{"id":821,"date":"2018-10-11T13:48:51","date_gmt":"2018-10-11T13:48:51","guid":{"rendered":"https:\/\/www.plastikcity.co.uk\/blog\/?p=821"},"modified":"2020-10-23T12:53:56","modified_gmt":"2020-10-23T12:53:56","slug":"can-environmental-stress-cracking-be-avoided","status":"publish","type":"post","link":"https:\/\/www.plastikcity.co.uk\/blog\/can-environmental-stress-cracking-be-avoided\/","title":{"rendered":"Can Environmental Stress Cracking Be Avoided?"},"content":{"rendered":"<p><strong>Environmental stress cracking (ESC) is the development of cracks and eventual catastrophic failure due to a combination of mechanical stress (from external loading or from moulding strain) and exposure to an \u2018aggressive\u2019 chemical (a \u2018near solvent\u2019 for the thermoplastic material).<\/strong><\/p>\n<p><!--more--><\/p>\n<p>ESC can appear in most unexpected scenarios and featured in the majority of troubleshooting consultancies I had to deal with as an academic.\u00a0 ESC suddenly became a problem when a supplier of assembly screws changed the type of grease used.\u00a0\u00a0 In another case ESC was accelerated because a moulder had pushed up the moulding temperature (contradicting the customer\u2019s specification) causing incipient degradation.\u00a0 A change of mould release spray caused another problem, which did not manifest itself until the mouldings reached the customer three days later.<\/p>\n<p>Predicting and avoiding ESC is not easy but I would suggest that:<\/p>\n<ul style=\"font-size: 100%; line-height: 170%; list-style-type: disc; padding-bottom: 10px;\">\n<li><strong>end users<\/strong> and <strong>designers<\/strong> be aware of service loading and chemical exposure;<\/li>\n<li><strong>component designers<\/strong> avoid stress raisers and include generous radii;<\/li>\n<li><strong>designers<\/strong> consider ESC as one of the criteria in the material selection process;<\/li>\n<li><strong>tool designers<\/strong> aim to design moulds to minimise moulded-in strain;<\/li>\n<li><strong>moulders<\/strong> optimise process conditions to minimise moulded-in strain and ESC.<\/li>\n<\/ul>\n<p>This Environmental stress cracking article was written by Dr.Charlie Geddes for <a href=\"https:\/\/www.hardiepolymers.com\/\" target=\"_blank\" rel=\"noopener noreferrer\">Hardie Polymers<\/a>.<\/p>\n<p>For more of Charlie\u2019s blogs why not also read more of our\u00a0<a href=\"https:\/\/www.hardiepolymers.com\/knowledge\/\" target=\"_blank\" rel=\"noopener noreferrer\">knowledge base articles<\/a>?<\/p>\n<p>For information on all the specified grades that we can offer please contact us today or try our\u00a0<a href=\"https:\/\/www.hardiepolymers.com\/polymers\/\" target=\"_blank\" rel=\"noopener noreferrer\">polymer search<\/a>.<\/p>\n<p><img decoding=\"async\" class=\"alignnone size-full wp-image-18552\" src=\"https:\/\/www.plastikcity.co.uk\/blog\/wp-content\/uploads\/2018\/02\/hardie-polymers-compressor.png\" alt=\"Hardie Polymers logo\" width=\"200\" height=\"45\" \/><\/p>\n<p><em>Hardie Polymers<\/em><br \/>\n<em>0141 952 1900<\/em><br \/>\n<a href=\"https:\/\/www.hardiepolymers.com\" target=\"_blank\" rel=\"noopener noreferrer\"><em>Website<\/em><\/a><br \/>\n<a href=\"mailto:hello@hardiepolymers.com\" target=\"_blank\" rel=\"noopener noreferrer\"><em>Email<\/em><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Environmental stress cracking (ESC) is the development of cracks and eventual catastrophic failure due to a combination of mechanical stress (from external loading or from moulding strain) and exposure to an \u2018aggressive\u2019 chemical (a \u2018near solvent\u2019 for the thermoplastic material).<\/p>\n","protected":false},"author":101012,"featured_media":819,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[343,270,342],"class_list":["post-821","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-plastikcity-blogs","tag-environmental-stress-cracking","tag-hardie-polymers","tag-stress-cracking","post-preview"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.plastikcity.co.uk\/blog\/wp-json\/wp\/v2\/posts\/821","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.plastikcity.co.uk\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.plastikcity.co.uk\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.plastikcity.co.uk\/blog\/wp-json\/wp\/v2\/users\/101012"}],"replies":[{"embeddable":true,"href":"https:\/\/www.plastikcity.co.uk\/blog\/wp-json\/wp\/v2\/comments?post=821"}],"version-history":[{"count":0,"href":"https:\/\/www.plastikcity.co.uk\/blog\/wp-json\/wp\/v2\/posts\/821\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.plastikcity.co.uk\/blog\/wp-json\/wp\/v2\/media\/819"}],"wp:attachment":[{"href":"https:\/\/www.plastikcity.co.uk\/blog\/wp-json\/wp\/v2\/media?parent=821"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.plastikcity.co.uk\/blog\/wp-json\/wp\/v2\/categories?post=821"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.plastikcity.co.uk\/blog\/wp-json\/wp\/v2\/tags?post=821"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}