Have anyone ever play a toy called Play-Doh? It is where you put a modeling compound (plasticine) into a toy machine and squeeze it into model like french fries (picture at right)? It is the very same concept here that is being used in aluminium extrusion. But instead of putting potatoes into the machine (hehe!), we are putting in aluminium alloys into a large extrusion machine to produce extruded aluminium.

Simple isn't it. Well it is easier say than done. Actually it is far more complicated than that. The process begins by heating the stock material. Then it is then loaded into the container in the press. A dummy block is placed behind it where the ram then presses on the material to push it out of the die. Afterward the extrusion is stretched in order to straighten it. If better properties are required then it may be heat treated or cold worked. There you have it.

So does this help you in understanding more about aluminium extrusion. If you got any question about it, please post a question in the comment and I'll gladly answer them for you.

Aluminium is the choice metal for making light weight parts of vehicles, aerospace and transport industries. Casting of liquid aluminium alloys into metal moulds utilizing systems like gravity, low pressure and high pressure die casting is an economical way of making difficult shapes which need minimum machining. Australia’s auto industry supports a large local die casting business, manufacturing parts that include cylinders, pistons and engine sumps etc.

Rising demand in world auto market for aluminium die cast parts is producing great opportunity and challenge for Australian business which wants to emerge as a global player. By setting partnerships between Nissan and Ford, CAST has developed and produced new and latest technology that has been benefiting our partner’s products. In turn these skills have created IP that is poised on the verge of commercialization.

To increase production of high pressure die casting by lessening its time cycle by 30%. The cycle time has been reduced by more than 20% on certain parts at two industry partner plants. The project involves identifying places where cycle time may be reduced, and doing it practically to prove the findings of research. This made it essential to involve shop floor staff to implement the changes needed in systems. These trails are generally in variation with day to day production and due to true co-operation of shop floor staff it become possible to achieve targets.

The third year of project has seen the true spirit of co-operation between researches and industrial partners in which latest research results got through simulated trails have been done practically on shop floor with help and support of Ford and Nissan staff. The changes once tested during trials have been incorporated in production systems giving benefits of reduced costs by reducing time of each part manufactured. An example of reduced time achieved is at Nissan on a gearbox side cover made in twin cavity die has given successful results after many months; from an initial cycle time of 75 seconds down to 60 seconds. While research at Ford on a changer housing casting, has been successfully implemented by lessening cycle time from 90 seconds to 74 seconds.

In future the reduction of time cycle will be tried for other parts as well.

Automatic fault detection in aluminium die casting:

This involves developing a system to detect surface and sub surface defects.

A fully automatic fault detecting machine named CAST vision has been produced and a prototype process is in place for extended in-plant on-line trials. This is the third year of this project and it is giving good results. The result of algorithm which was designed and developed in 2nd year has been put to test now. By prototyping the CAST team had designed and developed a working system CAST vision. This can discriminate between good and defective parts.

The prototype system has capacity to detect blocked holes on any of holes on this complex casting. Offline processes have also been readied which will detect hot tears and cold shuts on Ford’s structural sump casting.

Work at Nissan on their pump cover casting has led to a CAST vision type process for in-line fault detection. The process can take images and find certain types of defects on the surface part. This project has shown that advances in mechanical vision applied for finding faults of aluminium castings can be converted from project stage to a working prototype successfully. The next stage is take concepts from single stage to multistage processes capable to handle more complex shapes and surfaces. This result will become a strong contender for future commercialization.

More articles are available at http://www.article-ghost-writer.com & http://www.bhunit.co.in

Article Source: http://EzineArticles.com/?expert=Aman_Kumar

1. The site of the proposed conservatory.

2. Construction work begins. The trench is excavated to suit the relevant ground conditions, in this case, to a depth of 450mm (minimum depth) for the footings. The general ground level (within the area of the trench) is also reduced to a minimum of 300 mm below the DPC. Excavation exposes an underground pipe.

3. Concrete lintels should be placed to bridge the underground drainage pipe to prevent the pipe being crushed. Also additional steel reinforcement mesh introduced to the concrete foundation will provide additional support.

4. Stakes driven into the ground are set 450mm below DPC (Damp Proof Course) and 300mm below outside ground level. Concrete is then poured into the 450mm deep trench to a depth of 150mm.

5. The concrete is floated to form a level surface 450mm below the house DPC

6. The inner leaf of the cavity wall is built up to floor level, usually the house DPC.

7. Hardcore is laid to a minimum 100mm deep and compacted to form the base layer of the slab.

8. A blinding screed of sand 50mm thick is laid over the compacted hardcore layer to prevent any sharp stones puncturing the damp proof membrane (heavy duty plastic sheeting).

