Zomwe Zimayambitsa ndi Mayankho a Mbali Zapakhoma Dents a jekeseni Woumbidwa Mbali

"Dent" imayamba chifukwa cha kuchepa kwamkati kwamkati pambuyo posindikizidwa pachipata kapena kusowa kwa jekeseni.Kupsinjika maganizo kapena micro depression pamwamba pajekeseni kuumbidwa mbalindi vuto akale mu jekeseni akamaumba ndondomeko.

Ma denti nthawi zambiri amayamba chifukwa chakuchulukira kwazinthu zapulasitiki komweko chifukwa chakuchulukira kwa khoma lazinthu zapulasitiki.Zitha kuwoneka pafupi ndi ngodya zakuthwa zakunja kapena kusintha kwadzidzidzi kwa makulidwe a khoma, monga kumbuyo kwa ma bulges, zolimba kapena zonyamula, ndipo nthawi zina pazigawo zina zachilendo.Chomwe chimayambitsa mano ndikukula kwamafuta ndi kuzizira kwazinthu, chifukwa kuchuluka kwamafuta a thermoplastics ndikokwera kwambiri.

Kukula kwa kufalikira ndi kuchepetsedwa kumadalira zinthu zambiri, zomwe zimagwira ntchito zapulasitiki, kutentha kwakukulu ndi kutentha kochepa komanso kupanikizika kosungirako kupanikizika kwa nkhungu ndizofunikira kwambiri.Kukula ndi mawonekedwe azigawo zapulasitiki, komanso kuthamanga kwa kuziziritsa ndi kufanana kumakhalanso ndi zinthu zomwe zimakhudza.

Kuchuluka kwa kukulitsa ndi kuphatikizika kwa zinthu zapulasitiki munjira yowumba kumakhudzana ndi kuchuluka kwamafuta owonjezera apulasitiki okonzedwa.Coefficient yowonjezera kutentha mu njira yopangira imatchedwa "molding shrinkage".Ndi kuzizira kozizira kwa gawo lopangidwa, gawo lopangidwa limataya kukhudzana kwambiri ndi kuzizira pamwamba pa nkhungu.Panthawi imeneyi, kuzirala kwachangu kumachepa.Mbali yopangidwayo ikapitiriza kuziziritsa, mbali yopangidwayo imapitiriza kuchepa.Kuchuluka kwa shrinkage kumadalira kuphatikizika kwa zinthu zosiyanasiyana.

Makona akuthwa pagawo loumbidwa amaziziritsa mwachangu komanso amawumitsa kale kuposa mbali zina.Mbali yokhuthala yomwe ili pafupi ndi pakati pa gawo loumbidwa ili kutali kwambiri ndi kuzizira kwa patsekeke ndipo imakhala gawo lomaliza la gawo lopangidwa kuti litulutse kutentha.Zinthu zomwe zili pamakona zimachiritsidwa, gawo lopangidwa lidzapitirizabe kuchepa pamene kusungunuka pafupi ndi pakati pa gawolo kumazizira.Ndege pakati pa ngodya zakuthwa imatha kukhazikika unilaterally, ndipo mphamvu yake siili yofanana ndi yazinthu zomwe zili pamakona akuthwa.

Kuzizira kozizira kwa zinthu zapulasitiki pakatikati pa gawoli kumakoka malo omwe ali ofooka kwambiri pakati pa ngodya yoziziritsidwa pang'ono ndi ngodya yakuthwa yokhala ndi kuziziritsa kwakukulu mkati.Mwanjira imeneyi, chibowo chimapangidwa pamwamba pa gawo lopangidwa ndi jekeseni.

Kukhalapo kwa mano kumasonyeza kuti kufota komwe kumapangidwira kuno ndikwapamwamba kuposa kufota kwa mbali zake zozungulira.Ngati shrinkage ya gawo lopangidwa pa malo amodzi ndi apamwamba kuposa malo ena, ndiye chifukwa cha nkhondo ya gawo lopangidwa.Kupanikizika kotsalira mu nkhungu kudzachepetsa mphamvu ya mphamvu ndi kutentha kwa magawo opangidwa.

Nthawi zina, denti limatha kupewedwa posintha momwe zinthu ziliri.Mwachitsanzo, panthawi ya kupanikizika kwa gawo lopangidwa, zinthu zina zapulasitiki zimalowetsedwa mu nkhungu kuti zibwezere shrinkage.Nthawi zambiri, chipata chimakhala chochepa kwambiri kuposa mbali zina za gawolo.Pamene mbali yopangidwayo idakali yotentha kwambiri ndipo ikupitiriza kufota, chipata chaching'onocho chachiritsidwa.Pambuyo kuchiritsa, kuthamanga kusunga alibe mphamvu pa kuumbidwa mbali patsekeke.