1
Preform
Woven, stitched, unidirectional or 3D reinforcement stabilized to shape.
Process engineering guide · China supplier discovery
Resin Transfer Molding (RTM) FRP Manufacturers in China
Resin transfer molding (RTM) places a dry fiber preform inside a rigid two-sided mold, closes and clamps the tool, then injects low-viscosity resin before curing. It is used for repeatable complex parts requiring controlled thickness and finished surfaces on both sides.
resin transfer moldingresin transfer molding processRTM composite parts manufacturerclosed mold composites
- Geometry
- Complex closed-mold parts
- Reinforcement
- Dry preform
- Surface
- Two tool-controlled faces
- Volume
- Medium, scalable
Process principle
How the resin transfer molding process works
The mold cavity fixes geometry while the matched permeability of the preform, vent layout and injection strategy determines whether resin reaches every region before gel.
- 01
Build preform
Cut, shape and stabilize reinforcement, core and local inserts.
Control: Verify fiber orientation, areal weight, thickness and permeability consistency. - 02
Load & close
Position the preform in the prepared cavity and close the matched tool.
Control: Check alignment, seals, vents, inserts and clamp condition. - 03
Prepare resin
Meter, mix and condition the injection resin system.
Control: Control ratio, temperature, viscosity, degassing and usable time. - 04
Inject & vent
Drive resin through the preform while displaced air exits the planned vents.
Control: Record pressure, flow time, vent response and vacuum assist if used. - 05
Cure & demold
Hold the validated cure, open the tool and finish the molded part.
Control: Confirm cure, dimensions, surface, internal quality and trim.
Material system
What enters the process
2
Matrix
Low-viscosity thermoset formulated for injection and the selected cure window.
3
Core & inserts
Compatible closed-cell core and positively located hardware where designed.
4
Tool system
Rigid matched mold, seals, ports, vents, heating and clamping.
Strong process fit
- Repeat complex shells and structural panels
- Parts needing two controlled surfaces
- Integrated preforms, core and inserts
Engineering watch-outs
- Flow simulation and trials may be needed for large or variable-thickness parts
- Seal, port and vent changes can invalidate the qualified fill pattern
Buyer audit map
Critical process controls and evidence
A supplier claim is useful only when the process window is tied to the offered material, tooling, drawing revision and production batch.
| Stage | What must be controlled | Evidence to request |
|---|---|---|
| Preform | Material, architecture, compaction and permeability. | Kit traceability, preform traveler and weight/thickness checks. |
| Injection setup | Resin ratio and state, tool temperature, ports, vents and vacuum. | Approved recipe and pre-injection checklist. |
| Fill | Pressure-time trace, vent behavior and complete resin arrival. | Injection log and alarm/deviation record. |
| Release | Cure, dimensions, surface and internal discontinuities. | Cure record, inspection report and qualified NDT where required. |
Defect diagnosis
Common defects, causes and detection
DEFECT 01
Dry spot
Likely cause: Race tracking, low permeability, closed vent or resin gel before complete fill.
Detection: Visual/thermographic process monitoring, ultrasound or sectioning.
DEFECT 02
Porosity
Likely cause: Air entrapment, leaking mix, inadequate degassing or volatile release.
Detection: Ultrasound, microscopy or density/section checks as specified.
DEFECT 03
Preform wash or distortion
Likely cause: Injection force moves fibers or inserts.
Detection: Witness features, imaging, thickness and fiber-orientation review.
Typical resin transfer molding applications
Automotive structures
Aerospace and rail panels
Marine components
Industrial covers and housings
Source transparency
Technical references reviewed
This guide uses the JEC process taxonomy, CAMX/ACMA/SAMPE review framework and process-specific material from industry associations, national research centers or government laboratories. Sources explain the process; they do not endorse listed suppliers.
JEC Composites
About composites and manufacturing technologies
Industry-level process taxonomy covering RTM, infusion, pultrusion, winding, fibre placement and additive manufacturing.
