Which process should be used for leak proof castings?

Aluminium casting processes can be used for providing strong Helium Leak Proof and Water tight parts. There are various processes which if used correctly can produce these parts. The process of Gravity Die Casting (Permanent Mold Casting) if used with correct gating can be a very good cost effective method for producing leak proof castings. Moreover, traditionally Low Pressure Permanent Mold Casting (Low pressure Die Casting) is a process which is employed to produce high strength leak proof parts. Pressure Die Casting parts are not conventionally leak proof – unless of course impeccable gating is used along with remedies for air entrapment are taken care of in the die.

Aluminum Die Casting

Aluminum Die Casting Parts vs Plastic Parts

Aluminum Die Casting Parts vs Plastic Parts

Aluminum Die Casting Parts	Plastic Parts
Aluminium parts are more heat resistant than plastic	Less heat resistant as compared to Aluminium
Requires an iron mould	Requires an iron mould
Expensive tooling as compared to sand	Expensive tooling comparable to Aluminium casting
Has to be colour coated to achieve required colour	Required colour can be achieved from raw material selection
Has substantially higher strength than Plastic	Has lesser strength compared to Aluminium
Near net finish possible	Near net finish possible
Melting is expensive since higher temperature of upto 650-700 deg C required	Depending on material melting temperature varies but is lower than Aluminium
Aluminium is easily recyclable and bio degradable	Plastic is recyclable but not easily biodegradable
Weight of Aluminium (density avg 2700 m^3/kg) is more compared to plastic	Weight of plastic (average density 1500 m^3/kg )is less
Aluminium parts can be threaded or inserts can be provided	Plastic parts can also be threaded but better option is to use inserts

What is Low Pressure Die Casting / Low Pressure Permanent Mold Casting?

Low pressure die casting (LPDC) is a relatively newer process in which metal enters into a die (usually of steel, SG iron, Cast iron) in a very controlled and turbulence free manner.

An air tight furnace is kept underneath the metallic mold, and under air pressure (upto 25 psi - depending on the size of the casting)

Base Tank

The liquid metal rises up from the furnace into the metallic die on top of the furnace.

A very good control of the molten metal is achieved in this process since the speed of filling of the mould cavity is controlled resulting in reliable, pressure tight and homogenous parts.

Experimentally produced pars also show increased mechanical properties compared to other 

processes.

Flyer for Jute Industry

Various critical components in the industry are made through this process for eg: Engine blocks of automobiles,

Cylinder heads, alloy wheels, critical electrical components, special purpose pressure tight parts to name a few.

How Can Customers Benefit from us for Faster to Market Products?

It is imperative to decrease the time to market (lead times) for the development of parts and products to stay competitive in the 21st century.

This creates a need for the design team to consult at regular intervals of design stages with the die casting manufacturer.

Design For Manufacturability (DFM) becomes absolutely necessary when the designers are trying to reduce cost, decrease time to market and have other considerations to decrease weight of parts.

At Dr. Dinesh & Ramesh Engineers Pvt. Ltd. - We thoroughly understand the specific requirements of function and form of the customer before selecting a process, parting lines of parts, position of logos and contraction allowances. We have recommended and recommend to designers of our customers to modify parts for ease of manufacturability and faster development times. The designer and casting manufacturer should develop parts with mutual consultation and respect for each other’s expertise.

How Does Aluminium Sand Casting compare to Aluminium Permanent Mold Casting (Gravity Die Casting)?

Sand casting is an older process of Aluminium castings which is used for smaller production runs. Permanent mold casting (Gravity Die Casting) is a newer process for medium to high production runs, higher dimensional accuracy and better surface finish.

Below table illustrated both processes

	Sand Casting	Gravity Die Casting
Dimensional accuracy	Fair	Good
Tooling cost	Excellent	Good
Production runs	Poor	Good
Surface finish	Fair	Good
Pressure tightness	Good	Good
Castable alloys	Excellent	Good
Strength	Good	Good
Per piece cost	Fair	Good
Size limitation	Excellent	Good

What are consideration when using Die Casting Alloys?

Many things need to consideration while using Die Casting Alloys

Depending on the end use of the product - a die casting expert can suggest an Aluminium alloy which can be utilized for the production of parts.

Die Casting Alloys

Strength, fluidity, grain structure, corrosion resistance all depend on the alloy to be selected. The Aluminium casting expert can best suggest which alloy to use for a particular application.

For certain alloys the strength, elongation, hardness can increase substantially with correct alloy and correct heat treatment process.