--- title: What Is The Recommended Copper Weight For A Flex PCB? description: It is recommended to use the thinnest and lightest copper weight for a flex PCB that meets the electrical requirements to improve flexibility and reliability. image: https://blog.epectec.com/hubfs/Blog/small-flexible-circuit-boards-used-in-a-medical-device.jpg --- [![Epec Engineered Technologies](https://www.epectec.com/images/logo.png "Epec Engineered Technologies")](https://www.epectec.com/) [![Epec Engineered Technologies](https://www.epectec.com/images/logo.png "Epec Engineered Technologies")](https://www.epectec.com/) - [Articles](https://www.epectec.com/articles/) - [Blog](https://blog.epectec.com/) - [Webinars](https://www.epectec.com/webinar/) - [Videos](https://www.epectec.com/videos/) - [Case Studies](https://www.epectec.com/case-studies/) - [News & Events](https://www.epectec.com/news/) - [Customer Portal](https://system.netsuite.com/c.406760/site/NSlogin.html) - [About](https://www.epectec.com/about/overview/) - Back - [Company Overview](https://www.epectec.com/about/overview/) - [Our History](https://www.epectec.com/about/our-history/) - [Culture](https://www.epectec.com/about/culture/) - [Industries Served](https://www.epectec.com/about/industry/) - [Acquisitions](https://www.epectec.com/about/acquisitions.html) - [Operations](https://www.epectec.com/operations/) - Back - [Operational Excellence](https://www.epectec.com/operations/) - [Quality Philosophy](https://www.epectec.com/operations/quality-philosophy.html) - [Quality Assurance Process](https://www.epectec.com/operations/quality-assurance-process.html) - [Global Operations](https://www.epectec.com/operations/global-operations.html) - [Logistics & Supply Chain](https://www.epectec.com/operations/logistics-and-supply-chain.html) - [Inventory Stocking](https://www.epectec.com/operations/inventory-stocking.html) - [Approvals](https://www.epectec.com/operations/approvals.html) - [ITAR Registered](https://www.epectec.com/operations/itar-registered.html) - [Engineering](https://www.epectec.com/engineering/overview/) - Back - [Engineering Overview](https://www.epectec.com/engineering/overview/) - [Engineering Support](https://www.epectec.com/engineering/support/) - [Design Services](https://www.epectec.com/engineering/design-services/) - [EpecDFx™](https://www.epectec.com/engineering/epecdfx/) - [Free DFM File Check](https://www.epectec.com/engineering/free-dfm.html) - [PCB Impedance Calculator](https://www.epectec.com/engineering/impedance-calculator.html) - [Products](https://www.epectec.com/products/) - Back - [Overview](https://www.epectec.com/products/) - [Battery Packs](https://www.epectec.com/batteries/) - [Flex & Rigid-Flex PCBS](https://www.epectec.com/flex/) - [Cable Assemblies](https://www.epectec.com/cable-assemblies/) - [Printed Circuit Boards](https://www.epectec.com/pcb/) - [CNC Machining](https://www.epectec.com/cnc-machining/) - [User Interfaces](https://www.epectec.com/user-interfaces/) - [Flexible Heaters](https://www.epectec.com/flexible-heaters/) - [EC Fans & Motors](https://www.epectec.com/fans-motors/) - [Design Guides](https://www.epectec.com/guides/) - [Design Guides](https://www.epectec.com/guides/) - Back - Resources - Back - [Articles](https://www.epectec.com/articles/) - [Blog](https://blog.epectec.com/) - [Webinars](https://www.epectec.com/webinar/) - [Videos](https://www.epectec.com/videos/) - [Case Studies](https://www.epectec.com/case-studies/) - [News & Events](https://www.epectec.com/news/) - [Customer Portal](https://system.netsuite.com/c.406760/site/NSlogin.html) - [Contact Us](https://www.epectec.com/contact/) - Back - [Contact Information](https://www.epectec.com/contact/) - [Our Sales Team](https://www.epectec.com/contact/our-sales-team.html) - [Office Locations](https://www.epectec.com/contact/office-locations.html) - [Career Opportunities](https://www.epectec.com/contact/career-opportunities.html) - [InstantPCB*Quote*™](https://www.epectec.com/instantpcbquote/) - Back - [Overview](https://www.epectec.com/instantpcbquote/) - [Login](https://secure.epecpcb.com/epec/) - [Register](https://secure.epecpcb.com/epec/index2.jsp) - [Home](https://www.epectec.com/) - [Blog](https://blog.epectec.com/) - What Is The Recommended Copper Weight For A Flex PCB? Share This Page: [LinkedIn](https://blog.epectec.com/#linkedin) [X](https://blog.epectec.com/#x) [Facebook](https://blog.epectec.com/#facebook) [Email](https://blog.epectec.com/#email) # What Is The Recommended Copper Weight For A Flex PCB? [![Paul Tome](https://blog.epectec.com/hubfs/Blog-Authors/paul-tome.jpg "Paul Tome")](https://blog.epectec.com/author/paul-tome) Written by [Paul Tome](https://blog.epectec.com/author/paul-tome) Posted on July 18, 2014 at 10:05 AM ![Paul Tome](https://blog.epectec.com/hubfs/Blog-Authors/paul-tome.jpg "Paul Tome") - [Tweet](https://twitter.com/share) The copper weight and corresponding thickness used in a [flexible circuit board](https://www.epectec.com/flex/) need