When sourcing a vertical machining center, the Factory Acceptance Test (FAT) is your critical checkpoint before shipment. Many buyers only focus on machine specifications listed in brochures, which may lead to unexpected issues after the machine arrives at your workshop. A well-prepared FAT procedure helps you confirm the real performance of the equipment.
Geometric inspection is the first step during FAT. This procedure checks the static alignment of core components, including the spindle, worktable and tool magazine. Measurement tools are used to test flatness, perpendicularity and positioning accuracy of the machine frame. Any geometric defect must be fixed before moving on to cutting tests.
Positioning accuracy and repeatability are the next major indicators. Even small deviations will accumulate during multi-axis machining and ruin finished parts. The machine will run programmed movements repeatedly, so inspectors can record deviations and judge whether the machine meets your drawing tolerance requirements.
After static geometric checks, the test piece cutting trial begins. The workpiece sample uses your actual production material and typical part geometry. The finished sample will be measured with precision instruments to verify dimensional accuracy and surface finish. This test simulates your real manufacturing conditions.
Common Mistakes During Machining Center FAT
- No customized inspection checklist. Buyers use generic standards instead of requirements from their own parts.
- Ignore tooling and fixture requirements during test cutting.
- Fail to define report format, photos and video records in advance.
- Skip some optional functions testing that you plan to use in production.
Prepare Your FAT Request for Machine Supplier
Share these documents with your equipment manufacturer before FAT:
- Drawings or 3D models of your critical workpieces
- List of key dimensions, datums and tolerance requirements
- Workpiece material and blank type
- Planned machining operations: milling, drilling, boring, tapping or multi-axis machining
- Requirements for fixtures, cutting tools and measurement systems
- Optional machine functions and test scenarios you need verified
- Preferred format for FAT report, photo and video documentation
With all these details, the supplier can create a tailored FAT plan for your project. This method is far more reliable than selecting equipment only according to general specification tables.
Conclusion
How do you check machining center accuracy before FAT? Start with your actual workpiece and agreed inspection procedures. Geometric tests, positioning tests, repeatability checks, cutting trials and FAT documents should be treated as one complete validation system.
A properly organized FAT does not promise vague "high precision". It confirms that the configured machine passes all agreed tests, and its performance can match the tolerance demands of your future production.