Evaluation of Graphite as Tool Electrode Material in Low-Energy Electrical Discharge Machining Processes​

Evaluation of Graphite as Tool Electrode Material in Low-Energy Electrical Discharge Machining Processes​ | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Evaluation of Graphite as Tool Electrode Material in Low-Energy Electrical Discharge Machining Processes​ Eckart Uhlmann, Mitchel Polte, Sergio Lezama, Leonard Günther This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7978427/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Mar, 2026 Read the published version in The International Journal of Advanced Manufacturing Technology → Version 1 posted 5 You are reading this latest preprint version Abstract In sinking electrical discharge machining (S-EDM), graphite is a well-established tool electrode material for roughing processes as it enables high material removal rates \(\:{\dot{\text{V}}}_{\text{W}}\) while maintaining low relative tool wear ϑ. For finishing processes, other tool electrode materials, most notably copper, are regarded as superior due to lower achievable surface roughness Ra. With current process understanding, graphite tool electrodes reveal significant relative tool wear ϑ and low material removal rates \(\:{\dot{\text{V}}}_{\text{W}}\) when used in finishing processes. The achievable surface roughness is typically limited to Ra = 0.8 µm using graphite as tool electrode material with grain sizes D g < 3 µm. In the upstream preparation of tool electrodes by cutting, graphite offers significant advantages over copper since it enables higher aspect ratios φ and exhibits lower susceptibility to burr formation potentially diminishing the need for subsequent deburring processes. Due to these advantages, the development of finishing processes utilizing graphite tool electrodes promises to be highly advantageous. Expanding the application scope of graphite tool electrodes to include finishing processes could help reduce operational complexity in industrial manufacturing. There is currently no comprehensive understanding of the lower technological boundaries of graphite tool electrodes with respect to the achievable surface roughness Ra and the corresponding tool electrode wear behavior. Therefore, the transition regime from macro- to micro-EDM, around the threshold discharge energy of E d = 100 µJ, is explored. In this study, three tool electrode materials with grain sizes 1 µm ≤ D g ≤ 9 µm were investigated. To allow for a causal explanation of the observed process performance and wear behavior, their thermo- and electrophysical properties were characterized. Subsequently, experiments with discharge durations 1 µs ≤ t e ≤ 19 µs and varying tool electrode polarity P were conducted under otherwise constant process conditions, resulting in measured average discharge energies 36.49 µJ ≤ \(\:{\stackrel{\text{-}}{\text{E}}}_{\text{d}}\) ≤ 302.72 µJ. Cavities with surface roughness as low as Ra = 0.45 µm were produced while the lowest relative tool wear achieved was ϑ = 72.92%. This works aims to outline the capabilities of graphite as a tool electrode material in finishing processes and to motivate further research towards a coherent process understanding of its application in micro-EDM. sinking electrical discharge machining S-EDM graphite tool electrode electro- and thermophysical properties finishing Full Text Cite Share Download PDF Status: Published Journal Publication published 22 Mar, 2026 Read the published version in The International Journal of Advanced Manufacturing Technology → Version 1 posted Editorial decision: Major Revisions Needed 19 Dec, 2025 Reviewers agreed at journal 03 Nov, 2025 Reviewers invited by journal 03 Nov, 2025 Editor assigned by journal 03 Nov, 2025 First submitted to journal 30 Oct, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7978427","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":539429604,"identity":"10864a44-a73a-4503-bc5d-c0ed26639462","order_by":0,"name":"Eckart Uhlmann","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Eckart","middleName":"","lastName":"Uhlmann","suffix":""},{"id":539429605,"identity":"c2dfb0cd-cbaa-41e1-9ef3-0b7ff1ad8f4e","order_by":1,"name":"Mitchel 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Processes​","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"the-international-journal-of-advanced-manufacturing-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jamt","sideBox":"Learn more about [The International Journal of Advanced Manufacturing Technology](https://www.springer.com/journal/170)","snPcode":"170","submissionUrl":"https://submission.nature.com/new-submission/170/3","title":"The International Journal of Advanced Manufacturing Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"sinking electrical discharge machining, S-EDM, graphite tool electrode, electro- and thermophysical