When a case hinges on why a polymer failed, how a plastic component degraded, or whether a manufacturing defect caused a product liability event, the difference between winning and losing can come down to one thing: having the right plastics expert witness who can explain highly technical material science in a way that a judge or jury can understand. Whether you need a polymer expert witness to address chemical resistance issues or a plastics failure analysis expert witness to determine whether the root cause was a design flaw or processing error, the stakes are too high to rely on anyone less than a true specialist.
Finding and vetting these specialists is a significant hurdle for busy legal teams. GLG Law simplifies this process by connecting attorneys with high-caliber experts, handling the search so counsel can focus on case strategy. We sat down with Hermann Plank, a leading plastics expert witness with decades of experience in polymer sciences, to discuss his approach to technical testimony and how he helps legal teams navigate demanding litigation.
Key insights from this interview:
- The expert’s role: How a deep understanding of the full manufacturing value chain supports patent and liability cases.
- Effective communication: Strategies for translating dense polymer science into clear, persuasive jury testimony.
- Rebuttal strategy: A framework for objectively evaluating opposing expert methodologies.
- Early engagement: Why bringing in a technical expert during discovery prevents costly errors.
- Case preparation: What specific data attorneys should provide to ensure a precise expert match.
1. For attorneys encountering a plastics expert witness for the first time, how would you describe what you do and the types of cases where your expertise tends to be most valuable?
Over the course of nearly three decades in the plastics industry, I had the privilege to work with many of the world’s leading companies assisting in developing their products and have worked across the full value chain – from material selection and product design to processing, tooling, automation, and large-scale manufacturing operations. My experience spans major verticals including automotive, medical devices, packaging, consumer electronics, personal care, and construction.
Having spent many years with leading plastics processing equipment manufacturers, I gained insight not only into machine design and process engineering, but also into how raw materials, tooling, processing parameters, and automation strategies interact to produce a finished plastic component. This end-to-end perspective is particularly valuable in litigation involving patent infringement, product liability, failure analysis, manufacturing defects, and process-related disputes.
I am most helpful in cases where the interaction between material behavior, part design, tooling, and processing conditions is central to determining causation, feasibility, infringement, or standard of care.
2. As a plastics failure analysis expert witness handling dense cases like polymer degradation or environmental stress cracking, how do you translate technical concepts to ensure they are both scientifically accurate and accessible to a jury?
My primary objective is clarity without oversimplification. Plastics engineering concepts can be highly technical, but they are often explainable through structured visuals, step-by-step reasoning, and relatable comparisons drawn from everyday experience.
In written reports, I focus on organizing complex material into clearly structured sections that build logically from fundamentals to conclusions. In testimony, I avoid unnecessary jargon and instead explain mechanisms, such as stress concentration, polymer degradation, or weld line formation in practical terms that connect to observable behavior.
The goal is not only scientific accuracy, but also comprehensibility. Judges and juries should understand not just what happened, but why it happened.
3. When retained and the opposing side has their own expert, how do you approach rebuttal work and distinguish your analysis?
Rebuttal work begins with a careful, objective review of the opposing expert’s methodology, assumptions, and conclusions. I assess whether their analysis aligns with accepted engineering principles, industry standards, and practical processing realities.
Rather than focusing on the individual, I focus on the technical framework:
- Are the materials characterized correctly?
- Are processing variables appropriately considered?
- Are alternative root causes evaluated?
- Is the testing methodology consistent with established standards?
My role is to provide the legal team with a technically grounded assessment of strengths, weaknesses, and areas where additional clarification or cross-examination may be warranted. Clear differentiation typically comes from disciplined methodology and deep familiarity with real-world plastics manufacturing conditions.
4. What are the most common mistakes legal teams make when they bring in a failure analysis expert too late? What does early engagement make possible?
The most common issue with late engagement is limited time for technical development. Plastics cases often require review of drawings, processing records, material data sheets, testing protocols, incident documentation, and sometimes physical evidence. Thorough analysis cannot be compressed without risk.
Early engagement allows the expert to:
- Contribute to case strategy from a technical standpoint
- Identify additional data or testing needs
- Help frame discovery requests
- Evaluate preservation of physical evidence
- Prepare a coherent and well-supported theory of causation
Importantly, early involvement does not necessarily mean increased cost – it often improves efficiency by ensuring that technical issues are defined correctly from the outset.
5. For a litigator evaluating whether they need a plastics expert witness or patent infringement expert witness, what background and case details should they be ready to share with GLG?
At a minimum, it is helpful to provide:
- A concise description of the dispute
- The relevant products or components
- Applicable patents (if any)
- Incident or failure reports
- Testing data (if available)
- Key allegations or defenses
The more context available, the more precisely the appropriate expertise can be matched to the case. Initial screening conversations are particularly useful to clarify whether the matter primarily concerns materials science, processing technology, design for manufacturability, safety standards, patent scope, or a combination thereof.
A structured intake of technical facts significantly improves expert alignment.
6. You’ve worked with GLG Law on multiple matters. What has that experience been like, and what do you find most valuable about GLG’s process?
My experience working with GLG has been consistently professional and well-structured. One of the GLG’s strengths is the ability to efficiently match legal teams with experts who have directly relevant technical backgrounds.
From an operational standpoint, the engagement process is clearly defined, billing administration is streamlined, and communication channels are transparent. That allows me to focus fully on the technical work and client support.
Over many years of collaboration, I have found GLG’s team to be responsive, organized, and committed to ensuring that both clients and experts have what they need for a productive engagement.
Engage with a Plastics Expert Witness for Your Next Case
Whether your matter involves a complex patent dispute or a high-stakes product liability claim, securing the right technical authority is critical. You can engage directly with Plastics Expert Witness Hermann Plank or other similar experts through GLG Law. Some of the areas our plastics expert witnesses specialize in:
- Material Science & Polymer Engineering: Evaluating chemical resistance and material selection for automotive and industrial applications.
- Manufacturing & Injection Molding: Identifying defects in large-scale production, tooling, and processing parameters.
- Medical Device & Consumer Product Failures: Providing rigorous root-cause analysis for regulated industries and high-volume retail goods.
- Environmental & Toxics Litigation: Addressing emerging claims involving PFAS (“forever chemicals”), microplastics, and “greenwashing” or recyclability disputes.
Why Partner with GLG Law?
Finding a polymer expert witness or a plastics failure analysis expert witness who is both technically elite and courtroom-ready is a challenge. GLG’s expert witness services streamlines this process by providing:
- Precision Matchmaking: We identify experts with the exact technical niche required for your case.
- Vetted Transparency: Our rigorous screening process saves your team hours of administrative vetting and conflict checks.
- Speed and Scale: Access a global network of authorities ready to support discovery, depositions, and trial testimony on your timeline.
Ready to strengthen your case strategy? Start an expert witness search with GLG Law.
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