If you are dealing with fragile parts, don't panic. In this guide, we will break down the 5 main culprits behind brittle plastics and provide actionable solutions to fix them.<\/p>\n
![\"Brittle](\"https:\/\/ideal-pro.com\/wp-content\/uploads\/2026\/07\/how-to-fix-brittle-injection-molding-parts-2.jpg\" "\\"Brittle")
<\/p>\n
1. The 5 Root Causes of Brittle Plastic Parts<\/h2>\n
To solve the problem, you first need to identify where it’s coming from. Brittleness typically stems from one of five areas:<\/p>\n
Equipment Issues<\/h3>\n\n- Barrel Dead Spots:<\/strong> Obstructions or dead zones in the barrel can cause melt degradation.<\/li>\n
- Improper Machine Sizing:<\/strong> If the machine's plasticizing capacity is too small, the material won't melt properly. If it's too large, the plastic stays in the barrel too long, leading to thermal aging and brittleness.<\/li>\n
- Ejection Problems:<\/strong> Misaligned ejector pins or improper pin distribution can induce severe mechanical stress during part removal.<\/li>\n<\/ul>\n
Mold Design Flaws<\/h3>\n\n- Restricted Flow:<\/strong> Gates or runners that are too small create excessive shear heat, degrading the polymer.<\/li>\n
- Unbalanced Runners:<\/strong> Poorly configured runner systems lead to uneven filling and stress.<\/li>\n
- Poor Mold Structure:<\/strong> Flaws that cause abnormal cycle times or cooling issues.<\/li>\n<\/ul>\n
Param\u00e8tres de traitement<\/h3>\n\n- Temperature Extremes:<\/strong> Barrel\/nozzle temperatures that are too low prevent proper melting. Conversely, if the material is prone to degradation, temperatures may need to be carefully optimized.<\/li>\n
- Excessive Shear:<\/strong> High back pressure or screw speed generates too much friction heat, breaking down the plastic.<\/li>\n
- Mold Temperature Issues:<\/strong> A mold that is too cold causes premature cooling and poor weld line fusion (especially in high-melting-point plastics like Polycarbonate). A mold that is too hot makes ejection difficult.<\/li>\n
- Metal Inserts:<\/strong> Using metal inserts in brittle plastics (like Polystyrene) creates massive thermal stress due to differing expansion rates.<\/li>\n<\/ul>\n
Material & Resin Problems<\/h3>\n\n- Contamination:<\/strong> Impurities, wrong additives, or excessive solvents in the resin.<\/li>\n
- Moisture:<\/strong> Plastics like ABS undergo catalytic cracking when exposed to steam during heating, causing severe internal strain.<\/li>\n
- Over-Recycling:<\/strong> Using too much regrind, or regrind that has been processed too many times, drastically reduces molecular weight.<\/li>\n
- Poor Resin Quality:<\/strong> Wide molecular weight distribution or contamination from other polymers. For a deeper technical understanding of how molecular breakdown affects your parts, read our guide on injection molding plastic degradation causes and solutions<\/a>.<\/li>\n<\/ul>\n
Part Design Limitations<\/h3>\n\n- Stress Concentrators:<\/strong> Sharp corners, notches, or drastic wall thickness changes. These features are notorious for initiating failure; learn more in our article on how to prevent stress cracking in plastic product design<\/a>.<\/li>\n
- Thin Walls:<\/strong> Parts that are too thin or have excessive hollow sections lack structural integrity. It is crucial to understand how wall thickness affects the quality of plastic parts<\/a> to avoid weak spots.<\/li>\n<\/ul>\n
![\"Diagram](\"https:\/\/ideal-pro.com\/wp-content\/uploads\/2026\/07\/how-to-fix-brittle-injection-molding-parts-3.jpg\" "\\"Diagram")
<\/p>\n
2. Quick Troubleshooting Guide<\/h2>\n
Use this structured reference to quickly diagnose and fix brittleness on the production floor:<\/p>\n
\n\n\nCat\u00e9gorie<\/th>\n Potential Cause<\/th>\n Actionable Solution<\/th>\n<\/tr>\n<\/thead>\n \n\nMat\u00e9riau<\/strong><\/td>\nContamination par l'humidit\u00e9<\/td>\n Dry resin properly before processing. (Note: Avoid over-drying, as it can also degrade heat-sensitive materials).<\/em><\/td>\n<\/tr>\n\nMat\u00e9riau<\/strong><\/td>\nExcessive regrind usage<\/td>\n Reduce regrind percentage; increase virgin resin ratio.<\/td>\n<\/tr>\n \nConception des moules<\/strong><\/td>\nSmall gates\/runners<\/td>\n Increase gate and runner sizes to reduce shear heat and polymer decomposition.<\/td>\n<\/tr>\n \nEquipment<\/strong><\/td>\nUneven melting<\/td>\n Upgrade to a well-designed mixing screw for uniform temperature distribution.<\/td>\n<\/tr>\n \nProcessing<\/strong><\/td>\nHigh shear heat<\/td>\n Lower barrel\/nozzle temps, reduce back pressure, screw speed, and injection speed.<\/td>\n<\/tr>\n \nProcessing<\/strong><\/td>\nWeak weld lines<\/td>\n Increase melt temperature and injection pressure to improve weld line strength.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n3. Best Practices for Prevention<\/h2>\n