9. The damp proof membrane is laid over the sand blinding and lapped onto the inner leaf of brickwork

10. Optional floor insulation (50mm thick Styrofoam in this case) is placed upon the sheeting.

11. Concrete 100mm thick is laid to bring the slab up to the finished floor level which is then float finished to give a smooth finish for tiling or carpet finish

12. The outer leaf of the wall is built. In this case, artificial stone to match the house is used

13. The inner leaf of the cavity wall is built to complete the basework. The same material as the outer leaf has been used to provide a feature stone finish

14. The PVCu external cill is fitted to the dwarf wall and erection of the side frames begins.

15. On completion of the frames the structural aluminium eaves beam is fitted to the head of the frames.

16. The PVCu thermally clad aluminium glazing bars and ridge system are quickly assembled.

17. The polycarbonate glazing panels are installed (alternatively, double glazed units may be specified).

18. The side frames are glazed after the roof is complete

19. The ventilated aluminium ridge is ready to accept the clip fit PVCu internal cladding. Electrical cables may be concealed behind the cladding if a fan or lights are required.

20. The PVCu internal fascia is clipped onto the eaves beam to complete the internal finishing trims. Other internal work IS completed once the roof is on

21. The completed conservatory

Garden benches that are curved at the back and have a back rest are the ones known as curved garden benches. They are not only very comfortable and stylish, but are also highly attractive. Their designs usually depend on the materials being used in their manufacturing. They usually enhance the setting of the gardens, and the best part about them is that they can be left out in open all year through.

Most of the curved garden benches are made of metals as they are easily moulded into various shapes as compared to stone and other such hard materials. These metals include aluminium, wrought iron and brass among others. They can be placed anywhere in the garden as they not only provide comfortable seating options, but also look extremely beautiful in well maintained gardens. These can be placed next to ponds or in small hide- away place in ones garden. These curved garden benches help in adding to the beauty of the gardens because of their exquisite designs, shapes and sizes.

As a result of the materials used in the making of such curved garden benches, they require very little maintenance and are very easy to clean. Curved garden benches also last for very long because of the metals that go into their making. These metals make them weather resistant and also very durable and strong so that they can withstand large amounts of pressure.

The prices of curved garden benches depend on the kind of metal or other materials that are used for its making. They are slightly cheaper if they are made of aluminium or any other such material, but on being made with stone or concrete, the prices rise considerably. Prices also depend on the amount of handwork that goes into the making of one such curved bench. Benches with a lot of carvings are usually more expensive. Prices can range from $75-$250.

An important addition to any British back garden, the greenhouse is firmly established in the British way of life. It's probably the inclement weather that drives the british gardener 'inside'. If you are visiting this site then you are probably thinking about obtaining a new greenhouse. It is possible you don't know the type of greenhouse you need or even how to decide on the type of greenhouse. This site has a series of articles on many of the different things to consider when installing a greenhouse.

For example, you need to decide on size, shape, style, location, installation, maintenance, irrigation, heating and this is before you have grown anything. You can look at the different benefits of aluminium greenhouses, pvc-u greenhouses and wooden greenhouses -- we have discussed each one seperately. You mat wish for a standard greenhouse or choose a bespoke model. There is a lot to look into - viewing manufacturers sites can help to get a feel for what is available. However, don't be put off as with a little research and planning the whole process can be made much easier.

The benefits of a greenhouse would seem to be fairly obvious. They not only extend the growing season, but also allow you to grow more exotic plants. Even if you don't wish to recreate the 'Eden project' in your back garden, you can still be fairly ambitious with a very basic greenhouse. The downside may not be so apparent, but there is the constant battle against insects and disease. Also, the odd stray football to worry about. However, before too long you will be getting great enjoyment froim your greenhouse. Once in place a greenhouse makes a fantastic year round hobby and as each year goes by you will get more and more from your greenhouse.

Wooden Greenhouses are the choice for the traditionalist and the expert gardener. They are commonly made from Canadian Western Red Cedar, which is renowned for it's exceptional long life outdoors as a result of it's effective rot resistance. Wooden greenhouses are the traditional style of greenhouse before the aluminium greenhouses and plastic greenhouses became more popular towards the end of the last century.

A timber greenhouse will obviously blend in naturally with your garden and will become an integral feature rather than something of an eyesore which you wish to hide away. Timber is also the choice of the expert gardener and it is generally agreed that it is the best material for a greenhouse. One of the main reasons is that the red cedar greenhouses are much better at maintaining a constant temperature than aluminium ones, which obviously leads to a healthier and more natural environment. An experienced gardener will know the benefit of having things to hand and a wooden frame will allow the gardener to easily fix hooks and shelves exactly where he wants them, so those all important greenhouse accessories are to hand. The wooden frame also makes it easier to fix an extra layer of insulation of plastic bubble sheeting, such severe weather conditions prevail.

