ABS樹脂とは？特性、用途、製造ガイド

ABS (Acrylonitrile Butadiene Styrene) is one of the most widely used engineering thermoplastics in manufacturing today. You find it in everything from automotive dashboards to consumer electronics housings to LEGO bricks. But what exactly makes this material so versatile, and how do you know if it’s the right choice for your next project?

In this guide, we break down ABS plastic’s mechanical properties, compare it with alternatives, and explain how it performs across major manufacturing processes—CNC machining, injection molding, and 3D printing—so you can make an informed material decision.

What Is ABS Plastic Made Of?

ABS is a terpolymer—a material composed of three distinct monomers chemically bonded together:

• Acrylonitrile provides chemical resistance and thermal stability
• Butadiene contributes impact resistance and toughness
• Styrene delivers rigidity and a glossy surface finish

The exact ratio of these components varies by grade, which is why ABS isn’t a single material but a family of formulations. General-purpose ABS typically contains roughly 50% styrene, 30% acrylonitrile, and 20% butadiene by weight, though specialty grades can deviate significantly.

Key Properties of ABS Plastic

ABS occupies a practical middle ground in the engineering plastics spectrum—tougher than polystyrene, more affordable than polycarbonate, and easier to process than many high-performance alternatives.

プロパティ	価値	備考
密度	1.04 g/cm³	Lightweight, similar to PP
引張強度	40～50 MPa	Moderate strength
衝撃強さ（ノッチ付きアイゾット）	200～400 J/m	Good toughness from butadiene
熱偏向温度	88-98 degrees C (HDT-A)	Not suitable for high-heat environments
Glass Transition (Tg)	~105 degrees C	Softens above this temperature
溶融温度	220-250 degrees C	Processing range for injection molding
曲げ弾性率	2,100～2,500 MPa	Good dimensional stability
#ddd;”>Water Absorption (24h)	0.2-0.4%	Low; stable in humid environments

ABS Plastic Grades and Variants

Not all ABS is the same. Different grades serve different purposes:

高衝撃性ABS

Increased butadiene content dramatically improves impact resistance. Used in protective equipment, tool housings, and applications where drop-test performance matters.

ABS-FR (Flame-Retardant)

Treated with flame retardants to meet UL94 V-0 or V-2 ratings. Essential for electrical enclosures, automotive interiors, and consumer electronics.

ABS-PC (ABS-Polycarbonate Blend)

Glas

s-Fiber-Reinforced ABS

10-30% glass fiber reinforcement increases stiffness and dimensional stability, though impact resistance decreases. Suitable for structural components under load.

ABS-ESD (Electrostatic Discharge)

Specialty grade formulated to dissipate static charge. Critical for electronics manufacturing environments where electrostatic discharge can damage sensitive components.

ABS in Manufacturing: CNC Machining, Injection Molding, and 3D Printing

CNC Machining ABS

ABS machines cleanly with standard CNC equipment. It yields smooth surfaces with minimal burr formation, and chips evacuate freely without clogging flutes. Key considerations:

• Use sharp carbide or PCD tools – ABS is abrasive enough to dull HSS quickly in production runs
• Climb milling reduces burr formation on top surfaces
• Water-based coolant prevents thermal softening during high-speed cuts
• Clamping force must be controlled – ABS compresses more than metals, so excessive pressure causes part distortion

Injection Molding ABS

ABS is a forgiving material for injection molding with a wide processing window:

• Melt temperature: 220-260 degrees C
• Mold temperature: 40-80 degrees C
• Injection pressure: 60-100 MPa
• Shrinkage: 0.4-0.7% (moderate, predictable)

Warping is the most common defect, especially in thin-walled parts or large flat sections. Proper wall thickness design and balanced gating mitigate this. ABS also absorbs moisture – drying at 80-85 degrees C for 2-4 hours before molding prevents splay defects.

3D Printing with ABS

ABS filament prints at 230-260 degrees C on a heated bed (100-110 degrees C). It requires an enclosed print chamber to prevent warping from uneven cooling. Key requirements:

• Enclosure maintains ambient temperature above 35 degrees C
• PEI or glass bed with adhesion promoter
• Active part cooling fan should run at low speed or off for first layers
• ABS is hygroscopic – dry filament before printing

ASA is often preferred over ABS for outdoor applications due to superior UV resistance, though ASA prints similarly and shares the same warping challenges.

ABS vs. Other Engineering Plastics

プロパティ	ABS	ポリカーボネート	Nylon (PA6)	POM（アセタール）
耐衝撃性	グッド	素晴らしい	グッド	中程度
Heat Resistance	Moderate (88C)	High (135C)	High (190C)	Moderate (95C)
耐薬品性	中程度	中程度	グッド	素晴らしい
水分吸収	Low (0.3%)	Moderate (0.15%)	High (9%)	Low (0.2%)
加工性	素晴らしい	グッド	中程度	グッド
Cost Level	低～中	中～高	ミディアム	中～高

Common Applications of ABS

ABS’s balanced property profile makes it suitable for a wide range of industrial and consumer applications:

• 自動車: Instrument panels, interior trim, seat controls, mirror housings – most use ABS or ABS-PC blends
• エレクトロニクス: Computer keyboard caps (the classic example), TV housings, power tool casings, charger bodies
• Consumer goods: Luggage shells, helmet linings, household appliance panels, RC hobby parts
• インダストリアル: Pipe fittings, pump housings, instrumentation enclosures, conveyor components
• Medical (grade-dependent): Diagnostic equipment housings, drug delivery device components – requires biocompatible grades

Our Manufacturing Capabilities with ABS

We machine and mold ABS parts for prototyping and low-to-mid-volume production. Our facility handles:

• CNC milling and turning of ABS components with tolerances to +/-0.01 mm
• Injection molding of ABS in prototype quantities (50-5,000+ pcs)
• ABS 3D printing via FDM for functional prototypes and tooling aids
• 後処理：塗装、メッキ、超音波溶接、パッド印刷

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