Aluminium sections, or profiles, are designed for specific applications

Working with AluminiumAluminium sections, or profiles, are designed for specific applications.

These can include:

architectural systemsresidential systems

partitions

security systems

geometric shapes.

The production of aluminium products relies heavily on machining as part of the fabrication process. Machining is the mechanical operation used to remove material from a workpiece by means of cutting tools which divide, cut, penetrate or shape. Although the bulk of machining operations require the use of machine power to do the work, manual operations such as sawing, drilling and filing are regarded as machining processes. The ease or difficulty of performing a machining operation is called machinability. Machinability is determined by the:

interaction between the tool

workpiece

lubricant

speed or other features of the operation.

Aluminium can be machined on most machines used for metal or wood. It

can also be machined using hand tools such as files and hacksaws. As a general

rule, however, machines must be set to run at high speed and machine

sawblades should be tungsten.

Many aluminium sections are used for office buildings, factories, shops and other business

related sites. Aluminium sections for commercial fabrication would be

used to make items such as:

frames

doors

windows

partitions.

Below are some examples of different sections which make up

Aluminium shopfronts

Like all products in the construction industry, aluminium frames, windows

and doors must comply with Australian Standards. These standards are

regulations all workplaces and their workers must follow to ensure quality

products and safe work conditions. The relevant standards for aluminium used in residential windows and doors are as follows.

AS 4055 Wind loads for housing

AS 2047.1 Windows in buildings specifications for materials and

performance

AS 1107.2 SAA Loading Code Wind Loads

AS 1664 SAA Aluminium Structure Code

AS 4420 Series window tests

AS 4284 Testing of building facades

Aluminium is used extensively in the construction industry because of its:

appearance

corrosion resistance

formability

finishing variations

high strength to weight ratio.

Shopfitting uses aluminium for a variety of applications. Uses include:

internal fitments eg partitions and show cases

trims such as ducted skirtings

shopfronts.

Finishes on aluminium:

Aluminium comes in a range of finishes.

The standard finish is mill finish. This finish is the natural surface finish achieved when the material is forced through the extrusion process. The surface of the material is a clear aluminium finish showing die marks.

Aluminium extrusion can have three different finishes applied.

1. Chemical brightening.

2. electrochemical colouring known as anodising

3. applied finishes such as powder coating and spray painting

4. mechanical finishes such as buffing and scratch finishes.

Chemical finishes:

Include etching and bright-dipping process.Etching process is a chemical process to give a finish of silvery white and frosted appearance. This is done by applying a caustic solution to the aluminium surface. The aluminium profile is passed through a hot bath, rinsed, and then immersed in a chemical bath that removes undissolved alloy and other surface impurities. The process is completed by further rinses.

Bright dipping process is a specialized kind of chemical-finishing that yields a bright, mirror-like finish. The profile is first polished and then anodized to both protect the surface and apply desired color. Aluminium can be bright dipped without being first polished. This reduces the cost of achieving a bright appearance. But for that special finish the extrusion should be polished first.

For more in formation follow the link: chemical finishesAnodising:

Is an electrochemical process that thickens and toughens the naturally occurring protective oxide layer on the surface of aluminium. The tough finish is the second hardest substance known to man, second only to diamond, but because the layer is thin it can be scratched through by sharp protrusions. The anodic coating is part of the metal, but has a porous structure which allows the different dyes to soak into the surface producing coloured anodizing. Take care as the colour can be easily washed out if it comes in to contact with caustic material that included cement and lime products as well as dishwasher detergents.

For more in formation follow the link: Anodised aluminiumPowder coating and painting:

Paints and lacquers may be applied by brushing, rolling,pouring, flow coating, airless or hot spraying, electrostatic coating with liquid or powder, or immersion.

The method chosen depends upon the needs and requirements for efficiency, appearance, uniformity of the coating, and extrusion shape. Single coat finishes are used for decorative purposes in items that need to withstand on little stress or human interaction and only mild chemical contacts. Multi-coat finishes are best used for exposure to moisture, aggressive chemicals or high mechanical stresses.

For more information follow the link: CoatingsMechanical finishes:

This includes polishing and brushing. These techniques remove surface imperfections and produce a uniform appearance and allow for additional treatment in order to attain various finishes for decorative purposes.

For more information follow the link: Mechanical finishesJoining aluminium sectionsBefore joining aluminium there are some important processes you will need to follow before

joining the sections. They are processes that deal with:

quality assurance- sizes are correct etc. all sections are available

OH&S issues PPE and duty of care

any special protective equipment that may be used fro material and personal

selecting and checking the tools for the job. Tools sharp and set up properly

types of aluminium sections. Are profiles compatable.Now that you know how to identify the correct sections and their uses,

you will need to know how to join these sections.

