The importance of correct aluminium selection

Aluminium is extremely malleable which makes fabricating it easy and can be shaped to fit any kind of application design. Image credit: PMIT

Press Metal International provides a broad range of aluminium products across industries. Lim Heng Kam, general manager and executive director of Press Metal International, speaks to Manufacturers’ Monthly about the importance of correct aluminium selection for a variety of applications.


Aluminium is an alloy that is widely applied in industries such as marine, transportation, automotive, consumer electronics and 5G telecommunication. It is also used as a replacement alloy, and because of its light weight, the demand for it is refined according to the needs of the different industries.

Currently, PMI and PMIT serve these trending industries who have applications which have their own requirements that start with the basic requirement of alloy selection.

Mr Lim Heng Kam, general manager and executive director of Press Metal International Ltd, explained that in the marine industry (a key industry for PMI), lightweight and corrosion-proof qualities are the most essential requirements, therefore 6082 or 5series alloys are the balance between performance of high strength and good anti-corrosion. Friction Stir Weld (FSW) is widely used in the marine industry – it replaces traditional welding which is a big improvement on structural and engineering strength. Because the use of FSW is becoming trendy, it has driven costs down compared to previous times.

Consumer electronics such as handheld phone case requires strength in the material over its bending performance, and an anodised appearance as a visual cosmetic requirement. The 6013 alloy is the commonly used alloy for this.

In 5G telecommunications, aluminium alloys such as 1060 or 6101 are used in the big, wide heat sinks because of its physical properties and excellent thermos-conductivity.

Aluminium can be applied to various applications by customising the alloy. The customised aluminium alloy can have varying characteristics by adjusting the level of refinement to the alloy – to serve different applications. In order to gain the optimal benefits from aluminium, it is recommended to know the full extent of the application’s requirement before customising the aluminium alloy’s characteristics.

Exchanging knowledge on the strengths of aluminium

The density of aluminium is one third of that compared to steel, giving it a significantly higher unit strength that makes it suitable for various types of lightweight applications, said Lim.

“The anti-corrosion characteristic enables the product (with the aluminium alloy) to be used with minimum surface treatment. Its high-plasticity, narrow characteristic feasibility makes it suitable to fulfill specific requirements such as conductivity, excellent surface treatment and depth fabrication,” said Lim.

“With these great properties, it gives the opportunity for a product designer to draw up an idea and bring it to life. The production engineer then has wider options to customise the production chain to fulfill efficiency, EHS or even take into account the environmental aspects of the process.”

With Australia being one of the largest shipbuilding countries internationally, for the past two years, PMI has had an increased focus on its business here due to their focus on the maritime industry. It has been promoting the use of aluminium in the local shipbuilding industry. In the maritime industry, Lim explains that with the incorporation of aluminium into the parts of boats and ships, their overall weight is significantly decreased because aluminium is roughly about one-third the weight of a steel alloy.

“In any vessel, because aluminium is light weight and even after factoring in the loads it takes on like people or cargo, the required fuel needed to power the vessel would be less and this helps with the global drive to reduce emissions,” said Lim.

He said with the help of Wilson Yau, PMI’s representative in Australia, the promotion of aluminium has been getting a lot of interest. At the same time, he admires the high level of expertise that the Australian shipbuilding industry brings.

“We have taken this opportunity to learn about products and parts that can incorporate aluminium alloys,” said Yau. “The welding process is a complex one and the Australian shipbuilders are very advanced in their techniques and possess an extremely highly skilled workforce. So, we hope to learn more from them and bring this knowledge back to share it with our staff back home.”

Benefits of prefabricated products

Product fabrication is based on customers’ needs, and according to Lim, the company caters to customers across different levels. “We can supply from mill, surface treatment, light fabricated or even full fabrication,” he said. Lim explained that PMI’s main business is aluminium extrusion, whereas its subsidiary, PMIT, delivers value-added fabrication, so it is able to provide a flexibility and options to customers’ needs.

“If the aluminium alloy product’s properties are fully utilised, it could reduce the stress of overall production chain cost,” said Lim. “Its excellent malleability, in terms of extruding and fabrication compared to other material such as steel, makes fabrication easy and you can shape it to fit any kind of application design.”

In upstream process within the production chain, the stress of manufacturing and preassembly can be done and left to the downstream portion to only installation and build to construction. Also, because aluminium of its light weight, the supportive facility or tool can be lighter to operate in both upstream and downstream production.

Aluminium gradings in the manufacture of products

Generally, the aluminium alloy ingredient can be divided into two categories which are:

1) pure aluminium that is re-melted into alloy for extrusion uses involves smelting from the mineral (aluminium) which makes the alloy has a higher purity which is critical for every high requirement product. While the product quality can be guaranteed, however, the energy consumption rate is relatively higher but that can be brought down using renewable and clean energy for the processing.

2) the other category is recycled aluminium. In this case aluminium scrap collected from the market from sectors like door-window, automotive or construction is used for the alloy. It is re-melted and then cast into extrusion material for production. Due to the lower melting point of aluminium, the yield rate in terms of cost and manufacturing feasibility is better compared to other commonly used metal. However, due to scrap aluminium potentially containing impurities, the final resultant alloy will not be as high grade but is still good for lower grade products.

“One of the best features of aluminium is that it is recyclable,” Lim said.

Lim emphasises that PMI is committed to environmental sustainability by putting a lot of R&D efforts in the aluminium casting purification process and heat treatment to improve the quality when recycled aluminium is used.

“This is to achieve a balance of good performance with lower carbon footprint for selected application,” said Lim.

Bringing to balance: best product with the smallest ecological footprint

Because aluminium is a recyclable, it is ecologically friendly. However, one needs to consider the carbon footprint in the aluminium alloy production process in different parts.

“The material source is a big part on the upstream portion. When you look at it from the downstream, the other important factors to consider are fabrication, transportation for further fabrication, re-packaging and so on,” explained Lim. “There are many ways to reduce the downstream carbon footprint that could reduce the total carbon footprint but potentially other benefits on the side.

This is where PMI works in partnership with various customer to customise their product’s lifetime with the right kind of alloy while maintaining a low carbon footprint.
“With the ability of PMI who specialises as an extruder, and PMIT as fabricator and with the worldwide network of technical expertise and sales network, we are able offer the customer the most balanced aluminium solution,” said Lim.

Due to the varying products, there will be a difference on the energy used in their manufacture, and the kind of fabrication that is done is the biggest contributing factor.

“Currently, the main power sources PMI uses to manufacture are natural gas and electricity, which is mainly from the grid with auxiliary power from PMI coming from an in-house solar farm. There are benefits to the reliability by using power from the grid because the usage is reduced from about one to five per cent,” said Lim.