Tembakan singkat mengacu pada fenomena bahwa rongga cetakan plastik tidak terisi penuh karena fluiditas plastik yang tidak mencukupi, menghasilkan produk plastik yang tidak lengkap. Alasan utamanya adalah tekanan dan kecepatan injeksi yang tidak tepat (termasuk kehilangan tekanan berlebihan yang disebabkan oleh resistensi), yang terutama dipengaruhi oleh aspek-aspek berikut::
1、 Mesin cetak injeksi
(1) Kapasitas cetakan injeksi tidak mencukupi – ini disebabkan oleh tingginya kapasitas mesin injection moulding, which may also be caused by insufficient plasticizing capacity or insufficient injection quantity. The insufficient plasticizing capacity can be increased by prolonging heating time, increasing screw speed and increasing back pressure. If the injection volume is not high enough, a larger injection machine can be used to solve the problem.
2、 Improper design of plastic mould
(1) Local short shot caused by flow imbalance in each cavity of a multi cavity mold – when the injection molding capacity of the injection molding machine is sufficient, this defect is mainly caused by the uneven flow in each gate, itu adalah, the uneven distribution of the cavity in the plastic mold.
(2) The flow range of the melt is too long and the flow resistance is too large. The parts that hinder the melt flow include nozzle, gerbang, runner and the thin wall of the product. By increasing the nozzle diameter / temperature and using the nozzle with small flow resistance, the flow resistance of the nozzle can be reduced.
(3) Poor exhaust. When filling the cavity, air is trapped to produce a reaction force. Saat lelehan disuntikkan ke dalam rongga, the cavity is closed by the melt from the beginning, and the air is trapped in the unfilled local area. Demikian pula, due to the high filling speed, sometimes the air does not have enough time to discharge from the plastic mold through the parting surface, but is compressed, resulting in some unfilled areas in the cavity, thus shortening the production time of the molded parts.
3、 Improper molding process
(1) Improper injection molding process – low barrel temperature, slow injection speed, short injection time and insufficient back pressure lead to plastic shortage.
(2) Excess supply of plastic – if too much plastic enters the barrel, the injection pressure is lost due to the compression of the particles, which reduces the pressure required to inject the melt from the nozzle, which is necessary for injection molding, resulting in insufficient injection pressure. The solution is to adjust the feed rate, yaitu. melting rate, and make it just suitable for molding.
(3) Unstable production cycle: frequent machine shutdown and production inconsistent with normal cycle make some plastics stay in the barrel for a long time, resulting in the reduction of density and viscosity, resulting in short shot.
(4) Improper mold temperature results in lower injection rate and plastic filling.
4、 Choice of plastics
(1) Poor fluidity of plastics – if the plastic material does not have a high fluidity, it solidifies before reaching the furthest end of the cavity or before flowing into the overflow tank, which usually results in insufficient jet flow.
In order to eliminate these defects, the melt / mold temperature and injection pressure / velocity can be increased to make the melt reach the end of the cavity before solidification. produsen produk plastik cina, large plastic fluidity is particularly important, so choosing a plastic with good fluidity is also a solution. If the flow coverage is too long and the plastic does not fill the injection molding part correctly, it is recommended to change the gate location to reduce the plastic flow.
5、 Improper product design
In the process of product design, the principle of uniform wall thickness must be followed. If the uniform wall thickness cannot be maintained, please change the plastic mold design in time. Increase the number of flow channels or ribs in areas where feeding is difficult, so as to avoid the defect of insufficient filling due to too thin wall thickness.
Pendeknya, there are many reasons for short shot, which restrict and influence each other. In order to reduce and correct this defect, we need to comprehensively consider the relationship between these aspects, constantly practice and accumulate experience, so as to quickly determine the reasons for insufficient filling, so as to reduce the waste of resources and increase the production of products.
Tentang JasonMould Industrial Company Limited
Jasonmould adalah pembuat cetakan Cina dari cetakan plastik- cetakan injeksi, cetakan die casting, cetakan tiup plastik, cetakan rotasi, medis cetakan injeksi plastik, dua tembakan cetakan injeksi plastik, masukkan cetakan, overmolding, cetakan injeksi logam, cetakan injeksi mikro, cetakan injeksi bubuk, cetakan injeksi keramik, cetakan injeksi cair, cetakan injeksi husky, cetakan rumah tangga, pengecoran cetakan, alat cetakan mati, cetakan khusus, cetakan cina, perkakas prototipe cepat rapid, perkakas prototipe plastik plastic, perkakas tekan pukulan, mati dan perkakas untuk bagian ponsel / ponsel cell, bagian otomotif, penyedot debu, alat isi ulang, telepon, mesin fotokopi, komputer, speaker multimedia, dan banyak produk elektronik dan peralatan rumah tangga lainnya. Dan juga produsen produk plastik, produsen cetakan Cina- bagian-bagian yang terbuat dari plastik, tangki air plastik, bola plastik, wadah plastik, gesper plastik, jangkar plastik, gantungan plastik, sendok plastik, pemasangan pipa plastik, gelas plastik, peralatan makan plastik, gelas plastik, botol-botol plastik, nampan plastik, wadah kosmetik plastik, kotak plastik, wadah makanan plastik, kursi plastik, tutup plastik, penutupan tutup plastik, tabung plastik, pipa air plastik, kenop plastik, tabung plastik, kotak utilitas plastik, rak plastik dan sebagainya.
Kontak:
Orang: James Yuan
Perusahaan: JasonMould Industrial Company Limited
Menambahkan: Desa LongGang,Kota LongXi,Kabupaten BoLuo,Kota HuiZhou,Provinsi Guangdong, Cina
Telp: 86-752-6682869
Surel: [email protected]
Situs: https://www.jasonmolding.com/custom-injection-molding/
