Question

a 1.70 in. diameter hole, 4.00 in. deep (allowances 0.90 inches) is drilled in 1020 steel at a cutting speed of 300.00 fpm with a feed of 0.03 ipr. what is the cutting time (in minutes)? use two decimal places in the final answer.

Answer 1

The cutting time to drill a 1.70 inch diameter hole, 4.00 inches deep in 1020 steel at a 300 fpm cutting speed with a feed of 0.03 ipr, is calculated to be 0.59 minutes.

Step-by-step explanation:

The question asks to calculate the cutting time for drilling a hole in 1020 steel with given dimensions and cutting conditions. To do this, we must first determine the spindle speed in revolutions per minute (RPM) and then use the feed rate to find the time it takes to drill 4.00 inches deep.

First, we calculate the spindle speed using the formula Spindle Speed (RPM) = (Cutting Speed x 4) / (pi x Diameter). We have a cutting speed of 300 fpm and a diameter of 1.70 inches. Plugging these into the formula gives:

RPM = (300 x 4) / (pi x 1.70)
RPM = 224.86 (rounded to two decimal places)

Next, we calculate the cutting time using the feed rate and the depth of the hole. The formula for cutting time is Cutting Time (minutes) = Depth / (Feed x RPM). With a depth of 4.00 inches, a feed of 0.03 ipr, and RPM of 224.86, we get:

Cutting Time = 4.00 / (0.03 x 224.86)
Cutting Time = 0.59 minutes (rounded to two decimal places)

Hence, the cutting time to drill a 1.70 inch diameter hole that is 4.00 inches deep in 1020 steel at a cutting speed of 300 fpm with a feed of 0.03 ipr is 0.59 minutes.