Fixing brittle parts isn't just about tweaking one dial; it requires a holistic approach. Here are the best practices to ensure tough, durable parts:<\/p>\n
\n- Optimize Drying:<\/strong> Always follow the resin manufacturer's exact drying guidelines. Remember, drying a material for too many days or at excessively high temperatures can cause thermal degradation, especially in heat-sensitive polymers.<\/li>\n
- Upgrade Your Screw:<\/strong> If you frequently process engineering plastics, invest in a high-quality screw designed for uniform plasticizing. Localized heat buildup is a silent killer of polymer strength.<\/li>\n
- Design for Manufacturability (DFM):<\/strong> Work with engineers early to add proper draft angles, radius sharp corners, and maintain uniform wall thickness. <\/li>\n
- Balance the Process:<\/strong> When dealing with weak weld lines, increasing melt temperature and injection pressure can force the polymer chains to entangle properly, significantly boosting structural strength.<\/li>\n<\/ol>\n
![\"High-quality](\"https:\/\/ideal-pro.com\/wp-content\/uploads\/2026\/07\/the-ultimate-guide-to-ptfe-injection-molding-3.jpg\" "\\"High-quality")
<\/p>\n
Partner with IDEAL PRO for Robust Manufacturing<\/h3>\n
Solving complex issues like brittleness requires more than just troubleshooting—it requires a partner with deep technical expertise. At IDEAL PRO<\/strong>, we lead in custom plastic injection molding and product design, offering end-to-end solutions from rapid prototyping to full-scale production.<\/p>\nWith over 18 years of experience and nearly 3,000 diverse product developments, our top-tier design and technical teams specialize in new product development and cost-efficiency strategies. Whether you are a startup or an established industry player, our Turnkey Solution Service covers all phases of product development to ensure your parts are durable, high-quality, and market-ready.<\/p>\n
Over to You<\/h3>\n
Have you successfully fixed a severe brittleness issue on the production floor? Was it a material, mold, or processing problem? Share your experiences and tips in the form below!<\/p>","protected":false},"excerpt":{"rendered":"
Brittleness in injection molding is a frustrating defect that can ruin production runs and compromise product safety. When a plastic […]<\/p>\n","protected":false},"author":2,"featured_media":13884,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_titles_title":"","_seopress_titles_desc":"Are your Injection Molding parts cracking or breaking? Discover the root causes of brittle plastic parts and learn actionable solutions in material, mold design, and processing 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Mold Design Flaws<\/h3>\n\n- Restricted Flow:<\/strong> Gates or runners that are too small create excessive shear heat, degrading the polymer.<\/li>\n
- Unbalanced Runners:<\/strong> Poorly configured runner systems lead to uneven filling and stress.<\/li>\n
- Poor Mold Structure:<\/strong> Flaws that cause abnormal cycle times or cooling issues.<\/li>\n<\/ul>\n
Param\u00e8tres de traitement<\/h3>\n\n- Temperature Extremes:<\/strong> Barrel\/nozzle temperatures that are too low prevent proper melting. Conversely, if the material is prone to degradation, temperatures may need to be carefully optimized.<\/li>\n
- Excessive Shear:<\/strong> High back pressure or screw speed generates too much friction heat, breaking down the plastic.<\/li>\n
- Mold Temperature Issues:<\/strong> A mold that is too cold causes premature cooling and poor weld line fusion (especially in high-melting-point plastics like Polycarbonate). A mold that is too hot makes ejection difficult.<\/li>\n
- Metal Inserts:<\/strong> Using metal inserts in brittle plastics (like Polystyrene) creates massive thermal stress due to differing expansion rates.<\/li>\n<\/ul>\n
