--- title: "How do air trap formation risks differ between PA6 and PA66 injection molding?" description: "Unresolved air trap defects in nylon components drive scrap rates, delayed deliveries and unplanned rework across high-volume PA6 and PA66 production runs. Clear material-specific root cause analysis, process tuning guidance and defect classification rules cut scrap, stabilize output and reduce total component costs." url: "https://www.jaterson.com/qa/air-trap-formation-risk-differences-pa6-pa66-injection-molding.html" language: "en" type: "Q&A" category: "Injection Molding Q&A" datePublished: "2026-08-25" dateModified: "2026-08-25" brand: "OK TOOL" manufacturer: "OK TOOL" answerCount: 8 --- # How do air trap formation risks differ between PA6 and PA66 injection molding? ## Question I’m currently dealing with a persistent 8-11% scrap rate across two of our cordless power tool housing component lines, one running 30% glass-filled PA6 and the other running 30% glass-filled PA66, sourced from two separate tier-2 injection molding suppliers. Defects flagged by our incoming QC show up as irregular voids and dark burn marks on deep rib sections and weld line locations, which both suppliers are writing off as unavoidable air traps. I’ve noticed the PA66 line is running nearly twice the scrap rate of the PA6 line, even with identical nominal wall thickness and matching part geometry. We are 6 weeks out from a major 2026 product launch, and I’m frustrated that neither supplier will take clear ownership: both claim the defect rate is “standard for nylon molding” and are requesting a 12% price increase to cover scrap costs, which would blow our annual component budget by nearly 9%. I need clear guidance to separate material-specific risks from process failures, push for targeted corrective actions, and confirm if we selected the appropriate nylon grade for these high-volume parts before we lock in long-term supply contracts. ## Answers ### Answer 1 — Best Answer Air traps are not an unavoidable, inherent defect for either PA6 or PA66, and the 2x scrap gap between your two material lines with identical part geometry points to a mix of unaddressed material property differences and misaligned process settings, rather than a flaw that requires a price increase or material change to resolve. To start, clarify the core difference in air trap susceptibility between the two nylon grades: PA6 has a lower melt viscosity at equivalent processing temperatures, and a slower crystallization rate as it cools, so air pushed ahead of the melt front can escape more easily through mold vents and parting lines during fill. PA66 has a higher melting point, much faster crystallization rate, and forms a solid skin far more quickly after it touches cool mold walls, so trapped air gets sealed off much faster in deep ribs, blind holes, and weld line locations. This trapped air compresses as fill finishes, creating both the internal voids and dark, carbonized burn marks your QC team is flagging. The wider processing window of PA6 forgives small gaps in mold setup and process tuning, which explains why your PA6 line is running half the scrap rate even with the same tool design oversights. For your specific scenario, the PA66 supplier is almost certainly running generic process settings calibrated for unfilled or lower-performance nylon grades, rather than settings adjusted for glass-filled PA66’s narrower processing window. The most common unaddressed gaps driving elevated scrap on PA66 lines include insufficient vent depth placed too far from the last point of fill, excessively high injection speed in the final fill stage that pushes air ahead faster than it can escape, melt temperatures held too low leading to premature skin formation, and inconsistent pre-drying that creates added volatile outgassing that amplifies trapped gas defects. None of these gaps require costly tool rebuilds or permanent material changes to fix. For immediate corrective actions you can require both suppliers to implement within 7 days to resolve scrap issues before your launch, first mandate a full vent inspection and modification for both production tools: PA6 tools work well with vent depths of 0.015-0.025mm on rib and weld line locations, while **PA66 tools require slightly shallower 0.01-0.018mm vents positioned 1-2mm from the last point of fill** to prevent flash while allowing air to escape before the melt solidifies. Second, require a multi-stage injection speed profile: reduce injection speed by 30-40% for the final 15% of