Aluminum profile polishing key factors 

Aluminum profile polishing key factors

Aluminum profile polishing machine and aluminum profile polishing solution

There are many factors that affect the aluminum profile polishing machine for the mirror effect of polishing aluminum profile, each of these factors is most important, in order to achieve the perfect ideal of high-grade aluminum profile mirror effect in the production, each procedure must be strictly controlled, any small problems may affect the final polishing effect of the workpiece.

Here is a brief introduction to the key points for aluminum profile polishing

1. The microstructure of aluminum billet

The microstructure of extrusion billet is an important key factor to guarantee the surface brightness of the polished aluminum profile.

The microstructure of the extrusion billets can be guaranteed from the casting and homogenizing process.

First of all, as there is lower Fe content in the 6463 alloy, its microstructure is easier to get coarse grains;

TiB2 can reduce the brightness of the chemical polishing, making 6463 microstructure refinement be cautious for TiB2.

We can consider with the refinement of Al-Ti-C, which can not solve the refinement problem, but also avoid TiB2 impact.

On the other hand, the coarse grains in the casting will increase extrusion pit defect and produce the tearing.

The tearing reason is the low melting point phase generation or eutecticum, which caused the liquid phase temperature to reduce.

We must speed up the casting cooling rate and reduce water-cooled mold Sump depth to eliminate; well as to make the microstructure more uniform.

Homogenizing must be done to make Fe restructuring as equiaxial particles existing and uniform distribution, the main dimensions of 3 ~ 4μmMg2Si precipitated material all β ‘phase and uniformly within the grains, the grain main size is no bigger than 0.5μm.

The function of aluminum billet homogenizing processing is to reduce the inherent stress, which can reduce frictional force in the extrusion process to obtain a good surface.

2.Casting temperature and cooling water temperature

In addition, good control for the casting temperature of the molten aluminum and the cooling water temperature will have significantly improved for the aluminum extrusion profile surface.

3.Extrusion dies

Extrusion dies impact the quality of polished aluminum profiles in two ways, as the extrusion dies working causes the aluminum surface defects, which affect subsequent polishing quality.

On the other hand, due to diversion, porthole cavity, mold bridge and welding chamber reasons will arise the problem for aluminum profile surface defects, some defects can be appeared even after polishing or anodizing.

First, the quality of the dies land length has a very large impact on the quality of polished aluminum extrusion profile surface.

If the die land length can not be protected well, the lifetime of the die will be short.  

Under the premise of ensuring excellent mold material and heat treatment, the machining and repairing of die land length must be ensured; enough free tool position (≥ 2.5mm) to ensure free tool position non-stick aluminum;

Enough verticality and straightness (≤ 0.02mm), non-uplifting and no uneven and no corrosion to guarantee to die land length non-stick aluminum; enough surface hardness (HV ≥ 1000) and the appropriate surface finish.

In addition,  the die land length should be as short as possible (conventional 2 ~ 4mm), and make sure the arc transition to minimize the drop of die land length.

Secondly, the diversion, porthole, die bridge and seaming position of dies producing and repairing must be based on the wall thickness, the aluminum extrusion ratio, shape, and polished surface of aluminum extrusion profiles for comprehensive consideration. 

To ensure the following requirements: a sufficient amount of deformation processing, especially important for thick-walled and small extrusion ratio aluminum materials, to ensure microstructure uniform; fully seaming together; the metal flow in uniformity before going into die land length; minimize the die land length to reduce the impact of metal.

4.Extrusion process

From the extrusion process, besides how to take advantage of the high quality of the billet and extrusion dies to produce a high-grade mill finished aluminum profiles are key factors, there are some other key points:

First, to obtain a suitable aluminum extrusion ratio, generally, λ = 25 to 50, if it is too large or too small, that will affect the quality of the polishing aluminum material.

Secondly, the extrusion temperature (extruded outlet temperature) needs to be controlled in a lower temperature (500 ° C or so) under the premise of Mg2Si phase fully solid solution in 6463 alloy and combined with a big amount of wind cooling.

For different types and different extruded ratio aluminum profiles, how to adjust the three temperatures and extrusion speed to reach the critical control extrusion outlet temperature consistent, which is the key to ensure consistent quality of polishing aluminum profiles.

In addition, how to protect mill finished aluminum extrusion profile surface is an important part of the quality of aluminum polishing.

Aluminum polishing applications are very wide and the requirements for aluminum polishing quality are relatively high, all require a high-end mirror effect, so it needs a polishing process and equipment performance and automation of aluminum profile polishing machine very highly, as well as the selection of configuration and wearing parts are very high.

For the polishing aluminum extrusion profile production, in order to achieve the expected effect, we should pay more attention to all processing before aluminum profile polishing.

Aluminum profile polishing key factors