Mitre joints

Mitred bull joints are used to construct corners of sashes, flywire screens

and security screens. They are cut at 45 and are held together by a corner

stake internally.

Mitre cutting of corner joints offers a number of advantages, including

simplicity of preparation and neat appearance. The accuracy of the mitre

cut can only be achieved with first class sawing equipment including

facilities for clamping the workpiece during cutting. Some form of corner

stake is necessary to keep the joint in alignment.

Fitting mitre joints

Mitre joints can be secured a number of ways, including:

serrated stakes

pop rivets

dimpling

screws.

The serrated stake is designed to be a driven into each section without

distorting the walls. However, care must be taken when inserting the

corner stake into the frames as misalignment can result in dinting the

aluminium section. Screw or pop rivet fastening is necessary to secure the

joint.

Sometimes small projections are provided inside the frame section which

shear off as the stake is driven. Screw or rivet fastening completes the

joint.

In some cases dimpling is used to secure the joint. While this can be done

manually, a more positive result is achieved with a press operation. Stakes

for this method of jointing can be aluminium, nylon or a plastic material

specially designed with recesses that accept the dimpling and force the

connection into a tight joint.

The mitre joint can be secured by screws where flutes are provided in the

frame section. This is most effective where the frame is firmly set around

the base material, such as fitting glass in a sash. Where the frame is not

supported or restrained there is a tendency for the joint to ride up as the

screw is tightened and all clearances taken up, resulting in an untidy joint.Socket joint

This joint is made up of plain channel or box extrusions which have no

provisions for other forms of assembly. A spigot is fixed to one member

and the joint is completed by fixing the other member to the spigot.

Mortice and tenons

The members are machined to provide holes and tenons in corresponding

positions. The tenon is riveted over after assembly. This method is used to

frame sections under 50 mm and grille fabrication.

Screw and Spline joint

Screw grooves and self-tapping screws are most commonly used for

corner jointing and provide economical, secure and reliable fastening. The

advantages are that the joints can be assembled quickly and pulled up

tight. The end profiles are punched, milled or notched to provide a well matched

joint.

Besides normal strainless steel raised head screws, bolts and nuts, and a variety of self-tapping screws are commonly used in aluminium constructions. This type of screws are often very useful in assemblies with extruded profiles.

From left to right:

Sheet screw with fixed washer

Facade screw with sealing element

Self-locking screw with flange

Slotted round-head screw

Hexagonal-recess screw with shallow head

Cylindrical self-tapping screw with flange

Cross-head stud screw

Snap-in assembly

Aluminium products are designed and developed to finished product

standards. This means that any attachments or other sections or fittings

must use continuous extruded flutes without visible fixings. Designs are

such that the article snaps over a lug and clips into its final position.

More information regarding the joining of Alumimium can be found at: JoiningPreparing for joining

As previously explained, it is important you work in a safe environment

for the health and well being of everyone in your workplace. For this

reason it is essential to wear appropriate safety clothing and equipment.

You must follow all company requirements concerning protective

equipment. These requirements might include wearing:

safety boots

safety glasses

ear plugs or muffs

dust masks or respirators

gloves

overalls.

There are a number of different ways of preparing aluminium sections for

joining. They include:

cutting to length - Components must be cut accurately to length after

frame clearances have been allowed. drilling holes - Holes are accurately marked out to take assembly screws.

punching holes - Machines are set up to accurately punch holes for

assembly screws. This method is generally quicker than drilling. cutting for joint - Some sections may have to be cut specially prior to

jointing to allow for other components of a frame. For example, sashes

and doors to fit frames. trimming for fit. - Beads and adaptors may require

trimming prior to fitting.

Tools

The tools you use will depend on the job requirements and the process you

are using. Some of the tools you would use include:

measuring tape/rule, to measure aluminium sections to length prior

to cutting

mallets, to knock sections into place without damage

squares, to check angles

docking saw, to cut aluminium to length

clamps, to hold aluminium sections when using the docking saw

power drills, to be used together with the other power tools in the

preparation and fabrication processes

power routergrinder

air compressor and hoses

power leads.

Some of these more complex tools and equipment are pictured below.

Securing joins

Two of the more common joints used in fabrication are the screw joint and

the spigot joint.Screw joints are commonly used in frame fabrication, whilst spigot joints

are used in door and window fabrication.

Prior to assembly sealant is applied to the abutting surfaces of the joint.