Material & Resin Problems<\/h3>\n\n- Contamination:<\/strong> Impurities, wrong additives, or excessive solvents in the resin.<\/li>\n
- Moisture:<\/strong> Plastics like ABS undergo catalytic cracking when exposed to steam during heating, causing severe internal strain.<\/li>\n
- Over-Recycling:<\/strong> Using too much regrind, or regrind that has been processed too many times, drastically reduces molecular weight.<\/li>\n
- Poor Resin Quality:<\/strong> Wide molecular weight distribution or contamination from other polymers. For a deeper technical understanding of how molecular breakdown affects your parts, read our guide on injection molding plastic degradation causes and solutions<\/a>.<\/li>\n<\/ul>\n
Part Design Limitations<\/h3>\n\n- Stress Concentrators:<\/strong> Sharp corners, notches, or drastic wall thickness changes. These features are notorious for initiating failure; learn more in our article on how to prevent stress cracking in plastic product design<\/a>.<\/li>\n
- Thin Walls:<\/strong> Parts that are too thin or have excessive hollow sections lack structural integrity. It is crucial to understand how wall thickness affects the quality of plastic parts<\/a> to avoid weak spots.<\/li>\n<\/ul>\n
<\/p>\n
2. Quick Troubleshooting Guide<\/h2>\n
Use this structured reference to quickly diagnose and fix brittleness on the production floor:<\/p>\n
\n\n\nCat\u00e9gorie<\/th>\n Potential Cause<\/th>\n Actionable Solution<\/th>\n<\/tr>\n<\/thead>\n \n\nMat\u00e9riau<\/strong><\/td>\nContamination par l'humidit\u00e9<\/td>\n Dry resin properly before processing. (Note: Avoid over-drying, as it can also degrade heat-sensitive materials).<\/em><\/td>\n<\/tr>\n\nMat\u00e9riau<\/strong><\/td>\nExcessive regrind usage<\/td>\n Reduce regrind percentage; increase virgin resin ratio.<\/td>\n<\/tr>\n \nConception des moules<\/strong><\/td>\nSmall gates\/runners<\/td>\n Increase gate and runner sizes to reduce shear heat and polymer decomposition.<\/td>\n<\/tr>\n \nEquipment<\/strong><\/td>\nUneven melting<\/td>\n Upgrade to a well-designed mixing screw for uniform temperature distribution.<\/td>\n<\/tr>\n \nProcessing<\/strong><\/td>\nHigh shear heat<\/td>\n Lower barrel\/nozzle temps, reduce back pressure, screw speed, and injection speed.<\/td>\n<\/tr>\n \nProcessing<\/strong><\/td>\nWeak weld lines<\/td>\n Increase melt temperature and injection pressure to improve weld line strength.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n3. Best Practices for Prevention<\/h2>\n
Fixing brittle parts isn't just about tweaking one dial; it requires a holistic approach. Here are the best practices to ensure tough, durable parts:<\/p>\n
\n- Optimize Drying:<\/strong> Always follow the resin manufacturer's exact drying guidelines. Remember, drying a material for too many days or at excessively high temperatures can cause thermal degradation, especially in heat-sensitive polymers.<\/li>\n
- Upgrade Your Screw:<\/strong> If you frequently process engineering plastics, invest in a high-quality screw designed for uniform plasticizing. Localized heat buildup is a silent killer of polymer strength.<\/li>\n
- Design for Manufacturability (DFM):<\/strong> Work with engineers early to add proper draft angles, radius sharp corners, and maintain uniform wall thickness. <\/li>\n
- Balance the Process:<\/strong> When dealing with weak weld lines, increasing melt temperature and injection pressure can force the polymer chains to entangle properly, significantly boosting structural strength.<\/li>\n<\/ol>\n
<\/p>\n
Partner with IDEAL PRO for Robust Manufacturing<\/h3>\n
Solving complex issues like brittleness requires more than just troubleshooting—it requires a partner with deep technical expertise. At IDEAL PRO<\/strong>, we lead in custom plastic injection molding and product design, offering end-to-end solutions from rapid prototyping to full-scale production.<\/p>\nWith over 18 years of experience and nearly 3,000 diverse product developments, our top-tier design and technical teams specialize in new product development and cost-efficiency strategies. Whether you are a startup or an established industry player, our Turnkey Solution Service covers all phases of product development to ensure your parts are durable, high-quality, and market-ready.<\/p>\n
