Challenges in plastic testing is something many professionals face, whether you’re working with flexible films, rigid polymers, or specialty composites. Moreover, since plastics come in a wide variety of formulations and material behaviors, testing them isn’t always straightforward.
In this article, Qualitest will break down the most common issues in plastic testing and show you practical ways to overcome them. Stick around to the end for insights into the latest innovations shaping the future of plastic testing.
Why Plastic Testing Matters
Every engineer who's worked with plastics long enough knows one thing: no two batches behave exactly the same. That’s where the real challenge in plastic testing begins in accounting for all the variables that can quietly sabotage performance.
Take polyethylene, for example. You might have two samples labeled the same grade, but one’s been processed with recycled content and the other hasn’t.
Their tensile strength? Not the same. Their stress cracking behavior? Absolutely not the same. And if your test method isn’t sensitive or specific enough to catch those differences, the data you're relying on could be leading you off a cliff.
Plastics don’t just change from one type to another; they evolve based on heat history, filler content, stabilizers, and exposure. And because they’re viscoelastic, their response to stress is time-dependent.
Even something as basic as temperature control can throw things off. A high-impact polystyrene tested at 23°C behaves entirely differently when tested at 35°C (especially in terms of brittleness). If you’re not accounting for that, especially in QC environments, you’re flying blind.
So yes, plastic testing matters because it's the only way to translate molecular chaos into predictable performance. And in a material this complex, the challenge in plastic testing might be knowing which test to run in the first place.
Also Read: Top Material Testing Mistakes to Avoid: Common Errors and How to Prevent Them
Common Challenges in Plastic Testing
1. Fluctuating Results from Batch to Batch
Plastics, particularly blended or modified types, can vary subtly in composition even within the same product line. Add in factors like ambient humidity, machine drift, or even operator habits, and suddenly the same test gives you wildly different results.
This inconsistency makes trend analysis nearly impossible and can lead to false positives or missed failures in quality checks.
2. Navigating an Overlapping Web of Standards
Another major challenge in plastic testing lies in keeping up with shifting regulatory frameworks. Whether you’re testing for tensile strength per ASTM D638 or thermal stability under ISO 11357, each standard comes with its own protocols, tolerances, and test parameters.
What complicates it further is when you’re serving multiple markets it makes you juggling overlapping, or even sometimes conflicting compliance rules. In this case, a missing spec can cost rejected batches, failed audits, and redesigns.
Need plastic testing that aligns with ASTM, ISO, or IEC standards?
Discover our full range of internationally compliant plastic testing services here.
3. Material Instability Under Test Conditions
Certain plastics behave beautifully in storage but fall apart under test conditions. Polymers like PVC or certain bioplastics are especially vulnerable to heat, UV, or even oxygen exposure during testing.
So, while the data might show premature degradation, it could be your test chamber, not the material, that’s the real problem. This is one of the more invisible yet critical challenges in plastic testing.
4. Time-Intensive, Resource-Heavy Testing Cycles
High-volume production environments often don’t have the luxury of time. But plastic testing, especially mechanical and aging tests, often takes hours or even days. Add that to the cost of specialized fixtures and destructive testing processes, and you’re looking at a serious bottleneck.
For companies scaling fast, this delay can kill speed-to-market goals.
5. Equipment That Can’t Keep Up
Old or generalized test equipment might’ve worked when your product line was simpler. But with advanced polymers, filled composites, and multi-layered films becoming more common, legacy machines start to show their limitations.
Mismatched load cells, incorrect jaw faces, or incompatible grips can all skew results and can make one of the biggest hidden challenges in plastic testing a matter of having the wrong tools for today’s materials.
6. Interpreting the Right Story from the Data
Even with perfect procedures, interpreting the raw data isn’t always straightforward. Test curves for creep, fatigue, or modulus can be complex, and without a deep understanding of polymer behavior, it’s easy to misread what the numbers are really saying.
Industry-Specific Challenges
The challenge in plastic testing doesn’t play out the same way across every industry. What passes in one application might completely fail in another, simply because the test conditions weren’t tailored to the use-case.
1. Packaging Industry
In food and pharma packaging, plastics are expected to provide precise barrier protection against moisture, oxygen, or UV exposure. These properties can vary significantly depending on how the film is processed or stored.
