Mechanical Engineering.

23 May Mechanical Engineering.

Question 1

A machinist at a small job-shop has received an order for the milling of 5 round shafts of Aluminum Alloy (6061) that is 10” wide, 2’ long and 3” thick. The customer would like the round shafts to be reduced to a thickness of 1.5”. The milling machine has a tool that is 4” in diameter with 20 teeth. The maximum depth of each cut is .2” per pass. Assume that you have a cutting speed of 560 F.P.M. Also for every ten teeth on your cutting tool .075” is removed.

Determine the following:

1. Spindle speed in RPM

2. Chip Load or cut per tooth

3. Feed-rate in inches per minute

4. Number of passes required to meet specs.

5. Material Removal Rate in Cubic Inches Per Minute.

Assignment #2

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Question 2

A low carbon steel (1013) round shaft measuring 3 inches in diameter needs to be machined to a diameter of 2.145inches. The round shaft has a BHN hardness OF 145. The length of the cut needed is 2 inches. An allowance of .1 inches is made for touch-up when engaging the power feed. A High Speed Steel single point tool is being used to machine the round shaft. The depth of cut per pass is .035. Determine the following:

1. Spindle speed in R.P.M.

2. Feed Rate in I.P.R

3. The number of passes required

4. The total machining time in minutes

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Question 3

A block of ductile cast iron 4” long x 6” wide x 10” long. The cutter to be used has a 5 inch diameter with 6 C7 carbide inserts. The work piece has a hardness of BHN 180 and the depth of cut is .055.

Determine the following:

1. Spindle Speed in R.P.M

2. Recommended cut per tooth

3. Feed Rate in inches per minute.

Question 4

An aluminum plate requires a series of .5 diameter holes to be drilled through it with a 2 flute High Speed Steel drill bit. The work piece is 3” thick. The cutting speed in surface feet per minute is 250 and the feed rate is .035 inches per revolution

Determine the following

1. Spindle Speed in R.P.M

2. How much material is removed per cutting edge in one revolution

3. The time required for drilling per hole in seconds.

Question #5

A 4 inch diameter Aluminum round shaft needs to be turned down to a finishing diameter of 1.4 inches. The cutting tool to be used is a single point HSS tool. Cutting speed is 1100SPM and feed rate is .050 inches per revolution. Maximum depth of cut is .080 and the length of cut is 2.5 inches. A touch up length of .1 is added to the length of cut for the work piece. Find the following:

1. Spindle Speed

2. Total number of passes

3. Total machining time