--- title: "How to Optimize Multi-Cavity Mold Design for POM Injection Molding?" description: "Struggling with warpage, inconsistent part quality, and high tooling costs when using POM in multi-cavity injection molds? Access actionable guidance on material grade selection, mold design tweaks, process optimization, and cost tradeoffs to boost yield and cut production risks for your hardware components." url: "https://www.ok-tool.com/qa/optimize-multi-cavity-mold-design-pom-injection-molding.html" language: "en" type: "Q&A" category: "Injection Molding Q&A" datePublished: "2026-09-11" dateModified: "2026-09-11" brand: "OK TOOL" manufacturer: "OK TOOL" answerCount: 8 --- # How to Optimize Multi-Cavity Mold Design for POM Injection Molding? ## Question I’m a procurement engineer at a mid-sized hardware brand, and we’re currently sourcing new components for our upcoming line of adjustable wrench handles. The handle is made of POM, and we’ve specified a 16-cavity injection mold to meet our monthly demand of 50,000 units. Our previous supplier ran into major issues: nearly 8% of parts had warpage exceeding our tolerance of 0.2mm, and cavity-to-cavity dimension variation was inconsistent, leading to assembly delays with the metal wrench head. We’re now evaluating three potential suppliers, but I’m unsure what specific criteria to prioritize when assessing their ability to produce high-quality POM parts with multi-cavity molds. I need to balance production cost (we have a tight budget per unit) with part consistency and mold durability—what key factors should I focus on, and how can I avoid repeating the scrap and quality issues we faced before? ## Answers ### Answer 1 — Best Answer Your core issues—warpage, cavity-to-cavity dimension variation, and high scrap—stem from three interconnected factors: POM’s inherent material properties, multi-cavity mold design imbalance, and process parameter misalignment. POM has a relatively high shrinkage rate (1.5-2.5%), and homopolymer grades (often chosen for lower cost) exhibit more uniform but higher shrinkage, making them prone to warp if mold cooling or wall thickness is inconsistent. Multi-cavity molds, especially 16-cavity configurations, require precise runner and gate balancing to ensure equal material flow and pressure across all cavities; even minor imbalances lead to uneven cooling and dimensional variation. To resolve these issues, start with material grade selection. For your wrench handle application, a copolymer POM grade is preferable: it offers slightly lower shrinkage (1.2-2.0%) and better resistance to warp compared to homopolymer grades, while still maintaining sufficient impact strength and chemical resistance for hardware use. While copolymer POM costs 5-8% more per kilogram than standard homopolymer, the reduction in scrap (from 8% to an expected 1-2%) will offset this cost over volume production. Ensure suppliers can provide material certifications confirming grade consistency, as off-spec POM can exacerbate shrinkage and warpage. Next, evaluate mold design and manufacturing quality. Prioritize suppliers who perform **mold flow simulation** during the design phase to validate runner balancing, cooling channel placement, and wall thickness uniformity. For 16-cavity molds, a hot runner system with individually controlled gates is ideal to maintain consistent material temperature and flow across all cavities. Additionally, mold steel selection matters: S136 stainless steel is more resistant to corrosion from formaldehyde (a byproduct of POM processing) than H13 steel, extending mold life by 20-30% and reducing long-term maintenance costs. Request detailed mold drawings and cavity tolerance specifications to confirm all cavities meet your ±0.1mm dimension requirement. Finally, implement strict pre-production and in-process controls. Require suppliers to conduct a **cavity-by-cavity dimensional audit** on initial samples, measuring critical dimensions (such as the handle’s inner diameter for wrench head assembly) across all 16 cavities to identify any variation. During mass production, establish process monitoring protocols for injection pressure, melting temperature, and cooling time—these parameters directly impact POM shrinkage and warpage. To balance cost and quality, avoid suppliers who cut corners on mold balancing or use uncertified POM grades, as the long-term scrap and rework costs will far exceed initial savings. For prevention, include clauses in your supplier contract that require ongoing mold maintenance (such as periodic cleaning of cooling channels and runner systems) and provide access to real-time process data for critical production runs. This will help you catch dimensional drift or process deviations early, reducing the risk of assembly delays and scrap. **status:** accepted **Author:** Amy Li **Date:** 2026-09-11 ### Answer 2 For POM in multi-cavity molds, refining process parameters is critical to minimizing defects like warpage, sink marks, and flash. Start with melting temperature: copolymer POM performs best between 170–200°C, while homopolymer grades require a slightly higher range of 180–210°C; overheating can cause POM degradation, leading to brittle parts and surface discoloration. Injection pressure should be set between 80–120 MPa, with minor adjustments per cavity to ensure uniform fill—imbalanced pressure is a top cause of cavity-to-cavity dimension variation. Cooling time is equally important: aim for 10–15 seconds per cycle, as insufficient cooling leads to residual stress and warpage, while excessive cooling increases cycle time and production costs. Unlike many plastics, POM has low moisture absorption, so pre-drying isn’t necessary, but you should monitor for contamination in the hopper to avoid foreign particles in parts. To optimize the process window, run a design of experiments (DOE) to test combinations of temp, pressure, and cooling time, then lock in parameters that deliver consistent part quality across all cavities. **status:** suggested **Author:** Sophia Wang **Date:** 2026-09-11 ### Answer 3 When working with POM in multi-cavity molds, steel selection and machining tolerances directly impact mold life and part consistency. For 16-cavity configurations, S136 stainless steel is preferable over H13 tool steel because it resists corrosion from formaldehyde, a byproduct of POM processing, which can cause pitting and dimensional drift over time. S136 requires tighter machining tolerances (±0.05mm per cavity) to ensure uniform part dimensions, so verify that suppliers have precision CNC equipment capable of meeting these specs. Mold maintenance cycles should be scheduled every 50,000 shots: inspect gate surfaces for wear, clean cooling channels to remove scale buildup that impairs heat transfer, and re-polish cavity surfaces to maintain a mirror finish—this reduces ejection force and prevents part damage. Unfilled POM is less abrasive than filled grades, so a properly maintained S136 mold can last up to 1.5 million shots, compared to 1.2 million for H13. Additionally, ensure that the mold has a balanced ejection system with equal force across all cavities to avoid warping during part removal. **status:** suggested **Author:** Kevin Liu **Date:** 2026-09-11 ### Answer 4 Design-for-manufacture (DFM) adjustments are key to reducing POM part defects in multi-cavity molds. Start with draft angles: POM requires a minimum of 0.5° per side for smooth ejection, especially in areas with deep features like the handle’s inner cavity; insufficient draft can cause part warping or damage during ejection. Wall thickness uniformity is critical—avoid variations greater than 0.3mm, as thicker sections cool slower and trap residual stress, leading to warp or sink marks. If your design includes ribs, size them to 60% of the adjacent wall thickness to prevent sink marks without compromising structural integrity. Gate location also matters: place gates on non-critical surfaces (such as the bottom of the wrench handle) to minimize visible gate marks and ensure uniform material flow across the part. Additionally, consider adding a small radius to sharp corners to reduce stress concentration, which can prevent cracking during assembly or end-use. Before finalizing the mold, review the design with the supplier to identify any toolability risks that could lead to consistent defects across cavities. **status:** suggested **Author:** Michael Wu **Date:** 2026-09-11 ### Answer 5 Selecting the right POM grade involves balancing mechanical properties, processing ease, and cost for your multi-cavity mold application. Unfilled copolymer POM is the most versatile option for wrench handles, offering lower shrinkage (1.2–2.0%) and better warp resistance than homopolymer grades, while still meeting the impact strength and chemical resistance requirements for hardware. If your handle needs higher stiffness, consider a 10% glass-filled POM grade, but note that this increases shrinkage (2.0–3.0%) and requires mold adjustments to accommodate greater dimensional variation. For food-grade applications, FDA-compliant copolymer POM is available, though it costs 10–12% more than standard grades. Premium copolymer grades with enhanced flow properties can reduce cycle time by 1–2 seconds per shot, which translates to significant cost savings for monthly production of 50,000 units. Always request material data sheets (MDS) from suppliers to confirm that the grade meets your mechanical and processing requirements, and avoid off-spec or recycled POM, which can cause inconsistent shrinkage and part quality. **status:** suggested **Author:** Daniel Yang **Date:** 