Custom Nylon Injection Molds: PA6, PA66 & Glass Filled Tooling
When your project requires PA6, PA66, or glass-filled nylon, our molds ensure stability and reduce warpage in production.
Send STEP/IGES files, material grade, annual quantity, and assembly requirements for a 24H DFM review.
Nylon Injection Mold Parameters
| Molded Material | PA6, PA66, PA12, glass fiber (GF15-GF50), mineral-filled, carbon-fiber reinforced, flame-retardant (UL94 V-0), and custom impact-modified nylon compounds. |
|---|---|
| Common Reinforcement | GF15, GF30, GF33, GF50 to meet specific tensile strength, stiffness, and creep resistance requirements under mechanical load. |
| Mold Type | Export-grade production molds, multi-cavity systems, insert molds (for threaded brass/steel inserts), and hardened tools for abrasive reinforced nylon. |
| Runner System | Cold runner, hot sprue, or full hot runner (valve gate) based on material flow length, gate vestige limits, and expected mass production volume. |
| Mold Steel | P20, H13, S136, 718H, or fully hardened steel (HRC 48-52) inserts for high-wear areas when molding abrasive glass-filled nylon. |
| Part Applications | Automotive engine bay brackets, electrical terminal blocks, industrial gears, bearings, custom fasteners, and heavy-duty structural housings. |
| Key Mold Design Points | Shrinkage compensation (1.0%-2.5%), glass fiber orientation mapping, moisture control during molding, conformal cooling, and precise venting (0.01-0.02mm). |
| Mold Trial | T1 sample delivery in 15 days, detailed injection parameter logs, trial videos, and defect troubleshooting (flash, short shots, warpage). |
| Quality Documents | FAI (First Article Inspection) reports, CMM dimensional checks, material certificates (RoHS/REACH), mold maintenance logs, and safe export packaging. |
GBM Mold Technology
When your assembly requires tight tolerances in PA66 or GF30, standard tooling approaches often fail. Send your 3D CAD for a targeted mold structure review.
24H Response Time
What Is a Nylon Injection Mold?
Nylon injection molds require specific engineering considerations to handle the unique thermal and rheological properties of polyamides. Because nylon absorbs moisture and shrinks significantly, the mold must maintain stable temperatures and incorporate optimized cooling circuits. When using abrasive glass-filled grades, the tooling demands hardened steel inserts at gate locations and complex parting lines to prevent premature wear and flash.
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Designed specifically for the melt flow and cooling behavior of PA6, PA66, and reinforced compounds.
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Incorporates precise venting (typically 0.01mm - 0.02mm) to prevent gas traps and burn marks.
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Uses balanced cooling channels to manage anisotropic shrinkage and prevent part warpage.
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Utilizes hardened steel (e.g., H13, S136) in high-wear areas to withstand abrasive glass fibers.
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Gate positioning is calculated via mold flow analysis to control fiber orientation and structural strength.
Designing a snap-fit or load-bearing bracket?
Let us review your wall thickness and draft angles before you invest in tooling.
Nylon Materials We Support for Injection Molding
Different nylon grades behave differently in injection molding. The right choice depends on strength, heat resistance, moisture exposure, wear performance, dimensional stability, surface requirement and target cost.
PA6 / Nylon 6
Best For: Cost-effective structural components, snap-fits, automotive interior clips, and impact-resistant housings.
Watch Out: Absorbs moisture up to 8-10%, which can alter final assembly dimensions and reduce tensile strength if not conditioned.
Mold Design Note: Requires uniform wall thickness and balanced cooling circuits to mitigate post-molding deformation.
PA66 / Nylon 66
Best For: High-temperature automotive under-hood parts, electrical terminal blocks, and rigid mechanical gears.
Watch Out: Narrower processing temperature window; highly susceptible to thermal degradation and sink marks in thick sections.
Mold Design Note: Demands precise mold temperature control (often 80-100°C) to achieve proper crystallinity and structural integrity.
Glass Filled Nylon
Best For: Heavy-duty load-bearing brackets, power tool housings, and metal-replacement structural components.
Watch Out: Fiber orientation causes differential shrinkage (longitudinal vs. transverse), leading to predictable warpage risks.
Mold Design Note: Requires hardened mold steel (HRC 48+) and strategic gate placement to control weld line strength and tool wear.