to be carefully selected in order to meet both the electrical and [mechanical bend requirements](https://blog.epectec.com/flex-and-rigid-flex-pcb-concept-and-mechanical-designs) of specific flex circuit design. Copper weight for a flex PCB is both the stiffest and most critical component. [![Download Our Flex Circuits Design Guide](https://no-cache.hubspot.com/cta/default/707152/dd10ed46-954f-4043-81e6-17d81b30abd4.png)](https://cta-redirect.hubspot.com/cta/redirect/707152/dd10ed46-954f-4043-81e6-17d81b30abd4) ## Copper Flex PCB Weight Recommendations It is recommended to use the thinnest and lowest copper weight in your flexible circuit design that meets the proper electrical requirements in order to improve the flexibility and reliability of the flex circuit. ![Small Flexible Circuit Boards Used in a Medical Device](https://blog.epectec.com/hs-fs/hubfs/Blog/small-flexible-circuit-boards-used-in-a-medical-device.jpg?width=800&height=274&name=small-flexible-circuit-boards-used-in-a-medical-device.jpg) Small Flexible Circuit Boards Used in a Medical Device ### Base Copper - 0.33 oz. - 0.00046" (0.012mm) ED Copper - 0.5 oz. - 0.0007" (0.018mm) RA Copper - 1 oz. - 0.0014" (0.036mm) RA Copper - 2 oz. - 0.0028" (0.071mm) RA Copper RA = Rolled Annealed ED = Electro-Deposited ## Most Common Copper Weights The most common flex PCB copper weights are 0.5oz and 1oz, however, lighter copper weights are available. 2oz and [greater copper weights](https://blog.epectec.com/heavy-copper-weights-how-they-work-in-flexible-printed-circuit-boards) are also available when [manufacturing flexible PCBs](https://www.epectec.com/flex/gallery/) but may not allow the required flexibility needed for the particular application that they will be used in. Using 2oz and greater copper weights in your flex circuit could create additional design and manufacturing challenges. ## Summary When designing a flexible printed circuit board, it is always the best practice to make sure your design meets current IPC standards with regard to [specific flexible materials](https://www.epectec.com/flex/material-properties.html), circuit design, performance, and assembly processes involved in manufacturing flexible circuits. Visit our website for more information on [flexible PCB gerber layout & design recommendations](https://www.epectec.com/flex/design/). --- ## Key Takeaways - **Copper weight is the most critical factor in flex PCB design:** It directly impacts both electrical performance and the mechanical bend reliability of the circuit. - **Use the thinnest copper that meets electrical needs:** Minimizing copper weight improves flexibility, reduces stress during bending, and increases long-term reliability. - **Standard copper weights vary by process:** Common options include 0.33 oz ED copper, 0.5 oz RA copper, 1 oz RA copper, and 2 oz RA copper, with RA (rolled annealed) providing superior flexibility. - **5 oz and 1 oz copper are most commonly used:** These balance electrical performance with the flexibility needed for medical, consumer, and industrial flex applications. - **Heavier copper (2 oz or more) adds challenges:** While available, thick copper reduces flexibility and can create manufacturing difficulties, making it suitable only for specific high-current designs. - [Tweet](https://twitter.com/share) Topics: [Flex & Rigid-Flex PCB's](https://blog.epectec.com/topic/flex-rigid-flex-pcbs) --- [Next](https://blog.epectec.com/pcb-wave-soldering-and-minimum-pitch-distance) | [All posts](https://blog.epectec.com/all) | [Previous](https://blog.epectec.com/what-causes-circuit-board-blow-hole-defects) [![New Call-to-action](https://no-cache.hubspot.com/cta/default/707152/846c020a-b0a4-42f3-974e-1b694b491d92.png)](https://cta-redirect.hubspot.com/cta/redirect/707152/846c020a-b0a4-42f3-974e-1b694b491d92) ## Leave a Comment --- ## Related Posts --- ### Recent Posts --- ### Posts by Topic - [Printed Circuit Boards (160)](https://blog.epectec.com/topic/printed-circuit-boards) - [Product Design (135)](https://blog.epectec.com/topic/product-design) - [Battery Packs (120)](https://blog.epectec.com/topic/battery-packs) - [Cable Assemblies (100)](https://blog.epectec.com/topic/cable-assemblies) - [Flex & Rigid-Flex PCB's (94)](https://blog.epectec.com/topic/flex-rigid-flex-pcbs) - [Electronics Industry (61)](https://blog.epectec.com/topic/electronics-industry) - [User Interfaces (55)](https://blog.epectec.com/topic/user-interfaces) - [Quality Solutions (33)](https://blog.epectec.com/topic/quality-solutions) - [Flexible Heaters (30)](https://blog.epectec.com/topic/flexible-heaters) - [Events, Training, and Support (9)](https://blog.epectec.com/topic/events-training-and-support) - [RF Products (7)](https://blog.epectec.com/topic/rf-products) - [CNC Machining (3)](https://blog.epectec.com/topic/cnc-machining) - [Fans & Motors (1)](https://blog.epectec.com/topic/fans-motors) See All --- --- ### Need Help with A Project? 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