Question

Consider the drilling of through hole on the flashlight head. assume the feed of the drilling operation (i.e., the distance the drill penetrates per unit revolution) is f = 0.01 in/rev. a) calculate the material removal rate (in in3/s). b) knowing the specific energy for aluminum alloys is given as s = 0.275 hp×min/in3, estimate the power (in hp) required for this operation. c) estimate the rise in temperature at the tool-chip interface during the drilling (in f or °c). how close is it to the melting point of the workpiece material? for aluminum: - the density is 0.0975 lb/in3 - the specific heat is 166.5 ft×lb/lb×f - the thermal diffusivity is = 0.107 in2/s - the melting point is approximately 1220 °f = 660 °c

Answer 1

The question involves calculations for drilling a hole in aluminum, including material removal rate, power requirements, and potential temperature rise at the tool-chip interface. Specific formulae and conditions are required for precise calculations, but rough estimations indicate significant heat may be generated during the process.

Step-by-step explanation:

The question requires calculations related to the material removal rate, power required, and temperature rise in a drilling operation for aluminum.

Material Removal Rate Calculation

Given the feed f = 0.01 in/rev, we need to know the drill diameter and speed to calculate the material removal rate (MRR). Assuming we have that information, MRR can be calculated using the formula:

MRR = (pi * d^2 / 4) * f * N, where d is the drill diameter and N is the rotational speed in revolutions per second (rev/s).

Power Requirement Estimation

To estimate the power (P) in horsepower (hp) required for this drilling operation, we use the specific energy (s) given for aluminum alloys and the MRR using:

P = MRR * s, where the specific energy s = 0.275 hp×min/in3.

Temperature Rise Estimation

Estimating the temperature rise at the tool-chip interface is complex and requires detailed heat transfer analysis, which typically involves information about cutting conditions, tool geometry, and thermal properties of the material. Without specific formulae or cutting conditions provided, an accurate estimation cannot be given here.

However, it is known that the temperature can get very close to the material's melting point, which for aluminum is approximately 1220 °F or 660 °C, especially if cutting fluid is not used or if the cutting parameters are aggressive.