Reinforced Nylon
Best For: Custom bearings, sliding tracks, and components exposed to continuous mechanical friction or long-term static loads.
Watch Out: Carbon fiber or PTFE additives alter melt viscosity, requiring higher injection pressures and distinct gate sizing.
Mold Design Note: Tooling must be designed around the specific shrinkage rate (often 0.3%-0.8%) provided by the resin manufacturer's TDS.
Flame-Retardant / Electrical
Best For: PCB enclosures, wire harness connectors, and industrial switchgear requiring UL94 V-0 ratings.
Watch Out: Flame retardant additives can cause mold deposit buildup and require frequent cleaning of cavity surfaces.
Mold Design Note: Adequate venting is critical to prevent gas degradation, and mold maintenance plans must account for additive outgassing.
Black Nylon & Custom
Best For: UV-resistant outdoor equipment housings, hidden automotive chassis clips, and custom-colored industrial levers.
Watch Out: Pigments and UV stabilizers can slightly alter the shrinkage rate and mechanical properties compared to natural grades.
Mold Design Note: Masterbatch dispersion requires optimized runner and gate design to prevent flow marks or color streaking.
Nylon Injection Mold Types We Build
PA6 Nylon Injection Mold
Built for impact-resistant components like automotive clips and tool housings. We focus on balanced cooling circuits and uniform wall thickness transitions to prevent sink marks and ensure stable cycle times during mass production.
PA66 Nylon Injection Mold
Engineered for high-temperature and rigid parts like engine bay brackets. The tooling incorporates oil or pressurized water heating to maintain 80-100°C mold temperatures, ensuring proper material crystallinity and dimensional accuracy.
Glass Filled Nylon Injection Mold
Designed to withstand the abrasive nature of GF15-GF50 materials. We utilize fully hardened steel inserts (HRC 48-52) at gates and complex parting lines, while using mold flow analysis to predict and counter fiber-induced warpage.
Multi-Cavity Nylon Injection Mold
Optimized for high-volume runs of fasteners or connectors. We implement naturally balanced runner systems and conformal cooling to ensure identical filling pressure and shrinkage across 4, 8, or 16+ cavities.
Nylon Insert Mold
Integrates threaded brass or steel inserts directly into the nylon matrix. We design precise locating pins and shut-off areas to prevent flash around the inserts while ensuring structural integrity at the bonding interface.
Precision Nylon Molded Parts
Tailored for tight-tolerance gears and sliding mechanisms. The mold design accounts for post-molding moisture absorption, utilizing precise shrinkage compensation and CMM validation to meet ±0.02mm assembly tolerances.
Typical Nylon Injection Molded Parts We Support
Automotive Under-Hood & Chassis Components
Examples: Engine cover brackets, radiator end tanks, wire harness clips, fluid reservoirs, and heavy-duty chassis fasteners.
Buyer Concerns: Project engineers face strict constraints on heat deflection temperature (HDT), chemical resistance to automotive fluids, and vibration fatigue. We select specific PA66 or GF30 grades and design tooling to meet PPAP and long-term dimensional stability requirements.
Electrical Connectors & Switchgear Housings
Examples: High-voltage terminal blocks, PCB mounting brackets, DIN rail enclosures, battery casing parts, and wire management tracks.
Buyer Concerns: Assembly lines require zero-flash connectors with precise pin-hole alignments. We utilize UL94 V-0 flame-retardant nylon and design molds with micro-venting to prevent gas traps, ensuring clean surfaces and reliable mating fits.
Industrial Load-Bearing & Wear Parts
Examples: Power transmission gears, sliding track rollers, heavy-duty bushings, custom spacers, and conveyor system wear pads.
Buyer Concerns: Maintenance teams need parts that won't fail under continuous friction or static loads. We analyze the CAD for wall thickness consistency and design molds that maximize the material's inherent creep resistance and low friction coefficient.
Appliance Structural & Functional Parts
Examples: Washing machine internal brackets, power tool handles, blender motor mounts, and moving hinge joints.
Buyer Concerns: Procurement needs cost-effective volume production without sacrificing snap-fit strength. We balance the use of PA6 for toughness with optimized cold runner systems to minimize material waste and unit cost while maintaining structural integrity.
