This part of IEC 61188 describes those factors which control the flatness of rigid printed boards and their assemblies. The object of this standard is to inform the designer, manufacturer, assembler and user of rigid printed boards and their assemblies about those factors affecting their flatness. This standard incorporates advice regarding: – design (clause 3); – base material (clause 4); – unassembled printed boards (clause 5); – printed board assemblies (clause 6)