Design engineers today demand materials
that are simultaneously light, strong and corrosion resistant.
They want materials to meet the
structural, thermal, aesthetic and acoustic challenges of the 21st century.
Aluminium is an obvious choice for
engineering designers with its unique properties, making it a natural partner
for many applications.
Its use, in its extruded form, in a wide range of applications has grown over many years thanks to its strength, durability, corrosion resistance and lightness. Extruded aluminium offers the design engineer the optimum design flexibility. The component shown here allows elderly patients and nurses to operate tricky valves on oxygen cylinders.
Aluminium extrusion is the technique used
to transform aluminium alloy, pushed through, what can be intricate and complex
dies, into definitive, cross-sectional profiles for a wide range of
applications.
Using removable strips to achieve complex
shapes or challenging tolerances.
The extrusion process makes the
most of aluminium’s unique combination of physical characteristics,
specifically, malleability and ductility.
Its ductility allows it to be
easily extruded while its malleability allows it to be pressed and formed into
complex shapes even after extrusion.
Also, at one third the density and stiffness of steel the resulting products offer exceptional strength and stability making it a popular choice for many designers.
Aluminium extrusions can be found in a
diverse range of applications
Low weight to high strength ratio – aeronautical, marine, railway stock, automotive.
High conductivity of heat and electricity – air conditioning, radiators, heatsinks, electronics.
Corrosion resistance – mining, architectural, marine, military, cables and wires.
Aluminium extrusion is often the most viable solution that meets the specific manufacturing needs of design flexibility, cost savings, and product performance.
At Inal Metals we’ve done thousands of dies over the years many to very tight deadlines. So tasked in the week leading up to Easter to produce a new die with machined samples within 10 working days during a period of tool maker shutdowns proved too big a challenge to decline. Fantastic performance from everyone involved and hey presto in 9 working days…job done!
In recognition of our best first quarter in many a year star performer Sarah Lyon added to her impressive tattoo collection with a discreet triumvirate of our ornithological friends recently; see photo. No doubt further indicative of our phoenix like revival in recent months …Sarah we salute you! https://www.facebook.com/InalMetals/
Continuing our series on deconstructing the aluminium extrusion process, this post looks at the cooling, stretching, cutting and heat treating required to produce the profiles you need.
The billet ‘butt’ that remains from extrusion creation oxides from the billet skin. The butt is sheared off and discarded while another billet is loaded and welded to a previously loaded billet and the extrusion process continues.
When the extrusion reaches a desired
length, the extrusion is cut with a profile saw or a shear.
Metal is transferred (via belt or walking beams systems) from the run-out table to the cooling table.
After the aluminium has cooled and moved
along the cooling table, it is then moved to the stretcher.
Stretching straightens the extrusions and
performs ‘work hardening’ (molecular re-alignment which gives aluminium
increased hardness and improved strength).
The next step is sawing. After extrusions
have been stretched they are transferred to a saw table and cut to specific
lengths. The cutting tolerance on saws is 1/8 inch or greater, depending on saw
length.
After the parts have been cut, they are
loaded on a transportation device and moved into age ovens.
Heat-treating or artificial aging hardens the metal by speeding the aging process in a controlled temperature environment for a set amount of time.
As an aluminium extrusion exits the press, the temperature is taken to record the exit temperature of the extrusion.
The main purpose of knowing the
temperature is to maintain maximum press speeds. The target exit temperature
for an extrusion is dependent upon the alloy.
Extrusions are pushed out of the die to the run-out table and the puller, which guide metals down the run-out table during extrusion.
While being pulled, the extrusion is cooled by a series of fans along the entire length of the run-out and cooling table.
Only experienced extruders understand the importance and intricacies of the heating and cooling processes required in extrusion. Only companies that do this thing day in, day out have the equipment to hand to provide both a precision and volume service.
Ensure you check that your extruder of choice has the right process and equipment in place to deliver what you need.
As we’re the only aluminium company top heavy with women on the board it’s only fitting that we shout out in support of International Women’s Day on Friday. To all the great women within our supply chain our customer base and most of all here at Inal Metals…we salute you.
Under pressure the billet is crushed against the die, becoming shorter and wider until it has full contact with the container walls.
While the aluminium is pushed through the die, liquid nitrogen flows around some sections of the die to cool it.
This increases the life of the die and
creates an inert atmosphere which keeps oxides from forming on the shape being
extruded. In some cases, nitrogen gas is used in place of liquid nitrogen.
Nitrogen gas does not cool the die but does create an inert atmosphere.
Because of the pressure added to the billet, the soft but solid metal begins to squeeze through the die opening.
Billets must be heated to approximately 800-925°F. After a billet reaches the desired temperature, it is transferred to the loader where a thin film of smut or lubricant is added to the billet and to the ram.
The smut acts as a parting agent (lubricant) which keeps the two parts from sticking together. The billet is transferred to the cradle.The ram applies pressure to the dummy block which, in turn, pushes the billet until it is inside the container.
Under pressure the billet is crushed against the die, becoming shorter and wider until it has full contact with the container walls.
While the aluminium is pushed through the die, liquid nitrogen flows around some sections of the die to cool it.
This increases the life of the die and
creates an inert atmosphere which keeps oxides from forming on the shape being
extruded. In some cases, nitrogen gas is used in place of liquid nitrogen.
Nitrogen gas does not cool the die but does create an inert atmosphere.
Because of the pressure added to the
billet, the soft but solid metal begins to squeeze through the die opening.
At Inal Metals we don’t say things fit like a glove…we say they fit like a Konrad!. Awesome telescopic design by Konrad our in house designer ensuring a fit over 2000mm on this high volume consumer product. Super proud when a product reaches this stage after many weeks of design and prototyping. Come back for full case study in a few months time.
Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed through a die of the desired cross-section.
There are two main advantages of this process over other manufacturing processes.
The first is to create very complex cross-sections. The second is to work materials that are brittle, because the material only encounters compressive and shear stresses. As an additional benefit, it also forms parts with an excellent surface finish.
Extrusion may be continuous (theoretically producing indefinitely long material) or semi-continuous (producing many pieces). The extrusion process can be conducted with hot or cold material.
Dies
Commonly extruded materials include metals, polymers, ceramics, concrete, modelling clay and foodstuffs. The products of extrusion are generally called “extrudates”.
Hollow cavities within extruded material cannot be produced using a simple flat extrusion die, because there would be no way to support the centre barrier of the die.
Instead, the die assumes the shape of a block with depth, beginning first with a shape profile that supports the centre section. The die shape then internally changes along its length into the final shape, with the suspended centre pieces supported from the back of the die. The material flows around the supports and fuses together to create the desired closed shape.
The extrusion process in metals may also increase the strength of the material.
Aluminium extrusion
Aluminium extrusion is a technique used to transform aluminium alloy into objects with a definitive cross-sectional profile for a wide range of uses.
The extrusion process makes the most of aluminium’s unique combination of physical characteristics.
Aluminium is the most commonly extruded material and it can be hot or cold extruded. If it is hot extruded it is heated to 575 to 1100 °F (300 to 600 °C).
Examples of products include profiles for tracks, frames, rails and heat sinks.
