Appearance
Problems found at the FAT cost 1× to fix. Problems found after delivery cost 5–10×. A thorough FAT takes 2–8 days. Skipping it or treating it as a formality is one of the most expensive shortcuts in machine procurement.
Pre-FAT Preparation
Before You Travel
- [ ] Agree FAT date at least 4 weeks in advance
- [ ] Confirm the machine is fully assembled and powered
- [ ] Send test part drawings and material specifications
- [ ] Confirm the manufacturer has test materials available
- [ ] Agree the test cut parameters and acceptance criteria in writing
- [ ] Review and approve the FAT protocol document
- [ ] Arrange travel and accommodation near the factory
- [ ] Bring: dial indicators, test bar, camera, notebook, calibrated instruments
What to Bring to the FAT
| Item | Purpose |
|---|---|
| Dial indicator set (0.001 mm resolution) | Spindle runout, axis alignment |
| Precision spirit level (0.02 mm/m) | Machine level verification |
| Laser pointer (for initial alignment check) | Quick alignment verification |
| Test bar (if specified) | Spindle axis verification |
| Calibrated micrometer | Hole diameter verification |
| Bore gauge (if applicable) | Internal diameter measurement |
| Surface finish comparator or profilometer | Surface quality verification |
| Camera with timestamp | Document every check |
Mechanical Inspection
Machine Geometry
| Check | Method | Acceptance Criterion |
|---|---|---|
| Bed level, longitudinal | Precision level | 0.02 mm/m |
| Bed level, lateral | Precision level | 0.02 mm/m |
| Spindle axis to guideway | Test bar + indicator | 0.01 mm over 300 mm |
| Guideway straightness | Laser or wire method | 0.01 mm/m |
| Headstock alignment | Dial indicator | 0.005 mm TIR |
| Tailstock alignment | Dial indicator | 0.01 mm full travel |
| Steady rest alignment | Dial indicator | 0.02 mm |
Spindle Inspection
| Check | Acceptance Criterion |
|---|---|
| Radial runout at taper | 0.003 mm max |
| Radial runout at 100 mm from nose | 0.005 mm max |
| Axial runout | 0.003 mm max |
| Bearing temperature after 1 hr at max RPM | Rise of 15°C max above ambient |
| Vibration level (unloaded) | 1.5 mm/s RMS max |
Coolant System Testing
| Test | Procedure | Acceptance |
|---|---|---|
| Pressure at pump outlet | Run at max pressure, hold 10 min | Within 3% of specification |
| Pressure at spindle | Measure at tool holder | Within 5% of pump outlet pressure |
| Flow rate | Measure at return line | Within 5% of specification |
| Filtration quality | Sample at clean side | Particle count within spec |
| Chiller performance | Run 2 hours, measure temperature | Within ±2°C of setpoint |
| Leak test | Pressurise system, hold 15 min | No visible leaks |
Test Cut Protocol
Standard Test Cut Procedure
- Drill three test holes at conservative parameters
- Drill three test holes at production parameters
- Drill one continuous run of 10 holes at production parameters
- Measure and record results after each set
Test Cut Acceptance Criteria
| Parameter | Typical Acceptance | Measurement Method |
|---|---|---|
| Hole straightness | 0.1 mm per 100 mm depth | CMM or straightness gauge |
| Diameter tolerance | IT8 or better | Bore gauge |
| Surface finish | Ra 0.8 µm or better | Profilometer |
| Cycle time | Within 10% of quoted | Stopwatch |
| Chip formation | Short, broken chips | Visual inspection |
| Coolant pressure at depth | Within 10% of no-load | Pressure transducer |
Documentation to Collect
- [ ] Spindle runout certificate (signed)
- [ ] Laser alignment report
- [ ] Axis positioning accuracy test (laser interferometer)
- [ ] Coolant system performance report
- [ ] Test cut results with measured values
- [ ] CNC program backups (ISO or manufacturer format)
- [ ] Parameter list (machine and drive parameters)
- [ ] Spare parts list with part numbers
- [ ] Recommended spare parts for first year
- [ ] Operator manual (final version)
- [ ] Maintenance manual
- [ ] Electrical schematic
- [ ] Hydraulic schematic
- [ ] Coolant system schematic
- [ ] Foundation drawing (certified)
FAT Sign-Off
The FAT sign-off document should include:
- Machine identification (serial number, model, build number)
- Date and location of the FAT
- Names and titles of all attendees
- List of all tests performed and results
- Any deviations from specification and agreement on resolution
- Punch list of items to be completed before shipment
- Signatures from buyer and manufacturer representatives
FAQ
How long does a deep hole drilling machine FAT take?
2–5 days for a single-spindle machine. 4–8 days for multi-spindle or complex combination machines.
Who should attend the FAT?
At minimum: the person who will program the machine, the lead operator, and the process engineer or production manager responsible for the drilling operation.
Can I do the FAT remotely via video?
Remote FAT is possible for simple verification but not recommended for the full protocol. Critical checks like spindle runout and test cut evaluation require physical presence.
What if the machine fails the FAT?
Document all failures. The manufacturer must correct them and schedule a re-test. Do not authorise shipment until all acceptance criteria are met.
Should I do a FAT for a used machine?
Yes. For used machines, the FAT should focus on geometry verification, spindle condition, and coolant system performance. Acceptance criteria should reflect the machine's age and agreed condition.
FAT procedures vary by machine type and manufacturer. Customise this checklist for your specific machine configuration and quality requirements. This article reflects industry best practice as of 2026.