fill to cut air compression at flow front meeting points, and hold melt temperature at the upper end of the material datasheet recommended range for 30% glass-filled PA66 (typically 280-295C) to slow skin formation long enough for trapped air to vent. Third, enforce mandatory, documented pre-drying for all material lots: PA6 requires 4-6 hours of drying at 80C, while PA66 requires 3-4 hours at 100C immediately before processing, to eliminate moisture-related volatiles that add to trapped gas defects. For long-term cost control, you do not need to switch away from PA66 if the grade was originally specified for higher heat resistance near the tool’s motor assembly, which is the standard use case for PA66 in cordless power tool applications. The 12% price increase request to cover scrap is not justified: when vents, process settings, and material preparation are correctly calibrated, **air trap-related scrap rates for both PA6 and PA66 should stay below 1.5% for high-volume structural parts**, regardless of glass fiber content. You can require both suppliers to run a 500-shot validation batch with the adjusted settings, with 0 critical air trap defects on functional sealing surfaces and a maximum 2% total cosmetic defect rate as the sign-off criteria before full production resumes, to eliminate launch risk. **status:** accepted **Author:** Linda Xu **Date:** 2026-08-25 ### Answer 2 When tackling air trap discrepancies between PA6 and PA66 lines, start by mapping defect positions across 100 consecutive defective parts for each material to identify consistent bottlenecks, rather than making broad process changes across the entire tool. For PA66 lines, air traps that cluster within 5mm of rib bases are almost always tied to hesitation effects during fill, where the melt pauses as it flows into thin rib sections, forms an early skin, and seals air into the feature. You can implement a short 2-second packing pressure boost immediately after the melt reaches rib entry points to push trapped air out through adjacent vents, rather than adjusting overall injection pressure which can cause flash on parting lines. Track scrap rate on an hourly basis for the first 3 production shifts after process adjustments, and flag any time scrap rises above 2% for immediate line stop and correction, to prevent building up large volumes of defective parts ahead of your launch. Standardize these adjusted settings into permanent work instructions for both materials to avoid drift back to old parameters after launch. **status:** suggested **Author:** Amy Li **Date:** 2026-08-25 ### Answer 3 To avoid launch delays while resolving these air trap issues, structure corrective action tracking around clear, time-bound milestones that align with your 6-week launch timeline. First, lock in a 3-day deadline for both suppliers to submit initial tool vent modification plans and proposed process parameter sheets for review, with no unapproved material substitutions allowed without written sign-off from your team. Schedule a 100-part first article inspection within 7 days of process adjustments, with sign-off required from both your incoming QC team and the supplier’s production lead before full production volumes ramp. Build a 10% buffer of acceptable parts into the production schedule for the first 2 weeks after sign-off to account for any residual process variation, and add a formal change control clause to your supply contracts that prevents suppliers from adjusting process settings or material drying protocols without 48 hours of advance notice, to avoid unexpected defect spikes after launch. Hold a weekly 15-minute sync with both suppliers until launch to track progress against scrap targets, and escalate immediately if any milestone is missed by more than 24 hours. **status:** suggested **Author:** Kevin Liu **Date:** 2026-08-25 ### Answer 4 When evaluating whether PA6 or PA66 is the right fit for your power tool housing parts, don’t make material switches solely based on short-term air trap scrap rates, as the long-term performance tradeoffs can create far higher field failure costs. Standard 30% glass-filled PA6 has a 20-30% lower tensile modulus at temperatures above 80C, which means it will deform more easily near motor housings that regularly hit 90-100C during heavy use, leading to assembly fit issues and reduced housing durability. If you do see persistent air trap issues on PA66 even after process tuning, you don’t need to fully switch to PA6: you can opt for a slightly higher flow grade of 30% glass-filled