Engineering Sector Qualifying Activities For R&D

Engineering businesses often assume R&D tax relief is only for brand-new inventions, but the reality is that many of the UK’s strongest R&D claims come from applied engineering, developing a product, process, or manufacturing method. British engineering has a deep history of solving practical problems in world-leading ways, from Brunel’s era of infrastructure and manufacturing to today’s advanced aerospace, automotive, defence, energy, and precision engineering supply chains. The innovation is often not about inventing something from scratch, it’s about pushing what is technically achievable in performance, reliability, manufacturability, and real-world application.

This blog outlines examples of activities that can qualify for R&D tax purposes and how engineering-led companies can align to HMRC’s guidance, with examples across mechanical design, high-rate manufacturing, and polymer and product tooling development, including advanced materials and composite applications.

As with all qualifying R&D projects, a company must seek to achieve a scientific or technological advancement, whilst overcoming scientific or technological uncertainties. Alongside this, the company must be able to show that a competent professional in the field could not readily determine whether something was possible, or how to achieve it, without testing, modelling, or experimentation.

Many engineering R&D projects start with a simple question: can the intended function of this design perform as required outside of a simplified, simulated environment? Although something may be theoretically possible in a simulated environment, when it comes to physical production and real-world application, unforeseen circumstances can arise that render simulated performance unreliable. This is often where genuine technical uncertainty sits, particularly when moving from design intent to a certifiable, repeatable solution.

Activities which potentially align to this include the design of a new structural component where load paths, stress points, fatigue behaviour, or deformation characteristics have not been proven or certified previously, and there is no information or design framework within the public domain that can provide a viable solution. Another example is developing a solution with reduced material or dimensions compared to an industry standard certified product, while maintaining the performance metrics required for the product’s application. To achieve this, the team must undertake iterative design and validation work to reach a practical and certifiable solution.

A further common area is utilising, combining, or joining materials in a way that has not been proven in that application before. This is increasingly relevant for cutting-edge engineering using composite structures, hybrid material stacks, high-temperature polymers, and novel bonding methods, where behaviour under load, thermal cycling, moisture ingress, impact, or long-term fatigue may be uncertain until it is physically tested and refined. For clarity, activities that comprise simply copying an existing design, or making cosmetic or dimensional changes that do not affect performance, do not qualify for R&D tax credits.

Furthermore, prototyping can qualify where it is undertaken to develop and provide data, not just to manufacture the first unit. This can include building multiple prototype versions to test stiffness, vibration, wear, thermal behaviour, and failure modes, particularly where the aim is to surpass industry standard performance or capabilities. This is especially common in composite or advanced material development, for example where the team is proving a new layup strategy, resin system, core material, curing profile, or fibre architecture, and the performance cannot be confidently predicted from existing data.

The testing and determination that a design does not perform as required, followed by an iterative design process to create and test a product with certifiably improved performance, could potentially align to qualifying activities. Trials to extend knowledge and improve understanding of why something performs differently under real loads compared to simulated environments can also qualify. It is worth noting that even failed prototypes can qualify, as this demonstrates the complexity and uncertainty of the project. Please note that producing a prototype only to show customers or for marketing purposes does not qualify for R&D tax credits.

In addition, process improvements could qualify when they involve technical risk, not just minor or routine tweaks, and lead to efficiency and accuracy enhancements. Developing a new production methodology to achieve improved strength, finish, or tolerance that could not previously be achieved via known or readily deducible methods may lead to qualifying activities.

Alongside new production methodologies, increasing production speed without compromising quality, where material behaviour becomes unpredictable or has not been evaluated previously, can provide evidence of potential qualification. This often shows up in high-rate manufacturing and advanced processes, for example:

• • Developing certified additive manufacturing routes (for example laser powder bed fusion, directed energy deposition, binder jet) where properties are highly sensitive to parameter windows, build orientation, powder behaviour, thermal history, and post-processing. Uncertainty often sits in porosity control, residual stress, anisotropy, distortion, heat treatment response, and repeatability at production scale, especially where parts must meet safety-critical performance.
  • Developing next-generation composite manufacturing methods such as automated fibre placement or automated tape laying, out-of-autoclave curing, high-rate resin infusion, or thermoplastic stamp forming and consolidation, where defect formation (wrinkling, bridging, void content, fibre misalignment) and resulting mechanical performance cannot be reliably predicted without iterative trials and data generation.
  • Developing multi-material systems and advanced joining methods including composite-to-metal joining (bonded, co-cured, hybrid mechanical joints), thermoplastic composite welding, dissimilar metal joining, and new adhesive chemistries, where long-term durability, galvanic behaviour, environmental degradation, and fatigue performance are uncertain until validated.
  • Developing high-temperature, high-load, or aggressive-environment components where material behaviour is uncertain under extreme conditions, such as hydrogen compatibility and embrittlement, cryogenic cycling, thermal barrier coatings, oxidation resistance, and fatigue in corrosive environments. Uncertainty can sit in sealing, permeation, micro-crack growth, and long-term durability.
  • Developing advanced joining and forming processes at production scale such as friction stir welding, laser welding, electron beam welding, diffusion bonding, hot forming, or novel heat-treatment routes, where microstructure, heat-affected zones, distortion, defect susceptibility, and fatigue life cannot be determined without trials and iterative process development.
  • Developing power-dense electrification systems (high-speed e-machines, advanced winding strategies, SiC or GaN power electronics) where thermal management, insulation systems, EMI/EMC behaviour, partial discharge risk, and failure modes cannot be fully understood without modelling, instrumentation, and validation under representative duty cycles.
  • Developing new inspection and validation techniques that go beyond routine QC, such as CT scanning strategies for complex internal structures, advanced phased-array ultrasonics, thermography, in-process melt pool monitoring, or machine vision systems, where existing inspection methods cannot reliably detect the defects that matter for performance requirements.

However, activities which relate to routine automation or buying standard machinery, where this does not require fundamental modification, development, or technical problem-solving, do not align to the R&D guidance.