Within the EMS-Grivory polyamide 12 range, Grilamid LV-3H is documented by the manufacturer as a 30% glass fibre reinforced injection moulding compound based on PA12. The product descriptor “Conditioned” refers to test data generated after moisture equilibrium under ISO 1110:2019, typically at 23°C and 50% RH, rather than the dry-as-moulded state. The grade is positioned for load-bearing injection-moulded components that require a balance of stiffness, low moisture uptake, chemical resistance, and post-moulding dimensional stability. Compared with unreinforced PA12 grades, the addition of 30% short glass fibres raises tensile and flexural modulus while reducing elongation at break. Compared with PA66-GF30 and PA6-GF30, the PA12 matrix in LV-3H absorbs less moisture, producing a smaller modulus shift between dry and humid service and lower hygroscopic swelling. The grade is referenced in technical literature for thin-wall snap-fit connectors, cable management clips, pneumatic fittings, and underhood automotive components. Mechanical data are normally published under ISO 527-1:2012, ISO 527-2:2012, ISO 179-1eA:2010, ISO 178:2019, and ISO 1183-1:2019. The conditioning state is not a trivial packaging label; it alters the amorphous phase mobility of the polyamide matrix and therefore changes modulus, impact response, and failure elongation.

What Limits Ductility After Conditioning in a 30% Glass-Filled PA12?

The conditioned tensile response of Grilamid LV-3H reflects two competing mechanisms. Moisture absorption plasticises the PA12 matrix, increasing chain mobility and reducing yield stress. However, the glass fibres do not plasticise, and their ends remain as stress concentrators. As a result, the conditioned tensile modulus declines from the dry value, while elongation at break improves only moderately. Manufacturer-reported typical dry tensile modulus for 30% glass-filled PA12 is in the range of 5,500 MPa to 6,000 MPa under ISO 527-1/-2; after conditioning to 23°C and 50% RH, the modulus typically falls into the 4,000 MPa to 4,600 MPa band. Tensile strength at break follows a similar downward shift, commonly from approximately 85 MPa dry to 60–65 MPa conditioned. The Charpy notched impact strength under ISO 179-1eA tends to remain stable or rise slightly after conditioning because the matrix absorbs more energy before crack initiation. Fibre orientation, gate placement, and weld-line location can produce larger property deviations than the dry-to-conditioned shift itself. In thin-wall mouldings with wall sections below 1.2 mm, fibre orientation parallel to flow dominates, and transverse tensile strength may fall by 25% to 40% compared with flow-direction values. Designers using LV-3H data should therefore treat the conditioned isotropic datasheet values as a matrix baseline, not as a substitute for orientation-sensitive finite element input.

Mechanical Property Matrix Across Dry and Conditioned States

The following table consolidates typical manufacturer technical datasheet values for Grilamid LV-3H at 23°C. Values are not specification limits and may shift with colour, regrind content, moisture exposure time, and moulding conditions. The dry values represent injection-moulded specimens tested shortly after desiccant storage to a residual moisture content below 0.10% by weight. Conditioned values represent specimens equilibrated under ISO 1110:2019 conditions.

The dry-to-conditioned modulus loss of roughly 20% to 25% is lower than the corresponding shift in PA66-GF30, which can lose 30% or more of its dry tensile modulus after moisture conditioning because of higher equilibrium water absorption. This lower hygroscopic sensitivity is one of the primary selection criteria for LV-3H in humid service environments where snap-fit retention force must remain predictable.

On production lines equipped with reciprocating-screw injection moulding machines using general-purpose three-zone screws with L/D ratios from 20:1 to 25:1, the most common processing failure associated with LV-3H is splay caused by residual moisture. Although PA12 is less hygroscopic than PA6 or PA66, exposed pellet surfaces can still pick up sufficient atmospheric water in high-humidity plants to produce silver streaks and reduced weld-line strength. Desiccant hopper drying at 80°C for 4 h to 6 h to a residual moisture content below 0.10% is routinely specified, with a supply-air dew point of -30°C or lower. Pre-drying at relative humidity above 60% in an open container is not adequate. Regrind use above 20% introduces wider glass-fibre length distribution and can shift spiral flow length and impact data; production trials with the exact regrind fraction are required because published data for this specific configuration is limited. Barrel residence time should not exceed 10 min at melt temperature, and hot-runner dead spots should be avoided. Melt temperature is typically controlled between 220°C and 260°C, with mould temperature maintained between 40°C and 80°C. Higher mould temperatures improve surface finish and crystallinity but can extend cycle time. Mould temperature uniformity below ±5°C across the cavity is advisable for dimensional consistency in close-tolerance snap-fit geometries.

