MICRO MOLDING&MICRO MILLING7ME6.1A- Part II

Er. Mohit OstwalAssistant ProfessorDepartment of Mechanical EngineeringJodhpur Institute of Engineering and Technology- Coed, Jodhpur

What is Micromolding?

• Micromolding is defined as a very unique Injection Molding process requiring specialized molding machine capable of delivering high injection speed , high injection pressure, precise shot control, uniform melt temperature and ultra fine resolution using servo-electric drives and sophisticated controls.

Micromolding Features• Part weight… 0.1 to 0.001 gram

• Part size….0.100 in. diameter

• Specialized machines

• Intricate tooling

• Specialized part extraction

• Micromolding Technical expertise

• Microscope to see part geometry

Micro Molding Process

Micro Molding Processes

• Injection Molding Process

Micro Molding Processes

• Hot Embossing

Micro Molding Processes

• LASER assisted Embossing

Micro Molding Processes

Micro Molding Processes

Micro Molding Tools

• Micro structured mold inserts and tools

• Requirements of Mold inserts:-• Friction on sidewalls of microstructure – demolding

• Small inclination angle

• Tools and ejection system – metal processing• Mechanical micromachining

• Laser structuring

• EDM

• Lithographic : X-rays/UV rays

• Electroplating- for plastics and silicon etc. materials

Micro Mold Design

• Demolding - wear and tear of mold inserts

• Inclination angle of 2⁰ reduces demolding forces – important than roughness of sidewalls.

• Demolding forces – shrinkage of polymers

• Delicate microstructures, such as pins with high aspect ratios, can be protected against shearing forces resulting from shrinkage and mold filling by neighboring auxiliary structures that are stable enough to withstand these forces.

• If a mold insert is covered with areas microstructures of different height, or varying density, then these areas should be arranged symmetrically on the mold insert.

• In this way, tilting of the mold insert during molding is avoided.

Application

Application

Application

Application

Application

Application

Market for micromolding

Limitations for micromolding

• Structures of only few tens of nanometers in size are replicated very well.

• Limitations in achieving high aspect ratios of columns, grooves, walls etc.

• De-molding of microstructure.

• FEM calculations are only for mold filling but recently FEM calculations for demolding are available.

MICRO MILLING

Micro Milling

• Characteristics features and applications

Micro Milling

• Characteristics features and applications

• Complex 3-D mold cavities, chemical micro-reactors, fluidic parts, flow passages for micro compact heat exchangers, Lithography method complement.

• Micro-column arrays can be produced.

• Single crystal diamond – CER of 50nm- non ferrous – Brass, Al, Cu, electroless nickle.

• Tungsten Carbide tools – small CER – Rz<0.8μm.

• This method allows us to produce V-shaped grooves with high shape accuracy without burrs and surface roughness of 48 nm (Rz).

Micro Milling

• Micromills and tooling systems

• Diamond tools – limited to non ferrous

• Tungsten Carbide tool – grain size smaller than 600 nm.

Micro Milling

• Micromills and tooling systems

Micro Milling

• Machine Tools for Micro milling

• High speed machining – 40,000 to 50,000 rpm – CAM programming.

• Stable Spindle – minimize vibration and thermal expansion.- small vibrations are amplified relative to tool diameter as it is reduced.

• CNC automated milling center – Ultra compact CNC mill.

• Direct change type spindle.

• Smart Machines – CNC operated.

Micro Milling

• Machine Tools for Micro milling

Micro Milling

ALL THE BEST