MIM & PM DESIGN RESEARCH

Guided by a enquiry we have started this research as a concept work .

Shown below are the process parameters , material considerations, design markets,product research and status knowhow on growth of the industry.

The subject has been divided accordingly into several sections and details are linked.

(1) MIM process considerations overview

(2) Technology growth and maturity sans process history

(3) PM and ceramic injection moulding as sister processes

Metal Injection Moulding (MIM) is a manufacturing process that involves blending metal or ceramic powders by mixing them with polymer binders to create a blended rawmaterial which can be processed in traditional injection moulding presses. This Rawmaterial is then used to injection mould greenware which after sintering become high finish precision components.

Complex part features and forms that were difficult to machine and produce by traditional casting of gravity, pressure diecasting or investment casting have now a new answer in MIM process as in short gestation periods complex parts at fractional costs are possible. Intricate part detailing and threaded metal parts are now a thing of past as it can be easily incorporated in to the design. Even complex textures and surface effect , embossed brand logos, thin features on exterior and interior which are not possible in traditional casting are very easy in MIM process.

Considerable savings in lead times and quick turnaround and easy proessing are the order of the day with MIM giving cost savings from 30-40 percent on large volume complex small components. This results in better functionality and better utility to the end user.

The main initial phase of the operation involves selecting the right metal mix for the product application. The metal powder of 20 microns or so are mixed or blended with a variety of thermoplastic binders depending on the part details. The tooling usually is similar to injection mold tooling and the htermoplastic metal blend which is called the feedstock is fed to the hopper of the moulding machine. Parts that are demolded are called green compoenents.

The next stage involves debinding. The moulded green components are loaded into a thermal debinding oven where some of the binders are evaporated to obtain a brown component.

Next and final stage involves SIntering operation performed in a controlled atmosphere. Temperature of teh oven are controlled to be just below the melting point of the metal composite allowing menisci to be fomed in the particles. Controlled uniform shrinkage upto 20 percent occurs at this stage and the component densifies to its final shape , size -dimensions and tolerance parameters. After the sintering process the white final product has al the features and technical charecteristics of a wrought material. The parts can be heat treated, welded, polished and plated according to the final finish required by the application.

MIM components are available in various materials including:

The density and performance of the MIM products are comparable to those of cast and wrought components. Due to the nature of the process there will be some porosity left in the compnent after the sintering stage , However the proosity left will be very fine and isolated.

Major application market and sectors include: Medical, Defense hardware,Aerospace, Industrial, Automotive, Telecommunications, Gas analysis, Instrumentation, Agriculture and consumer durables.

MIM ADVANTAGES AND DESIGN CASE ANALYSIS

Please note this is compiled from Net referneces and all info are of therespective of the producers and the info is being used only for Research and as a case study...

Some of the common components in each segment include

Metal Injection Molding (MIM) is often compared to press and sinter powder metallurgy, P/M, and die casting. MIM is a unique and superior process in several ways:

Fibre optic alignment system

Medical Specialties Components

INTELLIGENT SOLUTION TO MOLDING

DESIGN FREEDOM

With MIM, there are virtually no design restrictions or compromising. MIM is an ideal production process for making:
tight tolerance parts
complex shaped parts
customized metal alloys
The Part You Want is the Part You Get…

MIM DELIVERS HIGH-DENSITY FINISHED
PARTS FOR STRENGTH
AND EXACTING TOLERANCES

MIM is an exacting technology. Tolerances of 0.5% of the dimension are commonplace. INJECTAMAX has produced over 20 million miniature parts with a tolerance of +.0005“/-.0007“.
��MIM can exceed densities of 99.0%.
��Compared to other methods, MIM produces smoother surface finishes-right from the mold cavity.
��MIM components can be plated and heat-treated just like wrought alloys.
��MIM parts also demonstrate hermetic integrity and can be used even in high-vacuum applications

THE METAL INJECTION MOLDING ADVANTAGE VS. MACHINING

TYPICAL PARTS & LIMITATIONS
Myriad of metal parts which are made by conventional methods have a high level of material waste, have high tooling costs, have design limitations and not good for intricate shapes.

MIM ADVANTAGE
��virtually no material waste
��short cycle time
��high repeatability
��excellent for intricate parts

THE METAL INJECTION MOLDING ADVANTAGE VS. CONVENTIONAL P.M.

Even MIM has one step advantage than PM parts which are used for gears, cams, sprockets and machinery components. Even in traditional PM complex shapes are difficult and this is clerly an advantage in MIM. Very high densities of 98 pecent are possible which again is a advantage.

MIM ADVANTAGE
��excellent for very intricate shapes
��very high densities
��cost-effective

THE METAL INJECTION MOLDING ADVANTAGE VS. INVESTMENT CAST

When you compare the Investment casting components Vs MIM the game goes one further. The typical components of the process include firearms, medical, defense , aerspace and automotive. It is slow and labor intensive. Part variations are difficult to control.Many secondary operations and expensive.

MIM ADVANTAGE
��lower cost
��short production cycles
��high repeatability
��excellent surface finish
��minimal, if any secondary ops

THE METAL INJECTION MOLDING ADVANTAGE VS. DIE CASTING

TYPICAL PARTS & LIMITATIONS

The conventional presuure diecasting and other metal casting process are used for firearms, tool assemblies, appliances and industrial components. They do have poor mechanical properties, rough finishes, partswith no stainless steel.

MIM ADVANTAGE
��excellent mechanical properties
��wide range of materials
��high repeatability

PROCESS TOLERANCES

The following tolerances (inches) are considered typical; tighter tolerances may require secondary machining operations.
Linear Dimensions:1.00 –1.25±.005
.75 –1.00±.004
.50 –.75±.003
.25 –.50±.002
.10 –.25±.001
.00 –.10±.0005
Surface Finish:40√As-sintered
16-32√With vibratory deburr/burnish and/or bead-blast
Flatness:.002/inch As-sintered.

METAL INJECTION MOULDING AT MICRO SCALE

This is one emerging new technolgy for moulding parts of small mechanical elemenst like gears to connecting elements in robotics to medical implant devices segment that is finding new uses for MIM processes.

MIM DESIGN GUIDE

DESIGN CONSIDERATION FOR PARTS

LINKS

CASE STUDIES and Products