Over to You<\/h3>\n
Have you successfully fixed a severe brittleness issue on the production floor? Was it a material, mold, or processing problem? Share your experiences and tips in the form below!<\/p>","protected":false},"excerpt":{"rendered":"
Brittleness in injection molding is a frustrating defect that can ruin production runs and compromise product safety. When a plastic […]<\/p>\n","protected":false},"author":2,"featured_media":13884,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_titles_title":"","_seopress_titles_desc":"Are your Injection Molding parts cracking or breaking? 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Param\u00e8tres de traitement<\/h3>\n\n- Temperature Extremes:<\/strong> Barrel\/nozzle temperatures that are too low prevent proper melting. Conversely, if the material is prone to degradation, temperatures may need to be carefully optimized.<\/li>\n
- Excessive Shear:<\/strong> High back pressure or screw speed generates too much friction heat, breaking down the plastic.<\/li>\n
- Mold Temperature Issues:<\/strong> A mold that is too cold causes premature cooling and poor weld line fusion (especially in high-melting-point plastics like Polycarbonate). A mold that is too hot makes ejection difficult.<\/li>\n
- Metal Inserts:<\/strong> Using metal inserts in brittle plastics (like Polystyrene) creates massive thermal stress due to differing expansion rates.<\/li>\n<\/ul>\n
Material & Resin Problems<\/h3>\n\n- Contamination:<\/strong> Impurities, wrong additives, or excessive solvents in the resin.<\/li>\n
- Moisture:<\/strong> Plastics like ABS undergo catalytic cracking when exposed to steam during heating, causing severe internal strain.<\/li>\n
- Over-Recycling:<\/strong> Using too much regrind, or regrind that has been processed too many times, drastically reduces molecular weight.<\/li>\n
- Poor Resin Quality:<\/strong> Wide molecular weight distribution or contamination from other polymers. For a deeper technical understanding of how molecular breakdown affects your parts, read our guide on injection molding plastic degradation causes and solutions<\/a>.<\/li>\n<\/ul>\n
Part Design Limitations<\/h3>\n\n- Stress Concentrators:<\/strong> Sharp corners, notches, or drastic wall thickness changes. These features are notorious for initiating failure; learn more in our article on how to prevent stress cracking in plastic product design<\/a>.<\/li>\n
- Thin Walls:<\/strong> Parts that are too thin or have excessive hollow sections lack structural integrity. It is crucial to understand how wall thickness affects the quality of plastic parts<\/a> to avoid weak spots.<\/li>\n<\/ul>\n
<\/p>\n
2. Quick Troubleshooting Guide<\/h2>\n
Use this structured reference to quickly diagnose and fix brittleness on the production floor:<\/p>\n
\n\n\nCat\u00e9gorie<\/th>\n Potential Cause<\/th>\n Actionable Solution<\/th>\n<\/tr>\n<\/thead>\n \n\nMat\u00e9riau<\/strong><\/td>\nContamination par l'humidit\u00e9<\/td>\n Dry resin properly before processing. (Note: Avoid over-drying, as it can also degrade heat-sensitive materials).<\/em><\/td>\n<\/tr>\n\nMat\u00e9riau<\/strong><\/td>\nExcessive regrind usage<\/td>\n Reduce regrind percentage; increase virgin resin ratio.<\/td>\n<\/tr>\n \nConception des moules<\/strong><\/td>\nSmall gates\/runners<\/td>\n Increase gate and runner sizes to reduce shear heat and polymer decomposition.<\/td>\n<\/tr>\n \nEquipment<\/strong><\/td>\nUneven melting<\/td>\n Upgrade to a well-designed mixing screw for uniform temperature distribution.<\/td>\n<\/tr>\n \nProcessing<\/strong><\/td>\nHigh shear heat<\/td>\n Lower barrel\/nozzle temps, reduce back pressure, screw speed, and injection speed.<\/td>\n<\/tr>\n \nProcessing<\/strong><\/td>\nWeak weld lines<\/td>\n Increase melt temperature and injection pressure to improve weld line strength.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n3. Best Practices for Prevention<\/h2>\n
Fixing brittle parts isn't just about tweaking one dial; it requires a holistic approach. Here are the best practices to ensure tough, durable parts:<\/p>\n
\n- Optimize Drying:<\/strong> Always follow the resin manufacturer's exact drying guidelines. Remember, drying a material for too many days or at excessively high temperatures can cause thermal degradation, especially in heat-sensitive polymers.<\/li>\n
