{"id":4132,"date":"2026-05-26T16:27:30","date_gmt":"2026-05-26T14:27:30","guid":{"rendered":"https:\/\/hamco-germany.com\/?post_type=fachbegriff&p=4132"},"modified":"2026-06-19T14:49:25","modified_gmt":"2026-06-19T12:49:25","slug":"praskliny-zpusobene-napetim-stribrnych-rybek","status":"publish","type":"fachbegriff","link":"https:\/\/hamco-germany.com\/cs\/fachbegriff\/silberfischchen-spannungsrisse\/","title":{"rendered":"St\u0159\u00edbrn\u00e1 rybka (trhliny zp\u016fsoben\u00e9 pnut\u00edm)"},"content":{"rendered":"

Hbit\u00e9 rybi\u010dky v koupeln\u011b nejsou zn\u00e1mkou nedostate\u010dn\u00e9 hygieny. Jsou sp\u00ed\u0161e indik\u00e1torem tepl\u00e9ho a vlhk\u00e9ho mikroklimatu. Ojedin\u011bl\u00fd \u017eivo\u010dich je tedy obvykle ne\u0161kodn\u00fd, ale hromadn\u00fd v\u00fdskyt slou\u017e\u00ed jako varovn\u00fd sign\u00e1l pro po\u0161kozen\u00ed vlhkost\u00ed, pl\u00edsn\u011b nebo konstruk\u010dn\u00ed vady.<\/p>\n

Zejm\u00e9na u pr\u016fhledn\u00fdch plast\u016f, jako je PMMA (zn\u00e1m\u00e9 jako akryl\u00e1tov\u00e9 sklo nebo plexisklo\u00ae). Prask\u00e1n\u00ed pod nap\u011bt\u00edm<\/a>\u00a0Obzvl\u00e1\u0161t\u011b z\u00e1ke\u0159n\u00e1 vada sou\u010d\u00e1stky: Ka\u017edou trhlinu zp\u016fsobenou pnut\u00edm, a\u0165 u\u017e je jakkoli jemn\u00e1, m\u016f\u017eete vid\u011bt, pokud podr\u017e\u00edte posti\u017een\u00fd v\u00fdrobek p\u0159ed zdrojem sv\u011btla tak, aby se v n\u011bm odr\u00e1\u017eely leskl\u00e9 st\u0159\u00edbrn\u00e9 skvrny kolem obvykle centr\u00e1ln\u00edho m\u00edsta vst\u0159iku. Tento efekt je nejl\u00e9pe pozorovateln\u00fd na sal\u00e1tov\u00fdch m\u00eds\u00e1ch, kter\u00e9 byly dlouho pou\u017e\u00edv\u00e1ny a pravideln\u011b myt\u00e9 v my\u010dce n\u00e1dob\u00ed.<\/p>\n

P\u0159\u00edli\u0161 rychl\u00e9 ochlazen\u00ed zp\u016fsobuje vnit\u0159n\u00ed po\u0161kozen\u00ed, zamrzl\u00e9 nap\u011bt\u00ed<\/a>. \u0158et\u011bzce molekul plastu jsou prakticky \u201ezamrzl\u00e9 v neuspo\u0159\u00e1dan\u00e9 poloze\u201c. Z tohoto d\u016fvodu je t\u0159eba p\u0159i v\u00fdrob\u011b db\u00e1t na to, aby hork\u00e1 plastov\u00e1 tavenina nebyla vst\u0159ikov\u00e1na p\u0159\u00edli\u0161 rychle, aby teplota ve form\u011b nebyla p\u0159\u00edli\u0161 n\u00edzk\u00e1, aby nedoch\u00e1zelo k extr\u00e9mn\u00edmu p\u0159\u00edtlaku a aby geometrie sou\u010d\u00e1sti byla navr\u017eena bez velk\u00fdch skok\u016f v tlou\u0161\u0165ce st\u011bny.<\/p>\n

Teplo pom\u00e1h\u00e1 vyrovn\u00e1vat nap\u011bt\u00ed nam\u00e1han\u00fdch molekul.<\/p>\n

Po vst\u0159ikov\u00e1n\u00ed takov\u00fdch, obvykle opticky v\u00fdznamn\u00fdch d\u00edl\u016f z PMMA, nap\u0159\u00edklad po v\u00fdrob\u011b zadn\u00edch sv\u011btel a ukazatel\u016f automobil\u016f, je vhodn\u00e9 d\u00edly tepeln\u011b zpracovat (\u017e\u00edh\u00e1n\u00ed). D\u00edly se \u0159\u00edzen\u011b zah\u0159ej\u00ed, tak\u0159\u00edkaj\u00edc se odstran\u00ed nap\u011bt\u00ed a pot\u00e9 se op\u011bt nechaj\u00ed pomalu vychladnout.<\/p>\n

T\u00edm se minimalizuje riziko setk\u00e1n\u00ed se st\u0159\u00edb\u0159it\u00fdmi rybkami.<\/p>","protected":false},"featured_media":0,"parent":0,"template":"","class_list":["post-4132","fachbegriff","type-fachbegriff","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/hamco-germany.com\/cs\/wp-json\/wp\/v2\/fachbegriff\/4132","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hamco-germany.com\/cs\/wp-json\/wp\/v2\/fachbegriff"}],"about":[{"href":"https:\/\/hamco-germany.com\/cs\/wp-json\/wp\/v2\/types\/fachbegriff"}],"wp:attachment":[{"href":"https:\/\/hamco-germany.com\/cs\/wp-json\/wp\/v2\/media?parent=4132"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}