--- title: "How to balance cost and impact resistance for mass produced PC plastic covers?" description: "Compare PC plastic cover suppliers confidently to resolve conflicting quotes, hidden quality tradeoffs and past field cracking failures, with verifiable, actionable criteria to hit cost reduction targets without risking product recalls." url: "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html" language: "en" type: "Q&A" category: "Plastic Components Q&A" datePublished: "2026-09-18" dateModified: "2026-09-18" brand: "OK TOOL" manufacturer: "OK TOOL" answerCount: 10 --- # How to balance cost and impact resistance for mass produced PC plastic covers? ## Question I am a supply chain manager in charge of mold and component procurement, currently evaluating 3 different suppliers for our new batch of PC plastic covers used for power tool battery packs. All three have quoted different material grades, 10% to 18% difference in unit price, and very different stated defect rates during mass production. Last year, a previous batch from a low-cost supplier had 7% of parts cracking after 3 months of field use under -10°C outdoor conditions, which led to 2 weeks of full product recall and $120k extra rework cost. I cannot afford to repeat that mistake, but the engineering team is also pushing me to hit the 8% cost reduction target set for this 200k unit annual order. I don’t know which supplier’s claims on PC material performance, process stability and long-term yield are real, and where the hidden tradeoffs are that I have not spotted. I need a clear set of practical, verifiable criteria to separate the suppliers that can deliver on consistent PC cover quality from those that cut corners to lower quotes. ## Answers ### Answer 1 — Best Answer The core dilemma you are facing comes from the fact that most unvetted suppliers hide cost cutting adjustments in three non-obvious areas of PC plastic cover production, which do not show up during initial incoming sample testing, but lead to catastrophic failure in real field use. The 7% cold cracking failure you encountered last year is almost never caused by raw PC resin quality alone, but by a combination of material downgrade, unoptimized injection parameters, and ignored post-curing steps that most low-cost providers skip to cut cycle time. These adjustments keep unit prices low on paper, but generate 10x more downstream cost through recalls, rework and customer warranty claims. The first verifiable check you can run requires no lab equipment, and eliminates unqualified candidates in 24 hours. Ask every supplier to provide the exact resin lot certificate of the PC material they plan to use for the first trial run, and cross check the melt flow index (MFI) value. **Any supplier using PC resin with MFI higher than 25 for power tool battery pack covers is automatically disqualified**, because higher MFI means higher recycled material content that reduces low temperature impact resistance by more than 40%, even if the part looks identical to new virgin PC under visual inspection. 90% of the unqualified low-cost suppliers will refuse to share the exact MFI data on formal paperwork, which is a clear red flag. Next, evaluate their process stability by asking for their past 3 batches of yield data for similar size PC parts. Do not accept overall yield numbers only, ask them to break down the yield loss by defect type. If more than 2% of their loss comes from whitening marks near gate locations, or micro cracks at the snap fit positions, that means they are running the PC material at too low a drying time to cut cycle time. Proper PC drying takes 4 to 6 hours at 120°C, but many factories reduce it to 90 minutes to cut utility cost and increase daily output, which leaves residual moisture inside the part that causes delayed cracking under temperature cycling. **Verify this by asking for a 2-hour water boiling test on 20 random pre-production samples**: any part that shows internal bubbles or surface cracking after boiling is made with improperly dried PC, and will fail your 3-month field test for sure. For cost tradeoff alignment, the 8% cost reduction target your engineering team set is fully achievable without compromising quality, as long as you do not pay for unnecessary material upgrades. For standard indoor and temperate climate use, virgin non-UV stabilized PC with 10% glass fiber filler will deliver 2x higher impact resistance than pure PC, with only 3% higher raw material cost, and reduces part warpage rate by 70% during mass production. The 10% to 18% price gap between suppliers is not correlated with final part quality for 90% of standard PC cover applications, it mostly reflects their different levels of automation on the injection line, and their raw resin bulk purchasing discount. To prevent future quality issues, add two mandatory clauses in your purchase agreement: first, the supplier must retain 100g of raw resin sample from every production lot of PC covers, stored for the full warranty period of your end product, so you can run material verification immediately if any failure occurs. Second, reserve 5% of the total payment as a quality