Metal Injection Molding vs Liquidmetal

Powder Metal Injection Molding

Powder Metal Injection Molding (PMIM or MIM) is used for steel alloys with high melting temperatures. A feed stock of the alloy is made into a fine powder and mixed with a polymer powder. A continuous mass of this mixture is conveyed with a rotating screw through a heated barrel.

The polymer is melted and acts as a carrier for the metal powder to be injection molded. A metering plunger presses the necessary material into a steel mold. The result is a metal part containing 20% polymer.

The polymer is removed from the molded part with a thermal/chemical process called debinding. After that, the porous metal part is compacted into a solid with a long heating process called sintering.

Metal Injection Molding

Liquidmetal Process

Amorphous Metal Molding uses a Non-ferrous alloy designed to have an amorphous atomic structure in a solid state. Small batches of feedstock are melted in a vacuum chamber to avoid contamination from Oxygen. The melted alloy is poured into the shot sleeve where a plunger pushes the material into a steel mold.

The Liquidmetal part comes out of the mold to net shape, great precision, and with full physical properties. Secondary processes to remove the part from the runner and overflows are necessary.

Amorphous Metal Molding

Material Properties​

A molding process can influence the material properties of a part due to the resulting porosity or grain structure, but the main contributor to the properties is the type of material that can be used in a particular process. The melting temperature of a material and the final part geometry will dictate which molding process to use.

MIM

VS

Liquidmetal

MIM

VS

Liquidmetal

MIM

VS

Liquidmetal

730-1090 (106-158)

Liquidmetal

Yield Strength
Mpa (ksi)

1250 (181)

liquidmeal

.44
Standard Elasticity

liquidmetal

% Strain

1.6
High Elasticity

liquidmeal

285-323 (285-320)
Improve with Heat-Treating

Liquidmetal

Hardness
HB (Vickers)

460 (500)
No Heat-Treating Available

liquidmeal

0 to < 500 hours salt spray
(Dependent on alloy)

Liquidmetal

Corrosion
Resistance

> 500 hours salt spray

liquidmeal

Molding Design Considerations

Parameters such as part geometry and size are dependent on the process used to make the part. Review the comparison of how these two manufacturing processes affect the capabilities.

MIM

VS

Liquidmetal

MIM

VS

Liquidmetal

MIM

VS

Liquidmetal

Complex Contoured Geometries
Limits on size and wall section

Liquidmetal

Design
Flexibility

Complex Contoured Geometries
Limits on size and wall section

Liquidmetal

+/- 0.075 mm

liquidmetal

Dimensional
Tolerances

+/- .02mm (critical dim)
+/- .05mm (standard)

liquidmeal

Draft preferred
Zero draft possible

Liquidmetal

Part Draft
Requirements

3 degrees internal features
1 degree external features

liquidmetal

< 1g to 100g

liquidmetal

Part Size

< 1g to 450g

Liquidmetal

0.08 – 1.1 Ra μm

Liquidmetal

Surface
Finish

0.05 – 0.35 Ra μm

liquidmeal

0.30 mm

Liquidmetal

Min Wall
Thickness

0.3 mm

Liquidmetal

6 mm

Liquidmetal

Max Wall
Thickness

3.5 mm

liquidmetal

Mold Process Considerations

It is advantageous to reduce the number of manufacturing post processes required to produce a finished part. This will reduce development time, and maximize yield rates once in production.

Liquidmetal’s net shape molding allows you to check critical dimensions right out of the mold. A MIM part cannot be measured until after several post processes. This can result in substantial scrap and time lost if there was a problem upstream. These manufacturing trade-offs may be offset by part cost and the speed at which you can make parts in high volume.

MIM

VS

Liquidmetal

MIM

VS

Liquidmetal

MIM

VS

Liquidmetal

Medium to Ultra-high

liquidmeal

Mass
Production

Medium to High

Liquidmetal

Ultra-low to Low
< $0.10 to $5.00

liquidmeal

Part
Costs

Low to Average
$1.00 to $20.00

Liquidmetal

Many alloys and ceramics

liquidmeal

Alloy
Alternatives

Amorphous alloys only

liquidmetal

Days

liquidmetal

Process
Qualification

Minutes

liquidmeal

High, $30K to $100K

liquidmetal

Tooling
Costs

High, $30K to $100K

liquidmetal

Molding Process Advantages and Disadvantages

The Liquidmetal molding process produces an amorphous metal part with high strength, high hardness, and final density. All properties and CNC precision are achieved directly out of the mold without manufacturing post processes such as heat-treating,  coatings, or machining. This simple molding process can reduce cost and part validation time.

Metal injection molding is an economical molding process that can achieve high volumes for mass production. It allows you to mold steels and ceramics that would otherwise have too high of a melting temperature for injection molding. Removing the polymer in post processing causes a part to shrink up to 20%, affecting dimensional stability and part shape retention. Machining, heat-treating and coatings are common to achieve the final dimensions and properties.