properties, finishing","lastPublishedDoi":"10.21203/rs.3.rs-7978427/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7978427/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn sinking electrical discharge machining (S-EDM), graphite is a well-established tool electrode material for roughing processes as it enables high material removal rates \\(\\:{\\dot{\\text{V}}}_{\\text{W}}\\) while maintaining low relative tool wear ϑ. For finishing processes, other tool electrode materials, most notably copper, are regarded as superior due to lower achievable surface roughness Ra. With current process understanding, graphite tool electrodes reveal significant relative tool wear ϑ and low material removal rates \\(\\:{\\dot{\\text{V}}}_{\\text{W}}\\) when used in finishing processes. The achievable surface roughness is typically limited to Ra = 0.8 µm using graphite as tool electrode material with grain sizes D\u003csub\u003eg\u003c/sub\u003e \u0026lt; 3 µm. In the upstream preparation of tool electrodes by cutting, graphite offers significant advantages over copper since it enables higher aspect ratios φ and exhibits lower susceptibility to burr formation potentially diminishing the need for subsequent deburring processes. Due to these advantages, the development of finishing processes utilizing graphite tool electrodes promises to be highly advantageous. Expanding the application scope of graphite tool electrodes to include finishing processes could help reduce operational complexity in industrial manufacturing.\u003c/p\u003e\n\u003cp\u003eThere is currently no comprehensive understanding of the lower technological boundaries of graphite tool electrodes with respect to the achievable surface roughness Ra and the corresponding tool electrode wear behavior. Therefore, the transition regime from macro- to micro-EDM, around the threshold discharge energy of E\u003csub\u003ed\u003c/sub\u003e = 100 µJ, is explored. In this study, three tool electrode materials with grain sizes 1 µm ≤ D\u003csub\u003eg\u003c/sub\u003e ≤ 9 µm were investigated. To allow for a causal explanation of the observed process performance and wear behavior, their thermo- and electrophysical properties were characterized. Subsequently, experiments with discharge durations 1 µs ≤ t\u003csub\u003ee\u003c/sub\u003e ≤ 19 µs and varying tool electrode polarity P were conducted under otherwise constant process conditions, resulting in measured average discharge energies 36.49 µJ ≤ \\(\\:{\\stackrel{\\text{-}}{\\text{E}}}_{\\text{d}}\\) ≤ 302.72 µJ. Cavities with surface roughness as low as Ra = 0.45 µm were produced while the lowest relative tool wear achieved was ϑ = 72.92%. This works aims to outline the capabilities of graphite as a tool electrode material in finishing processes and to motivate further research towards a coherent process understanding of its application in micro-EDM.\u003c/p\u003e","manuscriptTitle":"Evaluation of Graphite as Tool Electrode Material in Low-Energy Electrical Discharge Machining Processes​","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-13 12:54:07","doi":"10.21203/rs.3.rs-7978427/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major Revisions Needed","date":"2025-12-19T20:19:21+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-11-04T04:39:40+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-03T21:19:23+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-03T08:55:39+00:00","index":"","fulltext":""},{"type":"submitted","content":"The International Journal of Advanced Manufacturing Technology","date":"2025-10-31T03:34:27+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"the-international-journal-of-advanced-manufacturing-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jamt","sideBox":"Learn more about [The International Journal of Advanced Manufacturing Technology](https://www.springer.com/journal/170)","snPcode":"170","submissionUrl":"https://submission.nature.com/new-submission/170/3","title":"The International Journal of Advanced Manufacturing Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7fcbf987-dd51-42e3-8784-387dd813fb26","owner":[],"postedDate":"November 13th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-23T16:01:24+00:00","versionOfRecord":{"articleIdentity":"rs-7978427","link":"https://doi.org/10.1007/s00170-026-17878-0","journal":{"identity":"the-international-journal-of-advanced-manufacturing-technology","isVorOnly":false,"title":"The International Journal of Advanced Manufacturing Technology"},"publishedOn":"2026-03-22 15:58:38","publishedOnDateReadable":"March 22nd, 2026"},"versionCreatedAt":"2025-11-13 12:54:07","video":"","vorDoi":"10.1007/s00170-026-17878-0","vorDoiUrl":"https://doi.org/10.1007/s00170-026-17878-0","workflowStages":[]},"version":"v1","identity":"rs-7978427","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7978427","identity":"rs-7978427","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}