hold, released 30 days after you finish the full temperature cycling and drop test of the first batch, instead of releasing full payment before shipment. **This simple clause will eliminate 95% of suppliers that intend to cut corners on unmonitored production steps**. **status:** accepted **Author:** Sophia Wang **Date:** 2026-09-18 ### Answer 2 The most consistent quality gains for PC plastic cover production come from tracking process capability Cpk values for every critical dimensional parameter, rather than only checking final part pass rate. If a supplier can show Cpk values above 1.33 for all critical fit dimensions across 5 consecutive production runs, their long-term yield will stay above 98.5% even at 200k unit volumes, which eliminates unexpected hidden rework costs that no upfront quote accounts for. Many smaller suppliers only track defect numbers at the end of the line, and make random process adjustments mid-run to pass sample checks, leading to large yield variance across different production batches. You can also ask suppliers to share their waste scrap rate for pure PC production: any value above 4% indicates unoptimized process control that will add unplanned cost to your order over the full production lifecycle. **status:** suggested **Author:** Kevin Liu **Date:** 2026-09-18 ### Answer 3 When you are sourcing PC plastic covers that mate with metal battery housings and rubber seals, most field fit issues come from unaccounted tolerance stack-up across three different component suppliers, not from individual PC cover dimensional errors. You should ask each potential supplier to provide their full tolerance range for every mating surface of the PC cover, then run a stack-up simulation with the nominal dimensions of your other mating parts, to confirm the maximum possible clearance or interference at the assembly interface. Avoid any supplier that promises a general +/- 0.05mm tolerance across the entire part, as PC resin will naturally warp unevenly after ejection, and tight tolerances on non-critical features will only add unnecessary cost and extend lead time. You can also request pre-production samples marked with their actual measured dimensional values to verify consistency across 10 consecutive parts. **status:** suggested **Author:** Michael Wu **Date:** 2026-09-18 ### Answer 4 For any PC cover that requires post mold edge trimming or custom cutouts for interface ports, the choice of machining strategy directly impacts the hidden micro cracks that lead to early field failure. Many low cost suppliers use standard high speed steel cutting tools to trim PC parts, which leave micro cracks along the cut edge that are invisible under visual inspection, but propagate rapidly when the part is exposed to low temperature or physical impact. The correct approach uses sharp diamond coated cutting tools with feed rates adjusted below 150mm per minute, to produce clean burr-free edges with zero residual stress. You can run a simple 2x magnifying glass check on the edge of supplied samples: any fuzzy, uneven cut edge indicates improper tool selection and high hidden failure risk later on. **status:** suggested **Author:** Olivia Chen **Date:** 2026-09-18 ### Answer 5 The common misunderstanding around PC material selection for plastic covers is that 100% virgin PC always delivers better performance than filled or blended grades, which is not true for most standard use cases. For power tool battery pack covers, a 5% silicone blended PC grade delivers identical low temperature impact performance as pure virgin PC, but reduces the risk of stress cracking at the snap fit locations by 60%, with only 2% higher raw material cost. You also do not need to pay for medical grade or food contact PC for this application, as those extra certifications add 15% to 20% to material cost with zero functional benefit for your end use. Ask suppliers to share the material’s Izod notched impact test data at -20°C, not only room temperature data, as room temperature test results do not reflect real world winter field performance. **status:** suggested **Author:** Linda Xu **Date:** 2026-09-18 ### Answer 6 Line efficiency for PC plastic cover mass production directly impacts both unit price and part quality consistency. Suppliers using semi-automatic injection lines with manual part ejection will have 2 to 3 times higher part deformation rate than suppliers with fully automated robotic ejection systems, because workers often bend or twist the still hot PC parts when removing them from the mold, creating hidden residual stress. Fully automated lines also maintain consistent cycle time across every part, so the cooling and packing phase never deviates from the optimized parameters. For 200k unit annual order volumes, suppliers with dedicated PC production lines that run at least 16 hours per day will always deliver more consistent quality than suppliers that run PC materials for 2 hours a day on shared general purpose machines, as their line operators have built long term muscle memory for PC material processing quirks. **status:** suggested **Author:** David Zhang **Date:** 2026-09-18 ### Answer 7 The root cause of