High Temperature Product Characterisation
1. Description
The purpose of this page is to detail the qualification methodologies used on current and legacy Scotland Electronics components or assemblies. It is designed as an overview of the philosophies used and not a complete procedural instruction.
2. Philosophies – Parts
The testing philosophies used by Scotland Electronics can be broken down into 2 main subsets:
- Legacy
- New Design
2.1. Legacy Philosophy
Scotland Electronics has a heritage of assemblies tested for operation at extreme temperatures, for various clients in the oil and gas sector.The operation of these assemblies has been governed by the ability of the assembly to perform its given operation at temperature for the expected operating duration of the tool in the field, as specified by the client.
Screening of components is conducted to reduce the probability of failure of the unit during the development stages and before it goes into field use.
Components which cause failure of the unit under test during the development testing phase are removed from the design, and the process of selection and test conducted, until such a point as the tool operates as expected to complete its given operation.
During acceptance testing (ATP), the units under test are tested at the operating temperature for a period agreed with the client.
A cycle of continuous improvement is initiated during the production phase to further enhance the reliability of the assembly, with any proposed changes being passed to the client for approval as this will most likely effect their qualification program for the assembly when it is mounted into a tool.
Processes and procedures are put in place to maintain the repeatability and reliability of the manufacture and test of the assembly.
Test data on legacy designs is not permitted to be shared between Scotland Electronics and 3rd parties due to non disclosure agreements with the 3rd parties.
2.2. New Design Philosophy (Verify, Characterise and Soak)
For new designs Scotland Electronics has implemented a process for test and continuous improvement of components and/or assemblies depending on the nature of the testing required.
During this process:
- Parts are identified and assigned a Standard Temperature Part (STP) number, which relates to a single manufacturer and manufacturers part number
- The datasheet used during the selection of the part is saved and linked to the parts register for future use
- Suppliers for the parts are identified, with current pricing information etc. added
- Parts requiring temperature characterisation are given a HTP (high temperature part) number; this part number has one test temperature profile, and one test procedure.
- The HTP test procedure is designed to test the part for operational conditions as expected by design and beyond the scope of normal design
- The HTP is tested in accordance with its test procedure, if the HTP completes the test procedure successfully the HTP under test is identified as qualified
- During testing the units are verified as suitable for further test, characterised through a temperature range then soaked for the equivalent of 1000 hours at temperature. With an at temperature time reduction of 50% for every 5°C over 180°C which they are tested.
- All parts are given a “risk” coefficient derived from the STP temperature rating and the testing conducted. This number will dictate the nature of the production testing required for the part: batch test, individual test, assembly test etc.
- All parts that have passed testing are considered qualified for that instance of the part, re-qualification of a part may be conducted at any time as required depending on the temperature specification, batch control etc. of the part.
3. Philosophies – Assemblies
3.1. Legacy Philosophy
The legacy philosophy for assemblies, mirrors that used for parts, as the units would be tested as assemblies, and qualification granted based on a test basis.
3.2. New Design Philosophy
For new designs Scotland Electronics is using a similar process to that of the parts qualification, where the assembly is tested to a known test regime to confirm its operation at 175°C
