Printsip nima, xususiyatlar, Inyeksiya shakllantirish mashinasi tomonidan in'ektsiya shakllantirish va in'ektsiya qilish jarayoni?

Bugun biz printsip haqida gaplashamiz, xususiyatlar, tomonidan inyeksion kalıplamaning qo'llanilishi va jarayoni qarshi kalıplama mashinasi.

1. ning printsipi qarshi kalıplama. Inyeksiya mashinasining hunisiga granulalar yoki kukunli plastmassa qo'shing. Plastmassa oqimini ushlab turish uchun inyeksiya mashinasida isitiladi va eritiladi, va keyin ma'lum bir bosim ostida yopiq qolipga AOK qilinadi. Sovutgandan va shakllantirilgandan keyin, u eriydi Plastmassa kerakli plastik qismga aylanishi uchun qattiqlashadi. Kimga

2. Xususiyatlari inyeksion kalıplama
Inyeksion kalıplama qisqa ishlab chiqarish aylanishiga va yuqori mahsuldorlikka ega. Inyeksion kalıplama murakkab shakllarga ega bo'lgan plastik qismlarni ishlab chiqarishi mumkin, yuqori o'lchamdagi talablar va turli xil qo'shimchalar, boshqa plastik qoliplash usullari bilan erishish qiyin; ikkinchidan, inyeksion kalıplama ishlab chiqarish jarayonida avtomatlashtirishni amalga oshirish oson, in'ektsiya kabi, sökme, darvozani olib tashlash va boshqa operatsiyalarni avtomatlashtirish mumkin, shuning uchun inyeksion kalıplama keng qo'llanilgan.

2.1 Afzalliklar:
Kalıplama davri qisqa, ishlab chiqarish samaradorligi yuqori, va avtomatlashtirishni amalga oshirish oson. U murakkab shakllarni yaratishi mumkin, aniq o'lchamlar, metall yoki metall bo'lmagan qo'shimchalar bilan plastik qismlar, barqaror mahsulot sifati, va keng qo'llash doirasi.

2.2 Kamchiliklari:
Inyeksion kalıplama uskunalari narxi nisbatan yuqori; qarshi qoliplari tuzilishi murakkab; ishlab chiqarish tannarxi yuqori, ishlab chiqarish tsikli uzoq, va bir qismli va kichik partiyali plastik qismlarni ishlab chiqarish uchun mos emas.
3. Ilova Bir nechta termoplastiklardan tashqari (floroplastiklar), deyarli barcha termoplastiklar inyeksion kalıplama yo'li bilan plastik qismlarni ishlab chiqarish uchun ishlatilishi mumkin. Inyeksion kalıplama nafaqat termoplastiklarni qoliplash uchun ishlatiladi, lekin termoset plastmassalarni shakllantirishda ham muvaffaqiyatli qo'llanilgan. Ayni paytda, uning qoliplangan mahsulotlari hisobga olinadi 20-30% barcha joriy plastik mahsulotlar. Inyeksion kalıplanmış plastik qismlar ko'lamini yanada kengaytirish uchun, ba'zi maxsus in'ektsiya texnologiyalari maxsus xususiyatlarga yoki maxsus tizimli talablarga ega bo'lgan plastik qismlarni qoliplash uchun maxsus ishlab chiqilgan. Yuqori aniqlikdagi plastik qismlarni nozik in'ektsiya qilish kabi, kompozit rangli plastik qismlarni ko'p rangli quyish, ichki va tashqi turli materiallardan tashkil topgan sendvich plastmassa qismlarini sendvich in'ektsiyasi, va optik shaffof plastik qismlarni qarshi siqish kalıplama. Kimga

4. Inyeksion kalıplama jarayoni

4.1 Kalıplamadan oldin tayyorlash

Xom ashyo ko'rinishini tekshirish va jarayon samaradorligini o'lchash: plastik rangni tekshirish, shu jumladan, zarrachalar hajmi va bir xilligi, suyuqlik (erish indeksi, yopishqoqlik), termal barqarorlik va qisqarish tezligi. Kimga