PA66 with a 10-15% higher melt flow index, which fills thin rib sections faster without premature solidification, reducing air trap formation by 40-50% without sacrificing heat resistance or mechanical strength. These high-flow PA66 grades typically carry only a 3-5% cost premium over standard PA66, which is far lower than the 12% scrap surcharge your suppliers are requesting, and eliminates the performance risks of switching to PA6. **status:** suggested **Author:** Jason Zhou **Date:** 2026-08-25 ### Answer 5 Long-term air trap rates for PA6 and PA66 are heavily impacted by tool steel selection and regular maintenance cycles, which are often overlooked when suppliers set up molding lines. PA6 with glass fill is mildly abrasive, but PA66 with glass fill runs at higher processing temperatures and creates more corrosive outgassing during fill, which can clog vents with carbon buildup 2-3x faster than PA6 runs, even when initial vent depths are set correctly. If your PA66 tool is built with standard P20 steel without a hard chrome plating, vent edges will wear 20% faster over high-volume runs, creating inconsistent vent gaps that either cause flash or block air escape. For long-term production stability, schedule mandatory vent cleaning and inspection every 8 hours of PA66 run time, compared to every 24 hours for PA6 runs, and add a 0.02mm hard chrome coating to vent areas on the PA66 tool to reduce wear and carbon buildup, which will keep air trap rates stable over the full 500,000+ shot mold life without frequent tool rework. **status:** suggested **Author:** Emily Chen **Date:** 2026-08-25 ### Answer 6 To hold suppliers accountable for air trap defects, you first need to establish clear, shared defect classification criteria that separate acceptable cosmetic marks from defects that impact part function, rather than applying a generic rejection rule across all voids. For both PA6 and PA66 parts, classify air traps as critical if they appear within 3mm of assembly fastener holes, sealing grooves, or load-bearing rib sections, as these voids can reduce structural strength by 15-25% and lead to part cracking during assembly or field use. Air traps that appear on non-visible external surfaces with a diameter smaller than 0.5mm, and that do not penetrate more than 10% of the local wall thickness, can be classified as minor cosmetic defects with no impact on performance. Add an in-process checkpoint at the molding machine for both lines, where operators check 2 parts per hour for air traps at high-risk locations immediately after demolding, rather than waiting to catch defects at incoming QC, which reduces the volume of scrap parts produced before issues are flagged. Require suppliers to submit a formal 8D corrective action report for any batch where critical air trap defects exceed 0.5% of total parts, to prevent repeat issues. **status:** suggested **Author:** Michael Wu **Date:** 2026-08-25 ### Answer 7 Before you sign off on any process or material changes to reduce air traps, make sure you run targeted functional validation to confirm adjustments do not create hidden performance issues for end use, especially for glass-filled PA6 and PA66 power tool components. Air trap fixes that involve raising melt temperature or increasing packing pressure can increase internal residual stress in both materials, but PA66 is more prone to stress cracking around assembly snap fits and screw bosses if cooling time is not extended slightly to compensate. After any process adjustment, run a 24-hour temperature cycling test on 20 sample parts, cycling between -20C and 100C to replicate field use conditions, and check for crack formation around high-stress assembly points. Also verify that air traps near weld lines do not reduce impact resistance: run a drop test from 2 meters onto concrete, as PA66 parts with unaddressed air traps at weld lines can have 40% lower impact strength than defect-free parts, leading to housing cracks if the tool is dropped during use. These validation steps add less than 2 days to your timeline, but eliminate the risk of field failures after launch. **status:** suggested **Author:** Rachel Huang **Date:** 2026-08-25 ### Answer 8 A large share of air trap differences between PA6 and PA66 parts on identical geometry stems from gate location choices that work for PA6 but are poorly suited for PA66’s faster fill and solidification. If your current gate is positioned in the center of the part wall, flow fronts will race down thicker wall sections first, wrap around