First article inspection in CNC Programming

Introduction

First article inspection helps check if a CNC program makes the part correctly before making many parts. It saves time and materials by catching mistakes early.

After writing a new CNC program for a part.

When changing tools or machines before starting production.

When making a new part design for the first time.

After fixing errors found in previous parts.

Before starting a large batch to ensure quality.

Syntax

CNC Programming

1. Load the CNC program.
2. Run the program on a single part.
3. Measure the part dimensions carefully.
4. Compare measurements to the design specs.
5. Adjust the program if needed.
6. Repeat until the part matches specs.

This is a process, not a single command.

Use measuring tools like calipers or CMM machines for accuracy.

Examples

A simple cycle of running, measuring, and adjusting to get the hole size right.

CNC Programming

Run program on machine
Measure hole diameter
Compare to drawing
Adjust tool offset
Run again

Using a Coordinate Measuring Machine (CMM) to verify all dimensions precisely.

CNC Programming

Load new program
Cut first part
Use CMM to check all dimensions
Update program coordinates
Confirm with second part

Sample Program

This CNC program cuts a square 50mm by 50mm. After running, measure the square sides to check if they match 50mm exactly. Adjust tool offsets if needed.

CNC Programming

O1000 (First Article Inspection Example)
G21 (Set units to mm)
G90 (Absolute positioning)
T1 M06 (Tool change to tool 1)
G00 X0 Y0 Z5 (Move to start position)
G01 Z-5 F100 (Cut down 5mm)
G01 X50 Y0 F200 (Cut line 50mm)
G01 Y50 (Cut line 50mm)
G01 X0 (Cut line back to X0)
G01 Y0 (Cut line back to Y0)
G00 Z5 (Retract tool)
M30 (End program)

Important Notes

Always document measurements and adjustments during first article inspection.

Use proper safety gear and follow machine operation rules.

First article inspection reduces waste and improves product quality.

Summary

First article inspection checks the first part made by a CNC program.

It involves running the program, measuring the part, and adjusting if needed.

This process helps catch errors early and ensures quality before full production.