Plastmassani oldindan qizdirish va quritish: Kalıplamadan keyin plastik qismning yuzasida nuqsonlar yoki buzilishlarning oldini olish uchun materialdagi ortiqcha namlik va uchuvchan moddalarni olib tashlang, plastik qismning tashqi ko'rinishi va ichki sifatiga ta'sir qiladi. Materialni quritish usuli: kichik partiyalar ishlab chiqarish, pechda quritish yordamida; ommaviy ishlab chiqarish, qaynoq quritish yoki vakuum quritish yordamida.
Barrelni tozalash: Mahsulotlarni almashtirishda barrelni tozalash kerak, materiallar va ranglarni o'zgartirish. Kimga

Oldindan isitishni kiriting: material va qo'shimcha o'rtasidagi harorat farqini kamaytiring, qo'shimchaning atrofidagi plastmassaning qisqarish kuchlanishini kamaytiring, va plastmassa sifatini ta'minlash. Kimga

Chiqaruvchi vositani tanlash: Tez-tez ishlatiladigan bo'shatish vositalariga sink stearat kiradi, suyuq kerosin va silikon moyi. Kimga

4.2 Inyeksiya jarayoni

Oziqlantirish: Inyeksiya mashinasining hunisiga granulalar yoki kukunli plastmassa qo'shing. Kimga

Plastifikasiya: Inyeksiya mashinasining isitish moslamasini isitish orqali, vintdagi plastmassa xomashyosi eritilib, yaxshi plastika bilan plastik eritmaga aylanadi. Kimga

Kalıp to'ldirish: Plastmassalangan plastmassa eritma ma'lum bir bosim va tezlikda qolip bo'shlig'iga ko'krak va quyish tizimi orqali kirish va to'ldirish uchun qarshi mashinasining piston yoki vint tomonidan itariladi.. Kimga

Bosimni saqlash va oziqlantirish: eritma bo'shliqni to'ldirgandan keyin, qarshi mashinasining piston yoki vint ostida, eritma hali ham oziqlantirish uchun bosimni saqlab turadi, Shunday qilib, bochkadagi eritma bo'shliqdagi plastmassani to'ldirish uchun bo'shliqqa kirishda davom etadi..
Darvoza muzlatilgandan keyin sovutish uchun: Bir muncha vaqt o'tgach, bo'shliqdagi erigan plastmassa qattiq holga keltiriladi, bu plastik qism deformatsiyalanganda etarlicha qattiqlikka ega bo'lishini ta'minlaydi va burish yoki deformatsiyaga olib kelmaydi.. Kimga

Qolipdan tushirish: Plastmassa qismi ma'lum bir haroratgacha sovutiladi, va chiqarish mexanizmi plastik qismini qolipdan tashqariga chiqaradi. Kimga

4.3 Plastik qismlarga keyingi ishlov berish

Qayta ishlashdan keyingi sabablar va oqibatlari:
Noto'g'ri plastiklash yoki notekis kristallanish tufayli, bo'shliqda plastmassani yo'naltirish va sovutish; yoki metall qo'shimchalarning ta'siri yoki plastik qismlarga noto'g'ri ikkilamchi ishlov berish tufayli, plastik qismlarda ba'zi ichki stresslar muqarrar ravishda mavjud , Foydalanish jarayonida plastik qismlarning deformatsiyasi yoki yorilishiga olib keladi, shuning uchun biz ularni yo'q qilishga harakat qilishimiz kerak. Kimga

Tozalash bilan davolash: issiqlik bilan ishlov berish jarayoni, unda plastik qismlar doimiy haroratli isitish suyuq muhitiga joylashtiriladi (issiq suv kabi, issiq yog', suyuq kerosin, va boshqalar.) yoki bir muddat davomida issiq havo sirkulyatsiyasi o'choq, keyin asta-sekin xona haroratiga qadar sovutiladi.
a) Harorat: 10ish haroratidan ° ~ 15 ° yuqori yoki issiqlik buzilish haroratidan 10 ° ~ 20 ° pastroq.
b) Vaqt: Umuman, plastmassa turiga va plastmassa qismining qalinligiga bog'liq bo'lgan millimetrga taxminan yarim soatda hisoblash mumkin. Kimga
c) Funktsiya: Plastik qismning ichki kuchlanishini yo'q qiling, plastik qismning hajmini barqarorlashtirish, kristallik darajasini oshirish, kristall strukturani barqarorlashtirish, shu bilan uning elastik moduli va qattiqligi yaxshilanadi. Namlikni tozalash bilan ishlov berish: yangi demoled plastik qismlarni isitish muhitiga qo'yadigan keyingi ishlov berish usuli (qaynoq suv kabi, kaliy asetat eritmasi) namlik assimilyatsiya balansini tezlashtirish uchun. (Asosan yuqori gigroskopik va oson oksidlanadigan plastmassalar uchun ishlatiladi, PA kabi)