Metal-Replacement Structural Nylon
Examples: GF50 industrial pump housings, heavy machinery motor mounts, and structural support beams previously made of die-cast aluminum.
Buyer Concerns: Converting from metal to plastic introduces risks of weld line weakness and anisotropic shrinkage. We use mold flow simulation to place gates where fiber orientation maximizes tensile strength, using hardened steel to ensure the mold lasts through its intended lifecycle.
Engineering Challenges in Nylon Injection Molding and How We Solve Them
Nylon requires precise control over moisture, temperature, and mold design to achieve stable parts.
Pre-Molding Moisture & Hydrolysis
Polyamides absorb moisture. Molded above 0.2% water content, steam causes defects and weakens tensile strength.
Desiccant dryers reduce moisture below 0.1%, and T1 trials log injection parameters for consistent processing.
Ensures structural parts meet their designed load-bearing capacity without hidden internal voids, reducing assembly line rejections.
Anisotropic Shrinkage & Warpage
In glass-filled grades, shrinkage differs along and across fiber flow, causing bowing and misaligned holes.
Mold flow analysis predicts fiber orientation. Gates optimize flow along the structural axis, and conformal cooling ensures even heat extraction.
Mounting holes align perfectly with your metal chassis, eliminating the need for manual rework or forceful assembly on the production line.
Abrasive Wear from Glass Fibers
High-pressure injection of GF30 or GF50 erodes P20 steel molds, leading to flash within thousands of shots.
Hardened steel (HRC 48-52) like S136 or H13 is used for core, cavity, and gate inserts, with replaceable sub-inserts for easy maintenance.
Guarantees flash-free parts throughout the mold's lifecycle, protecting your investment and preventing mid-production tooling delays.
High Viscosity & Short Shots
Highly filled nylon compounds cool rapidly, causing viscosity increases that may freeze thin walls or long flow sections before full cavity packing.
DFM review identifies thin-wall risks early, sizes gates for nylon grade, and uses high-speed injection to fill cavities before freezing.
Consistent part density and complete filling of complex features like thin ribs or fine connector pins, ensuring structural integrity.
Gas Traps & Diesel Effect Burn Marks
High injection speeds for nylon trap air, causing diesel effect, burn marks, and polymer degradation.
We create venting channels (0.01mm - 0.02mm) along the parting line and use ejector pin venting to release gas quickly without flashing.
Eliminates cosmetic defects and localized material degradation, ensuring parts pass visual and functional QC inspections.
Post-Molding Dimensional Shifts
A freshly molded PA6 part is brittle and undersized but toughens and swells over weeks as it absorbs moisture, risking tolerance specs.
We design molds to target conditioned dimensions. T1 samples are moisture treated before CMM inspection to simulate their final state.
Prevents the common issue where parts fit during the prototype phase but fail on the assembly line months later due to moisture expansion.
Nylon Injection Molding Process
CAD & Application Analysis
We analyze your STEP/IGES files against the specific PA6/PA66 TDS, verifying how load requirements, operating temperatures, and moisture exposure will impact the tooling strategy.
DFM & Shrinkage Evaluation
We identify sink mark risks on thick bosses, evaluate draft angles for rigid GF materials, and calculate precise shrinkage compensation based on fiber orientation.
3D Mold Structure Design
Our engineers layout the parting lines, design replaceable hardened inserts for abrasive GF nylon, and map conformal cooling circuits to manage uneven heat distribution.
Precision Machining & Assembly
Using high-speed CNC and EDM, we cut the hardened steel to ±0.005mm tolerances, ensuring flash-free shutoffs and precise venting for the low-viscosity nylon melt.
T1 Trial & Parameter Logging
We mold the first articles using dried resin, logging injection speeds, holding pressures, and mold temperatures to establish a repeatable, scientific molding process.
CMM Inspection & Mass Production
Samples undergo CMM dimensional checks and visual inspection. Once approved, we establish the SOP for stable mass production and safe export packaging.
Facing tight tolerances on a glass-filled bracket? Send your 3D CAD for a detailed DFM review and tooling cost breakdown.
