, fatigue resistance and creep resistance.
Buyers should avoid requesting the highest possible value for every property. Increasing one property may affect density, cost, flow, surface appearance or another performance characteristic.
For example, increasing glass fiber content may improve strength and stiffness, but it may reduce material flow and make it more difficult to obtain a smooth molded surface.
Glass fiber content is an important SMC parameter, but it should not be treated as the only indicator of material quality.
Many conventional SMC formulations contain approximately 20% to 35% glass fiber by weight. Specialized grades may use different reinforcement contents depending on the application.
Mechanical performance: Higher reinforcement content may improve strength and stiffness within a suitable formulation range.
Part geometry: Complex parts and long flow distances may require a balance between reinforcement content and material flow.
Surface quality: High reinforcement content can make it more difficult to achieve a smooth visible surface.
Molding conditions: Press capacity, pressure, temperature and charge pattern influence how effectively the material flows.
Density and cost: Reinforcement level must be considered together with filler selection, target density and total material cost.
Customers should specify the required performance of the finished component rather than selecting a glass fiber percentage without considering the complete SMC formulation.
Electrical SMC is widely used for meter boxes, distribution enclosures, switchgear parts, insulator supports and electrical housings.
The important requirements may include dielectric strength, Comparative Tracking Index, arc resistance, insulation resistance, volume resistivity, surface resistivity, water absorption, UL 94 flammability classification and Heat Deflection Temperature.
Comparative Tracking Index, or CTI, evaluates the resistance of an insulating material to electrical tracking under specified test conditions. Applications such as switchgear components and electrical enclosures may require a high CTI value.
The buyer should provide both the required CTI value and the applicable test method.
Dielectric strength indicates the level of electrical stress the material can withstand before breakdown. The required value should be defined together with the specimen thickness and testing method.
Arc resistance may be important for components exposed to electrical arcing. It should not be confused with CTI or dielectric strength because these tests evaluate different electrical behaviors.
JLON can help customers organize these electrical requirements before recommending an electrical insulation SMC grade.
“Flame-retardant SMC” is not a complete technical specification. Buyers must identify the required fire test, classification and specimen conditions.
Flammability classification: State the required rating, such as the applicable UL 94 classification.
Test standard: Provide the full standard number and any customer-specific testing method.
Specimen thickness: Confirm the thickness at which the material must achieve the required result.
Certification scope: Explain whether the requirement applies to a raw-material test specimen or the finished molded component.
Additional requirements: Identify any smoke-density, toxicity, halogen, railway, automotive or electrical-industry requirements.
UL 94 V-0 is frequently requested for electrical SMC. However, the test result depends on material formulation, specimen thickness and testing conditions.
A raw-material test report does not automatically mean that every finished component will obtain the same certification. The molded-part manufacturer must validate the final product according to the applicable standard and certification program.
The custom SMC RFQ should state the continuous operating temperature, short-term peak temperature, required Heat Deflection Temperature, thermal cycling conditions and exposure duration.
The customer should also confirm whether the component will carry a mechanical load at elevated temperature.
A high HDT value does not automatically define long-term thermal performance. Continuous-use temperature and short-term temperature peaks should be considered separately.
Outdoor SMC applications may require UV resistance, color stability, water resistance, freeze-thaw resistance, temperature cycling resistance, low moisture absorption, corrosion resistance and long-term surface durability.
Outdoor electrical boxes, utility covers and SMC manhole covers often require a combination of mechanical strength and environmental resistance.
The customer should identify all chemicals that may contact the finished component. Relevant substances may include acids, alkalis, fuels, oils, cleaning agents, salt water, wastewater and industrial chemicals.
The RFQ should also specify chemical concentration, exposure temperature and contact duration. Occasional splashing and continuous immersion require different material evaluations.
Surface and dimensional requirements can significantly influence the custom SMC formulation.
The customer should define whether the component requires a general industrial surface, smooth molded surface, paintable surface, low fiber read-through, low waviness, Class A automotive surface, tight dimensional tolerance, minimal warpage or compatibility with in-mold coating.
Low-shrink SMC and low-profile SMC are related but not identical. A functional electrical enclosure may mainly require dimensional stability, while an automotive exterior panel may require extremely low shrinkage and a high-quality visible surface.
Current molding defects should be described in the RFQ. Possible problems include pinholes, porosity, fiber read-through, sink marks, waviness, blisters, cracks, poor gloss, color variation, mold sticking and incomplete filling.
These defects may be related to the SMC formulation, mold design, charge pattern, molding temperature, pressure or curing cycle. Changing the material alone may not solve every processing problem.
The customer should provide a RAL, Pantone or customer-specific color code whenever an exact color is required.
The RFQ should also describe the required gloss level, surface texture, color tolerance, UV color stability and any painting or coating process used after molding.
Color matching should be confirmed with an approved molded sample. Fillers, flame retardants and pigments may influence the appearance of the finished component.
Conventional mineral-filled SMC is generally denser than many engineering thermoplastics. Low-density SMC can be developed by modifying the filler system or incorporating lightweight additives.
A lightweight SMC request should include the maximum material density, target component weight, minimum mechanical properties, required surface quality and target cost.
Reducing density can affect strength, stiffness, flow, surface quality and price. The density requirement should therefore be based on the finished component rather than simply requesting the lowest possible value.
The RFQ should identify all mandatory testing and certification requirements before formulation selection and quotation.
Depending on the application and target market, the requirements may include UL-related testing, RoHS, REACH, automotive OEM specifications, railway fire standards, electrical-industry standards, local utility requirements, customer-specific testing, third-party inspection, material traceability and batch test reports.
