Three contenders walk into a custom plastic injection molding company: ABS, the people’s champion — cheap, glossy, easy to process. Polycarbonate, the heavyweight — nearly unbreakable, crystal clear, quietly afraid of a solvent wipe. Nylon, the veteran — tough as boot leather in an engine bay, but it drinks water and swells like a sponge left in the rain. Your part can only hire one of them (or a blend of two), and the wrong hire shows up later as a cracked bracket, a jammed gear, or a chrome trim that never plated.

This article is the fight: six rounds, measured numbers, a judges’ scorecard by application, and — the part most articles skip — the exact seven-step algorithm a serious custom plastic injection molding company runs in its corner before it ever quotes your part.

📋 The Tale of the Tape (ABS vs PC vs Nylon) Resin Selection

🥊 Six Rounds, Six Verdicts

ROUND 1 · Impact & low-temperature toughness

The numbers: PC lands 600–900 J/m notched Izod and still smiles at −40 °C. ABS posts 150–300 and gets brittle below −20 °C. Nylon reads 50–110 dry — then conditions with moisture and fights again.

Verdict: PC wins. Nylon wins the humidity-assisted rematch; ABS sits this round out in winter.

ROUND 2 · Heat & creep under load

The numbers: at 1.8 MPa load, GF30 nylon stands at ~250 °C HDT — untouchable. PC holds 130–140. ABS taps out at 85–100. Unfilled nylon, note, is only 70–80 under load: the glass is what carries the heat.

Verdict: GF-nylon wins. PC takes silver; ABS never entered.

ROUND 3 · Chemicals & fuels

The numbers: nylon shrugs off fuels, oils, greases. PC — the heavyweight — gets knocked down by solvents, alkalis and even alcohol wipes via environmental stress cracking (see our cracking autopsy↗). ABS resists dilute acids/bases but folds to esters and ketones.

Verdict: Nylon wins. PC must wear a mouthguard (ESC audit) to compete.

ROUND 4 · Dimensional honesty

The numbers: ABS and PC move less than 0.4% with humidity. Nylon absorbs 2.5–3.5% at equilibrium and swells — a 50 mm gear can grow 0.4 mm between a dry winter and a humid summer.

Verdict: ABS & PC co-win. Nylon must be designed in its conditioned state, not its dry one.

ROUND 5 · Aesthetics, clarity & plating

The numbers: ABS is the only one of the three with dedicated electroplating grades and best-in-class gloss and paint adhesion. PC owns transparency. Nylon looks like what it is: utilitarian.

Verdict: Split decision — ABS for plated/painted cosmetics, PC for clear.

ROUND 6 · Cost & processability

The numbers: ABS: cheapest resin, widest window, gentlest drying. PC: disciplined drying (<0.02%), hot molds, higher energy. Nylon: strict drying, crystallization warpage, abrasive GF wear on screws. Add secondary-op fit: ABS and PC weld beautifully; nylon needs shear joints.

Verdict: ABS wins on pure economics; the others win only when the application pays the difference.

🧑‍⚖️ The Judges’ Scorecard — By Application

🧠 The Corner’s Playbook — How a Molder Actually Chooses

1. Rank the non-negotiables: impact temperature, heat under load, chemical contact, clarity, regulatory (UL 94, FDA, ISO 10993).

2. Map to families and blends: PC/ABS, PC/PBT, GF-nylon, FR grades — blends exist precisely to settle these fights.

3. DFM reality check: shrinkage and warpage budget, flow length vs wall, weld-line placement in loaded zones.

4. Factory capability check: dew-point drying per resin, mold-temperature range, GF-abrasion-hardened screws, FR-corrosion plating.

5. Secondary-op compatibility: plating, painting, ultrasonic weldability↗, adhesion — the resin must survive everything after the press.

6. Regulatory & flammability gate: UL 94 V-0 file, food/medical listings, outdoor rating if exposed.

7. Cost at volume: resin
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🗂 Case Files — Six Wrong Hires, Corrected

❓ FAQ (Snippet-Optimized)

Q1: Is polycarbonate stronger than ABS?
In impact, overwhelmingly — 600–900 J/m vs 150–300, and PC holds toughness at −40 °C. But ABS beats PC in chemical resistance, plating, and cost. Strength is one round, not the fight.

Q2: When is nylon better than polycarbonate?
Under-hood heat, fuels/oils, wear parts and creep under load — nylon (especially glass-filled) wins. For clarity, dimensional stability and easy processing, PC wins.

Q3: What is PC/ABS blend used for?
It splits the difference: PC’s impact and heat with ABS’s processability, gloss and cost — the default for power tools, automotive interiors and tough enclosures.

Q4: Which of the three is cheapest to mold?
ABS — lowest resin cost, widest process window, gentlest drying. Nylon and PC add drying discipline, hotter molds and (for GF nylon) abrasive wear costs.

Q5: How does a custom plastic injection molding company choose my resin?
By ranking non-negotiables, mapping families and blends, then checking DFM, factory capability, secondary-op compatibility, regulatory gates and cost-at-volume — the seven-step playbook above.

🎯 CTA — Free Material Selection Board

Still torn between two resins? Send the part, the environment and the one requirement you’d die for. Within 48 hours Ulite returns a free Material Selection Board: ranked shortlist, blend recommendation, DFM risks per candidate, and landed-cost deltas at your volume — the corner’s playbook, run on your part. Ulite — a custom plastic injection molding company that picks fighters, not favorites.

💬 Real-time: The online chat window in the lower-right corner

📧 Email: inquiry@ulitemech.com

🌐 Visit: https://ulitemech.com

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