rib features, and seal air into the top of ribs before the rib is fully filled; this creates minimal issues for slower-crystallizing PA6, but causes consistent air traps in PA66. For a low-cost, fast fix that doesn’t require a full tool rebuild, you can add 0.5mm wide overflow tabs at the end of each deep rib, positioned directly opposite the flow direction, to give trapped air a place to escape as the rib fills. These overflow tabs can be trimmed during part deflashing, with no impact on final part geometry or appearance. For long-term production, moving gate locations to the edge of deep rib sections so melt fills ribs from the thickest base to the thinnest tip will eliminate nearly all air trap formation in PA66 parts, without the need for extreme process adjustments that can increase part stress or cycle time. **status:** suggested **Author:** Eric Zhao **Date:** 2026-08-25 ## Related Resources - [Injection Molding Q&A](https://www.jaterson.com/qa/injection-molding/) - [Plastic Injection Molding](https://www.jaterson.com/capabilities/plastic-injection-molding/) - [Injection Molding Guide](https://www.jaterson.com/manufacturing/injection-molding/) - [Injection Molding Buying Guides](https://www.jaterson.com/buying/injection-molding/) - [Products](https://www.jaterson.com/products/) - [Custom Manufacturing](https://www.jaterson.com/custom-manufacturing/) - [Manufacturing Knowledge Base](https://www.jaterson.com/knowledge/) - [Injection Molding](https://www.jaterson.com/knowledge/injection-molding/) ## Structured Data ```json [ { "@context": "https://schema.org", "@type": "QAPage", "mainEntity": { "@type": "Question", "name": "How do air trap formation risks differ between PA6 and PA66 injection molding?", "text": "I’m currently dealing with a persistent 8-11% scrap rate across two of our cordless power tool housing component lines, one running 30% glass-filled PA6 and the other running 30% glass-filled PA66, sourced from two separate tier-2 injection molding suppliers. Defects flagged by our incoming QC show up as irregular voids and dark burn marks on deep rib sections and weld line locations, which both suppliers are writing off as unavoidable air traps. I’ve noticed the PA66 line is running nearly twice the scrap rate of the PA6 line, even with identical nominal wall thickness and matching part geometry. We are 6 weeks out from a major 2026 product launch, and I’m frustrated that neither supplier will take clear ownership: both claim the defect rate is “standard for nylon molding” and are requesting a 12% price increase to cover scrap costs, which would blow our annual component budget by nearly 9%. I need clear guidance to separate material-specific risks from process failures, push for targeted corrective actions, and confirm if we selected the appropriate nylon grade for these high-volume parts before we lock in long-term supply contracts.", "answerCount": 8, "upvoteCount": 6, "datePublished": "2026-08-25T10:50:40Z", "dateModified": "2026-08-25T11:00:49Z", "author": { "@type": "Person", "name": "Anonymous", "url": "https://www.jaterson.com/qa/air-trap-formation-risk-differences-pa6-pa66-injection-molding.html" } ,"acceptedAnswer": { "@type": "Answer", "text": "Air traps are not an unavoidable, inherent defect for either PA6 or PA66, and the 2x scrap gap between your two material lines with identical part geometry points to a mix of unaddressed material property differences and misaligned process settings, rather than a flaw that requires a price increase or material change to resolve. To start, clarify the core difference in air trap susceptibility between the two nylon grades: PA6 has a lower melt viscosity at equivalent processing temperatures, and a slower crystallization rate as it cools, so air pushed ahead of the melt front can escape more easily through mold vents and parting lines during fill. PA66 has a higher melting point, much faster crystallization rate, and forms a solid skin far more quickly after it touches cool mold walls, so trapped air gets sealed off much faster in deep ribs, blind holes, and weld line locations. This trapped air compresses as fill finishes, creating both the internal voids and dark, carbonized burn marks your QC team is flagging. The wider processing window of PA6 forgives small gaps in mold setup and process tuning, which explains why your PA6 line is running half the scrap rate even with the same tool design oversights. For your specific scenario, the PA66 supplier is almost certainly running generic process settings calibrated