a) Harorat: 100~121℃ (yuqori chegara issiqlik buzilish harorati yuqori bo'lganda olinadi, pastki chegara esa aksincha olinadi).
b) Vaqt: Saqlash vaqti plastik qismning qalinligi bilan bog'liq, odatda 2 ~ 9 soat. Kimga
c) Maqsad: Qolgan stressni yo'q qiling; foydalanish paytida o'lchamdagi o'zgarishlarni oldini olish uchun mahsulotni iloji boricha tezroq namlik assimilyatsiya qilish muvozanatiga keltiring. Kimga

5. Inyeksion kalıplamaning texnologik parametrlari

5.1 Harorat

a) Barrel harorati

Barrel harorati viskoz oqim harorati orasida bo'lishi kerak (yoki erish nuqtasi) va termal parchalanish harorati. Piston barrelining harorati vintli bochkaning haroratidan 10-20 ° S yuqori. Kimga

Plastik xususiyatlari: polioksimetilen kabi issiqlikka sezgir plastmassalar, polivinil ftorid, va boshqalar. barrelning maksimal harorati va bochkada qolish vaqtini qat'iy nazorat qilishi kerak; shisha tolali termoplastik plastmassa zaif suyuqlik tufayli barrel haroratini oshirishi kerak. Eritmaning barrelda erta qotib qolishiga yo'l qo'ymaslik uchun, barrelning harorati kichik qiymatni olishga intiladi.
Plastik qismlar va qolip tuzilishi: Yupqa devorli qismlar uchun, barrel harorati qalin devorli qismlardan yuqori; murakkab shaklli yoki qo'shimchali qismlar uchun, barrel harorati ham yuqori bo'lishi kerak. Kimga

Barrelning harorat taqsimoti odatda yuqori old va pastki orqa tamoyiliga amal qiladi, anavi, barrelning orqa qismidagi harorat (oziqlantirish porti) eng past va nozul harorati eng yuqori.

Vintli qarshi mashinasi uchun, vint va eritma orasidagi kesish ishqalanish issiqligi tufayli plastmassaning termal degradatsiyasini oldini olish uchun, eritma va eritma, va eritma va barrel, barrelning old qismining harorati o'rta qismdan bir oz pastroq bo'lishi mumkin. Barrelning harorati mos keladimi yoki yo'qligini aniqlash uchun, havo quyish usuli plastik qismlarning sifatini kuzatish yoki bevosita kuzatish uchun ishlatilishi mumkin.

Havo in'ektsiyasi paytida, agar material oqimi bir xil bo'lsa, silliq, pufaksiz, va bir xil rangda, material harorati mos keladi; agar material oqimi qo'pol bo'lsa, kumush sim yoki rang o'zgarishi, bu materialning harorati mos emasligini anglatadi. Kimga

b) Yarchagining harorati

Umuman, erigan materialning nozulda oqishi oldini olish uchun u barrelning maksimal haroratidan bir oz pastroqdir.. Lekin u juda past bo'lmasligi kerak, aks holda eritma nozulda muddatidan oldin qotib qoladi va ko'krakni to'sib qo'yadi, yoki erta qotib qolib qolib bo'shlig'iga AOK qilinadi va plastik qismlarning sifatiga ta'sir qiladi. Kimga

c) Qolib harorati

Mog'or harorati plastmassaning xususiyatlari bilan belgilanadi, plastik qismning o'lchami va tuzilishi, ishlash talablari va boshqa jarayon shartlari. Qolib harorati ↑, suyuqlik ↑, zichlik va kristallik ↑, qisqarish tezligi va mahsuldorlik ↓.
The mold temperature is usually controlled by a constant temperature cooling medium; there is also a way to maintain a certain temperature by injecting the molten material into the mold to achieve a balance between natural heating and natural heat dissipation; in special cases, resistance wires and resistance heating rods can also be used to maintain a certain temperature. The mold is heated to keep the mold at a constant temperature. But no matter what, for the plastic melt, it is a cooling process. Kimga

