EMS-Grivory Grilamid® LV-3H PA12-GF30 is a heat-stabilised polyamide 12 injection-moulding compound containing 30% glass fibre by weight. The grade designation identifies a PA12 base resin, fibre reinforcement, filler level 3, and heat stabilisation; the corresponding ISO 1043-1 nomenclature is PA12-GF30. The material is supplied as granules in natural, black, and matched-colour variants. Density measured according to ISO 1183 is approximately 1.22 g/cm³, and the glass content can be verified by ash determination under ISO 3451-4. Published dry-as-moulded tensile properties under ISO 527-1/-2 include a tensile modulus near 7,200 MPa, tensile strength near 120 MPa, and nominal strain at break of approximately 3%. The grade is specified for pneumatic and hydraulic connectors, fluid-handling brackets, fuel-system components, snap-fit housings, valve bodies, and similar parts requiring low moisture uptake, dimensional stability in humid air, and low-temperature toughness. Because PA12 has a lower amide group density than PA6 or PA66, the compound absorbs less moisture under ISO 62 exposure and retains a larger share of its dry modulus after conditioning.

How Does 30 wt% Glass-Fibre Reinforcement Modify the Mechanical Envelope Relative to Unfilled Polyamide 12?

Replacing unfilled PA12 with a 30 wt% short-glass compound produces a three- to four-fold increase in tensile modulus. Unfilled PA12 typically exhibits a dry tensile modulus below 2,000 MPa under ISO 527-1/-2; Grilamid LV-3H PA12-GF30 reaches approximately 7,200 MPa. The stiffness gain is accompanied by a reduction in tensile elongation, with nominal strain at break falling below 5%, and a change from ductile yielding toward semi-brittle fracture at room temperature. Notched Charpy impact at 23 °C under ISO 179-1/1eA is approximately 15 kJ/m², which is adequate for many snap-fit and clip functions but lower than the un-reinforced PA12 matrix. Fibre orientation controls local mechanical anisotropy. Short glass fibres align parallel to the melt-flow direction during mould filling; test coupons removed parallel to flow show higher modulus and strength than coupons removed perpendicular to flow. Gate location must therefore place primary service stress in the fibre-flow direction, and weld lines should be located away from tensile hot spots. Weld-line strength in glass-reinforced polyamide is commonly 50–70% of un-welded ISO tensile strength because fibres at the weld interface orient parallel to the weld plane and the local failure is matrix-dominated. The heat-stabilised PA12 matrix reduces moisture sensitivity but does not eliminate the weld-line strength deficit.

Processing of Grilamid LV-3H PA12-GF30 on injection-moulding equipment requires closed-loop control of moisture, melt temperature, and mould temperature. Material exposed to uncontrolled storage should be dried in a desiccant dryer at 80–100 °C for 4–8 h to a residual moisture target below 0.10%; a drying-circuit dew point below -30 °C prevents re-absorption during conveying and hopper residence. Melt temperature is maintained between 250 °C and 290 °C. The lower bound preserves short-glass fibre length during screw recovery; the upper bound reduces the risk of discolouration, polymer-chain scission, and degradation deposit formation during prolonged residence. Mould temperature is controlled at 80–110 °C to raise crystallinity sufficiently for dimensional stability and to reduce post-mould shrinkage. On production machines with three-zone screws of L/D 20–25 and a general-purpose compression profile, glass-fibre abrasion causes progressive screw and barrel wear; bimetallic barrels, hard-coated screws, and shot-count-based replacement audits are used to prevent melt-temperature drift and viscosity variation. Back pressure is usually kept at low to moderate hydraulic pressure, commonly below 10 bar, and screw peripheral speed is limited to 0.2–0.4 m/s to limit fibre breakage and adiabatic shear heating. Shot-to-shot transition-pressure variation is a practical control parameter for dimensional capability; processors should establish in-house limits by pressure-transfer repeatability studies on the intended tool.

