Question

Design a study to test the effectiveness of different nano-material coatings to improve the wear resistance of industrial cutting tools. What would be a key variable to control?

• A. Coating thickness
• B. Ambient temperature
• C. Tool design
• D. Cutting speed

Hint:

Controlled Experiments. To compare the effect of one variable (e.g., coating material), keep all other potentially influencing factors (e.g., testing conditions like speed/temp, and sample parameters like coating thickness, tool geometry) constant.

Answer 1

The Correct Option is A

When designing a study to compare the effectiveness of *different* nano-material coatings, the goal is to isolate the effect of the coating material itself on wear resistance.
To do this, all other factors that could influence wear must be kept constant (controlled variables).
These external factors include ambient temperature, tool design/geometry, cutting speed, feed rate, workpiece material, use of coolant, etc.
(Options 2, 3, 4).
However, the properties of the coating application itself, such as its thickness and uniformity, can also significantly affect wear performance.
If you are comparing *different coating materials*, you need to ensure they are applied under comparable conditions to allow a fair comparison.
Therefore, controlling the coating thickness (i.
e.
, applying each different material to the same, consistent thickness) is a key variable related to the coating process itself that must be controlled to ensure the observed differences in wear resistance are primarily due to the material composition and not variations in thickness.