Aluminium Pressure Die Casting (Upto 0.75 kg)

Introduction

Though tremendous technological advancements in the metal casting industry have taken place in recent years, the foundry industry faces increasing demands to achieve higher productivity at minimum cost, even while producing high quality cast components of intricate shapes. By proper selection of a casting technique with careful foundry and metallurgical controls, castings of high quality are being commercially manufactured. Amongst a large number of foundry techniques one is low and high pressure die-casting. It has been developed and industrially employed to produce castings of near-net shape components. The near net shape cast parts are famous for their fine details, good surface conditions, complex shapes and economy. Under the present scenario of industrial development, metal casting has moved from an art and craft industry to the industry based on science and technology. The pressure die casting manufacturing processes have been systematically developed so that structure may be controlled and quality may be assured. Die casting provides the foundry man with one of the fastest means of producing castings with a much higher degree of accuracy than that normally obtained by conventional sand casting. In fact, this method is unexcelled for mass production work as numerous castings can be produced very rapidly at low cost. The castings can be made to very close tolerances and with a fine surface finish.

Pressure die casting in aluminium alloy offers means for very rapid production of engineering and other related components even or intricate design. The technique has obvious advantages when a component is required in large quantities. However, for engineering components such as those required for aeronautic space, defence and automotive applications, mechanical properties and durability are of primary importance. It is therefore essential that the best features of design should be employed and optimum casting technique with minimum cost be adopted. Pressure die cast products are used in the form of components of various electrical, electronic, mechanical instruments and appliances used in domestic as well as industrial fields.

Market Potential

The popularity of pressure die cast aluminium alloy components arises from the following advantages it offers as compared to other methods of castings:

– High Productivity
– Good as cast surface finish and appearance.
– Compact casting–sound strength.
– Do not require further machining.
– Can be cast within close dimensional tolerance.
– Very thin section, can be cast with ease.
– Metal wastage in the casting is low.
– Rejection due to casting defects is low.

Demand mainly arises from the sources like Defence, Telephone industry, Automobile components and fittings, Electrical appliances, Electronic components, Builders hardwares and fittings etc. Demand in these areas again depends upon the primary market, replacement market and substitution market.

– The Primary Market is expected to continue as the leading market and, with the trend of demand growth, to cater to the requirement of more and more new industries coming up in the above areas of consumption. The replacement market is also likely to expand with more marketability of new products.

– There are very few units in the small scale sector producing pressure die cast components. Hence there is good scope for setting up this industry.

Basis and Presumptions

1. The Scheme has been prepared on the basis of 75% efficiency on three shift basis of 8 hours' duration considering working days 300 working days in a year.

2. The rate of interest in the scheme has been worked out on the basis of 12% upon an average. However, this figure is likely to vary depending upon the financial outlay of the project as well as location of the unit.

3. The break–even point in the scheme has been calculated on the 80% capacity utilization basis.

4. The cost of machinery and equipment as indicated are approximate which are ruling locally at the time of preparation of the scheme. When a tailor cut project is prepared, necessary changes are to be made.

5. The rates quoted in respect of salaries and wages for workers and others are the minimum rates in the state/neighbouring states.

6. Margin money required is minimum 30% of Projected investment i.e Rs. 16.75 lakhs. However, it may differ from Project to Project and type of entrepreneurs such as Women, SC/ST, Physically Handicapped etc.

7. Pay back period of the Project: After the initial gestation period of one and half years it will require approximately 5 years to pay back the loans.

8. Profile life is estimated to be 10 years. The project should be reviewed every 3 to 4 years for modernisation of the plant and machinery, technology etc. so that its life is prolonged.

Implementation Schedule

Technical Aspects
Process of Manufacture

Because of its high melting point, aluminium silicon alloy is die cast in cold chamber pressure die casting machine. In pressure die casting the molten metal is introduced under pressure into a metallic die and allowed to solidify to produce near-net-shapes. Two types of die casting machines known as cold chamber and hot chamber are usually used. The production rate depends on casting thickness, specified properties of the cast metal and the complexity of the cast shape. This technique produces castings of very good surface finish with high dimensional accuracy. The process provides high yield due to absence of riser and feeding system. Production rate is high and the casting generates more metallurgical integrity. Finer grains and absence of porosity make the casting mechanically compact. Casting size, weight, design and melting point of cast metal limit the use of the process. Cost of die confines the process only to relatively small parts.