A multilayer PET/PE pouch might perform flawlessly in lab conditions but fail in the real world due to unnoticed micro-defects or instability during shelf-life simulations. One common challenge in plastic testing here is replicating real-life shipping or refrigeration environments without introducing artificial degradation.
Also, extremely thin films often present difficulty in tensile and puncture testing without specialized grips or pressure-controlled test heads.
2. Construction
For pipes, panels, or fittings used in infrastructure, testing must account for years (or even decades) of exposure to heat, cold, and mechanical stress. However, aging tests are notoriously difficult to accelerate without distorting the results.
HDPE pipes, for instance, may pass tensile tests but still fail in long-term hydrostatic pressure tests if stress cracking isn’t captured properly. One persistent challenge in plastic testing for this industry is aligning accelerated testing with real-life aging behavior.
In short, a mismatch here can result in under-designed components being certified too easily.
3. Consumer Electronics
From smartphone casings to power tool enclosures, plastics in electronics must resist flame while maintaining tight dimensional tolerances. UL 94 flammability testing is a standard, but the challenge in plastic testing here lies in understanding how additives like flame retardants affect impact strength and warpage.
Certain FR compounds can weaken mechanical integrity, so trade-offs must be carefully assessed with the right suite of mechanical, thermal, and aging tests. For fast-paced product cycles, delays in resolving this trade-off can disrupt launches or fail safety audits.
How to Overcome Plastic Testing Challenges
- Align your test setup with real-world application stressors. Don’t rely solely on static tensile tests. Incorporate methods that replicate the actual conditions your plastic will face, like temperature swings, humidity exposure, or mechanical fatigue over time.
- Use environmental control where it counts. Plastics are highly sensitive to testing conditions. For accurate, repeatable data, conduct tests in climate-controlled chambers, especially for materials prone to moisture absorption or UV degradation.
- Upgrade from generic grips and fixtures. Sample slippage, stress concentrations, and uneven loading can all skew your results. Choose application-specific grips, inserts, or jigs that match the shape, thickness, and flexibility of your test specimens.
- Verify material stability through staged testing. Conduct multi-phase tests. For examples like, thermal aging followed by tensile, or flammability followed by impact, and else. By doing so, you can detect how properties shift under exposure or stress over time.
- Match your sensors to the scale of your test. For delicate films or micro-molded parts, use high-sensitivity load cells and extensometers that can pick up subtle mechanical changes without introducing test error.
- Audit your equipment calibration and test methods regularly. Even the best machines can generate unreliable data if left unchecked. Schedule routine calibrations, and review whether your testing method still aligns with updated ASTM or ISO standards.
- Simplify your analysis pipeline. Testing isn’t just about raw numbers, it’s about interpreting trends. Integrate data acquisition software that flags inconsistencies and lets you visualize how a material performs under multiple stress factors.
- Invest in targeted training. Skilled technicians can spot a faulty sample prep or irregular break pattern before it skews your data. So, always upskill your team to fully understand the nuance behind each test standard and the machine capabilities.
Latest Innovations in Plastic Testing
Plastic testing has come a long way, especially with how modern labs approach flammability and safety standards. These days, one of the biggest shifts is the use of more compact testing chambers that don’t compromise on performance.
They support both horizontal and vertical flame tests that makes them much more flexible for different types of materials. What makes them stand out even more is the high-precision flame calibration.
The presence of tools like K-type thermocouples with 0.1°C resolution allows labs to get extremely accurate flame temperature readings. And now come with digital mass flow meters to control methane flow more precisely. Beyond that, adjustable sample holders allow tests at multiple angles, like 0°, 20°, and 45° which really helps simulate how materials behave in real-world conditions.
These innovations are also catching up with international testing standards like ASTM, ISO, and IEC, so the results are not only reliable but also widely recognized. On top of all that, improved user-friendly features like tempered glass doors, anti-corrosion coatings, and remote-controlled timing are making daily testing workflows smoother.
Final Thoughts
Whether you're validating flame resistance, ensuring product quality, or simply need expert insight into testing options, Qualitest are here to help.
- Need to assess your plastic’s flammability or safety compliance? Explore our specialized UL 94 flame testing solutions for precise and standardized results.
- Looking for other types of plastic testing? From tensile strength to environmental aging, we cover a wide range of testing to fit your product’s unique needs.
- Still figuring out what kind of test is right for your material? Book a consultation with our technical experts to map out the best approach for your application.
Let’s take the guesswork out of plastic testing, so you can focus on building better, safer products!
