Introduction: Accuracy vs. Repeatability

In precision motion, "Accuracy" is a broad term that often leads to confusion. Does it mean how close you get to a target, or how consistently you return to it?

When browsing TOCO Mono Stages, you will encounter grades like C (Common), H (High), and P (Precision). Understanding these tiers is the key to balancing machine performance with your project budget.

1. The Three Tiers of TOCO Precision

2. What Determines the Grade?

The difference between a C grade and a P grade isn't just a label; it’s a result of the manufacturing process:

• Rail Grinding: Precision (P) grades undergo multiple passes of high-precision grinding to ensure the track is perfectly straight.

• Ball Screw Quality: P-grade stages use ground ball screws (C3 or C5 class), while C-grade stages might use high-quality rolled screws.

• Assembly Environment: Higher grades are assembled in temperature-controlled rooms to prevent thermal expansion from affecting the micron-level measurements.

3. The Impact of Geometric Tolerances

Beyond just "moving from point A to point B," the higher grades offer better Geometric Accuracy:

• Running Parallelism: As the carriage moves, does it stay perfectly parallel to the base? A P-grade stage minimizes "weaving" during travel.

• Flatness: Ensures the payload doesn't tilt or "dip" as it traverses the length of the rail.

4. Choosing the Right Grade for Your TCO

Buying a P-grade stage for a simple palletizing robot is an unnecessary expense. Conversely, using a C-grade stage for wafer inspection will lead to system failure.

• Rule of Thumb: Always specify the accuracy grade based on your tightest tolerance requirement, but don't over-specify where it isn't needed.

• This is the essence of optimizing your Total Cost of Ownership.