How Material Choice Affects Plastic Injection Molding Price?

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Choosing the right material for your plastic injection molded part is like picking the perfect coffee blend—get it wrong, and the whole experience turns bitter. Beyond just cost per kilogram, material selection impacts mold design, production efficiency, and even post-processing needs.

Below, we break down the 6 key ways materials influence pricing, helping you balance performance with budget—without compromising quality.

Basic Plastics vs. Engineering Grades: The Price Jump

Not all polymers are created equal. While commodity plastics (PP, ABS) keep costs low for everyday products, engineering resins (PC, Nylon, PEEK) ramp up pricing significantly—especially when high strength, heat resistance, or chemical stability are required.

Swap smarter: Does your consumer gadget really need that aerospace-grade plastic?
Hidden savings: Downgrading from PC to ABS can slash material costs by half without sacrificing durability for most housings.
Rule of thumb: The more syllables in the material name, the heavier the price tag.

Need guidance? Explore our guide to plastic injection molding materials.

Flowability: Why Thinner Isn’t Always Cheaper

Some plastics flow like honey, while others move like cold peanut butter. A material’s viscosity determines:

Mold complexity: Low-flow resins (e.g., POM) may require hot runners or higher-pressure machines.
Cycle time: Faster-filling materials (like PP) boost productivity, reducing cost per part.
Avoiding defects: Poor flow leads to short shots or sink marks—costing you in rejects.

Pro tip: If your design has ultra-thin walls, don’t just pick the cheapest material. Talk to your injection molding supplier early to avoid costly mold revisions.

Recycled Content: The Double-Edged Sword

Using regrind (reprocessed plastic) can trim costs—but beware the trade-offs:

Pros	Cons
☑ Saves 10–30% on material	☒ May weaken tensile strength
☑ Eco-friendly appeal	☒ Inconsistent color/ surface finish

When to use it? Ideal for non-critical components like pallets or interior brackets—not for medical or high-stress parts.

The “Over-Engineering” Trap

Specifying flame-retardant PC for a desk organizer is like wearing a hazmat suit to bake cookies. Unnecessary material upgrades inflate costs when:

Performance exceeds real-world needs (e.g., UV resistance for indoor parts).
Standard grades meet safety certs (e.g., household electronics rarely need medical-grade plastic).

Solution? Challenge every "nice-to-have" property—your CFO (and our high precision injection molding team) will thank you.

Additives & Colors: The Sneaky Cost Boosters

Want your parts in Pantone 448C (aka "the world’s ugliest color")? Custom colors and additives add:

Masterbatch costs (0.50–0.50–0.50–2.00/kg extra).
Longer machine purging times between batches.
Testing overhead for color matching.

Fun fact: Opting for stock black/white eliminates 90% of color-related headaches.

Shrinkage & Warping: The Mold Maker's Nemesis

Ever seen a warped part fresh out the mold? Blame material shrinkage:

High-shrink resins (e.g., POM) demand tighter mold tolerances, increasing tooling costs.
Amorphous plastics (like ABS) shrink predictably, simplifying mold design.

Emily

Hi, I'm Emily, a passionate storyteller who's dedicated to turning cold facts into warm connections. At FlourishLegend, I'm responsible for content strategy, ensuring our writing brings as much warmth as our products. With my background in writing and years of experience in manufacturing, I craft articles that are both professional and easy to understand. When I'm not writing or editing, you might find me hiking in the mountains or curled up with a book and a warm cup of tea. I believe content is more than information - it's about trust, personality, and a touch of warmth.

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