noocyada

Dhimista Wax taaj oo kale ee Mudista Caaga ah

Yaraanshaha wax taaj oo kale oo lagu durayo caaga waa mid ka mid ah sifooyinka marka heerkulka maaddadu uu qulqulayo. Qiyaasta cirbadda wareejinta waxqabadka ee duritaanka ayaa loo baahan yahay si loo go'aamiyo cabbiraadaha ugu dambeeya ee shaqada. Qiimuhu wuxuu muujinayaa qadarka foosha ee workpiece soo bandhigo ka dib marka laga saaro caaryada ka dibna la qaboojiyo 23C muddo 48 saacadood ah.

Yaraynta waxaa lagu go'aamiyaa isla'egta soo socota:

S = (Lm-Lf) / Lf * 100%

halka S ay tahay heerka yareynta caaryada, Lr cabbirada shaqooyinka ugu dambeeya (in. ama mm), iyo Lm cabirka caaryada cabirka (gudaha ama mm). Nooca iyo kala soocida walxaha balaastigga ah waxay leeyihiin qiimo is bedbedel ah oo ku yaraanaya. Yaraanshaha waxaa saameyn ku yeelan kara dhowr doorsoomayaal ah sida qaboojinta dhumucda shaqada aaladda, cirbadeynta iyo cadaadiska degganaanshaha. Isku-darka buuxinta iyo xoojinta, sida fiber-ka dhalada ama buuraha macdanta, ayaa yareyn kara yaraanshaha.

Yaraynta alaabada balaastigga ah ka dib marka la farsameeyo waa wax caadi ah, laakiin polymer crystalline iyo amorphous ayaa si ka duwan sidii hore u yaraanaya. Dhammaan shaqooyinka balaastigga ah way yaraadaan ka dib marka si fudud loo farsameeyo natiijada ka dhalan karta iskudhafidooda iyo foosha kuleylka maadaama ay ka qaboojinayaan heerkulka wax lagu shaqeynayo.

Waxyaabaha loo yaqaan 'Amorphous' waxay leeyihiin hoos u dhac yar. Markay walxaha amorphous qaboobaan inta lagu gudajiro wajiga qaboojinta ee habka wax taaj oo kale ee duritaanka, waxay dib ugulaabtaan plymer adag. Silsiladaha polymer-ka ee ka kooban walxaha amorphous-ka ah ma laha jihayn gaar ah. Tusaalooyinka por amorphous waa polycarbonate, ABS, iyo polystyrene.

Qalabka wax lagu burburiyo waxay leeyihiin bar dhalaal dhalaal ah oo la caddeeyay silsiladaha polymer-ka ayaa iskood isu sii hagaajiyaa qaab isku dheelitiran oo molikal ah. Meelahan la amray waa kareemooyin sameeya markii polymer-ka laga qaboojinayo xaaladdiisa dhalaalka ah. Qalabka polymer-ka loo yaqaan 'semicrystalline polymer', sameynta iyo xirxirashada kordhaysa ee silsiladaha meerkulka ee ku yaal meelahan la isku qurxiyo Yaraynta isku-darka cirbadeynta ee qalabka semicrystalline ayaa ka sarreeya walxaha amorphous. Tusaalooyinka maaddooyinka loo yaqaan 'crystalline materials' waa naylon, polypropylene, iyo polyetylen. Waxay liis garaysaa dhowr waxyaalood oo caag ah, amorphous iyo semicrystalline, iyo caaryadoodii oo yaraanaya.

Yareynta thermoplastics /%
wax yaraynta caaryada wax  yaraynta caaryada wax yaraynta caaryada
ABS 0.4-0.7 polycarbonate 0.5-0.7 PPO 0.5-0.7
Looxa 0.2-1.0 PC-ABS 0.5-0.7 polystyrene 0.4-0.8
ABS-nylon 1.0-1.2 PC-PBT 0.8-1.0 Polysulfone 0.1-0.3
Saxarada 2.0-3.5 PC-PET 0.8-1.0 PBT 1.7-2.3
Nylon 6 0.7-1.5 Polyetylenka 1.0-3.0 PET 1.7-2.3
Nylon 6,6 1.0-2.5 Polypropylene 0.8-3.0 TPO 1.2-1.6
PEI 0.5-0.7        

Saamaynta is-beddelka isbeddelka macnaheedu waa in ka-shaqeynta dulqaadka la gaari karo ee loogu talagalay polymer amorphous ay aad uga fiican tahay kuwa loogu talagalay polymer crystalline, maxaa yeelay crystallites waxaa ku jira amarro badan oo ka fiican oo xirmooyinka silsiladaha polymer, marxaladda kala-guurka ayaa si aad ah u yaraanaya. Laakiin balaastig amorphous ah, tani waa qodobka kaliya oo si fudud ayaa loo xisaabiyaa.

Polymer-ka amorphous, qiimayaasha yaraanshaha kaliya ma ahan kuwo hooseeya, laakiin yaraanshaha lafteeda ayaa dhaqso u dhaca. Wixii polymer-ka caadiga ah ee loo yaqaan 'amorphous polymer' sida PMMA, yareynta waxay noqon doontaa sida ay u kala horreeyaan 1-5mm / m. Tani waxay sabab u tahay qaboojinta illaa 150 (heerkulka dhalaalka) illaa 23C (heerkulka qolka) waxayna la xiriiri kartaa isku dheelitirka ballaarinta kuleylka.


Waqtiga boostada: Sep-19-2020