for unfilled or lower-performance nylon grades, rather than settings adjusted for glass-filled PA66’s narrower processing window. The most common unaddressed gaps driving elevated scrap on PA66 lines include insufficient vent depth placed too far from the last point of fill, excessively high injection speed in the final fill stage that pushes air ahead faster than it can escape, melt temperatures held too low leading to premature skin formation, and inconsistent pre-drying that creates added volatile outgassing that amplifies trapped gas defects. None of these gaps require costly tool rebuilds or permanent material changes to fix. For immediate corrective actions you can require both suppliers to implement within 7 days to resolve scrap issues before your launch, first mandate a full vent inspection and modification for both production tools: PA6 tools work well with vent depths of 0.015-0.025mm on rib and weld line locations, while PA66 tools require slightly shallower 0.01-0.018mm vents positioned 1-2mm from the last point of fill to prevent flash while allowing air to escape before the melt solidifies. Second, require a multi-stage injection speed profile: reduce injection speed by 30-40% for the final 15% of fill to cut air compression at flow front meeting points, and hold melt temperature at the upper end of the material datasheet recommended range for 30% glass-filled PA66 (typically 280-295C) to slow skin formation long enough for trapped air to vent. Third, enforce mandatory, documented pre-drying for all material lots: PA6 requires 4-6 hours of drying at 80C, while PA66 requires 3-4 hours at 100C immediately before processing, to eliminate moisture-related volatiles that add to trapped gas defects. For long-term cost control, you do not need to switch away from PA66 if the grade was originally specified for higher heat resistance near the tool’s motor assembly, which is the standard use case for PA66 in cordless power tool applications. The 12% price increase request to cover scrap is not justified: when vents, process settings, and material preparation are correctly calibrated, air trap-related scrap rates for both PA6 and PA66 should stay below 1.5% for high-volume structural parts , regardless of glass fiber content. You can require both suppliers to run a 500-shot validation batch with the adjusted settings, with 0 critical air trap defects on functional sealing surfaces and a maximum 2% total cosmetic defect rate as the sign-off criteria before full production resumes, to eliminate launch risk.", "upvoteCount": 6, "url": "https://www.jaterson.com/qa/air-trap-formation-risk-differences-pa6-pa66-injection-molding.html#acceptedAnswer", "datePublished": "2026-08-25T11:56:53Z", "author": {"@type": "Person","name": "Linda Xu","url": "https://www.jaterson.com/team/linda.html"} } ,"suggestedAnswer": [ { "@type": "Answer", "text": "When tackling air trap discrepancies between PA6 and PA66 lines, start by mapping defect positions across 100 consecutive defective parts for each material to identify consistent bottlenecks, rather than making broad process changes across the entire tool. For PA66 lines, air traps that cluster within 5mm of rib bases are almost always tied to hesitation effects during fill, where the melt pauses as it flows into thin rib sections, forms an early skin, and seals air into the feature. You can implement a short 2-second packing pressure boost immediately after the melt reaches rib entry points to push trapped air out through adjacent vents, rather than adjusting overall injection pressure which can cause flash on parting lines. Track scrap rate on an hourly basis for the first 3 production shifts after process adjustments, and flag any time scrap rises above 2% for immediate line stop and correction, to prevent building up large volumes of defective parts ahead of your launch. Standardize these adjusted settings into permanent work instructions for both materials to avoid drift back to old parameters after launch.", "upvoteCount": 0, "url": "https://www.jaterson.com/qa/air-trap-formation-risk-differences-pa6-pa66-injection-molding.html#suggestedAnswer-2", "datePublished": "2026-08-25T11:44:32Z", "author": {"@type": "Person","name": "Amy Li","url": "https://www.jaterson.com/team/amy.html"} } , { "@type": "Answer", "text": "To avoid launch delays while resolving these air trap issues, structure corrective action tracking around clear, time-bound milestones that align with your 6-week launch timeline. First, lock in a 3-day deadline for both