Submit CAD for DFM ReviewNylon Injection Molding Temperature & Processing Notes
Establishing a stable injection molding process for polyamides requires strict control over moisture and thermodynamics. The parameters below illustrate the engineering considerations we apply during T1 trials to ensure the final parts meet your mechanical and dimensional specifications.
| Processing Item | Engineering Notes |
|---|---|
| Desiccant Drying Protocol | PA6/PA66 must be dried at 80-90°C for 4-6 hours in a desiccant dryer to bring moisture below 0.1%. Failure to do so results in splay, voids, and severe loss of tensile strength. |
| Melt Temperature Control | Typical melt ranges are 240-270°C for PA6 and 270-300°C for PA66. Precise barrel temperature profiling prevents material degradation while maintaining adequate flow for thin-walled sections. |
| Mold Temperature & Crystallinity | We often utilize oil or pressurized water heaters to maintain mold temperatures between 80-100°C. This promotes proper polymer crystallinity, enhancing structural rigidity and high-temperature performance. |
| High-Pressure Filling | GF compounds exhibit rapid viscosity increases. We utilize high injection pressures (often 80-120 MPa) to pack out the cavity fully before the material freezes, preventing short shots. |
| Injection Velocity Profiling | Fast injection speeds are typically required to prevent premature freezing and to achieve a resin-rich surface finish on glass-filled parts, hiding the glass fibers. |
| Micro-Venting Strategy | Due to high injection speeds, trapped air must escape rapidly. We machine parting line vents at 0.01-0.02mm depth to allow gas evacuation without the low-viscosity nylon flashing. |
| Balanced Thermal Extraction | Uneven cooling leads to differential shrinkage and bowed parts. We design cooling channels close to thick sections and utilize beryllium copper inserts in hard-to-reach core pins for rapid heat transfer. |
| Regrind Management | For load-bearing structural parts, we strictly limit or eliminate regrind. Glass fibers break during recycling, significantly reducing the mechanical strength of the subsequent molded parts. |
Injection parameters are highly specific to the mold's thermal dynamics and the exact resin grade's TDS. We establish and document a unique scientific molding SOP for every tooling project to guarantee batch-to-batch consistency.
PA6 vs PA66 vs Glass Filled Nylon for Injection Molding
| Material | Typical Use | Strengths | Watch Out | Mold Design Focus |
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| PA6 / Nylon 6 | Snap-fit clips, interior automotive trim, power tool housings, and general-purpose structural brackets. | Excellent impact resistance, high elongation at break, and superior surface finish capability. | High moisture absorption (up to 10%) reduces stiffness and causes significant dimensional swelling over time. | Focus on balanced cooling to prevent sink marks and utilizing appropriate shrinkage rates (1.2-1.8%) for unconditioned dimensions. |
| PA66 / Nylon 66 | Engine bay components, high-voltage terminal blocks, rigid gears, and high-temperature industrial fasteners. | Superior tensile strength, higher heat deflection temperature (HDT), and better chemical resistance than PA6. | Narrow processing window; prone to thermal degradation and requires high mold temperatures for proper crystallization. | Requires hot oil/water mold heating, robust draft angles, and micro-venting to handle rapid injection speeds. |
| Glass Filled Nylon | Metal-replacement structural beams, heavy-duty pump housings, and continuous-load mechanical mounts. | Drastically reduced creep under load, lower thermal expansion, and exceptional rigidity. | Highly abrasive to tooling steel; fiber alignment causes severe differential shrinkage and potential warpage. | Demands fully hardened steel (HRC 48+), mold flow analysis for fiber orientation, and replaceable gate inserts. |
Engineering Insight
Specify PA6 for impact resistance and cost-efficiency. Upgrade to PA66 when operating temperatures exceed 100°C or higher rigidity is required. Move to GF30/GF50 when replacing metal parts, prioritizing creep resistance and structural stiffness over impact toughness.
Not sure which nylon grade fits your part? Send your application and drawing for material review.