Supplier laboratory data: Test values generated by the material supplier under defined internal or standard conditions.
Third-party material report: Results issued by an independent testing organization for submitted material samples.
Raw-material recognition: Recognition or listing associated with a specific material grade and defined conditions.
Finished-product certification: Certification based on the design, thickness, manufacturing process and performance of the final molded product.
Factory certification: A quality-management or manufacturing-system certificate that does not directly certify every material property.
These documents are not interchangeable. JLON will evaluate which documents are already available and which additional tests may be required for the project.
Technical requirements alone are not sufficient for a practical quotation.
Trial quantity: State the quantity required for laboratory testing or initial molding trials.
Order quantity: Provide the estimated quantity for each regular purchase order.
Annual consumption: Estimate the projected yearly demand after mass production begins.
Delivery destination: Provide the destination country, city and port where applicable.
Trade terms: State the preferred Incoterm and any special shipping requirements.
Project schedule: Provide the target dates for sampling, testing, approval and mass production.
Target price: If available, provide a realistic target price or current material cost for reference.
Custom colors and formulations may require a minimum production quantity. Small trial quantities may be possible depending on the selected grade and development requirements.
Because Sheet Molding Compound has a limited shelf life, order quantity should be planned according to the customer’s molding capacity and storage conditions.
Sheet Molding Compound should be packed to reduce contamination, moisture change and loss of volatile components.
Packaging format: Confirm whether the material should be supplied as rolls, folded sheets or pre-cut charges.
Package weight: State the preferred roll or package weight and the maximum safe handling weight.
Pallet requirements: Identify pallet dimensions, stacking restrictions and export-packaging requirements.
Storage facilities: Confirm whether controlled-temperature or refrigerated storage is available.
Storage temperature: Provide the expected warehouse and production-area temperatures.
Required shelf life: State the minimum shelf life required upon arrival.
SMC should be stored under controlled conditions according to the supplier’s instructions. Excessive temperature or extended storage can change viscosity, tack, flow and molding performance.
Before molding, refrigerated SMC may require controlled conditioning to the recommended processing temperature. The package should normally remain closed during conditioning to reduce the risk of condensation.
Final product: Name and function of the molded component.
Operating environment: Indoor or outdoor use and exposure to heat, electricity, moisture, chemicals, sunlight or impact.
Current material: Existing SMC, BMC, metal, thermoplastic or other material.
Development objective: Required improvement in cost, performance, appearance, weight or processing.
Drawing: PDF drawing, CAD file or three-dimensional model.
Dimensions: Overall size, wall thickness, ribs, bosses, openings and flow distance.
Component weight: Current weight and target weight where applicable.
Surface requirement: General industrial, paintable, low-profile or Class A surface.
Tolerances: Critical dimensional and assembly requirements.
Equipment: Press type, press tonnage and platen dimensions.
Mold: Mold dimensions, cavity structure and relevant design information.
Process: Mold temperature, molding pressure, curing time and production cycle.
Charge pattern: Number, size and location of SMC charges.
Current problems: Flow, release, curing, cracking, warpage or surface defects.
Resin system: Unsaturated polyester, vinyl ester or another required thermoset system.
Reinforcement: Required glass fiber content or final mechanical performance.
Physical properties: Density, shrinkage, flow and water absorption.
Mechanical properties: Tensile, flexural, impact and other required values.
Electrical properties: CTI, dielectric strength, arc resistance and resistivity.
Fire performance: Required classification, standard and test thickness.
Environmental properties: Heat, UV, weather, moisture and chemical resistance.
Appearance: Color, gloss, texture and surface-quality requirements.
Testing standards: Full names and numbers of all applicable standards.
Certificates: Required material, factory or finished-product certificates.
Third-party testing: Required testing organization or laboratory qualification.
Regulatory requirements: Market-specific environmental, chemical or safety requirements.
Trial demand: Quantity required for initial evaluation and molding trials.
Regular order: Estimated quantity for each production order.
Annual demand: Expected consumption after commercial approval.
Delivery: Destination, preferred Incoterm and required delivery date.
Packaging: Roll, sheet, package weight, pallet and storage requirements.
Project schedule: Target dates for sampling, qualification and mass production.
JLON supplies Sheet Molding Compound for a wide range of industrial, transportation and electrical applications. Instead of recommending one generic SMC grade for every component, JLON evaluates the customer’s application, part drawing, molding conditions and performance requirements.
JLON can provide preliminary requirement review, existing-grade matching, application-specific formulation recommendations, coordination with qualified manufacturing partners, color and property adjustment, sample preparation, technical datasheet preparation, third-party testing coordination, export packaging and delivery support.
JLON can also follow the customer’s molding trials and help communicate technical feedback to the manufacturing partner during material adjustment.
Because many SMC products are application-specific, an initial technical datasheet should be treated as a formulation reference. Final performance and production suitability must be confirmed through material testing and molding trials using the customer’s actual mold and processing conditions.
To receive an accurate custom SMC recommendation and quotation, please send JLON the final component description, application, part drawing, required technical properties, applicable testing standards, color requirements, surface requirements, molding equipment, processing conditions, estimated order quantity, annual consumption, delivery destination and project schedule.
JLON will review the information and recommend a suitable existing Sheet Molding Compound grade or coordinate the development of a custom SMC formulation.
Contact JLON to discuss custom SMC materials for electrical insulation, automotive components, EV battery enclosures, energy-storage enclosures, meter boxes, distribution boxes, utility covers, bathroom products and other compression-molded composite parts.