2026-09-11 ### Answer 6 Improving yield for POM multi-cavity mold production starts with identifying and addressing bottlenecks in the manufacturing process. First, implement a scrap tracking system to categorize defects (warpage, dimension variation, flash) by cavity and root cause—this will help you pinpoint if issues stem from runner imbalance, process parameters, or mold wear. Use statistical process control (SPC) to monitor critical dimensions across all cavities over time; set control limits for each dimension to catch drift early before it leads to scrap. Lean manufacturing practices like 5S can reduce contamination risks, as foreign particles in POM can cause surface defects and part failure. To reduce cycle time, optimize the mold’s cooling system to ensure uniform heat transfer, and consider implementing quick changeover methods to minimize downtime between batches. Additionally, train operators to perform routine checks of process parameters (temperature, pressure, cooling time) and mold condition, empowering them to address minor issues before they escalate into major quality problems. **status:** suggested **Author:** David Zhang **Date:** 2026-09-11 ### Answer 7 Ensuring end-use fit and performance of POM wrench handles from multi-cavity molds requires targeted functional validation and assembly constraint checks. First, verify that the handle’s inner diameter meets your tolerance requirement (±0.1mm) to ensure a secure fit with the metal wrench head—even a small variation can lead to loose or tight fits that compromise tool performance. Conduct torque tests on assembled wrenches, applying up to 150 Nm of force to confirm the POM handle doesn’t crack or deform under load. Environmental testing is also important: subject parts to temperature cycling (-20°C to 60°C) to check for warpage or dimensional change, as POM’s shrinkage can be affected by temperature fluctuations. If the wrench will be used with oils or solvents, ensure the POM grade is chemically resistant to avoid swelling or degradation. Additionally, simulate real-world use by dropping the assembled wrench from 1.5 meters to test impact resistance, ensuring the handle remains intact and doesn’t separate from the metal head. **status:** suggested **Author:** Eric Zhao **Date:** 2026-09-11 ### Answer 8 For consistent assembly of POM wrench handles with metal heads, focus on tolerance stack-up, assembly sequence, and volume consistency. Use Geometric Dimensioning and Tolerancing (GD&T) to define critical features, such as the position of the handle’s inner diameter relative to its outer shape, to account for tolerance stack-up between the POM part and metal wrench head. Implement a pneumatic press with controlled pressure (set to 50–70 kN) for pressing the metal head into the handle—this ensures consistent force across all assemblies, reducing the risk of cracking the POM. To maintain consistency at volume, use automated inspection equipment to check critical dimensions (inner diameter, handle length) before assembly, rejecting out-of-tolerance parts early to avoid rework. Design fixtures to hold handles during assembly, ensuring proper alignment between the handle and wrench head to minimize fit variation. Additionally, establish a regular calibration schedule for assembly equipment to ensure pressure and alignment remain accurate over time, reducing the likelihood of assembly defects. **status:** suggested **Author:** Rachel Huang **Date:** 2026-09-11 ## Related Resources - [Injection Molding Q&A](https://www.ok-tool.com/qa/injection-molding/) - [Plastic Injection Molding](https://www.ok-tool.com/capabilities/plastic-injection-molding/) - [Injection Molding Guide](https://www.ok-tool.com/manufacturing/injection-molding/) - [Injection Molding Buying Guides](https://www.ok-tool.com/buying/injection-molding/) - [Products](https://www.ok-tool.com/products/) - [Custom Manufacturing](https://www.ok-tool.com/custom-manufacturing/) - [Manufacturing Knowledge Base](https://www.ok-tool.com/knowledge/) - [Injection Molding](https://www.ok-tool.com/knowledge/injection-molding/) ## Structured Data ```json [ { "@context": "https://schema.org", "@type": "QAPage", "mainEntity": { "@type": "Question", "name": "How to Optimize Multi-Cavity Mold Design for POM Injection Molding?", "text": "I’m a procurement engineer at a mid-sized hardware brand, and we’re currently sourcing new components for our upcoming line of adjustable wrench handles. The handle is made of POM, and we’ve specified a 16-cavity injection mold to meet our monthly demand of 50,000 units. Our previous supplier ran into major issues: nearly 8% of parts had warpage exceeding our tolerance of 0.2mm, and cavity-to-cavity dimension variation was inconsistent, leading to assembly delays with the metal wrench head. We’re now evaluating