Request Material DFMNylon Injection Mold vs ABS Injection Mold
Nylon and ABS are both common injection molding materials, but they are used for different part functions. ABS is often selected for housings and cosmetic parts, while nylon is more common for functional, wear-resistant and mechanically loaded parts.
| Comparison Item | Nylon Injection Molding | ABS Injection Molding |
|---|---|---|
| Typical Function | Structural brackets, sliding gears, chemical-resistant engine parts, and load-bearing electrical connectors. | Electronic enclosures, consumer appliance housings, cosmetic bezels, and display monitor frames. |
| Mechanical Strength | High tensile strength, excellent fatigue resistance, and low friction coefficient for moving parts. | Good impact resistance and stiffness, but susceptible to fatigue and wear under continuous friction. |
| Moisture | Highly hygroscopic; requires strict desiccant drying and post-molding dimensional conditioning. | Mildly hygroscopic; requires basic drying but dimensions remain stable in ambient humidity. |
| Mold Design Focus | Anisotropic shrinkage control, hardened steel for GF grades, high mold temperatures, and micro-venting. | Cosmetic surface finishes (SPI A2 / VDI 3400), hiding weld lines, and preventing sink marks on thick ribs. |
| Best Choice | When the part must survive mechanical stress, friction, chemicals, or high temperatures. | When the priority is a flawless cosmetic surface, electroplating compatibility, and cost-effective rigid enclosures. |
The best material should be selected according to load, working temperature, chemical exposure, surface requirement, assembly method and target cost.
How to Choose a Nylon Injection Mold Supplier
Sourcing a tooling partner for nylon components requires looking beyond the initial mold cost. The right manufacturer must demonstrate expertise in managing moisture, controlling anisotropic shrinkage, and designing hardened tooling that survives abrasive glass-filled compounds.
PA6/PA66 & GF Compound Expertise
Your supplier must understand the specific drying protocols, melt thermodynamics, and shrinkage behaviors of PA6, PA66, and custom GF/mineral-filled compounds.
Pre-Tooling DFM & Mold Flow
A reliable partner runs mold flow analysis to predict fiber orientation and warpage, reviewing wall thickness transitions and draft angles before cutting any steel.
Hardened Tooling Strategy
If you specify GF30, the supplier must quote fully hardened steel (HRC 48-52) and design replaceable gate inserts to prevent premature tool washout and flash.
Transparent T1 Trial Reporting
You should receive detailed injection parameter logs, trial videos, and a comprehensive defect analysis (addressing any short shots or sink marks) alongside your T1 samples.
CMM & Dimensional Validation
The facility must have in-house CMM capabilities to verify tight tolerances, especially after the nylon parts have undergone natural or artificial moisture conditioning.
Stable Mass Production & Export
Whether running mass production in-house or exporting the mold, the supplier should provide FAI reports, mold maintenance schedules, and secure rust-preventative packaging.
RFQ Checklist
To receive a precise tooling breakdown and DFM feedback, please provide:
- 3D CAD file
- 2D drawing with critical dimensions
- Nylon material grade or application requirement
- Annual quantity
- Surface finish requirement
- Assembly or load condition
- Target market or compliance requirement if any
- Expected mold life or production plan
Providing this data allows our engineers to calculate exact shrinkage, select the right steel hardness, and layout the optimal cavity configuration.
What Affects Nylon Injection Mold Cost?
Tooling quotes for nylon parts vary significantly based on the engineering required to guarantee stability. Factors like glass fiber content, tight assembly tolerances, and expected lifecycle dictate the steel hardness, cooling complexity, and runner systems needed.
Geometry & Undercuts
Complex features requiring hydraulic sliders, lifters, or unscrewing mechanisms for internal threads significantly increase CNC/EDM machining time and mold base size.
Abrasive Fillers & Steel Hardness
Specifying GF30 or GF50 mandates upgrading from standard P20 to fully hardened S136 or H13 steel (HRC 48-52) to prevent the abrasive fibers from destroying the mold cavity.
Production Volume & Cavitation
A 1x4 or 1x8 multi-cavity mold lowers the per-part cost for high-volume runs but requires a larger mold base, perfectly balanced runners, and complex conformal cooling.
Cold vs. Hot Runner Systems
While cold runners are cheaper to build, a valve-gate hot runner system eliminates nylon material waste and reduces cycle times, paying for itself in high-volume production.
Assembly Tolerances & CMM
Achieving ±0.02mm tolerances on a PA66 gear requires high-precision slow-wire EDM machining, strict mold temperature control, and extensive CMM validation.
Tooling Lifecycle (SPI Classes)
An SPI Class 101 mold designed for 1 million+ shots requires premium steel, wear plates, and guided ejection, costing more upfront than a Class 103 prototype tool.
