Die – casting aluminum process technology

With economic development rapidly , and china manufacturing industry also is  developed in modern society rapidly. Improving industrial level and innovation, it is the trend in die casting industry.

Die casting is a kind of precision casting method which let the metal change to complex metal mold shape by the high pressure. In 1964, the Japanese Association defined die casting as “in the high temperature will be pressed into the molten alloy precision casting , casting in a short time a large number of production of high precision and excellent casting surface”.

The USA called it Die Casting, the UK called it Pressure Die Casting, but in china are familiar with the Japanese saying, known as Die Casting, so the castings are manufactured by the die casting method called die castings, and you know the tensile strength of these materials is almost twice as high as that of ordinary cast alloy. next let’s discuss the application and die casting characteristics of aluminum alloy die-casting products in die casting industry.

die-casting-aluminum-process-technology

The aluminum alloy die-casting products are mainly used in electron, household appliance and communications industry etc. Now it is also applied in many LED lights, as heat sink of the LED flood lights is used integral die-casting aluminum radiator technology.Its advantages is weight lighter, transportation costs lower,an excellent luminous efficiency and a long service life, rather than other heat sink slowly.

However, now the aluminum alloy die casting products are more widely used because of its own unique characteristics, it is used in large aircraft, ship and other relatively high requirements of the industry.

LED aluminum shell die-casting is zinc ingot mold generally, the transmission rate of about 80~90W/M.K (w / M. C), small power many basic 1-3W using this process. The advantages is low cost, fast production,but the heat dissipation is worse.

Aluminum Purity: 98% the following properties of aluminum, hard and brittle, only foundry casting products. Therefore, most of the aluminum alloy die castings, including LED lamps die casting shell is the use of aluminum, because the production of aluminum is only suitable for the production of die castings, and high hardness, low cost. In addition, the die casting LED lamp shell has an advantage in mass production, because the production of die casting speed is very fast, the production cost is low.

The aluminum alloy die casting is high performance on strength and hardness commonly, because its surface is special treatment, such as electroplating, electrophoretic paint, spray, sand blasting, anodizing, paint, high temperature paint, rust and passivation etc. Different surface treatment process, the product of the requirements are not the same as the tolerance.

In general speaking, the aluminum alloy die casting main resistance testing includes neutral salt spray, RCA tape abrasion test, abrasion test, pencil hardness test, 100 lattice test etc.

aluminum-alloy-die-casting-main-resistance-testing

Now more and more design use luminum alloy die casting,due to the good heat dissipation, low transportation costs, metal utilization, the structure advantages.

Electronic Ballast Introduction

The electronic ballast is used electronic technology to drive electric light source, which is one requirement of lighting electrical equipment. Now more and more LED lights also used electronic ballast because it’s lighter and even is integrated with the light .And more, it is as starter, which can remove the individual starter. And improving the current frequency or current waveform to adjust the phenomenon of the flicker of fluorescent lights. Let fluorescent light can use DC power supply.

traditional-electronic-ballast

 

The electronic ballast is a conversion device that converts the power frequency AC power source into the high frequency DC power source, its basic principle is the power supply directly become DC power supply through the radio frequency interface filter, full wave rectifier and passive(or active) power factor corrector(PPFC or APEC).

electronic-ballast-circuit

Through DC/AC converter, high frequency AC power output of 20K-100KHZ, and the lamp is connected to a series resonant circuit and resonant heating filament, high voltage on the capacitor, and at both ends of the lamp, but the lamp “discharge” into the “on” state, then enter the luminous state at high frequency inductive limits current increase effect of guarantee lamp to obtain a lamp voltage and lamp current required for normal work, often set up all kinds of protection circuit, such as abnormal protection, surge voltage and current protection, temperature protection and so on.

led-electronic-ballast

The electronic ballast has 4 series of 16 varieties, include one common type and special electronic ballast, lamp box type is divided into 20W, 30W, 40W a total of 6 species, one for two, ordinary and special electronic ballast box type is divided into 2x20W、2x30W, 2x40W a total of 6 species, ring lamp electronic ballast is divided into 22W, 32W, 40W, a total of 3 species, last one is the quartz bactericidal lamp ballast for 35-60W a total of 1 species.

