The right way for determine the extrusion speed of aluminum profiles

The extrusion speed refers to the speed of extruded profile or the speed of press main piston moves forward. In actual production, the speed of extruded profile is controlled by adjusting the forward speed of the main piston. The extrusion speed is an important factor that affects production efficiency and also affects product quality (such as product surface and size), so an appropriate extrusion speed is crucial. The extrusion speed range for 6063 aluminum alloy profiles (die outlet speed) is 9~60m/min, with solid parts being 9~20m/min.

The extrusion speed is related to factors such as kind of alloy, billet condition and size, product shape, deformation degree (or extrusion ratio), temperature, tool (mold) structure, and process conditions.

1.1: Extrusion temperature

When aluminium is extruded, the non-uniformity of its fluidity increases with the increase of temperature. During the entire extrusion process, the temperature of the billet gradually increases, and the faster the extrusion speed, the higher the temperature, with a temperature rise of about 100C. When the temperature of the metal exceeds the maximum allowable, the metal will enter a hot brittle state and form extrusion cracks. Therefore, when the temperature of the billet is very high, the extrusion speed must be gradually reduced during the extrusion process. 6063 aluminum alloy ingots are generally preheated to 480~520C, and the extrusion cylinder is preheated to 400~450C.

1.2: Profile shape

Profile with simple geometric shapes, good symmetry, and small aspect ratios can be relatively higher; On the contrary, products with complex geometric dimensions, large wall thickness differences in width to thickness ratios, and poor symmetry should have relatively slower extrusion speeds. 

1.3:  Deformation degree

The greater the degree of deformation of the product, the greater the required extrusion force, and at the same time, the greater the heat of metal deformation, resulting in a slower flow rate of the product; On the contrary, if the degree of deformation is small and the metal flow is uniform, the extrusion speed can be faster.

1.4:  Mold Shape

For 6063 alloy, the solid die has lower resistance than the hollow die, so the extrusion speed can be higher. The tendency of the profile surface to produce extrusion cracks is higher, so the extrusion speed needs to be correspondingly reduced. 

Aluminium extrusion speed