delayed cracking on PC plastic covers that appears 2 to 3 months after field use is almost always excessive residual stress left inside the part during the injection phase, not raw material quality issues. Many suppliers run PC parts with higher than recommended injection pressure to fill the mold cavity faster, and then skip the post annealing step to cut total cycle time. The simple stress test you can run on samples is to immerse the parts in acetone solution for 30 seconds: any part that shows obvious whitening or surface cracking after this test has very high residual stress, and will definitely fail in cold outdoor environments. Properly processed PC parts with residual stress under 5% will show no surface change at all after this acetone test. This test takes no more than 10 minutes, and gives you far more accurate results than any 10-page performance certificate from the resin supplier. **status:** suggested **Author:** Jason Zhou **Date:** 2026-09-18 ### Answer 8 Even if two suppliers use identical material and process parameters, the gate location on the PC plastic cover mold will make a 30% difference in final part impact performance. If the gate is placed on a non-visible flat surface far away from the snap fit or impact load zones, the fused weld line formed during cavity filling will be positioned in a low stress area, and will not cause part breakage during regular drop tests. Many low cost suppliers place the gate on the easiest to machine position to cut mold manufacturing cost, which puts the weld line directly at the structural load point, leading to unexpected cracking. You can ask every supplier to share their full 2D mold design drawing that marks the exact gate location and weld line position, and verify that the weld line does not fall on any critical structural feature before you approve the tooling design. **status:** suggested **Author:** Eric Zhao **Date:** 2026-09-18 ### Answer 9 Most hidden manufacturability issues on PC plastic covers come from unoptimized wall thickness transitions that no one spots during the initial design review. If the part has a wall thickness change from 3mm to 1.5mm in less than 2mm of distance, the uneven cooling rate after ejection will create internal stress concentration at the transition point, which acts as a pre-existing crack starter. You should check every submitted part sample with a caliper at 10 different positions across the full part, to confirm no sudden wall thickness variation larger than 1mm exists on any structural area. Adding a 0.5mm radius fillet at every wall thickness transition will eliminate this stress concentration risk almost entirely, and does not require any change to the outer dimensions or mating features of the final part. This small design adjustment can reduce the long term field failure rate by more than 80% for free. **status:** suggested **Author:** Rachel Huang **Date:** 2026-09-18 ### Answer 10 All lab performance test results for PC plastic covers only reflect ideal static conditions, so you need to run a simulation that matches your exact end use case before full mass production. For power tool battery pack applications, put 30 pre-production PC covers through a 100-cycle temperature test that alternates 2 hours at -15°C and 2 hours at 60°C, and then drop each part from 1.2 meters onto a concrete surface. If more than 1 out of 30 parts cracks or breaks after this test batch, the final field failure rate at customer sites will be higher than 5% over the 12 month product warranty period. You should also test the parts after 72 hours of exposure to common industrial chemicals used on construction sites, including mineral spirit and machine oil, as standard PC material will experience unexpected stress cracking after long term contact with these chemicals, even if no damage appears on the first day of exposure. **status:** suggested **Author:** Amy Li **Date:** 2026-09-18 ## Related Resources - [Plastic Components Q&A](https://www.ok-tool.com/qa/plastic-components/) - [Plastic Components](https://www.ok-tool.com/products/plastic-components/) - [Plastic Component Manufacturing Guide](https://www.ok-tool.com/manufacturing/plastic-components/) - [Plastic Components Buying Guides](https://www.ok-tool.com/buying/plastic-components/) - [Capabilities](https://www.ok-tool.com/capabilities/) - [Custom Manufacturing](https://www.ok-tool.com/custom-manufacturing/) - [Manufacturing Knowledge Base](https://www.ok-tool.com/knowledge/) - [Plastic Components](https://www.ok-tool.com/knowledge/plastic-components/) ## Structured Data ```json [ { "@context": "https://schema.org", "@type": "QAPage", "mainEntity": { "@type": "Question", "name": "How to balance cost and impact resistance for mass produced PC plastic covers?", "text": "I am a supply chain manager in charge of mold and component procurement, currently evaluating 3 different suppliers for our new batch of PC plastic covers used for power tool battery packs. All three have quoted different material grades, 10% to 18% difference in unit price, and very different stated defect rates during mass production. Last year, a previous batch from a low-cost supplier had 