Because conditioned PA12-GF30 retains a higher proportion of its dry stiffness under humid service than PA6-GF30 or PA66-GF30, LV-3H is used in underhood automotive clips, fuel-system retention brackets, cable harness clamps, pneumatic connectors, and sensor housings where hydrocarbon exposure and thermal cycling are present. The glass reinforcement provides the creep resistance needed for sustained clamping loads, while the PA12 matrix contributes low water absorption and resistance to automotive fuels, oils, greases, and aliphatic hydrocarbons. In fuel vapor management components, the material is evaluated using prolonged fuel immersion and heat ageing because PA12 can undergo oxidative embrittlement at elevated temperature if antioxidant packages are depleted. Continuous-use temperature limits must be established by heat ageing under ISO 188 or equivalent OEM test methods with a retained elongation criterion, not by a single HDT value. Zinc chloride resistance is a differentiation point against PA6 and PA66 in winter road-salt environments; PA12 grades show less stress-cracking sensitivity, although published comparative data under specific field conditions is limited. For parts exposed to hot water, glycol, or strong acids, the standard LV-3H grade is not recommended without component-level validation.

When Dimensional Stability in Humid Load Paths Excludes PA66-GF30 Grades

Moisture uptake at 23°C and 50% RH for PA12-GF30 is typically below 0.8% by weight, whereas PA66-GF30 commonly reaches 2.3% to 2.8% and PA6-GF30 can exceed 3% under the same exposure. At saturation, the difference widens further: PA12-GF30 may absorb approximately 1.5%, while PA66-GF30 can approach 8%. This lower water absorption translates into smaller dimensional growth, reduced modulus drop, and higher retention of snap-fit force in humid environments. In gears, clips, and connector bodies subject to seasonal humidity variation, PA66-GF30 parts can show enough hygroscopic swelling to alter mating clearances or increase insertion force. PA12-GF30 reduces that variation, but it does not eliminate it. Dimensional change from dry to conditioned still occurs at the level of a few tenths of a percent, so precision fits require moisture-conditional tolerancing. Against PA6-GF30, the PA12 backbone also provides lower density and better low-temperature impact behaviour, although PA6-GF30 tends to provide higher dry stiffness at equal glass loading. Against unreinforced PA12, LV-3H offers higher modulus, lower thermal expansion, and improved creep resistance, but sacrifices isotropy and ductility. For parts requiring maximum chemical resistance and electrical insulation rather than stiffness, an unfilled PA12 grade may be a more appropriate selection.

For regulatory documentation, the standard Grilamid LV-3H grade is typically covered under EU RoHS Directive 2011/65/EU Annex II and REACH Regulation (EC) No 1907/2006 as reported on the supplier safety data sheet. WEEE Directive obligations may apply only to finished electrical and electronic equipment, not to the polymer raw material. If the application requires food-contact status, FDA 21 CFR or EU Regulation 10/2011 compliance must be confirmed for the specific pigment and lot because standard engineering grades are not automatically cleared for food-contact use. The material should not be combined with amine-based cleaning agents or strongly oxidizing process aids without verification of surface degradation or discolouration.

Processing Window Boundaries and Production Floor Failure Signals

Melt temperature for LV-3H is bounded by two failure modes. Below approximately 210°C, the melt viscosity rises rapidly and the risk of incomplete filling and excessive orientation in thin sections increases. Above 270°C, residence-time-dependent chain scission and oxidative yellowing become more probable, particularly at hot-runner valve gates or in machines with large shot capacity. Mould temperature below 40°C can produce a coarse surface, low crystallinity, and poor knit-line strength; above 80°C the part may require extended cooling and may stick to the core. Injection speed should be set to avoid excessive shear heating in gates smaller than 0.8 mm. Shear-induced fibre breakage in small gates can reduce tensile strength and impact performance. Weld lines in glass-filled PA12 are particularly sensitive: under ISO 527 testing of welded or knit-line specimens, strength retention relative to the bulk material can fall by 25% to 40% depending on glass fibre orientation at the meeting front. Mould-filling simulation with fibre orientation modelling is used to reposition knit lines away from snap-fit roots or other high-tensile locations. Dimensional checks should be performed after conditioning, not immediately after ejection, because PA12-GF30 continues to absorb moisture during storage and the resulting small expansion can shift hole-to-hole distances by more than the tolerance band in precision connectors.