Power Consumption

  The power consumed depends on product of actual pressure(read on pressure guage and not set pressure) and injection speed. These parameters depend on geometry of part and viscosity of melt . If the connected power is lower,  than it may not be enough to fill larger parts of thin wall thickness(long flow ratio) even […]

Continue Reading...

What is Significance of Clamp Force?

What is Significance of Clamp Force? The clamping force should be greater than the cavity force In the mould, i.e. mould opening force exerted by the melt in cavity. The cavity force depends on injection pressure and projected area of moulded part Injection pressure depends on maximum flow ratio of part and melt viscosity. The […]

Continue Reading...

Significance of each zone of screw length

The screw length is divided in right proportion for feed, compression, metering zones. Longer feed zone creates a greater potential throughput. Longer compression zone results in less shear heat and more time to compress and melt the plastic Longer meter zone allows the screw to develop more pumping pressure and greater opportunity to homogenise Shorter […]

Continue Reading...

Importance of Injection Rate

  If mould is filled with lower injection rate, skin thickness increases at faster rate and area for melt to flow reduces quickly, thereby increasing the resistance to flow. This results in higher demand for injection pressure. This can leave moulded-in stresses in the mouldings, which is not desirable. If the part has unbalanced flow […]

Continue Reading...

Can Additives in polymer damage the screw

Some Additives are corrosive in nature. Some additive has limited residence time. They degrade  and generate corrosive gases. Such polymers should be considered as material of lower stability and handled very carefully with out exceeding the thermal stability time limit. Flame retardant grades produce corrosive acids at certain temperature. Therefore, the moulding should be done […]

Continue Reading...

FAQs

.   Fault Probable Cause Suggested Remedy Parison stretch is more Melt temperature high, slow extrusion rate, low melt index material. Reduce material temperature, increase extrusion rate, use right melt index material Rough surface, melt fracture or chatter marks in parison Low melt temperature, melt fracture of material, die causing fracture of material.   Extrusion […]

Continue Reading...

Materials

            Properties of some thermoplastic materials[32][33] name Symbol Density [g/cm3] Tensile strength [MPa] Flexural strength [MPa] Elastic modulus [GPa] Elongation at rupture [%] Thermal stability [°C] Expansion at 20°C [10−6/°C]   High Density Polyethylene HDPE 0.95 31 40 1.86 100 120 126 [32] Low Density Polyethylene LDPE 0.92 17 14 0.29 500 […]

Continue Reading...

Types of Blow Moulding

Extrusion blow moulding In extrusion blow moulding (EBM), plastic is melted and extruded into a hollow tube (a parison). This parison is then captured by closing it into a cooled metal mold. Air is then blown into the parison, inflating it into the shape of the hollowbottle, container, or part. After the plastic has cooled sufficiently, the […]

Continue Reading...

Blow Moulding

Blow moulding (also known as blow moulding or blow forming) is a manufacturing process by which hollow plastic parts are formed. In general, there are three main types of blow moulding: Extrusion blow moulding, Injection blow moulding, and Stretch blow moulding. The blow moulding process begins with melting down the plastic and forming it into a parison or preform. The parison […]

Continue Reading...