Harsashi mold simintin gyaran kafawani tsari ne wanda yashi gauraye da resin thermosetting aka bari ya hadu da wani zazzafan farantin karfen karfe, ta yadda za'a samu harsashi mai karfi da bakin ciki a kusa da ginshikin. Sa'an nan kuma a cire harsashi daga tsarin kuma a cire cope da ja tare a ajiye a cikin flask tare da kayan da ake bukata na baya kuma a zuba narkakken karfe a cikin mold.
Gabaɗaya, bushe da yashi mai kyau (90 zuwa 140 GFN) wanda ba shi da yumbu gaba ɗaya ana amfani da shi don shirya yashin ƙera harsashi. Girman hatsin da za a zaɓa ya dogara da ƙarshen saman da ake so akan simintin. Matsakaicin girman hatsi yana buƙatar babban adadin guduro, wanda ke sa ƙirar ta yi tsada.
Resins na roba da aka yi amfani da su wajen gyare-gyaren harsashi su ne ainihin resins na thermosetting, waɗanda ke yin taurare ta hanyar zafi. Abubuwan resin da aka fi amfani dasu sune resin phenol formaldehyde. Haɗe da yashi, suna da ƙarfi sosai da juriya ga zafi. Resin phenolic da ake amfani da su wajen gyare-gyaren harsashi yawanci na nau'in mataki ne guda biyu, wato, guduro yana da phenol da ya wuce kima kuma yana aiki kamar kayan zafi. A lokacin shafa tare da yashi an haɗa guduro tare da mai kara kuzari kamar hexa methylene tetramine (hexa) a cikin adadin kusan 14 zuwa 16% don haɓaka halayen thermosetting. Matsakaicin zafin jiki na waɗannan zai zama kusan 150 C kuma lokacin da ake buƙata zai zama 50 zuwa 60 seconds.
Fa'idodin Tsarin Simintin Tsarin Shell Mold
1.Simintin gyare-gyare na Shell-mouldgabaɗaya sun fi daidai girman girman simintin gyare-gyaren yashi. Yana yiwuwa a sami juriya na +0.25 mm don simintin ƙarfe da +0. 35 mm don simintin gyare-gyaren simintin ƙarfe mai launin toka daductile baƙin ƙarfe simintin gyaran kafaƙarƙashin yanayin aiki na yau da kullun. A cikin yanayin ƙirar harsashi na kusa, ana iya samun shi a cikin kewayon +0.03 zuwa +0.13 mm don takamaiman aikace-aikace.
2. Za a iya samun wuri mai laushi a cikin simintin harsashi. Ana samun wannan da farko ta mafi girman girman hatsi da aka yi amfani da shi. Matsakaicin kewayon rashin ƙarfi shine na tsari na 3 zuwa 6 microns.
3. Kusurwoyi na zane, waɗanda suke ƙasa da na yashi simintin gyaran kafa, ana buƙata a cikin kwasfa na harsashi. Rage kusurwoyin daftarin zai iya kasancewa daga 50 zuwa 75%, wanda ke adana tsadar kayan aiki da kuma farashin injina na gaba.
4. Wasu lokuta, ana iya kawar da maƙala na musamman a cikin gyare-gyaren harsashi. Tun da yashi yana da ƙarfi mai ƙarfi za a iya ƙirƙira ƙirar ta yadda za a iya kafa kogon ciki kai tsaye tare da buƙatun harsashi.
5. Har ila yau, sassa na bakin ciki sosai (har zuwa 0.25 mm) na nau'in kawunan silinda mai sanyaya iska za a iya yin shi da sauri ta hanyar gyare-gyaren harsashi saboda ƙarfin yashi da ake amfani da shi don yin gyare-gyare.
6. Permeability na harsashi yana da girma kuma sabili da haka babu iskar gas da ke faruwa.
7. Ana buƙatar amfani da yashi kaɗan.
8. Injiniya yana yiwuwa a shirye saboda sauƙin sarrafawa da ke cikin gyare-gyaren harsashi.
Iyakance Tsarin Simintin Tsarin Shell Mold
1. Alamomin suna da tsada sosai kuma saboda haka suna da tattalin arziki kawai idan aka yi amfani da su a cikin manyan kayayyaki. A cikin aikace-aikacen yau da kullun, gyare-gyaren harsashi ya zama tattalin arziƙi akan gyaran yashi idan abin da ake buƙata ya wuce guda 15000 saboda ƙimar ƙirar ƙira.
2. Girman simintin da aka samu ta hanyar gyare-gyaren harsashi yana iyakance. Gabaɗaya, ana iya yin simintin gyare-gyare masu nauyin kilogiram 200, ko da yake a ƙananan yawa, ana yin simintin da ya kai kilogiram 450.
3. Ba za a iya samun siffofi masu rikitarwa ba.
4. Ana buƙatar ƙarin kayan aiki na yau da kullun don kula da gyare-gyaren harsashi kamar waɗanda ake buƙata don ƙirar ƙarfe mai zafi.
Lokacin aikawa: Dec-25-2020