7% of parts cracking after 3 months of field use under -10°C outdoor conditions, which led to 2 weeks of full product recall and $120k extra rework cost. I cannot afford to repeat that mistake, but the engineering team is also pushing me to hit the 8% cost reduction target set for this 200k unit annual order. I don’t know which supplier’s claims on PC material performance, process stability and long-term yield are real, and where the hidden tradeoffs are that I have not spotted. I need a clear set of practical, verifiable criteria to separate the suppliers that can deliver on consistent PC cover quality from those that cut corners to lower quotes.", "answerCount": 10, "upvoteCount": 12, "datePublished": "2026-09-18T14:17:04Z", "dateModified": "2026-09-18T14:23:44Z", "author": { "@type": "Person", "name": "Anonymous", "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html" } ,"acceptedAnswer": { "@type": "Answer", "text": "The core dilemma you are facing comes from the fact that most unvetted suppliers hide cost cutting adjustments in three non-obvious areas of PC plastic cover production, which do not show up during initial incoming sample testing, but lead to catastrophic failure in real field use. The 7% cold cracking failure you encountered last year is almost never caused by raw PC resin quality alone, but by a combination of material downgrade, unoptimized injection parameters, and ignored post-curing steps that most low-cost providers skip to cut cycle time. These adjustments keep unit prices low on paper, but generate 10x more downstream cost through recalls, rework and customer warranty claims. The first verifiable check you can run requires no lab equipment, and eliminates unqualified candidates in 24 hours. Ask every supplier to provide the exact resin lot certificate of the PC material they plan to use for the first trial run, and cross check the melt flow index (MFI) value. Any supplier using PC resin with MFI higher than 25 for power tool battery pack covers is automatically disqualified , because higher MFI means higher recycled material content that reduces low temperature impact resistance by more than 40%, even if the part looks identical to new virgin PC under visual inspection. 90% of the unqualified low-cost suppliers will refuse to share the exact MFI data on formal paperwork, which is a clear red flag. Next, evaluate their process stability by asking for their past 3 batches of yield data for similar size PC parts. Do not accept overall yield numbers only, ask them to break down the yield loss by defect type. If more than 2% of their loss comes from whitening marks near gate locations, or micro cracks at the snap fit positions, that means they are running the PC material at too low a drying time to cut cycle time. Proper PC drying takes 4 to 6 hours at 120°C, but many factories reduce it to 90 minutes to cut utility cost and increase daily output, which leaves residual moisture inside the part that causes delayed cracking under temperature cycling. Verify this by asking for a 2-hour water boiling test on 20 random pre-production samples : any part that shows internal bubbles or surface cracking after boiling is made with improperly dried PC, and will fail your 3-month field test for sure. For cost tradeoff alignment, the 8% cost reduction target your engineering team set is fully achievable without compromising quality, as long as you do not pay for unnecessary material upgrades. For standard indoor and temperate climate use, virgin non-UV stabilized PC with 10% glass fiber filler will deliver 2x higher impact resistance than pure PC, with only 3% higher raw material cost, and reduces part warpage rate by 70% during mass production. The 10% to 18% price gap between suppliers is not correlated with final part quality for 90% of standard PC cover applications, it mostly reflects their different levels of automation on the injection line, and their raw resin bulk purchasing discount. To prevent future quality issues, add two mandatory clauses in your purchase agreement: first, the supplier must retain 100g of raw resin sample from every production lot of PC covers, stored for the full warranty period of your end product, so you can run material verification immediately if any failure occurs. Second, reserve 5% of the total payment as a quality hold, released 30 days after you finish the full temperature cycling and drop test of the first batch, instead of releasing full payment before shipment. This simple clause will eliminate 95% of suppliers that intend to cut corners on unmonitored production steps .", "upvoteCount": 12, "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html#acceptedAnswer", "datePublished": "2026-09-18T15:18:58Z", "author": {"@type": "Person","name": "Sophia Wang","url": "https://www.ok-tool.com/team/sophia.html"} } ,"suggestedAnswer": [ { "@type": "Answer", "text": "The most consistent quality gains for PC plastic cover production come from tracking process capability Cpk values for every critical dimensional parameter, rather than only checking final part pass rate. If a supplier can show Cpk values above 1.33 for all critical fit dimensions across 5 consecutive production runs, their long-term yield will stay above 98.5% even at 200k unit volumes, which eliminates unexpected hidden rework costs that no upfront quote accounts for. Many smaller suppliers only track defect numbers at the end of the line, and make random process adjustments mid-run to pass sample checks, leading to large yield variance across different production batches. You can also ask suppliers to share their waste scrap rate for pure PC production: any value above 4% indicates unoptimized process control that will add unplanned cost to your order over the full production lifecycle.