three potential suppliers, but I’m unsure what specific criteria to prioritize when assessing their ability to produce high-quality POM parts with multi-cavity molds. I need to balance production cost (we have a tight budget per unit) with part consistency and mold durability—what key factors should I focus on, and how can I avoid repeating the scrap and quality issues we faced before?", "answerCount": 8, "upvoteCount": 9, "datePublished": "2026-09-11T13:21:54Z", "dateModified": "2026-09-11T13:27:33Z", "author": { "@type": "Person", "name": "Anonymous", "url": "https://www.ok-tool.com/qa/optimize-multi-cavity-mold-design-pom-injection-molding.html" } ,"acceptedAnswer": { "@type": "Answer", "text": "Your core issues—warpage, cavity-to-cavity dimension variation, and high scrap—stem from three interconnected factors: POM’s inherent material properties, multi-cavity mold design imbalance, and process parameter misalignment. POM has a relatively high shrinkage rate (1.5-2.5%), and homopolymer grades (often chosen for lower cost) exhibit more uniform but higher shrinkage, making them prone to warp if mold cooling or wall thickness is inconsistent. Multi-cavity molds, especially 16-cavity configurations, require precise runner and gate balancing to ensure equal material flow and pressure across all cavities; even minor imbalances lead to uneven cooling and dimensional variation. To resolve these issues, start with material grade selection. For your wrench handle application, a copolymer POM grade is preferable: it offers slightly lower shrinkage (1.2-2.0%) and better resistance to warp compared to homopolymer grades, while still maintaining sufficient impact strength and chemical resistance for hardware use. While copolymer POM costs 5-8% more per kilogram than standard homopolymer, the reduction in scrap (from 8% to an expected 1-2%) will offset this cost over volume production. Ensure suppliers can provide material certifications confirming grade consistency, as off-spec POM can exacerbate shrinkage and warpage. Next, evaluate mold design and manufacturing quality. Prioritize suppliers who perform **mold flow simulation** during the design phase to validate runner balancing, cooling channel placement, and wall thickness uniformity. For 16-cavity molds, a hot runner system with individually controlled gates is ideal to maintain consistent material temperature and flow across all cavities. Additionally, mold steel selection matters: S136 stainless steel is more resistant to corrosion from formaldehyde (a byproduct of POM processing) than H13 steel, extending mold life by 20-30% and reducing long-term maintenance costs. Request detailed mold drawings and cavity tolerance specifications to confirm all cavities meet your ±0.1mm dimension requirement. Finally, implement strict pre-production and in-process controls. Require suppliers to conduct a **cavity-by-cavity dimensional audit** on initial samples, measuring critical dimensions (such as the handle’s inner diameter for wrench head assembly) across all 16 cavities to identify any variation. During mass production, establish process monitoring protocols for injection pressure, melting temperature, and cooling time—these parameters directly impact POM shrinkage and warpage. To balance cost and quality, avoid suppliers who cut corners on mold balancing or use uncertified POM grades, as the long-term scrap and rework costs will far exceed initial savings. For prevention, include clauses in your supplier contract that require ongoing mold maintenance (such as periodic cleaning of cooling channels and runner systems) and provide access to real-time process data for critical production runs. This will help you catch dimensional drift or process deviations early, reducing the risk of assembly delays and scrap.", "upvoteCount": 9, "url": "https://www.ok-tool.com/qa/optimize-multi-cavity-mold-design-pom-injection-molding.html#acceptedAnswer", "datePublished": "2026-09-11T14:19:08Z", "author": {"@type": "Person","name": "Amy Li","url": "https://www.ok-tool.com/team/amy.html"} } ,"suggestedAnswer": [ { "@type": "Answer", "text": "For POM in multi-cavity molds, refining process parameters is critical to minimizing defects like warpage, sink marks, and flash. Start with melting temperature: copolymer POM performs best between 170–200°C, while homopolymer grades require a slightly higher range of 180–210°C; overheating can cause POM degradation, leading to brittle parts and surface discoloration. Injection pressure should be set between 80–120 MPa, with minor adjustments per cavity to ensure uniform fill—imbalanced pressure is a top cause of cavity-to-cavity dimension variation. Cooling time is equally important: aim for 10–15 seconds per cycle, as insufficient cooling leads to residual stress and warpage, while excessive cooling increases cycle time and production costs. Unlike many plastics, POM has low moisture absorption, so pre-drying isn’t necessary, but you should monitor for contamination in the hopper to avoid foreign particles in parts. To optimize the process window, run a design of experiments (DOE) to test combinations of temp, pressure, and cooling time, then lock in parameters that deliver consistent part quality across all cavities.