Production experience of multi-pieces aluminum profile from one die at one time extrusion

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Production experience of multi-pieces aluminum profile from one die at one time extrusion

Technique to extrude multi-pieces aluminum profile from one die at one time extrusion means one die can produce two or more pieces of same aluminum profile, for example, one 600T aluminum extrusion press, can use one die to produce two or more pieces of 30mm*30mm aluminum profile at the same time. It is so advanced that it can raise extrusion output, production efficiency, and quality of aluminum profiles, which conforms to the China policy ‘energy- saving and cost- reducing’; playing an important roles in development of enterprises.

1. Design and manufacture of extrusion die

Strength of steel should be considered and avoid the distance between holes too large or too small when designing the position of multi- holes in order to get optimization of aluminum profiles. On the base of symmetry, holes should be placed horizontally while distance between holes should be widened when vertical placing. During dies processing, advanced die making equipment with high precision are the premise to ensure the dies quality. For example, by-pass hole and welding room should be produced in CNC processing center in order to reach the related accuracy, while diecavity (working zone) have to adopt EDM wire-cut to ensure degree of verticality, parallel, smooth and glossiness.

2. Management of aluminum extrusion production craft

2.1Parameter of craft

2.1.1Temperature of aluminum billet

1) Aluminum billets temperature for multi-holes flat dies extrusion usually is between 390? and 480?. Aluminum billet temperature control adopts stair cooling method, usually initial temperature adopts upper limit temperature of 390? ~ 480?, follow every aluminum billet decrease progressively 10? until the minimum of range of 390? ~ 480?.

2) Aluminum billet temperature for multi-holes porthole dies usually is between 430? ~500?,Aluminum billet temperature control adopts stair cooling method, usually initial temperature adopts upper limit temperature of 430? ~ 500?, follow every aluminum billet decrease progressively 10? until the minimum of range of 430? ~500?.??

2.1.2 Temperature of dies

Usually, the temperature of dies should be controlled around 430?~480?.

2.1.3 Temperature of container (for aluminum extrusion press)

In general, temperature of aluminum extrusion container should be controlled among 410?~440?. Control the temperature at the upper limit according to during actual production process.?

2.1.4 The temperature of exit of aluminum extrusion press

Generally speaking, temperature of discharging exit of aluminum extrusion press ought to be among 520?-580?, while the temperature of exit will affect the hardness and quality of aluminum profile when the temperature is too high or too low.

2.2 Requirements of craft operation ?

2.2.1 Aluminum billet heating

Newsday, aluminum billets are usually heated in furnace separately from high temperature to low or from low to high.

In order to ensure the heat can go through aluminum billet, multi-pieces aluminum profile from one die is usually heated from high temperature to low. That means temperature of aluminum billet is controlled from high to low separately from billet feeding to furnace to billet discharging. Temperature is diminishing according to the quantity of heating zones of furnace.

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2.2.2 Die heating

Die with mat and cover is usually heated within 6 hours so that the heat can go through it. However, it will be harmful to surface quality of aluminum profile surface if heating time too long.

While heating, die should be placed in the middle with enough distance (at least 5cm) among dies. Do not close to the furnace wall and fans.

Die furnace should be clean, no dust, and avoid the dust coming into the working zone of the dies in case of quality problems on aluminum profile surface.

2.3 Management of extrusion process

1) The time can’t over three minutes from the die get out from the die heating furnace to extrusion; otherwise it may cause disunity of discharging of aluminum profile.

2) When starting to extrude, the first aluminum billet does not release gas. And use short aluminum billet and the billet length is among 200-300mm.

3) The first aluminum billet pressure should begin to work from ‘0’ section, after aluminum profile discharging speed up slowly the extrusion speed.

4) High temperature mat is used in the exit of aluminum extrusion press in case of scratch and on the bottom of aluminum profiles. Every piece of aluminum profiles is isolated by graphite plate in order to avoid such quality problems.

5) Adjust the tension force of puller discontinuity to ensure physical dimension of aluminum profiles meet the requirements of tolerance. At the beginning of aluminum billet extrusion, the tension force is increased, adjust back the tension force slowly till aluminum profile discharging.

6) Usually the speed of aluminum profile discharging should be controlled among 30-40m/minutes.

7) During extrusion processing, the quenching process of wind-cooling or air-cooling should be carried out strictly according to the character of aluminum alloy.

8) During extrusion processing, do not stop working machines unless they broke down because the die must returned back to die heating furnace when aluminum extrusion press stop over three minutes; The temperature of die must reach to 500?. But ensure the superior quality of aluminum profile extrusion; we suggest that the upload and cool down the die and clean, fix the die. Because the requirement of temperature of multi-holes dies is very high, re-heat die may be easy to damage and produce inferior quality of aluminum profile.

2.4 Control the temperature and speed of aluminum profile at discharging exit of aluminum extrusion press

1) Adjust timely the temperature of aluminum billet according to the temperature of aluminum profile at discharging exit of aluminum extrusion press

2) The temperature of aluminum profile at discharging exit of aluminum extrusion press is controlled between 520? ~ 580?. If it is lower than 520?; the hardness of aluminum profiles cannot reach the normal standard and can’t reach the appropriate mechanical properties; if it is higher than 580?, damage may be caused to the die and aluminum profile may not shape.

3) Once surface of aluminum profile turns black when discharging, temperature of aluminum billets and extrusion speed must be lowered in case of over-heat.

4) During multi-holes die extrusion process, operators should observe the temperature of aluminum billet and aluminum profile at discharging exit, surface of aluminum profile, running condition of aluminum extrusion press. When accident happens, operators must stop the aluminum extrusion press; otherwise possibility of damaging the die is very high, which affects the working life of the extrusion dies.

3. Aluminum extrusion equipment for multi-pieces aluminum profile from one die

Aluminum extrusion is system engineering project. In order to realize technique ‘multi-pieces aluminum profile from one die’, high finished rate and production efficiency, attention should not only be paid into stability of aluminum extrusion machine and quality of extrusion dies, but also related aluminum extrusion auxiliary equipment, such as double puller with flying saw, die heating furnace, billet heating furnace, technique of long log heating and hot shear, and so on.

4. Summary

As aluminum extrusion process is improving, production efficiency and finished rate of multi-pieces aluminum profile from one die extrusion is getting higher and higher. Differences of this technique exist at aluminum extrusion factories because of differences of aluminum extrusion equipment, material and design of dies and extrusion process. Making an available aluminum extrusion process need to summarize previous working experience and based on real situation of your aluminum extrusion equipment performance.
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