| A number of EU directives require a "Technical | | | | - Design review records |
| Construction File" to be maintained and to be | | | | An extremely difficult decision is when to start |
| available as part of their documentary | | | | the creation of the TCF. From an engineering |
| requirements. Two examples are the Low | | | | perspective it is preferable to defer the creation |
| Voltage and R&TTE directives. While the | | | | until the first production batch is to be |
| directives place specific requirements on the | | | | manufactured, as only then is the design likely to |
| contents of the Technical Construction File (TCF) | | | | be stable. However in terms of capturing and |
| there are some general principles that are | | | | protecting the businesses investment into product |
| common throughout. The TCF is a document or | | | | Intellectual Property (IP) the pressure is to start |
| series of documents that contain the full technical | | | | the TCF on the first day of the project. We have |
| details of a product, and it is usually required to | | | | found that in most cases the best timing is |
| have a unique serial number. At a minimum the | | | | immediately following the release of the Alpha |
| TCF should contain the following information: | | | | prototyping phase. Although the design is not yet |
| - Table of contents | | | | stable it is critical to carefully control engineering |
| - Design calculations and tradeoffs | | | | changes from this point and into production and a |
| - Bill of Materials | | | | rigorous approach to documentation is natural at |
| - Electrical schematics | | | | this point. |
| - PCB layouts | | | | Any technically competent member of staff is |
| - Mechanical design details including enclosure | | | | capable of compiling the TCF, although it is better |
| materials if applicable | | | | to have someone who is not intimately involved in |
| - Test results for both internal and "approvals" | | | | the design and development process. If your |
| related tests | | | | company has a Quality Manager they would make |
| - User Manual | | | | the ideal candidate, as it is an excellent |
| - Certificate of Conformance | | | | opportunity to audit the design and its associated |
| In addition to the above I would recommend | | | | documentation. Where a company does not have |
| adding the following for completeness: | | | | the resource an independent third party can be |
| - Software source code and project files | | | | used. However the TCF contains extremely |
| - Assembly photographs and details | | | | valuable information and suitable contractual |
| - Change notes and revision change history. | | | | protection should be put in place. |