All different dimension lights are used in different field, such as the one for one and one for two light electronic ballast are designed specifically for outdoor light boxes and outdoor billboard, because it has the advantages of waterproof, high insulation performance, and the light box cloth doesn’t turn yellow because of the heat.

Electronic ballast is suitable for different occasion for general lighting. Ring lamp electronic ballast is suitable for the installation of the balcony in the home lighting, staircase corridor lighting and other public places. The quartz bactericidal lamp ballast can be used for shops, display windows, exhibition halls, jewelry stores, bars, museums, shops, etc.

Of course, the electronic ballast is more widely used in different because of its products have many advantages. Firstly what most attracts attention is the energy-saving, the lamp with the electronic ballast has low power consumption, the total input power of the lamp is decreased by about 20%, and the energy-saving effect is better.

It has no flicker and light more stable, it’s also beneficial to improve the visual resolution,improve the power efficiency, alleviate visual fatigue so that is beneficial to eye protection. Its power factor reach about 0.95, it means that not only reduces the cost of investment, but also reduces the loss of energy.

Furthermore, it has the stability of input power and output luminous flux, although power supply, voltage deviation maybe is very large, it can still maintain a constant power source, stable light intensity, energy-saving as well, the last is that can prolong the lifespan of the product. However, it has some disadvantages such as the problem of heat dissipation, because heat dissipation is an important factor affecting the lifespan of electronic ballast, and this aspect still needs to improve, but in a word , the electronic ballast has a big development space.

 

How important secondary optics design is in led applications

Due to the variety and complexity of lighting requirements, based on the principle of light distribution, we use the optical transmission design with traditional design method. Then  secondary optical design is published according to its feature of unique light distribution, it meet the national lighting standard , and reduce the design complexity, which is used LED flood light or LED street light design .

The basic function of secondary optical design is to make light source spread out, next to gather the light in a smaller range. Now it is used material with silica gel lens, optical lenses PMMA lens, PC lens and the glass lens commonly, etc.

led-lens

Considering the transmittance, production efficiency, manufacturing difficulty, heat resistance and processing cost, PMMA lens is widely used in many fixture and become mainstream increasingly, its light transmittance can reach 93% . You know most of LED flood light adopts the PMMA lens, its advantages is high thermal conductivity, small light failure, light color purity, no ghosting, and high brightness.

Then let us deeply know the optical lens design. It’s said that the designing idea of the traditional lamp is band coefficient method, which is under the condition of known light distribution and target light distribution, divided the target lamp into a series of light band according to appropriate view, so each band has a corresponding band coefficient, corresponding to the light source is also divided into a series of band, also to calculate the flux in the band, so it’s too difficult for us.

Lens simulation software to establish the secondary optical lens entities, and entities need to be given material properties and surface properties, according to the previous analysis, PMMA lens is the main product material. Surface feature corresponding to the light transmittance of the material, the penetration rate of 3mm thickness generally can reach about 93%, and the material of different wavelengths of light refraction properties is relatively uniform,when tracing, using a single wavelength to improve the efficiency of

The LED light is used in different field. For instance, the LED flood light is installed on the wall for passers in the night.Due to the influences of light source, a normal light maybe easy to form a glare and round without the light distribution. In order to solve this problem, need to improve the light distribution of LED, it means that should design a secondary light distribution. At the same time, you know people prefer to warm white,if it is required the light penetration in fog days, so the light need yellow spectrum to create a better lighting environment for people.

Actually, the purpose of secondary transmission design is to meet the application requirements by changing the light beam angle and light distribution . The secondary optical lens design can solve the problems of LED flood light and LED street light,just like the light efficiency/the light uniform/the angle of light distribution/glare and safety effectively etc. Of course, the secondary optical transmittance lens still has a reference significance to realize green lighting.