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/optimize-multi-cavity-mold-design-pom-injection-molding.html#suggestedAnswer-2", "datePublished": "2026-09-11T14:17:43Z", "author": {"@type": "Person","name": "Sophia Wang","url": "https://www.ok-tool.com/team/sophia.html"} } , { "@type": "Answer", "text": "When working with POM in multi-cavity molds, steel selection and machining tolerances directly impact mold life and part consistency. For 16-cavity configurations, S136 stainless steel is preferable over H13 tool steel because it resists corrosion from formaldehyde, a byproduct of POM processing, which can cause pitting and dimensional drift over time. S136 requires tighter machining tolerances (±0.05mm per cavity) to ensure uniform part dimensions, so verify that suppliers have precision CNC equipment capable of meeting these specs. Mold maintenance cycles should be scheduled every 50,000 shots: inspect gate surfaces for wear, clean cooling channels to remove scale buildup that impairs heat transfer, and re-polish cavity surfaces to maintain a mirror finish—this reduces ejection force and prevents part damage. Unfilled POM is less abrasive than filled grades, so a properly maintained S136 mold can last up to 1.5 million shots, compared to 1.2 million for H13. Additionally, ensure that the mold has a balanced ejection system with equal force across all cavities to avoid warping during part removal.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/optimize-multi-cavity-mold-design-pom-injection-molding.html#suggestedAnswer-3", "datePublished": "2026-09-11T14:12:32Z", "author": {"@type": "Person","name": "Kevin Liu","url": "https://www.ok-tool.com/team/kevin.html"} } , { "@type": "Answer", "text": "Design-for-manufacture (DFM) adjustments are key to reducing POM part defects in multi-cavity molds. Start with draft angles: POM requires a minimum of 0.5° per side for smooth ejection, especially in areas with deep features like the handle’s inner cavity; insufficient draft can cause part warping or damage during ejection. Wall thickness uniformity is critical—avoid variations greater than 0.3mm, as thicker sections cool slower and trap residual stress, leading to warp or sink marks. If your design includes ribs, size them to 60% of the adjacent wall thickness to prevent sink marks without compromising structural integrity. Gate location also matters: place gates on non-critical surfaces (such as the bottom of the wrench handle) to minimize visible gate marks and ensure uniform material flow across the part. Additionally, consider adding a small radius to sharp corners to reduce stress concentration, which can prevent cracking during assembly or end-use. Before finalizing the mold, review the design with the supplier to identify any toolability risks that could lead to consistent defects across cavities.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/optimize-multi-cavity-mold-design-pom-injection-molding.html#suggestedAnswer-4", "datePublished": "2026-09-11T14:04:32Z", "author": {"@type": "Person","name": "Michael Wu","url": "https://www.ok-tool.com/team/michael.html"} } , { "@type": "Answer", "text": "Selecting the right POM grade involves balancing mechanical properties, processing ease, and cost for your multi-cavity mold application. Unfilled copolymer POM is the most versatile option for wrench handles, offering lower shrinkage (1.2–2.0%) and better warp resistance than homopolymer grades, while still meeting the impact strength and chemical resistance requirements for hardware. If your handle needs higher stiffness, consider a 10% glass-filled POM grade, but note that this increases shrinkage (2.0–3.0%) and requires mold adjustments to accommodate greater dimensional variation. For food-grade applications, FDA-compliant copolymer POM is available, though it costs 10–12% more than standard grades. Premium copolymer grades with enhanced flow properties can reduce cycle time by 1–2 seconds per shot, which translates to significant cost savings for monthly production of 50,000 units. Always request material data sheets (MDS) from suppliers to confirm that the grade meets your mechanical and processing requirements, and avoid off-spec or recycled POM, which can cause inconsistent shrinkage and part quality.