The best time to add a protective coat to a timber frame is before winter sets in. Choose a good day in the late autumn and give the frame any attention it needs. Look for any wear and tear and treat it immediately. Most good timber frames come with a ten year gaurantee, but don't wait for 10 years before checking.

When backpacking or camping you will need a good set of cooking gear. Cooking in the outdoors is a lot harder than cooking at home in a nicely furnished kitchen. So the Backpacking Cookware that you will use outdoors will be quite a bit different from what you use at home.

To make your choice of the right Backpacking Cookware to take, you will first need to know what is available on the market for you to buy. Below is a list of the most popular types, along with their good and bad points.

ALUMINIUM.

This used to be the first choice of backpackers, lightweight campers, and hikers because it is very light. However it is not as strong or durable as some of the other materials used for cookware. Food tends to stick to it making it difficult to clean in an outdoor situation. Also Aluminium has been linked to some health problems, as it tends to breakdown over time and can contaminate the food cooked in it. Having said this, I have used Aluminium for many years with no harmful effects. (I would still rate it as a good choice as you will properly only be using it for a few weeks of any one year.)

STAINLESS STEEL.

The main drawback here is the weight, as it is a lot heavier than other types of backpacking cookware. Also it is not the best at distributing the heat evenly and the food must be stirred or moved constantly to ensure even cooking. Stainless steel is very tough and strong though, and will stand up to almost anything that can happen to it in the outdoors.

LIGHTWEIGHT STAINLESS STEEL.

The introduction of new technology has come up with a lighter weight stainless steel, it has all the durability and strength, but as its name suggests is considerably lighter.

TITANIUM.

The modern first choice. It is very light, it is also very durable and tough, and a better distributor of heat when compared to stainless steel. A good set of Titanium cookware will last a very long time. The only downside is its price, as it can be expensive when compared with the other materials.

A FEW BASIC TIPS.

(1)Are you choosing a solo backpacking set of cookware, or do you want a kit that will do for two or more people?
(2)Pots with a slightly rounded bottom will distribute heat better than flat bottomed ones.
(3)Make sure the pots have a good fitting lid, as this will cut down on your cooking times, saving you fuel.
(4)Try to buy proper Backpacking Cookware as opposed to ordinary cookware, as the former should have folding or detachable handles to make packing it into your backpack much easier.

Hard Turning Definition

David Richards define “Hard Turning “ as machining hardened steels above 40 HRc, not hard in terms of “difficult”. Alloy Steels with a hardness below 40 HRc are not generally machined using CBN inserts because other tool materials work as well or better and cost less. Soft materials often stick to PCBN cutting tools causing “build up” on the cutting edge. This results in poor surface finish and tool life. The geometry of PCBN tools used for machining hardened steel is very blunt with no chip groove geometry to provide swarf control, not ideal for machining soft steels. However, some steels with a high alloy content and 30+ HRc are successfully finish machined with DR-50 because nothing else will do the job. If there is no adhesion, reliable size control and consistent surface finish can more than justify the cost of the tools.

Aluminum Alloy Machining

Aluminium alloys cannot be machined with CBN inserts. PCBN has a trace content of Aluminium nitride. Aluminium builds up on the cutting edge very quickly causing rapid tool wear and poor surface finish.

Cast Iron Machining

Cast iron and Iron based hard facing alloys with a significant ferrite content are not machined with CBN inserts. The soft gooey ferrite sticks to the CBN insert cutting edge causing rapid wear and poor surface finish.

D2 Machining

Interrupted cutting D2 tool steel is very difficult and unpredictable. D2 contains up to 14% Chromium and was designed to be used at 50-56 HRc. If the material is hardened to +60 HRc and not tempered very carefully, Chromium Carbide formation at the grain boundaries makes the material impossible to machine with interrupted cutting.

HSS Machining

Interrupted cutting of High Speed Steel – HSS is temperature resistant and does not soften in the shear zone. Interrupted cutting Nitrided steel is difficult. When continuous cutting, the super-hard surface is machined away by a part of the cutting edge that is not controlling surface finish and size. When interrupted cutting, the entire cutting edge impacts with a superhard surface resulting in poor tool life.

Hard Facing Alloy Machining

Hard facing alloys – Stellite (Cobalt/Chrome Alloys)and Colmonoy (Nickel/Chrome alloy) with more than 20% Chrome is not practically machined with PCBN – Tool life is too short. Chromium cannot be machined using PCBN. PCBN can be used to remove hard Chromed plated surfaces and expose a hardened steel base material, but it is not possible to machine within the Chrome.

High Temperture Alloy Machining

Machining high temperature alloys – Inconel, Hastalloy, Waspalloy, Titanium, Nimonics etc are not machined with PCBN. Tool life is negligible due to chemical affinity.