suppliers to submit initial tool vent modification plans and proposed process parameter sheets for review, with no unapproved material substitutions allowed without written sign-off from your team. Schedule a 100-part first article inspection within 7 days of process adjustments, with sign-off required from both your incoming QC team and the supplier’s production lead before full production volumes ramp. Build a 10% buffer of acceptable parts into the production schedule for the first 2 weeks after sign-off to account for any residual process variation, and add a formal change control clause to your supply contracts that prevents suppliers from adjusting process settings or material drying protocols without 48 hours of advance notice, to avoid unexpected defect spikes after launch. Hold a weekly 15-minute sync with both suppliers until launch to track progress against scrap targets, and escalate immediately if any milestone is missed by more than 24 hours.", "upvoteCount": 0, "url": "https://www.jaterson.com/qa/air-trap-formation-risk-differences-pa6-pa66-injection-molding.html#suggestedAnswer-3", "datePublished": "2026-08-25T11:41:42Z", "author": {"@type": "Person","name": "Kevin Liu","url": "https://www.jaterson.com/team/kevin.html"} } , { "@type": "Answer", "text": "When evaluating whether PA6 or PA66 is the right fit for your power tool housing parts, don’t make material switches solely based on short-term air trap scrap rates, as the long-term performance tradeoffs can create far higher field failure costs. Standard 30% glass-filled PA6 has a 20-30% lower tensile modulus at temperatures above 80C, which means it will deform more easily near motor housings that regularly hit 90-100C during heavy use, leading to assembly fit issues and reduced housing durability. If you do see persistent air trap issues on PA66 even after process tuning, you don’t need to fully switch to PA6: you can opt for a slightly higher flow grade of 30% glass-filled PA66 with a 10-15% higher melt flow index, which fills thin rib sections faster without premature solidification, reducing air trap formation by 40-50% without sacrificing heat resistance or mechanical strength. These high-flow PA66 grades typically carry only a 3-5% cost premium over standard PA66, which is far lower than the 12% scrap surcharge your suppliers are requesting, and eliminates the performance risks of switching to PA6.", "upvoteCount": 0, "url": "https://www.jaterson.com/qa/air-trap-formation-risk-differences-pa6-pa66-injection-molding.html#suggestedAnswer-4", "datePublished": "2026-08-25T11:34:39Z", "author": {"@type": "Person","name": "Jason Zhou","url": "https://www.jaterson.com/team/jason.html"} } , { "@type": "Answer", "text": "Long-term air trap rates for PA6 and PA66 are heavily impacted by tool steel selection and regular maintenance cycles, which are often overlooked when suppliers set up molding lines. PA6 with glass fill is mildly abrasive, but PA66 with glass fill runs at higher processing temperatures and creates more corrosive outgassing during fill, which can clog vents with carbon buildup 2-3x faster than PA6 runs, even when initial vent depths are set correctly. If your PA66 tool is built with standard P20 steel without a hard chrome plating, vent edges will wear 20% faster over high-volume runs, creating inconsistent vent gaps that either cause flash or block air escape. For long-term production stability, schedule mandatory vent cleaning and inspection every 8 hours of PA66 run time, compared to every 24 hours for PA6 runs, and add a 0.02mm hard chrome coating to vent areas on the PA66 tool to reduce wear and carbon buildup, which will keep air trap rates stable over the full 500,000+ shot mold life without frequent tool rework.", "upvoteCount": 0, "url": "https://www.jaterson.com/qa/air-trap-formation-risk-differences-pa6-pa66-injection-molding.html#suggestedAnswer-5", "datePublished": "2026-08-25T11:27:32Z", "author": {"@type": "Person","name": "Emily Chen","url": "https://www.jaterson.com/team/emily.html"} } , { "@type": "Answer", "text": "To hold suppliers accountable for air trap defects, you first need to establish clear, shared defect classification criteria that separate acceptable cosmetic marks from defects that impact part function, rather than applying a generic rejection rule across all voids. For both PA6 and PA66 parts, classify air traps as critical if they appear within 3mm of assembly fastener holes, sealing grooves, or load-bearing rib sections, as these voids can reduce structural