- Upgrade Your Screw:<\/strong> If you frequently process engineering plastics, invest in a high-quality screw designed for uniform plasticizing. Localized heat buildup is a silent killer of polymer strength.<\/li>\n
- Design for Manufacturability (DFM):<\/strong> Work with engineers early to add proper draft angles, radius sharp corners, and maintain uniform wall thickness. <\/li>\n
- Balance the Process:<\/strong> When dealing with weak weld lines, increasing melt temperature and injection pressure can force the polymer chains to entangle properly, significantly boosting structural strength.<\/li>\n<\/ol>\n
<\/p>\n
Partner with IDEAL PRO for Robust Manufacturing<\/h3>\n
Solving complex issues like brittleness requires more than just troubleshooting—it requires a partner with deep technical expertise. At IDEAL PRO<\/strong>, we lead in custom plastic injection molding and product design, offering end-to-end solutions from rapid prototyping to full-scale production.<\/p>\nWith over 18 years of experience and nearly 3,000 diverse product developments, our top-tier design and technical teams specialize in new product development and cost-efficiency strategies. Whether you are a startup or an established industry player, our Turnkey Solution Service covers all phases of product development to ensure your parts are durable, high-quality, and market-ready.<\/p>\n
Over to You<\/h3>\n
Have you successfully fixed a severe brittleness issue on the production floor? Was it a material, mold, or processing problem? Share your experiences and tips in the form below!<\/p>","protected":false},"excerpt":{"rendered":"
Brittleness in injection molding is a frustrating defect that can ruin production runs and compromise product safety. When a plastic […]<\/p>\n","protected":false},"author":2,"featured_media":13884,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_titles_title":"","_seopress_titles_desc":"Are your Injection Molding parts cracking or breaking? Discover the root causes of brittle plastic parts and learn actionable solutions in material, mold design, and processing 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Material & Resin Problems<\/h3>\n\n- Contamination:<\/strong> Impurities, wrong additives, or excessive solvents in the resin.<\/li>\n
- Moisture:<\/strong> Plastics like ABS undergo catalytic cracking when exposed to steam during heating, causing severe internal strain.<\/li>\n
- Over-Recycling:<\/strong> Using too much regrind, or regrind that has been processed too many times, drastically reduces molecular weight.<\/li>\n
- Poor Resin Quality:<\/strong> Wide molecular weight distribution or contamination from other polymers. For a deeper technical understanding of how molecular breakdown affects your parts, read our guide on injection molding plastic degradation causes and solutions<\/a>.<\/li>\n<\/ul>\n
Part Design Limitations<\/h3>\n\n- Stress Concentrators:<\/strong> Sharp corners, notches, or drastic wall thickness changes. These features are notorious for initiating failure; learn more in our article on how to prevent stress cracking in plastic product design<\/a>.<\/li>\n
- Thin Walls:<\/strong> Parts that are too thin or have excessive hollow sections lack structural integrity. It is crucial to understand how wall thickness affects the quality of plastic parts<\/a> to avoid weak spots.<\/li>\n<\/ul>\n
<\/p>\n
2. Quick Troubleshooting Guide<\/h2>\n
Use this structured reference to quickly diagnose and fix brittleness on the production floor:<\/p>\n
\n\n\nCat\u00e9gorie<\/th>\n Potential Cause<\/th>\n Actionable Solution<\/th>\n<\/tr>\n<\/thead>\n \n\nMat\u00e9riau<\/strong><\/td>\nContamination par l'humidit\u00e9<\/td>\n Dry resin properly before processing. (Note: Avoid over-drying, as it can also degrade heat-sensitive materials).<\/em><\/td>\n<\/tr>\n\nMat\u00e9riau<\/strong><\/td>\nExcessive regrind usage<\/td>\n Reduce regrind percentage; increase virgin resin ratio.<\/td>\n<\/tr>\n \nConception des moules<\/strong><\/td>\nSmall gates\/runners<\/td>\n Increase gate and runner sizes to reduce shear heat and polymer decomposition.<\/td>\n<\/tr>\n \nEquipment<\/strong><\/td>\nUneven melting<\/td>\n Upgrade to a well-designed mixing screw for uniform temperature distribution.<\/td>\n<\/tr>\n \nProcessing<\/strong><\/td>\nHigh shear heat<\/td>\n Lower barrel\/nozzle temps, reduce back pressure, screw speed, and injection speed.<\/td>\n<\/tr>\n \nProcessing<\/strong><\/td>\nWeak weld lines<\/td>\n Increase melt temperature and injection pressure to improve weld line strength.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n3. Best Practices for Prevention<\/h2>\n
