Metal Cutting Flashcards
What is the objective of the Metal Cutting Lab?
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.
What is the procedure for this lab? Part 1
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.
What is the procedures for this lab? Part 2
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.
What is the procedures for this lab? Part 3
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.
What is the conclusions for this lab?
The study examined how sequence number and machining parameters (length, diameters, and geometric features) correlated in solid vs. hollowed-out coupons. Key findings include:
Solid vs. Hollow Coupons: Solid components were more consistent across parameters compared to hollow ones.
Correlation Insights: Only length showed a clear correlation with sequence; other parameters lacked direct trends, possibly due to drill wear and human error.
Velocity and Diameter: Smaller diameters led to lower cutting velocities, with inside diameters showing slower velocities than outside diameters in hollow coupons.
Accuracy and Precision: Mean values were close, and standard deviations were small, indicating the machining process was accurate and measurements reliable.
This suggests the cutting process was effective, though minor discrepancies arose from tool wear and operator variability.
What are some specific things to remember?
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