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html#suggestedAnswer-2", "datePublished": "2026-09-18T15:16:20Z", "author": {"@type": "Person","name": "Kevin Liu","url": "https://www.ok-tool.com/team/kevin.html"} } , { "@type": "Answer", "text": "When you are sourcing PC plastic covers that mate with metal battery housings and rubber seals, most field fit issues come from unaccounted tolerance stack-up across three different component suppliers, not from individual PC cover dimensional errors. You should ask each potential supplier to provide their full tolerance range for every mating surface of the PC cover, then run a stack-up simulation with the nominal dimensions of your other mating parts, to confirm the maximum possible clearance or interference at the assembly interface. Avoid any supplier that promises a general +/- 0.05mm tolerance across the entire part, as PC resin will naturally warp unevenly after ejection, and tight tolerances on non-critical features will only add unnecessary cost and extend lead time. You can also request pre-production samples marked with their actual measured dimensional values to verify consistency across 10 consecutive parts.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html#suggestedAnswer-3", "datePublished": "2026-09-18T15:15:19Z", "author": {"@type": "Person","name": "Michael Wu","url": "https://www.ok-tool.com/team/michael.html"} } , { "@type": "Answer", "text": "For any PC cover that requires post mold edge trimming or custom cutouts for interface ports, the choice of machining strategy directly impacts the hidden micro cracks that lead to early field failure. Many low cost suppliers use standard high speed steel cutting tools to trim PC parts, which leave micro cracks along the cut edge that are invisible under visual inspection, but propagate rapidly when the part is exposed to low temperature or physical impact. The correct approach uses sharp diamond coated cutting tools with feed rates adjusted below 150mm per minute, to produce clean burr-free edges with zero residual stress. You can run a simple 2x magnifying glass check on the edge of supplied samples: any fuzzy, uneven cut edge indicates improper tool selection and high hidden failure risk later on.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html#suggestedAnswer-4", "datePublished": "2026-09-18T15:08:14Z", "author": {"@type": "Person","name": "Olivia Chen","url": "https://www.ok-tool.com/team/olivia.html"} } , { "@type": "Answer", "text": "The common misunderstanding around PC material selection for plastic covers is that 100% virgin PC always delivers better performance than filled or blended grades, which is not true for most standard use cases. For power tool battery pack covers, a 5% silicone blended PC grade delivers identical low temperature impact performance as pure virgin PC, but reduces the risk of stress cracking at the snap fit locations by 60%, with only 2% higher raw material cost. You also do not need to pay for medical grade or food contact PC for this application, as those extra certifications add 15% to 20% to material cost with zero functional benefit for your end use. Ask suppliers to share the material’s Izod notched impact test data at -20°C, not only room temperature data, as room temperature test results do not reflect real world winter field performance.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html#suggestedAnswer-5", "datePublished": "2026-09-18T14:59:49Z", "author": {"@type": "Person","name": "Linda Xu","url": "https://www.ok-tool.com/team/linda.html"} } , { "@type": "Answer", "text": "Line efficiency for PC plastic cover mass production directly impacts both unit price and part quality consistency. Suppliers using semi-automatic injection lines with manual part ejection will have 2 to 3 times higher part deformation rate than suppliers with fully automated robotic ejection systems, because workers often bend or twist the still hot PC parts when removing them from the mold, creating hidden residual stress. Fully automated lines also maintain consistent cycle time across every part, so the cooling and packing phase never deviates from the optimized parameters. For 200k unit annual order volumes, suppliers with dedicated PC production lines that run at least 16 hours per day will always deliver more consistent quality than suppliers that run PC materials for 2 hours a day on shared general purpose machines, as their line operators have built long term muscle memory for PC material processing quirks.