Fixing brittle parts isn't just about tweaking one dial; it requires a holistic approach. Here are the best practices to ensure tough, durable parts:<\/p>\n
\n- Optimize Drying:<\/strong> Always follow the resin manufacturer's exact drying guidelines. Remember, drying a material for too many days or at excessively high temperatures can cause thermal degradation, especially in heat-sensitive polymers.<\/li>\n
- Upgrade Your Screw:<\/strong> If you frequently process engineering plastics, invest in a high-quality screw designed for uniform plasticizing. Localized heat buildup is a silent killer of polymer strength.<\/li>\n
- Design for Manufacturability (DFM):<\/strong> Work with engineers early to add proper draft angles, radius sharp corners, and maintain uniform wall thickness. <\/li>\n
- Balance the Process:<\/strong> When dealing with weak weld lines, increasing melt temperature and injection pressure can force the polymer chains to entangle properly, significantly boosting structural strength.<\/li>\n<\/ol>\n
<\/p>\n
Partner with IDEAL PRO for Robust Manufacturing<\/h3>\n
Solving complex issues like brittleness requires more than just troubleshooting—it requires a partner with deep technical expertise. At IDEAL PRO<\/strong>, we lead in custom plastic injection molding and product design, offering end-to-end solutions from rapid prototyping to full-scale production.<\/p>\nWith over 18 years of experience and nearly 3,000 diverse product developments, our top-tier design and technical teams specialize in new product development and cost-efficiency strategies. Whether you are a startup or an established industry player, our Turnkey Solution Service covers all phases of product development to ensure your parts are durable, high-quality, and market-ready.<\/p>\n
Over to You<\/h3>\n
Have you successfully fixed a severe brittleness issue on the production floor? Was it a material, mold, or processing problem? Share your experiences and tips in the form below!<\/p>","protected":false},"excerpt":{"rendered":"
Brittleness in injection molding is a frustrating defect that can ruin production runs and compromise product safety. When a plastic […]<\/p>\n","protected":false},"author":2,"featured_media":13884,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_titles_title":"","_seopress_titles_desc":"Are your Injection Molding parts cracking or breaking? 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Part Design Limitations<\/h3>\n\n- Stress Concentrators:<\/strong> Sharp corners, notches, or drastic wall thickness changes. These features are notorious for initiating failure; learn more in our article on how to prevent stress cracking in plastic product design<\/a>.<\/li>\n
- Thin Walls:<\/strong> Parts that are too thin or have excessive hollow sections lack structural integrity. It is crucial to understand how wall thickness affects the quality of plastic parts<\/a> to avoid weak spots.<\/li>\n<\/ul>\n
<\/p>\n
2. Quick Troubleshooting Guide<\/h2>\n
Use this structured reference to quickly diagnose and fix brittleness on the production floor:<\/p>\n
\n\n\nCat\u00e9gorie<\/th>\n Potential Cause<\/th>\n Actionable Solution<\/th>\n<\/tr>\n<\/thead>\n \n\nMat\u00e9riau<\/strong><\/td>\nContamination par l'humidit\u00e9<\/td>\n Dry resin properly before processing. (Note: Avoid over-drying, as it can also degrade heat-sensitive materials).<\/em><\/td>\n<\/tr>\n\nMat\u00e9riau<\/strong><\/td>\nExcessive regrind usage<\/td>\n Reduce regrind percentage; increase virgin resin ratio.<\/td>\n<\/tr>\n \nConception des moules<\/strong><\/td>\nSmall gates\/runners<\/td>\n Increase gate and runner sizes to reduce shear heat and polymer decomposition.<\/td>\n<\/tr>\n \nEquipment<\/strong><\/td>\nUneven melting<\/td>\n Upgrade to a well-designed mixing screw for uniform temperature distribution.<\/td>\n<\/tr>\n \nProcessing<\/strong><\/td>\nHigh shear heat<\/td>\n Lower barrel\/nozzle temps, reduce back pressure, screw speed, and injection speed.<\/td>\n<\/tr>\n \nProcessing<\/strong><\/td>\nWeak weld lines<\/td>\n Increase melt temperature and injection pressure to improve weld line strength.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n3. Best Practices for Prevention<\/h2>\n
