1. Preparation

1. Wear safety goggles, gloves, and an apron before starting the experiment.
2. Clean both the upper and lower compression dies thoroughly to remove dust, oil, or old lubricants.
3. Select the standard ring specimen
   (Example: Inner Diameter = 6 mm, Outer Diameter = 18 mm, Height = 6–12 mm).
4. Measure and record the initial inner diameter, outer diameter, and height using a Vernier caliper.
5. Apply a uniform layer of lubricant on the ring specimen (if a lubrication test is being performed).
6. Ensure the compression testing machine is switched on, calibrated, and the platens are aligned parallel.

2. Specimen Placement & Alignment

1. Place the ring specimen at the center of the lower die to ensure uniform loading.
2. Ensure the specimen stands perfectly vertical without inclination.
3. Slowly lower the upper die until it barely touches the top surface of the ring (zero-load position).
4. Verify that there is no misalignment between the specimen and the tool surfaces.

3. Compression Operation

1. Set the required loading speed or strain rate on the compression machine (typically slow for accuracy).
2. Begin applying compressive load gradually to avoid sudden deformation.
3. Observe the reduction in height during deformation.
4. Continue applying load until the specimen reaches the desired height reduction:
   • 25% reduction
   • 40% reduction
   • 50% reduction (as instructed)
5. Stop the machine once the target reduction is achieved.
6. Carefully remove the compressed ring specimen using pliers if it is hot.

4. Post-Compression Measurement

1. Clean the specimen surface to remove lubricant or metal debris.
2. Measure the final inner diameter, outer diameter, and height using a Vernier caliper or profile projector.
3. Take measurements at multiple points around the ring for accuracy.
4. Calculate:
   • Percentage reduction in height
   • Percentage change in inner diameter

5. Interpretation Using Calibration Curves

1. Use the Ring Compression Calibration Curves (Height Reduction vs. ID Change).
2. Plot or locate your experimental values on the chart.
3. Determine the friction factor (m) or coefficient of friction (μ).
4. Compare results for lubricated vs. unlubricated conditions (if applicable).
5. ID change interpretation:
   • ID decreases → High friction
   • ID increases → Low friction

6. Observations & Analysis

1. Record all initial and final measurements in a table.
2. Observe deformation patterns (collapse or expansion of inner diameter).
3. Note any barreling effect (indicating friction).
4. Check whether deformation is symmetrical.
5. Identify sources of error such as misalignment, measurement errors, or non-uniform lubrication.

7. Cleanup

1. Clean the dies and machine surface to remove lubricant or metal particles.
2. Switch off the compression testing machine.
3. Store measuring instruments properly.
4. Dispose or store the deformed ring specimen as per lab instructions.