powder metal-Introduction to Metal Injection Molding

Metal injection sintered metalmolding is a technique of making metallic parts， which makes use of the process of powder metallurgy。 Though the process uses metals in powdered form， it is unlike the usual powder metal dispensation。 Metal injection molding requires metallic powders to be ten to hundred times smaller in size， compared to powder metal processes。 The final product in case of metal injection molding has a higher density。 The features and benefits of metal injection molding are comparable to that of rubber and plastic molding， but the final product you get is much stronger。 This technique is often used for producing surgical tools， components of firearms， hard disk drives for computers， electrical connectors and automotive locks。

Process of Metal Injection Molding

This process comprises of five steps， which include the mixing， the injection molding， the de-binding， the sintering and the part finishing。 This process is becoming more popular by the day。

The first step involves the mixing of metallic powders， which are known to be strong and have inherent characteristics， like high impact strength， wear resistance， hardness， machine ability and temperature characteristics。 The binding agent is also added at this stage。 The purpose of mixing different metallic powders is to derive a metallic compound that has all the positive characteristics of different metals， while eliminating their respective weaknesses。

As a result of the mixing of powders， we get what is known as feedstock， which is injected into the desired molds， as it is done in the case of rubber or plastic moldings。 The component that we get as a result of molding is called as green part。

The de-binding stage involves the immersion of the green part in water baths to get rid of the binder that has gone in the part matrix。 During cross linking， the de-bounded green component is subjected to ultraviolet light， resulting to a thermo setting of the binding agents that were used among the metallic powders。

After the binding stage is over， the component is heated to a temperature of above 2000 º Fahrenheit in a furnace。 This process is known as sintering， and it fuses the metallic parts to give them a solid shape。 At the end， the sinteredsintered metal components are delivered to the finishing stage for eliminating the imperfections and burrs。 The component is now ready for dispatch。

powder metal-Go Speedy With Selective Laser Sintering

Machine maintenapowder metalnce， oiling， operating woes and drones of a factory！ Well， these words may be frustrating for those who are associated with it。 Stop worrying about the same and welcome to a new age of SLS that means selective laser sintering。 So what is this new type of technology? It is a very simple processsintered metal。 In the process of SLS a very high powered laser acts on a variety of powdered materials like metal or glass and forms it into a 3D object as defined by a computer aided design。 So basically， this process involves a high powered laser changing the state of certain materials to form an object。

And how does it work? How does it help? Let us take it one step at a time。

Step 1: Getting ready for selective laser sintering

The first step would involve getting together in one place all the material required。 The material is limited and basically involves:
1。powder metal Powder materials that have been chosen from a wide variety found commercially - these could include glass， polymers， metals and green sand。
2。 A SLS system。

Step 2: Changing forms
In the second step， a computer-aided design is worked on as a model for the finished product。 The laser part of the selective laser sintering system has a powder bed where the powder materials are layered for the laser to act on。 The laser then uses the 3D description provided to it to scan cross-sections on the powder bed of the design required and accordingly works on fusing the powder materials into parts of objects。 It works on one cross section at a time and uses one layer at a time of the powder bed。 This is taken care of when a new layer is added to the top of the bed after each layer used。

The layer of material is made into a mass by either melting it fully or partially， or sintering it in the liquid phase。

Advantages of selective laser sintering
As compared to conventional methods of manufacturing， selective laser sintering can achieve even up to 100% density depending on the materials used with comparable material properties。 Also， since a large number of parts can be filled into a powder bed， the productivity is very high。

SLS is an additive manufacturing。 However， as compared to other additive manufacturing methods， selective laser sintering can produce using a very wide range of powder materials。 Also， as opposed to other kinds of additive manufacturing procedures， selective laser sintering systems are free from extra support structures as its structure is built to have it surrounded by unsintered powder all the time。

SLS systems are also able to easily manufacture complex geometrics based just on computer aided design。

Some lesser-known facts
Although this type of sintering is used widely in manufacturing， few know that its use is rapidly increasing in thesintered metal area of art。

In 1979， R。F。 Householder patented a system much like selective laser sintering but this was not commercialized。 In the 1980s， Dr。 Carl Deckard of the University of Texas at Austin， under a sponsorship from DARPA， developed and patented the selective laser sintering system and it then became commercialized。