SCF Microcellular Injection Material

DKM Material Database Support

SCF Microcellular Injection Material Selection

Different polymers exhibit varying solubility in supercritical fluid, as well as differences in melt strength and nucleation behavior—all of which directly affect cell structure, surface quality, and the mechanical properties of the final part.

DKM has established a comprehensive material selection system for SCF microcellular foaming. Whether you are using ABS, PP, PA, PBT, PC/ABS, or TPE, we can provide targeted process parameter recommendations and material modification directions to help you find the optimal balance among weight reduction, cycle time, surface appearance, and cost.

Material Classification for SCF Microcellular

The microcellular foaming process is applicable to most thermoplastics, but different materials respond differently to foaming conditions. DKM classifies materials into three major categories:

1. Amorphous Plastics

Material	Foaming Characteristics	Typical Applications
ABS	Moderate melt strength, uniform nucleation, fine cell structure, relatively good surface quality	Automotive interiors, appliance housings, electronic devices
PC	High melt strength, suitable for thick-wall foaming, high weight reduction potential, requires higher processing temperature	Transparent part substitute (non-transparent apps), automotive lens brackets, electrical components
PC/ABS	Combines PC heat resistance with ABS processability, wide foaming window,excellent comprehensive performance	IP carriers, electronic housings
PS	Easy foaming, uniform cells, low cost, but more brittle	Packaging, insulation materials

2. Crystalline Plastics

Material	Foaming Characteristics	Typical Applications
PP	High crystallinity, requires enhanced melt strength (HMS-PP or modification), significant weight reduction	Automotive door panels, packaging containers, appliance internal parts
PA6/PA66	Moisture absorption affects foaming stability, requires thorough drying; glass-filled grades show 10-15% viscosity reduction after foaming, better flow	Automotive functional parts (tanks, fans), power tool housings
PBT	Good flow, suitable for thin-wall foaming, high strength retention with glass fiber	Connectors, relay housings, automotive electronics
TPE/TPV	Elastomer foaming achieves soft-touch feel, used for overmolded parts	Soft-touch grips, seals, interior wraps

3.High-Performance Engineering Plastics

Material	Foaming Characteristics	Typical Applications
POM	More difficult to foam, requires specialized process window, limited weight reduction but eliminates voids	Gears, sliding components
PET	Fast crystallization, narrow foaming window, requires rapid cooling	Food containers, packaging

Foaming Agent for SCF Microcellular

The micro-foaming process uses gases in the atmosphere as foaming agents and does not require chemical additives. Two gas options are available:

Foaming Agent	Characteristics	Suitable Materials
N₂	Moderate diffusion rate, fine cell structure, relatively good surface quality	Most materials including ABS, PC, PA, PBT, PP
CO₂	Higher solubility, obvious plasticizing effect, can reduce processing temperature, but larger cells	Specific materials like PLA, PS, some bioplastics

Selection Recommendations:

For the vast majority of microcellular applications, nitrogen is the preferred choice—low cost, readily available, and delivers stable cell quality.
For heat-sensitive materials or applications requiring a significant reduction in processing temperature, carbon dioxide may be considered.

Glass-Filled Material Selection for SCF Microcellular

Glass-filled materials offer unique advantages in microcellular foaming: 10-15% viscosity reduction after foaming, increased flow length, and glass fibers aid cell nucleation.

Material	Glass Content	Foaming Characteristics
PA66-GF30	30%	cavity pressure reduction, 4-10% weight reduction, 60% warpage improvement
PBT-GF30	30%	Increased flow length, gate reduction possible (e.g., 2 to 1 gate)
PP-GF20/30	20-30%	Stiffness improvement with weight reduction, for structural parts

Key Considerations for Material Selection:

Glass-fiber reinforced materials may exhibit a rougher surface after foaming; surface appearance can be improved with subsequent painting or IMD/IML processes.
Screw design must account for glass fiber wear—DKM employs wear-resistant bimetallic barrels and hardened screws.
Weight reduction targets: For functional structural parts, it is recommended to stay within 10%; for non-load-bearing parts, 20–30% weight reduction is achievable.

Tell us your part material and application requirements, and a DKM engineer will recommend the optimal microcellular material solution for you.