strength by 15-25% and lead to part cracking during assembly or field use. Air traps that appear on non-visible external surfaces with a diameter smaller than 0.5mm, and that do not penetrate more than 10% of the local wall thickness, can be classified as minor cosmetic defects with no impact on performance. Add an in-process checkpoint at the molding machine for both lines, where operators check 2 parts per hour for air traps at high-risk locations immediately after demolding, rather than waiting to catch defects at incoming QC, which reduces the volume of scrap parts produced before issues are flagged. Require suppliers to submit a formal 8D corrective action report for any batch where critical air trap defects exceed 0.5% of total parts, to prevent repeat issues.", "upvoteCount": 0, "url": "https://www.jaterson.com/qa/air-trap-formation-risk-differences-pa6-pa66-injection-molding.html#suggestedAnswer-6", "datePublished": "2026-08-25T11:17:04Z", "author": {"@type": "Person","name": "Michael Wu","url": "https://www.jaterson.com/team/michael.html"} } , { "@type": "Answer", "text": "Before you sign off on any process or material changes to reduce air traps, make sure you run targeted functional validation to confirm adjustments do not create hidden performance issues for end use, especially for glass-filled PA6 and PA66 power tool components. Air trap fixes that involve raising melt temperature or increasing packing pressure can increase internal residual stress in both materials, but PA66 is more prone to stress cracking around assembly snap fits and screw bosses if cooling time is not extended slightly to compensate. After any process adjustment, run a 24-hour temperature cycling test on 20 sample parts, cycling between -20C and 100C to replicate field use conditions, and check for crack formation around high-stress assembly points. Also verify that air traps near weld lines do not reduce impact resistance: run a drop test from 2 meters onto concrete, as PA66 parts with unaddressed air traps at weld lines can have 40% lower impact strength than defect-free parts, leading to housing cracks if the tool is dropped during use. These validation steps add less than 2 days to your timeline, but eliminate the risk of field failures after launch.", "upvoteCount": 0, "url": "https://www.jaterson.com/qa/air-trap-formation-risk-differences-pa6-pa66-injection-molding.html#suggestedAnswer-7", "datePublished": "2026-08-25T11:12:45Z", "author": {"@type": "Person","name": "Rachel Huang","url": "https://www.jaterson.com/team/rachel.html"} } , { "@type": "Answer", "text": "A large share of air trap differences between PA6 and PA66 parts on identical geometry stems from gate location choices that work for PA6 but are poorly suited for PA66’s faster fill and solidification. If your current gate is positioned in the center of the part wall, flow fronts will race down thicker wall sections first, wrap around rib features, and seal air into the top of ribs before the rib is fully filled; this creates minimal issues for slower-crystallizing PA6, but causes consistent air traps in PA66. For a low-cost, fast fix that doesn’t require a full tool rebuild, you can add 0.5mm wide overflow tabs at the end of each deep rib, positioned directly opposite the flow direction, to give trapped air a place to escape as the rib fills. These overflow tabs can be trimmed during part deflashing, with no impact on final part geometry or appearance. For long-term production, moving gate locations to the edge of deep rib sections so melt fills ribs from the thickest base to the thinnest tip will eliminate nearly all air trap formation in PA66 parts, without the need for extreme process adjustments that can increase part stress or cycle time.", "upvoteCount": 0, "url": "https://www.jaterson.com/qa/air-trap-formation-risk-differences-pa6-pa66-injection-molding.html#suggestedAnswer-8", "datePublished": "2026-08-25T11:00:49Z", "author": {"@type": "Person","name": "Eric Zhao","url": "https://www.jaterson.com/team/eric.html"} } ] } }, { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ {"@type": "ListItem", "position": 1, "name": "Home", "item": "https://www.jaterson.com/"},{"@type": "ListItem", "position": 2, "name": "Q&A", "item": "https://www.jaterson.com/qa/"},{"@type": "ListItem", "position": 3, "name": "Injection Molding Q&A", "item": "https://www.jaterson.com/qa/injection-molding/"} ,{"@type": "ListItem", "position": 4, "name": "How do air trap formation risks differ between PA6 and PA66 injection molding?"} ] } ] ```