Valued for its high strength-to-weight ratio and natural corrosion resistance, aluminium is a cornerstone material in modern engineering.
Aluminium fabrication is the industrial process that converts aluminium, generally available as extrusions, sheets, plates or tubes into functional components and complex structures through cutting, shaping, joining, and finishing.
It is possible at the design stage to construct an aluminium extrusion which will minimise the need for further work and make fitting and assembly more efficient. However, some form of fabrication is often required. Aluminium extrusions are highly suitable for all types of fabrication.
Aluminium Fabricators employ a variety of specialized methods to manipulate this versatile metal, for example cutting, forming and shaping, bending, stamping, machining, joining, welding and fastening.
Core Fabrication Techniques:
Machining
Aluminium is eminently suitable for all kinds of machining on high-speed CNC machining centres this includes milling and other examples below. Machining a profile can allow tight tolerances to be applied when required.
Milling
Milling is machining using a rotary cutter to remove material from and extruded profile. It covers a wide variety of different operations and machines. It is one of the most frequently used processes in industry. Today milling is most often carried out on modern CNC machining centres with automatic tool changers, tool magazines or carousels, coolant systems, and enclosures.
Turning
Certain grades of aluminium are more suited to being turned, but attention should be paid to finishing when these grades are used as most are not suitable for anodising. Turning can be carried out on standard, special and automatic lathes and needs to be at a high speed of rotation. Due to the amount of vibration caused during this process parts need to be very securely fixed.
Sawing
All aluminium alloys can be sawn either through circular rotary saws or hand saws.
Drilling
While all aluminium can be successfully drilled the harder grades generally offer a better, cleaner quality of finish.
Tapping
Internal and external threads can be made using conventional drilling, machining and semi-automatic end tapping. The higher temper alloys (such as T6 temper) give good quality results.
Pressing
This can be a hand press or a power press and is the most simple and cost-effective way to cut holes in an extruded profile. A tool is made in the shape of the hole required; this is used with pressure to cut the shape out of the profile.
Deburring
Deburring is a process for removing small chips and any remaining burrs on the cut end of the extrusion.
Rasamat Deburring The most common method is mechanical, using a brush or grinding machine which is known as a Rasamat.
Barrel processing This is a very good method for removing burrs from smaller aluminium parts, it can also remove sharp edges and to a certain extent polish the part. The process is a form of abrasive tumbling where fragments are removed by friction using circulating stones; the level of abrasiveness can be influenced by the right choice of material and shape of the circulating stones.
Rasamat orbital deburring machines
Brush deburring
Manual deburring
Vibro deburring
Etch deburring
Abrasive wheel deburring
Welding
The extrusion design process can often eliminate the need for joints. But where welded joints are required, features such as bevels, integral backing bars can be built into the extruded shape to facilitate the welding process.
Welding has the following advantages: Welding is one of the safest and easiest methods of creating airtight and watertight joints. It is possible to weld materials in thicknesses below 1mm and up to several centimetres thick. In general welding can be a cost-efficient method of creating a joint however welding is a specialised job.
TIG Welding TIG welding can be carried out on all weldable aluminium alloys and when controlled to the correct standards and procedures can produce high quality welded joints. TIG welding is more suitable to thinner materials and shorter weld runs.
MIG Welding MIG welding has been developed from TIG welding and can offer a faster welding process and is better suited for thicker material and longer weld runs. This can often mean lower heat input into the welded joint which aids extent of heat affected zone and control of distortion.
Forming
Forming can take place with higher temper (T6) metal for larger radii but smaller ones usually require lower tempers such as T4, as manufactured (F) or possibly annealed (o). It is possible to harden to full strength after forming, for example, bending in T4 and then ageing to the T6 temper. Forming should be carried out before anodising to reduce the risk of the anodised layer cracking.
Bending This is used for high shaping accuracy. The extrusion is held tightly in position and bending takes place by the tool and former moving.
Stretch forming The extrusion is held tightly in tension and rotates around a specially shaped form to achieve the desired shape.
Roller bending This is used to bend extrusions with large radii. The extrusion is rolled between three wheels one of which one is adjustable. It is possible to vary the radius on the same component using CNC-controlled machines.
Press bending This is used for simpler operations, in large batches. The parts are shaped in a two-part tool using, for example, an eccentric or hydraulic press.
BAL Group Fabrication Centre
At BAL Group we provide a comprehensive fabrication and finishing service to our customers. Our complete programme of aluminium fabrication includes:
Saw cutting
CNC Machining
Laser Cutting
Press Brake
Presswork
Bonding
Assembly
Deburring
Our aluminium fabrication centre performs complex and high added-value operations.
We have made significant investments in the very best machines available in the marketplace to enable us to process products with maximum efficiency at a very low cost, which translates into savings that we pass on to you, our valued customer.
These extensive facilities provide us with significant flexibility across a variety of fabrications allowing us to develop customized solutions to create your aluminium profile requirements in exactly the right design, shape and size.
Through our fabrication centre, we can produce products that align perfectly with your specifications, allowing you to enhance the value of your products while minimizing costs.
At BAL Group we offer fabrication to the most exacting standards and delivery requirements. We deliver to all industry sectors in the UK and Ireland.
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by david@dm-design.co.uk
