Is it necessary to take the workpiece to test the used YCM?

Author:J           Date:2025-11-01

1. Reveal Dynamic Performance Issues Hidden by Static Inspection
A used YCM may appear pristine at rest, with minimal wear on the guideways and leadscrews. However, its true condition is revealed once cutting forces are applied.

Machine Rigidity & Stability: Performing heavy cutting with your own workpiece and programming allows you to test the machine's vibration and stability under typical loads. Minor bearing wear, leadscrew backlash, or guideway defects may be difficult to detect during idle runs, but will manifest as chatter marks, unusual noises, or dimensional instability under cutting forces.

Spindle Performance: Spindle temperature rise, vibration, and power output under high speed and high load are critical. Using your own workpiece for testing verifies that the spindle maintains accuracy and smoothness at your required speeds and torques, avoiding the purchase of a "spitting" spindle.

2. Verify Machining Accuracy, Exceeding Standard Test Pieces
Sellers may use standard square or round test pieces to demonstrate that the machine's "accuracy meets standards."

Your Accuracy is True Accuracy: Standard test piece programming is typically optimized and uses simple materials. Your workpieces may have complex shapes, require multi-axis linkage, or use specific materials (such as stainless steel or titanium alloys). Built-in workpiece testing directly verifies whether the machine tool can meet your drawing requirements when machining your products, including positioning accuracy, repeatability, and contour accuracy.

Discovering Geometric Errors and Compensation Effectiveness: Minor perpendicularity and straightness errors that may exist in the machine tool may not be noticeable on simple test pieces, but can be amplified in specific features of your workpiece, thus exposing problems.

3. Testing the Practical Reliability of Key Auxiliary Functions

Tool Magazine and Tool Changer: Frequent, programmed tool changes using your own tool holders and tools thoroughly test the accuracy and stability of the tool magazine's robotic arm, and the presence of risks of tool drop or jamming. This is incomparable to no-load tool change testing.

CNC System and Programming Compatibility: Testing with familiar G-code programs identical to those used in production allows you to check for any potential compatibility issues with the machine tool's CNC system (such as Fanuc or Mitsubishi), program processing speed, and the actual effectiveness of high-speed, high-precision functions (such as look-ahead control).

4. Serving as the Core Basis for Final Negotiation and Decision-Making

Test results are the most powerful negotiation tool.

The Cornerstone of Bargaining Power: If the test reveals unsatisfactory surface finish, slight dimensional deviations, or abnormal noises during heavy cutting, these are not just "feelings," but concrete grounds for price negotiation. You can negotiate for potential subsequent repair and adjustment costs.

Avoiding Post-Purchase Disputes: "Seeing is believing." After testing, both parties can witness the machine tool's condition, effectively preventing disputes arising from substandard performance after delivery.

More Articles