Moisture Uptake, Dimensional Stability, and Weld-Line Consequences

The PA12 backbone in Grilamid LV-3H PA12-GF30 has fewer amide groups per unit chain length than PA6 or PA66, and the 30% glass filler further reduces the resin fraction available for water absorption. Equilibrium moisture under ISO 62 at 23 °C and 50% RH is consequently below 1.0%, compared with 1.5–2.0% for typical PA6-GF30 compounds. The lower equilibrium moisture content directly affects dimensional stability and modulus retention. PA12-GF30 can lose approximately 15–20% of dry tensile modulus after conditioning under 23 °C and 50% RH, while PA6-GF30 may lose 30–40% under the same conditions. Thermal expansion in injection-moulded glass-fibre compounds is anisotropic. Representative values under ISO 11359-2 are 0.4–0.5 × 10⁻⁴ K⁻¹ parallel to flow and 0.8–1.0 × 10⁻⁴ K⁻¹ transverse. This anisotropy requires toolmakers to apply differential machining allowances and to avoid flatness tolerancing that assumes isotropic contraction. Fibre orientation also affects post-mould warpage; filling pattern, gate position, and wall thickness must be developed together so that differential shrinkage does not distort sealing surfaces.

Weld-line performance remains a process-dependent boundary condition. In glass-filled polyamides, fountain flow aligns fibres near the melt front, and at the meeting of two flow fronts the fibres do not interpenetrate across the weld plane. The weld line therefore behaves as a matrix-rich plane with lower local strength than the bulk composite. For a grade with bulk tensile strength near 120 MPa under ISO 527-1/-2, weld-line tensile strength can fall to 50–70% of that value unless tool design uses sequential valve gates, overflow tabs, or increased melt and mould temperatures to improve local fusion. The heat-stabilised PA12 matrix provides low moisture sensitivity and improved low-temperature ductility, but it does not eliminate the strength reduction at flow-front junctions. Parts with pressure-cycling requirements should be qualified on the actual service geometry because weld-line failure is not fully predicted by bulk tensile data.

Chemical compatibility is a central selection criterion for PA12-GF30. Under ISO 175 immersion testing, PA12 grades typically exhibit low mass change in aliphatic hydrocarbons, diesel fuel, hydraulic oils, and many automotive greases, along with lower moisture-driven dimensional change than PA6 or PA66. The glass-fibre interface, however, can become a site of attack in strong acids, oxidising media, and some chlorinated solvents. Stress-cracking resistance in road-salt environments is generally higher for PA12 than for PA6 because PA6 is susceptible to zinc chloride stress cracking; nonetheless, stressed components exposed to salt-loaded conditions should be validated with the specific service medium and temperature. Published data for the exact grade-medium combination may be limited; end-use immersion testing and pressure cycling are therefore required for qualification.

When Is PA12-GF30 Selected Over PA6-GF30 or PA66-GF30?

The selection boundary is set primarily by density, moisture uptake, heat resistance, and low-temperature ductility. Grilamid LV-3H PA12-GF30 has a density of approximately 1.22 g/cm³ under ISO 1183, lower than the 1.35–1.40 g/cm³ range common for PA6-GF30 and PA66-GF30. For a fixed part volume, the PA12-GF30 part is lighter, which is relevant in automotive fluid connectors, clips, and pneumatic valve bodies. The moisture advantage is expressed under ISO 62 at 23 °C and 50% RH: PA12-GF30 absorbs below 1.0%, while PA6-GF30 and PA66-GF30 absorb approximately 1.5–2.0% and 1.0–1.5% respectively. The practical result is better retention of modulus and dimensions in humid or water-adjacent service. Heat resistance is lower than PA66-GF30. The heat deflection temperature of Grilamid LV-3H PA12-GF30 at 1.80 MPa is near 160 °C under ISO 75-1/-2, whereas PA66-GF30 grades often exceed 240 °C. The product is therefore not specified for continuous high-temperature under-hood locations where PA66-GF30 or PPA-based materials are required. Processing also differs: PA12-GF30 melts and processes at 250–290 °C, while PA66-GF30 generally requires 280–310 °C or higher. The lower melt temperature reduces plastication energy and can allow faster cycling in thin-wall connectors, but it also limits the upper service temperature.

Documentation for EMS-Grivory Grilamid LV-3H PA12-GF30 should be requested by grade, colour, and production lot. Compliance statements relevant to automotive and electrical components include RoHS 2011/65/EU as amended by (EU) 2015/863, REACH SVHC candidate-list screening, and UL Yellow Card data where applicable. The 30% glass reinforcement is an E-glass fibre with proprietary surface sizing; fibre sizing affects melt viscosity, hydrolysis stability, and fuel-contact performance. No food-contact statement under FDA 21 CFR 177.1500 or drinking-water approval should be assumed unless the supplier has issued a specific certification for the exact colourant package. Changes in colourant can shift melt flow and mould shrinkage; therefore, the in-house process tolerance must be re-established when changing from natural to black or matched-colour variants.