5.2 Pressure

(1) Plasticizing pressure (orqa bosim): refers to the pressure of the melt on the top of the screw when the screw retreats when the screw injection machine is used. Kimga

The plasticizing pressure increases, the temperature of the melt and its uniformity are improved, the color materials are mixed uniformly, and the gas in the melt is discharged. But the plasticization rate is reduced, and the molding cycle is prolonged. Kimga

In general operation, under the premise of ensuring the quality of plastic parts, the plasticizing pressure should be as low as possible, generally about 6MPa, and usually rarely more than 20MPa
Kimga
(2) Inyeksiya bosimi: refers to the pressure exerted by the plunger or the top of the screw on the plastic melt. Kimga

Funktsiya: Overcome the flow resistance of the melt flow during the filling process during injection, so that the melt has a certain filling rate; when the pressure is maintained, the melt is compacted and prevented from flowing backward. Kimga

Size: It depends on the type of injection machine, the type of plastic, the mold structure, the mold temperature, the wall thickness of the plastic part, and the structure and size of the pouring system. Under normal circumstances: injection pressure of high-viscosity plastic> low-viscosity plastic; high injection pressure for thin-walled, large-area, and complex-shaped plastic parts; simple mold structure, larger gate size, and lower injection pressure; plunger injection machine Injection pressure> screw injection machine; the barrel temperature and mold temperature are high, and the injection pressure is low. Kimga

5.3 Vaqt

The time required to complete an injection molding process is called the injection molding cycle.

6. Formulation of plastic molding process regulations According to the use requirements of plastic parts and the process characteristics of plastics, the correct molding method is selected, the molding process and molding process conditions are determined, and the selection of plastic molds and molding equipment are rationally designed to ensure the smooth molding process Carrying out this series of work for the plastic parts to meet the requirements is usually called the formulation of the process specifications for the plastic parts.
It is a guiding technical document in plastic molding production and an important basis for organizing production. It runs through all stages of the production process and must be strictly implemented.6.1 Analysis of plastic parts

The shape and structure of the plastic part determine the structure of the mold, and it has a great influence on whether the plastic part can be formed smoothly and the quality after forming.

In order to ensure the quality of plastic parts, usually the following points need to be paid attention to:

6.1.1 Analysis of plastics

(1) Analysis of the performance of plastics
(2) Analysis of plastic process performance

6.1.2 Analysis of the structure, dimensions, tolerances, and technical standards of plastic parts

(1) Does the structure of the plastic part meet the requirements of molding processability?
(2) Dimensions, tolerances and technical standards of plastic parts

6.2 Determination of the molding method and process flow of plastic parts

According to the characteristics of the plastic, the requirements of the plastic parts, and the structure, hajmi, production batch, use conditions and molding equipment of the plastic parts, a series of feasible molding programs are proposed. Through the comparative analysis of each plan, the best molding method of plastic parts is determined according to the actual production conditions on site. After the molding method of plastic parts is determined, the process flow should be determined.
6.3 Determination of molding process conditions

Appropriate process conditions should be selected for qualified plastic parts formed by various molding methods. There are many factors that affect the plastic molding process, and there are many process conditions that need to be controlled, and the relationship between the process conditions is very close. Shuning uchun, a comprehensive analysis must be made according to the characteristics and actual conditions of the plastic, and the more reasonable process conditions must be selected initially, and then tested During the molding process, the process conditions are gradually revised according to the actual situation of the molding of the plastic parts and the inspection results of the plastic parts. Kimga

6.4 Selection of equipment and tools

When the molding method is determined, the appropriate molding equipment must be selected, and the relevant process and installation parameters of the equipment and mold must be checked. Different molding methods use different molding equipment. In addition to the molding equipment, other processes also need to select the corresponding equipment, and indicate the specifications and technical parameters of the equipment used in accordance with the process. Kimga

6.5 Formulation of process documents

The preparation of process documents is to summarize the content and parameters of the above process regulations and determine them in the form of appropriate process documents as the basis for production preparation and production process. Plastic parts process card is the most important process document in production.