2.Requirements for mold
Because the mold of the custom heat sink profile is a lot of slender teeth, it has to bear a large compression force, and each tooth must have high strength and toughness. If there is a large difference in performance between them, it will be easy. Fractures those teeth that are poor in strength or toughness. Therefore, the quality of the mold steel must be reliable, it is best to use H13 steel produced by a reliable manufacturer, or select high-quality imported steel. The heat treatment of the mold is very important. To use vacuum heating and quenching, it is best to use high-pressure pure nitrogen quenching, which can ensure the uniform performance of all parts of the mold after quenching. After quenching, three times of tempering should be adopted to ensure that the hardness of the mold has sufficient toughness under the premise of HRC48 ~ 52. This is an important condition to prevent mold breakage.
The key to successful extrusion is that the mold design must be reasonable and the manufacturing must be accurate. Generally led round aluminum heat sink supplier try to avoid the ingots being directly squeezed onto the mold work belt. For the flat and wide comb-shaped heat sink profile, design a small guide mold with a small middle and large sides to make the metal flow to both sides, reduce the pressing force on the working belt of the mold, and make the pressure distribution uniform. Due to the large difference in wall thickness in the section of the heat sink profile, the difference should be maintained when designing the working belt of the mold, that is, the working belt in the place with large wall thickness should be particularly enlarged, which can be as large as 20mm to 30mm, and the position of the tooth tip must be broken Routinely minimize work belts. In short, the uniformity of metal flow must be guaranteed. For the flat wide heat sink, in order to ensure the mold has a certain rigidity, the thickness of the mold should be appropriately increased. The thickness increase is about 30% to 60%. The production of the mold must also be very precise. The empty knife must be symmetrical up and down, left and right, and the middle. The processing error between the teeth must be less than 0.05mm. The large processing error is easy to produce partial teeth, that is, the thickness of the heat sink is uneven. There may even be broken teeth.
For a section with a mature design, using an inlay alloy steel mold is also a better method, because the alloy steel mold has better rigidity and abrasion resistance, is less prone to deformation, and is beneficial to the formation of heat sink profiles.
Aluminum Heatsink For Led
4.Extrusion process
The key to the production of heat sink extrusion aluminum profile is the first test of the extrusion die. If possible, you can do a simulation test on a computer to see if the working belt of the mold design is reasonable, and then test the die on the extruder. The first mold test is very important. The operator must make the main plunger move slowly at a low pressure of less than 8 MPa when the pressure is advanced. It is best to have someone look at the die exit with a flashlight and wait for each heat dissipation of the squeeze die After the sheets are uniformly squeezed out of the die hole, the pressure can be gradually accelerated to perform the extrusion. When the extrusion is continued after the successful test, care should be taken to control the extrusion speed to achieve smooth operation. When producing heat sink profiles, pay attention to the heating temperature of the mold, and make the mold temperature close to the temperature of the ingot. If the temperature difference is too large, because the extrusion speed is slow when the pressure is applied, the metal temperature will drop, and the phenomenon of mold plugging or uneven flow velocity is easy to occur.