The cold chamber machine is used for the alloy which has higher melting point than the zinc-alloy. Higher pressure is applied, so lower molten metal feeding temperature is used. Casting traps lesser amount of air as compared to the air trapped in hot chamber machine. In pressure die casting, die temperature, molten metal pouring temperature, injection pressure and speed are optimised for a special casting.

Metal for a single shot is loaded into a cylindrical chamber through a pouring aperture. A piston then forces the metal into the die, the entire operation being completed in a few seconds, so that iron contamination is virtually eliminated. Using this technique much higher injection pressure in the range of 70–140 Mpa is feasible, enabling lower metal to be employed and greater intricacy achieved. The castings are less prone to entrapped air and a higher standard of soundness ensures from the smaller amount of liquid and solidification shrinkage occurring within the die.

In cold chamber operations the molten metals is usually maintained at constant temperature in an adjacent holding furnace, where transfer of successive shots to the machine chambers can be accomplished manually. Holding furnaces may be electrically heated types or the one using immersion heating types or the one using immersion heating device, which has a close control over the molten metal.

Chemical Compositions -% of

- The molten metal is degassed by chlorine or hexachloroethane followed by modification with suitable modifier. For thinner sections the working temperature of the molten metal should be 680 deg. C to 690 deg C and for thicker sections this should be between 650 deg. C to 680 deg C.

– The die temperature should be maintained so that castings of good quality are produced.

– The die cast components are subjected to fettling operation for removal of getting system and fins, if any.

Quality Control and Standards

Alloys suitable for pressure die casting and their chemical composition are given below. Alloys 4420 or LM-24M, 4520 or LM-2M, 4600 or LM-20M are widely used alloys for general engineering work and are suitable for Pressure diecasting.

These alloys have excellent fluidity good corrosion resistance, medium strength and can be cast in intricate shapes. The die cast component should be free from blowholes and Pinholes porosity, shrinkage, cold shut etc. They should be free from dimensional inaccuracies. No patching or welding shall be allowed to cancel or rectify any defects.

Production Capacity

Motive Power (per month)

Total motive power requirement = 17550 kW

Pollution Control

The industry does not create extensive pollution hazard. The workshop should be well ventilated, properly lighted and fitted with exhaust fans.

Energy Conservation

There is little scope for energy conservation in this industry except in the melting practice where the furnace should be properly insulated to reduce radiation loss and should be fitted with automatic pyrometric control to maintain the furnace at the proper temperature.

Financial Aspects

A. Fixed Capital (per month)

(ii) Machinery and Equipments

(a) Production Unit

(iii) Pre-operative Expenses

B. Working Capital (per month)

C. Total Capital Investment

Financial Analysis

(6) Break-even Point

2. M/s. Indo Japanese Proto Type
Training Centre
Baltikuri, Dasnagar,
Howrah, Kolkata.

3. M/s. Hindustan Machine Tools
Jeevan Tara Building,
Parliament Street,
New Delhi-110001

4. M/s. Wesman Engineering Co. (P) Ltd.
B-99 Mayapuri Indl. Area,
New Delhi

5. M/s. Batliboy and Co. Ltd.
Jeevan Vihar,
Parliament Street,
New Delhi-110001

6. M/s. Perfect Machine Tools,
44E, Connaught Circus,
New Delhi-110001.

7. M/s. Pioneer Equipment Co. (P) Ltd.
36/8 Nizammudin West,
New Delhi.

Addresses of Raw Material Suppliers

1. M/s. Hindustan Aluminium Co.
United Commercial Bank
Building,
Parliament Street,
New Delhi-110001

2. M/s. Indian Aluminium Co.
Bank Building,
Parliament Street,
New Delhi-110001

3. Local Market

Contact for more information:

Information Manager
TIMEIS Project
E-mail: timeis@ficci.com