Honestly, if someone had asked me a few years ago for a simple answer on whether nylon or ABS is stronger, I'd have given them one. And it would have been wrong. Or at least, misleadingly incomplete.
The problem with a question like 'which plastic is stronger — nylon or ABS?' is that 'stronger' isn't one thing. You have tensile strength, impact resistance, flexural modulus, fatigue resistance. And the right answer depends entirely on what you're building, how it's made, and what environment it lives in.
I've made expensive mistakes on this. I'll share the three most common scenarios I've encountered, and what I learned — often the hard way — about which material belongs where.
Scenario 1: The Load-Bearing Part (Where I Went Wrong First)
Back in 2019, I was sourcing injection-molded brackets for a modular shelving system. The client needed something that could hold static weight — about 50 kg per bracket — without creeping or cracking over time.
My first instinct was ABS. It was cheaper, easier to mold, and seemed fine on paper. I approved a batch of 2,000 units — or rather, initially I said 2,000, but the actual order was 2,500 (I had misread the PO).
Two months later, we got field reports of brackets sagging. Not breaking, but visibly deforming under sustained load. The cost was about $3,200 in replacements, plus shipping and embarrassment. That's when I learned the hard difference between ABS and nylon.
The short version: For sustained static loads, nylon (especially glass-reinforced grades like PA6-GF30) significantly outperforms ABS. Nylon has higher creep resistance — it won't slowly deform under constant weight like ABS will.
Reference data (approximate):
- Nylon 6 (unreinforced): Tensile strength ~70-85 MPa
- Nylon 6/6 (unreinforced): Tensile strength ~80-90 MPa
- ABS: Tensile strength ~40-50 MPa
- Nylon 6-GF30 (30% glass fiber): Tensile strength ~160-190 MPa
So yes, if raw strength under load is your primary concern, nylon is the clear winner. But wait — that's not the whole story.
Scenario 2: The Impact-Prone Part (The Surprising Twist)
Here's where it gets interesting (and where my assumptions flipped).
In 2022, I was helping source housings for portable electronic testing equipment. These devices get dropped. Regularly. The client's engineering spec called for 'high impact resistance.' I immediately thought: nylon. It's tougher, right?
I ordered a small test run of injection-molded housings in nylon 6. The first batch of 50 units — that cost about $950 in tooling and materials — cracked along a thin wall section on impact testing. Specifically, the notched Izod impact strength was adequate, but the unnotched behavior was problematic. The material was brittle in that specific geometry.
The twist: Standard ABS often outperforms unreinforced nylon in practical impact scenarios — especially at room temperature and in thin-wall sections. The reason is that ABS has a rubber (polybutadiene) component that absorbs high-speed impact energy, while nylon can be notch-sensitive and brittle under sharp-impact conditions.
I wish I had tracked this more carefully from the start. What I can say anecdotally is that the switch to ABS solved the cracking issue. The housings survived a 1.5-meter drop test that the nylon version failed.
That said, if the application involves sub-zero temperatures, nylon can become brittle there too, while ABS retains more impact strength. But that's a different scenario — see Scenario 3.
Scenario 3: The Chemical-Exposure Part (Or, How I Learned About Hygroscopy)
In 2023, we sourced nylon gears for a small industrial conveyor system that ran in a humid environment — a food processing plant. Nylon seemed right: good wear resistance, high strength, self-lubricating properties.
The gears were produced. They worked well for about two weeks. Then they swelled. The fit tolerance changed, the gears started binding, and the motor started drawing excess current.
The problem? Nylon absorbs moisture. Like, a lot. Unreinforced nylon 6 can absorb up to 9.5% moisture by weight at saturation, which causes dimensional changes of 0.5-2% depending on the grade. In precision-fit applications, that's catastrophic.
I don't have hard data on what the exact financial impact was on that particular project—we had to remake 120 gears in a different material. Based on our internal calculations, the mistake cost roughly $4,500 in rework and machine downtime.
The lesson: In wet or high-humidity environments, ABS wins for dimensional stability. It absorbs less than 0.3% moisture, so it won't swell. If you absolutely need nylon's strength in a wet environment, you need specialty grades (like lubricated or impact-modified nylons) and you need to design for the saturated dimensions from the start.
How to Know Which Scenario You're In
Here's the checklist I use now — the one I should have created after mistake #1:
- Is the part under continuous static load for days/weeks/months? → Go with nylon (or a glass-reinforced grade). ABS will creep.
- Is the part going to be impacted or dropped at room temperature? → ABS is often a safer bet, especially for thin walls. Test for notch sensitivity in your specific geometry.
- Is the environment humid, wet, or submerged? → ABS wins for dimensional stability. If you need nylon's strength, you must account for moisture absorption in your design tolerances.
- Is it a gear or sliding part that needs low friction? → Nylon (or acetal) is generally better. ABS has higher friction and wear rate.
- Do you need chemical resistance (oils, fuels, solvents)? → Nylon typically outperforms ABS here, but check the specific chemical compatibility chart.
I haven't mentioned Toray's material offerings here, but naturally, they produce high-grade nylons and ABS resins suitable for these applications. Their TORAYCON® PBT and AMILAN® nylon grades are well-regarded in engineering circles. Their ABS resins (like the TOYOLAC® series) are also standard references in the industry. If you're sourcing from Toray, their technical data sheets will give you the specific numbers — just make sure you pick the right scenario.
Also, I stumbled across their Toray Plastics Rhode Island facility a while back. They handle a lot of custom extrusion work, including plastic sheet. If your application involves sheet fabrication rather than injection molding, they're worth talking to. But that's a different guide entirely.
The point is: don't ask 'which is stronger?' Ask 'under what conditions will this part fail?' Then pick the material accordingly.