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/optimize-multi-cavity-mold-design-pom-injection-molding.html#suggestedAnswer-5", "datePublished": "2026-09-11T14:01:58Z", "author": {"@type": "Person","name": "Daniel Yang","url": "https://www.ok-tool.com/team/daniel.html"} } , { "@type": "Answer", "text": "Improving yield for POM multi-cavity mold production starts with identifying and addressing bottlenecks in the manufacturing process. First, implement a scrap tracking system to categorize defects (warpage, dimension variation, flash) by cavity and root cause—this will help you pinpoint if issues stem from runner imbalance, process parameters, or mold wear. Use statistical process control (SPC) to monitor critical dimensions across all cavities over time; set control limits for each dimension to catch drift early before it leads to scrap. Lean manufacturing practices like 5S can reduce contamination risks, as foreign particles in POM can cause surface defects and part failure. To reduce cycle time, optimize the mold’s cooling system to ensure uniform heat transfer, and consider implementing quick changeover methods to minimize downtime between batches. Additionally, train operators to perform routine checks of process parameters (temperature, pressure, cooling time) and mold condition, empowering them to address minor issues before they escalate into major quality problems.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/optimize-multi-cavity-mold-design-pom-injection-molding.html#suggestedAnswer-6", "datePublished": "2026-09-11T13:43:55Z", "author": {"@type": "Person","name": "David Zhang","url": "https://www.ok-tool.com/team/david.html"} } , { "@type": "Answer", "text": "Ensuring end-use fit and performance of POM wrench handles from multi-cavity molds requires targeted functional validation and assembly constraint checks. First, verify that the handle’s inner diameter meets your tolerance requirement (±0.1mm) to ensure a secure fit with the metal wrench head—even a small variation can lead to loose or tight fits that compromise tool performance. Conduct torque tests on assembled wrenches, applying up to 150 Nm of force to confirm the POM handle doesn’t crack or deform under load. Environmental testing is also important: subject parts to temperature cycling (-20°C to 60°C) to check for warpage or dimensional change, as POM’s shrinkage can be affected by temperature fluctuations. If the wrench will be used with oils or solvents, ensure the POM grade is chemically resistant to avoid swelling or degradation. Additionally, simulate real-world use by dropping the assembled wrench from 1.5 meters to test impact resistance, ensuring the handle remains intact and doesn’t separate from the metal head.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/optimize-multi-cavity-mold-design-pom-injection-molding.html#suggestedAnswer-7", "datePublished": "2026-09-11T13:38:25Z", "author": {"@type": "Person","name": "Eric Zhao","url": "https://www.ok-tool.com/team/eric.html"} } , { "@type": "Answer", "text": "For consistent assembly of POM wrench handles with metal heads, focus on tolerance stack-up, assembly sequence, and volume consistency. Use Geometric Dimensioning and Tolerancing (GD&T) to define critical features, such as the position of the handle’s inner diameter relative to its outer shape, to account for tolerance stack-up between the POM part and metal wrench head. Implement a pneumatic press with controlled pressure (set to 50–70 kN) for pressing the metal head into the handle—this ensures consistent force across all assemblies, reducing the risk of cracking the POM. To maintain consistency at volume, use automated inspection equipment to check critical dimensions (inner diameter, handle length) before assembly, rejecting out-of-tolerance parts early to avoid rework. Design fixtures to hold handles during assembly, ensuring proper alignment between the handle and wrench head to minimize fit variation. Additionally, establish a regular calibration schedule for assembly equipment to ensure pressure and alignment remain accurate over time, reducing the likelihood of assembly defects.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/optimize-multi-cavity-mold-design-pom-injection-molding.html#suggestedAnswer-8", "datePublished": "2026-09-11T13:27:33Z", "author": {"@type": "Person","name": "Rachel Huang","url": "https://www.ok-tool.com/team/rachel.html"} } ] } }, { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ {"@type": "ListItem", "position": 1, "name": "Home", "item": "https://www.ok-tool.com/"},{"@type": "ListItem", "position": 2, "name": "Q&A", "item": "https://www.ok-tool.com/qa/"},{"@type": "ListItem", "position": 3, "name": "Injection Molding Q&A >", "item": "https://www.ok-tool.com/qa/injection-molding/>"} ,{"@type": "ListItem", "position": 4, "name": "How to Optimize Multi-Cavity Mold Design for POM Injection Molding?"} ] } ] ```