Fixing brittle parts isn't just about tweaking one dial; it requires a holistic approach. Here are the best practices to ensure tough, durable parts:<\/p>\n
\n- Optimize Drying:<\/strong> Always follow the resin manufacturer's exact drying guidelines. Remember, drying a material for too many days or at excessively high temperatures can cause thermal degradation, especially in heat-sensitive polymers.<\/li>\n
- Upgrade Your Screw:<\/strong> If you frequently process engineering plastics, invest in a high-quality screw designed for uniform plasticizing. Localized heat buildup is a silent killer of polymer strength.<\/li>\n
- Design for Manufacturability (DFM):<\/strong> Work with engineers early to add proper draft angles, radius sharp corners, and maintain uniform wall thickness. <\/li>\n
- Balance the Process:<\/strong> When dealing with weak weld lines, increasing melt temperature and injection pressure can force the polymer chains to entangle properly, significantly boosting structural strength.<\/li>\n<\/ol>\n
<\/p>\n
Partner with IDEAL PRO for Robust Manufacturing<\/h3>\n
Solving complex issues like brittleness requires more than just troubleshooting—it requires a partner with deep technical expertise. At IDEAL PRO<\/strong>, we lead in custom plastic injection molding and product design, offering end-to-end solutions from rapid prototyping to full-scale production.<\/p>\nWith over 18 years of experience and nearly 3,000 diverse product developments, our top-tier design and technical teams specialize in new product development and cost-efficiency strategies. Whether you are a startup or an established industry player, our Turnkey Solution Service covers all phases of product development to ensure your parts are durable, high-quality, and market-ready.<\/p>\n
Over to You<\/h3>\n
Have you successfully fixed a severe brittleness issue on the production floor? Was it a material, mold, or processing problem? Share your experiences and tips in the form below!<\/p>","protected":false},"excerpt":{"rendered":"
Brittleness in injection molding is a frustrating defect that can ruin production runs and compromise product safety. When a plastic […]<\/p>\n","protected":false},"author":2,"featured_media":13884,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_titles_title":"","_seopress_titles_desc":"Are your Injection Molding parts cracking or breaking? 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<\/p>\n
2. Quick Troubleshooting Guide<\/h2>\n
Use this structured reference to quickly diagnose and fix brittleness on the production floor:<\/p>\n
| Cat\u00e9gorie<\/th>\n | Potential Cause<\/th>\n | Actionable Solution<\/th>\n<\/tr>\n<\/thead>\n | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Mat\u00e9riau<\/strong><\/td>\n| Contamination par l'humidit\u00e9<\/td>\n | Dry resin properly before processing. (Note: Avoid over-drying, as it can also degrade heat-sensitive materials).<\/em><\/td>\n<\/tr>\n | Mat\u00e9riau<\/strong><\/td>\n | Excessive regrind usage<\/td>\n | Reduce regrind percentage; increase virgin resin ratio.<\/td>\n<\/tr>\n | Conception des moules<\/strong><\/td>\n | Small gates\/runners<\/td>\n | Increase gate and runner sizes to reduce shear heat and polymer decomposition.<\/td>\n<\/tr>\n | Equipment<\/strong><\/td>\n | Uneven melting<\/td>\n | Upgrade to a well-designed mixing screw for uniform temperature distribution.<\/td>\n<\/tr>\n | Processing<\/strong><\/td>\n | High shear heat<\/td>\n | Lower barrel\/nozzle temps, reduce back pressure, screw speed, and injection speed.<\/td>\n<\/tr>\n | Processing<\/strong><\/td>\n | Weak weld lines<\/td>\n | Increase melt temperature and injection pressure to improve weld line strength.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n | \n 3. Best Practices for Prevention<\/h2>\nFixing brittle parts isn't just about tweaking one dial; it requires a holistic approach. Here are the best practices to ensure tough, durable parts:<\/p>\n
|