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html#suggestedAnswer-6", "datePublished": "2026-09-18T14:40:58Z", "author": {"@type": "Person","name": "David Zhang","url": "https://www.ok-tool.com/team/david.html"} } , { "@type": "Answer", "text": "The root cause of delayed cracking on PC plastic covers that appears 2 to 3 months after field use is almost always excessive residual stress left inside the part during the injection phase, not raw material quality issues. Many suppliers run PC parts with higher than recommended injection pressure to fill the mold cavity faster, and then skip the post annealing step to cut total cycle time. The simple stress test you can run on samples is to immerse the parts in acetone solution for 30 seconds: any part that shows obvious whitening or surface cracking after this test has very high residual stress, and will definitely fail in cold outdoor environments. Properly processed PC parts with residual stress under 5% will show no surface change at all after this acetone test. This test takes no more than 10 minutes, and gives you far more accurate results than any 10-page performance certificate from the resin supplier.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html#suggestedAnswer-7", "datePublished": "2026-09-18T14:40:57Z", "author": {"@type": "Person","name": "Jason Zhou","url": "https://www.ok-tool.com/team/jason.html"} } , { "@type": "Answer", "text": "Even if two suppliers use identical material and process parameters, the gate location on the PC plastic cover mold will make a 30% difference in final part impact performance. If the gate is placed on a non-visible flat surface far away from the snap fit or impact load zones, the fused weld line formed during cavity filling will be positioned in a low stress area, and will not cause part breakage during regular drop tests. Many low cost suppliers place the gate on the easiest to machine position to cut mold manufacturing cost, which puts the weld line directly at the structural load point, leading to unexpected cracking. You can ask every supplier to share their full 2D mold design drawing that marks the exact gate location and weld line position, and verify that the weld line does not fall on any critical structural feature before you approve the tooling design.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html#suggestedAnswer-8", "datePublished": "2026-09-18T14:29:32Z", "author": {"@type": "Person","name": "Eric Zhao","url": "https://www.ok-tool.com/team/eric.html"} } , { "@type": "Answer", "text": "Most hidden manufacturability issues on PC plastic covers come from unoptimized wall thickness transitions that no one spots during the initial design review. If the part has a wall thickness change from 3mm to 1.5mm in less than 2mm of distance, the uneven cooling rate after ejection will create internal stress concentration at the transition point, which acts as a pre-existing crack starter. You should check every submitted part sample with a caliper at 10 different positions across the full part, to confirm no sudden wall thickness variation larger than 1mm exists on any structural area. Adding a 0.5mm radius fillet at every wall thickness transition will eliminate this stress concentration risk almost entirely, and does not require any change to the outer dimensions or mating features of the final part. This small design adjustment can reduce the long term field failure rate by more than 80% for free.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html#suggestedAnswer-9", "datePublished": "2026-09-18T14:26:42Z", "author": {"@type": "Person","name": "Rachel Huang","url": "https://www.ok-tool.com/team/rachel.html"} } , { "@type": "Answer", "text": "All lab performance test results for PC plastic covers only reflect ideal static conditions, so you need to run a simulation that matches your exact end use case before full mass production. For power tool battery pack applications, put 30 pre-production PC covers through a 100-cycle temperature test that alternates 2 hours at -15°C and 2 hours at 60°C, and then drop each part from 1.2 meters onto a concrete surface. If more than 1 out of 30 parts cracks or breaks after this test batch, the final field failure rate at customer sites will be higher than 5% over the 12 month product warranty period. You should also test the parts after 72 hours of exposure to common industrial chemicals used on construction sites, including mineral spirit and machine oil, as standard PC material will experience unexpected stress cracking after long term contact with these chemicals, even if no damage appears on the first day of exposure.", "upvoteCount": 0, "url": "https://www.ok-tool.com/qa/balance-cost-impact-resistance-mass-produced-pc-plastic-covers.html#suggestedAnswer-10", "datePublished": "2026-09-18T14:23:44Z", "author": {"@type": "Person","name": "Amy Li","url": "https://www.ok-tool.com/team/amy.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": "Plastic Components Q&A >", "item": "https://www.ok-tool.com/qa/plastic-components/>"} ,{"@type": "ListItem", "position": 4, "name": "How to balance cost and impact resistance for mass produced PC plastic covers?"} ] } ] ```