Views:0 Author:JIA HUA ALUMINIUM CO., LTD Publish Time: 2020-09-26 Origin:Site
With light weight, good conductive and plasticity, it’s widely use in cooler machines. There are few types of aluminum heat sink. Flat and wide, comb-shaped or fish bone-shaped; round or oval outer heat sink is radial and branch-shaped. The same characteristic of these types of aluminum profiles is the slot between every fin of the heat sink is deep. And the distance of fin is short. But the root of the aluminum radiator is big. So the production of aluminum heat sink profiles is hard.
Sometime the small aluminum profiles is easy to be produced. But the big size and asymmetry heat sink with deep slot of fin is very hard to be produced. It required that design, moulding, production cooperate together to produce it. The alloy used for extruding heat sink profiles must have good extruded ability and thermal conductivity. Generally, alloys such as 1A30, 1035 and 6063 are used. At present, 6063 alloy is widely used because it has good mechanical properties in addition to good extruded ability and thermal conductivity. We need to control the impurity content to make sure the purity of aluminum ingot. For 6063 we need to control the content of Fe. Mg. Si. Fe: less than 0.2%. Mg: 0.45%. Si:0.25-0.35%
There are many thin and long fin on the heat sink which will afford big extrusion. So it have high requirement for the fin. It need the fin have the high strength. If not, it is easy to break. So the quality of the mould also important.
Die heat treatment is very important, to use vacuum heating quenching, using high-pressure pure nitrogen quenching, can ensure that after quenching all parts of the mold performance uniformity. After quenching to take three times tempering, so that the hardness of the mold to ensure that the premise of HRC48 ~ 52, has enough toughness. This is an important condition to prevent the die broken teeth.
Heat sink profile to be able to extrude successfully, the key is the die design should be reasonable, manufacturing to be precise. Generally try to avoid direct extrusion of ingots to the die work belt. For the flat wide comb radiator profile, design a middle smaller, both sides of the larger infusion die, so that the metal to both sides of the flow, reduce the die work belt extrusion pressure, but also to make its pressure distribution uniform. Because of the heat sink profile section wall thickness difference, the design of the mold with the corresponding work to maintain their differences, that is, the wall thickness of the place to work with a special increase, can be as large as 20mm ~ 30mm, and the position of the tip of the teeth to break through the conventional, the work to reduce the belt. In short, to ensure that the metal flow in all parts of the uniformity.
For flat wide radiator, in order to ensure a certain degree of rigidity of the mold, the thickness of the mold should be increased. The thickness increase about 30% ~ 60%. The production of the mold should be very fine, empty knife to do up and down, left and right, the middle to maintain symmetry, the processing error between the teeth and teeth to be less than 0.05mm, processing error is easy to produce partial teeth, that is, the thickness of the heat sink is uneven, and even produce broken teeth of the phenomenon.
Less extrusion force
In order to prevent the mold from breaking the teeth, the extrusion force should be reduced as much as possible, and the extrusion force is related to the length of the ingot, the size of the alloy deformation resistance, the state of the ingot, and the degree of deformation. So the length of aluminum billet should be 0.6~0.85 times.
The processing of extrusion
We can use the computer to do the Simulation test. It can help to check the work belt whether reasonable. And then we can test it on the extrusion machine.
After the test of mould, we should control well the speed of extrusion. Also, we should pay attention to the temperature of the mould and aluminum billet. Make sure the temperature difference will not be too big.