This makes it waterproof.

Self-tapping stainless steel screws are used to avoid corrosion.

Before assembling section of a frame, you mustMeasure sections according to job requirements. Components must

be cut accurately to length after frame clearances have been

allowed.

Select the appropriate aluminium sections. Aluminium sections

cannot be forced to fit other sections If the sections do not fit

together as designed, bruising may appear.

Set out the aluminium sections. Setting out prior to cutting will

determine:

- cutting size of each section

- assembly sequence

- machine operations- jointing methods.Setting out prior to cutting components for fabrication is determined by

the different sections that will be used in its final construction.

You must consider the following factors that can determine section

lengths.

An assembly sequence is required so that you know which sections

are to run through and which sections run between. This will help

you to develop a cutting list.

Which jointing methods you use will determines how the

aluminium will be cut. This will also affect the cutting list.

How aluminium sections are cut to length and prepared for jointing.

This can alter the section lengths if they are filed or shaped to fit.

Remember to use your personal protective equipment when cutting and to

clean off any excess lubricant with a soft clean cloth.

Prepare the aluminium sections for jointing. Depending on the

jointing method, all surfaces must finish flush and without twist.

Jigs and templates will help you achieve this.

A jig can be made from an off-cut ofsection that is to butt into another section.

The off-cut is aligned into position and the holes are marked where the screws are to go.

Securing the joins

After joining sections, the next step is to make sure the joins do not

separate.

When drilling for self-tapping screws, care must be taken in selecting the

correct sized hole to ensure the screw has maximum holding strength.

If spigots on corner stakes are required to join frames together, a screw or

pop rivet fastening is necessary to secure the joint.

Where joints must be waterproof, as is the case in windows and doors, it is

good practice to apply joint sealant to the abutting surfaces just prior to

final assembly. It is important that the surfaces be thoroughly cleaned of

all dirt and cutting oil, as this will prevent the sealant from sticking.

Metal threads are used mainly for securing replaceable hardware items

such as:

locks

pull handles

door closers

hinges.

They are applied into tapped holes and provide excellent fixing where

permanence of thread is required for subsequent re-use.

Where heavy forces are likely to be encountered resulting in pullout

because of thread stripping, it is necessary to provide reinforcing backing

plates to increase the threaded thickness to a minimum of 6 mm.

Pop rivets enable you to attach two items together without having access to the back side of the item. For this reason, they are sometimes called "blind rivets".

POP - Rivets

They come in different lengths and diameters. Most rivets are aluminum, but it's possible to also get steel, stainless steel and other metal rivets.

A pop rivet has a pin up the centre that goes into the pop rivet gun. The gun grabs hold of the pin and tries to pull it through the rivet body. As this is done, the head of the center pin bends out the body and crimps it tight. When done, the center pin breaks off.

When using pop rivets, the rivet should be a snug fit in the hole through the material. The length of the rivet should be such that before crimping, it's sticking out the blind side about 6mm. If using rivets on soft material, you should use a washer on the blind side to spread out the load (there are special washers for this).

There are a range of different head types to suite most finishes. Aluminium heads can be annodised to match the finish on the aluminium section being used.

Steps involved in inserting pop rivets:

Pnuematic guns are available to assist the riveting process.

For more information relating to rivets go to: Blind POP RivetsCleaning tools

To maintain tools in their best condition, it is important that you clean

them after use. Dirty hand or power tools can affect the quality of the job.

Storing tools

As blades and cutters used to cut aluminium are usually tungsten-carbide,

it is important to store them safely as the slightest knock can damage teeth

and result in uneven cutting.

Cleaning the work area of all waste material

Rack longer off-cuts neatly and safely to prevent them toppling

over and causing a possible hazard.

All small off-cuts should be cleared from machines and

workbenches so the workplace is left clean and safe.

As aluminium can be recycled, all off-cuts should be placed in

containers labelled Aluminium Only.Serrated stake

Socket Joint

Mortise and tenon joints

Screw and spline

Snap in assemblies

Safety glasses

Hearing protection

No rings or watches

No loose cuffs

Steel capped work shoes

protected hair

When cutting aluminium always wear a full face shield

Aluminium, cut off saw with extension table and stops

Spring pins

Spigot

Door stile

Door rail

S.S. Screw

Electric drill

Off cut jig from sill or transom

Mullion piece

Seal the joint with silicone or other sealer before inserting the screws.

1. Select the right size drill bit and drill the hole

2. insert the rivet into the rivet gun.

3. insert rivet in hole making sure it penetrates both pieces.

4. squeeze the gun until the pin pops off.