How do you carry out an effective Critical Design Review (CDR)?

Haughton Design Critical Design Review

Critical Design Reviews (CDR) are an essential formal check-point in the product development process. They ensure designs are fit for purpose, ready for production and checked before further financial investment.

An organised and robust CDR helps to identify mistakes, highlights risks, any concerns or areas for optimisation and any further improvements to the design. A thorough CDR saves time, reduces risks and shares responsibility across all stakeholders.

Designer’s Self-Checks (in preparation for a CDR meeting) 

  • Thoroughly review your design solution against your Project Brief & Product Design Specification
  • List any concerns, issues, concessions or problems – try to be self-critical
  • At this stage in the project it is likely you have a detailed 3D CAD model. Therefore, you should run in-built CAD system tests, such as; interference detection, hole alignment and draft analysis etc.
  • Ensure your project’s risk log is fully up-to-date
  • Prepare a component interaction map, ensure all parts are listed, so you can systematically cross-check all interactions and their inter related features
  • Check the assembly sequence, perhaps animate this using exploded CAD views
  • Check any proprietary CAD Models against supplier datasheets, it’s surprising how often we find incomplete or incorrect models
  • Ensure that all your pre-check activities have been recorded and are ready to present to present in a formal CDR

Once you have covered the above points, the next stage is to request a formal in-house CDR. Invite along the design team, design manager, and all key stakeholders, who may include manufacturing representatives, clients etc. Use BS.7000:2 to help you identify who should be in the meeting for your business.

Critical Design Review Meeting

The goal of any CDR meeting is to make sure designs meet the requirements of all interested parties. Remind those attending the CDR of their responsibility in it too. It’s a shared responsibility, not just the designers to make the project a success!

The project’s lead designer should be prepared to cover the following agenda:

  • Explain the overall purpose of your design and how it meets the Product Design Specification
  • Walk the team through the CAD files, showing each part, sub-assembly and the general assembly, using section tools and isolated views, so the detail is clear
  • Explain the general functionality
  • Discuss the key performance parameters
  • Explain the intended user interaction and experience
  • Explain how the design will be manufactured, i.e. process, projected volumes, manufacturing cost estimates
  • Explain how the design will be assembled, perhaps using 3D CAD exploded views or simple animations
  • Explain any design logic, calculations, FEA that supports the design
  • Openly review the risk log (include technical, safety, project & commercial risks) and if applicable review any other risk assessment methods, such as FMEA or Fault Tree Analysis (FTA).
  • Senior managers should ask challenging questions throughout the process, with a view to finding solutions where possible. If there are no or few questions, its likely people haven’t understood, or are not paying attention. You need to be challenged now so don’t be afraid to remind them again of their responsibility – it’s too late once something’s made.
  • If the design is of a complex nature then the senior designers reviewing the project should then take more time to study CAD files meticulously, measuring and critiquing the fine details of the design.
  • The Project Manager should record all comments, findings, concerns and further actions in a standard review template, using CAD screen captures for clarity.

Following the meeting, minutes should be complied and distributed to those involved.

Once approved, the design team can work on the agreed changes.

Once the changes are deemed complete, then organise a ‘back mod’ review meeting with your design management team to ensure changes are complete. If so, then the Design Manager will formally approve the designs for prototype manufacture.

By keeping to a formal method of review, you can limit your exposure to unnecessary risk which could hinder your project, in terms of its delivery schedule, development costs and ultimately the return on investment. Hopefully, these guidelines are useful and help you develop your own formal review system.