CAMX · ACMA & SAMPE
Manufacturing and processing conference resources
Peer-reviewed conference framework for manufacturing, processing, NDE and testing topics.
ACMA CompositesLab
Resin transfer molding
Dry preform loading, closed-tool injection, vacuum assist and cure sequence.
Reviewed 16 August 2026. Verify current standards editions, material datasheets and project-specific acceptance requirements before award.
PUBLIC SUPPLIER RECORDS
Matching supplier profiles
Each row shows the terms its public profile mentions. A match is a discovery signal, not a qualification.
HRC GroupChangshu, Jiangsu, ChinaProcessComposite intermediate-material development and formulationStandardNot publicly listedMOQNot publicly listedLead timeNot publicly listedHRC Group is an advanced-composites solution provider whose current official website identifies Changshu, Jiangsu as the location of its China R&D, automotive, aerospace and carbon-neutrality operations. The 2026 China Composites Expo directory lists HRC for R&D, engineering, consulting, industrialized serial production, recycling and finished composite parts. HRC's current pages publish thermoplastic injection molding, HP-RTM, wet compression molding, autoclave curing and filament winding, together with recycled-carbon injection pellets, nonwoven, thermoplastic mat, prepreg, thermoplastic sheet, building formwork, pickleball paddle, luggage and automotive or aerospace parts. GetFRP therefore assigns measured-demand phrases including carbon fiber sheets, carbon fiber pickleball paddle and carbon fiber products only to explicit catalog evidence. Engineering services and generic process capability are not relabeled as stock material. HRC is presented as the exhibitor brand/group; buyers must identify the exact HRC legal entity, plant and contracting party for each project.
Product categoriesCarbon fiber sheets — thermoplastic compositeRecycled carbon-fiber reinforced injection-molding pelletsRecycled carbon-fiber nonwoven fabricWhy matchedProfile mentions: resin transfer moldingWebsitegrouphrc.com
Chengdu Zhengxi Intelligent Equipment Group Co., Ltd.Chengdu, Sichuan, ChinaProcessComposite hydraulic-press engineering, manufacture and customizationStandardNot publicly listedMOQNot publicly listedLead timeNot publicly listedChengdu Zhengxi Intelligent Equipment Group Co., Ltd. is based in Qingbaijiang, Chengdu, Sichuan. The official site says the Zhengxi brand began focusing on hydraulic-forming equipment in 2009 and that the group completed a shareholding reform in 2024. Its composites directory covers SMC, PCM, HP-RTM and carbon-fiber molding presses plus automated SMC, LFT-D, GMT and BMC/DMC compression lines, with wider automation, digital-workshop and smart-factory solutions. China Composites Expo lists the same mainland-China entity and publishes booth 8N08 for 2026 under finished-composite production systems, accessory equipment and tools, mold-related equipment and other equipment and tools. Establishment, group scale, project count, market coverage and technology-position statements are company- or organizer-published and have not been independently site-audited by GetFRP.
Product categoriesSMC and PCM composite-molding hydraulic pressesHP-RTM high-pressure resin-transfer-molding pressesCarbon-fiber composite-molding hydraulic pressesWhy matchedProfile mentions: resin transfer moldingWebsitezhengxi.com
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Buyer FAQ
RTM normally injects resin into a rigid matched mold, while vacuum infusion uses a flexible bag over dry reinforcement and vacuum-driven flow. RTM offers two tool-controlled surfaces; infusion favors larger parts and lower tooling cost.
At minimum, record preform and resin lots, tool and recipe identity, resin mix state, tool temperature, injection pressure/time, vent events, cure cycle and final inspection results.
Not automatically. Fiber format, binder, architecture, compaction and splices affect both structural performance and resin flow, so material or preform changes need controlled engineering review.
Related searches
Pultrusion suppliersFilament Winding suppliersHand Lay-up suppliersCompression Molding suppliersSMC Molding suppliersSpray-up suppliersVacuum Bagging suppliersVacuum Infusion suppliersPrepreg & Autoclave suppliersAutomated Fiber Placement suppliers
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