Metal Cutting

Question 1

What is the objective of the Metal Cutting Lab?

Answer 1

The objective of this lab is to familiarize students with the operation and components of a lathe, perform basic metal cutting operations, and apply measurement techniques to evaluate the parts produced. This experiment aims to enhance students’ understanding of metal cutting processes, precision machining, and metrology, providing hands-on experience in producing and measuring solid and hollow aluminum parts.

Question 2

What is the procedure for this lab? Part 1

Answer 2

Machining Solid Coupons
Setup and Safety

Mount the aluminum rod in the lathe chuck with no more than 2 inches exposed. Ensure proper alignment and secure with chuck teeth.
Familiarize yourself with the machine’s speed, feed rate, and safety features, especially the emergency foot brake.
Cutting Coupons

Use the high-speed range (325–385 RPM) to cut six solid 0.5-inch coupons. Mark each coupon sequentially.
Adjust the dial indicator to measure the desired length plus the tool width (0.610 inches).
Cut using the cross-slide hand-wheel with a uniform motion, ensuring cuts cross the rod’s center.
Facing Coupons

Mount the facing tool and create a flat surface on both sides of each coupon.

Question 3

What is the procedures for this lab? Part 2

Answer 3

Machining Hollow Coupons
Drilling Holes

Switch to low-speed range (315–385 RPM). Drill a 0.25-inch diameter hole into the aluminum rod to a depth of 3.75 inches using a center drill and a tailstock-mounted drill bit.
Withdraw the drill periodically to remove chips.
Cutting Coupons

Similar to solid coupons, cut six hollow 0.5-inch coupons. Ensure the rod extension remains under 2 inches to avoid deflection.
Facing Coupons

Use the facing tool to smooth both sides of each hollow coupon.

Question 4

What is the procedures for this lab? Part 3

Answer 4

Measurements
Dimensional Measurements

Use Vernier calipers to measure length, outer diameter, and inner diameter.
Parallelism

Evaluate parallelism between flat surfaces using a granite block, test indicator, and stand.
Circularity

Assess roundness using a v-block and test indicator on the outer diameter.
Concentricity

Measure alignment of inner and outer diameters using the same setup as circularity.
Perpendicularity

Measure the flat face’s alignment to the cylinder’s axis with a v-block and square block.

Cleanup
Clean the lathe and work area using a vacuum.
Return all tools and remaining materials.

Question 5

What is the conclusions for this lab?

Answer 5

1. Regression Analysis
   Regression analysis was performed to examine the relationship between sequence numbers and various parameters:
   Length
   Diameters
   Concentricity
   Circularity
   Parallelism
   Perpendicularity
2. Observations
   Solid Components:
   Showed more consistent parameter values compared to hollow coupons.
   Length Graph: The only parameter with a noticeable correlation to sequence number.
   Hollow Components:
   Displayed more variability, potentially due to tool wear and human error during machining and measurement.
3. Velocity Insights
   Calculations revealed that smaller diameters resulted in lower velocities:
   This was evident when comparing inside and outside diameters of the hollow components.
4. Overall Accuracy
   Standard Deviation and Mean:
   Values for all parameters were relatively close, indicating:
   Accurate machining processes.
   Reliable measurements.
   Minor deviations were present but did not significantly impact validity.

Question 6

What are some specific things to remember?

Answer 6

The material used was 1/2 inch diameter aluminum rod which was 8 inches long.
The goal of the lab was to make 6 solid and 6 hollow coupons with each have a length of 0.5 inches.
Carriage Movement (before cutting) = 0.61 inches toward the chuck.
Measurement Tool used “Vernier Calipers”
Facing Tool = Remove metal shaving and create a clean, flat surface.

Spindle Speed to drill hollow coupons = 315 RPM Hole size 1/4