We have a team of assembly engineers that are each assigned their own orders to build but often collaborate with colleagues when there are lengthy processes involved or simply need another pair of hands.
The assigned engineer will then perform pre-acceptance testing and at later stages this will involve the Sales Engineer who sold the system.
When ready the customer is invited to site to run their own FAT and assess that performance and accuracy is within agreed tolerance.
For simpler systems or repeat orders, many customers will accept a video FAT before shipping but generally an in-person "sign-off" is performed.