Surface Finish & Draft Angles
Specific textures (e.g., VDI 3400) require specific draft angles to prevent scuffing during ejection. Integrating threaded brass inserts requires precise core pin design and manual/robotic loading time.
Don't settle for rough estimates. Send your STEP file and material TDS, and we'll provide a line-item tooling quote outlining steel choice, cavity count, and unit price.
Request Detailed Tooling QuoteQuality Control for Nylon Injection Mold Projects
Ensuring consistency in nylon molding requires scientific process control. Because PA6 and PA66 shrink and absorb moisture, our QC protocols validate not just the T1 sample, but the repeatability of the injection parameters and the final conditioned dimensions.
Quality Control Flow
- 1Resin & Additive Verification (RoHS/REACH)
- 2Tool Steel Hardness & Certification Check
- 3CNC/EDM Dimensional Verification (±0.005mm)
- 4Core/Cavity Alignment & Shut-off Validation
- 5T1 Scientific Molding Trial & Parameter Logging
- 6Visual QC for Flash, Splay, and Burn Marks
- 7CMM Inspection of Critical Assembly Tolerances
- 8Defect Analysis & Mold Modification Strategy
- 9FAI Report Submission & Client Approval
- 10Mass Production SOP or Export Packaging
Project Documents Provided
Stop struggling with warped brackets and flashing gates. Let our engineers design a mold built specifically for the thermal dynamics of your nylon grade.
Upload CAD for DFMYour Engineering Partner for High-Performance Polyamide Tooling
Polyamide-Specific DFM Analysis
We don't treat nylon like ABS. We analyze your CAD specifically for anisotropic shrinkage, predicting fiber orientation and optimizing wall thickness to prevent sink marks and warpage before cutting steel.
Hardened Tooling for GF Compounds
GF30 and GF50 destroy standard molds. We specify HRC 48-52 hardened steel (S136/H13) and design replaceable gate inserts to ensure your mold survives high-volume abrasive production.
Scientific T1 Molding Trials
We dry the resin to <0.1% moisture and log precise melt/mold temperatures. You receive transparent trial data, highlighting any short shots, flash, or diesel-effect burn marks, along with our correction plan.
Scalable Tooling Strategies
From single-cavity P20 prototype molds for testing snap-fits, to 16-cavity fully hardened hot-runner systems for mass production, we align the mold class with your budget and volume.
Seamless Technical Communication
Our English-speaking engineers provide clear DFM reports, CMM data, and trial videos, ensuring you have total visibility and control over your tooling project without needing to visit the factory.
Value-Engineered Tooling Costs
We identify cost-saving opportunities in the CAD—such as modifying an undercut to eliminate a costly slider—and recommend the optimal cold/hot runner balance to minimize material waste.
Ready to tool up your nylon project? Send your STEP files, material grade, and annual volume. We'll provide a comprehensive DFM review and an itemized tooling quote within 24 hours.
Related Injection Molding Capabilities
Custom Plastic Injection Molding
End-to-end manufacturing for engineering plastics, from DFM to mass production.
Precision Injection Mold Tooling
Export-grade mold design, CNC machining, and rigorous T1 trial validation.
Glass-Filled Nylon Expertise
Specialized tooling and processing for abrasive, high-strength GF15-GF50 components.
ABS Injection Molding Services
High-quality cosmetic enclosures and rigid housings with SPI/VDI surface finishes.
Nylon Injection Mold FAQ
Can nylon be injection molded?
What is a nylon injection mold?
Which nylon is better for injection molding, PA6 or PA66?
What is glass filled nylon injection molding?
How long should nylon be dried before injection molding?
What causes warpage in injection molded nylon parts?
Can ABS and nylon use the same injection mold?
What are common defects in nylon injection molding?
How do I choose a nylon injection mold supplier?
What affects the cost of a nylon injection mold?
Is nylon better than ABS for injection molded parts?
Do glass filled nylon molds need special tooling?
Ready to Tool Up Your Nylon Project?
Upload your CAD files, tolerances, material specs, and volume needs. We’ll assess shrinkage risks and deliver a DFM report with a tooling quote.
Email Us Directly
Annie@gbminjection.comCall or WhatsApp
+86 15268369865Factory Address
Room 101, Jiumo Technology Park, Gangsheng Road, Yabian Village, Shajing Street, Baoan District, Shenzhen City