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 ð‘¢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

Calculations for material removal rate and power estimation for drilling cannot be conducted without additional information such as spindle speed and cutting force. Estimating the temperature rise precisely at the tool-chip interface also requires detailed process efficiency data. Without this, a precise answer cannot be provided.

Step-by-step explanation:

The question involves a drilling operation on a flashlight head made of aluminum, where the feed rate is given as 0.01 in/rev. The task requires calculation of material removal rate, estimation of power required, and estimating the rise in temperature at the tool-chip interface during drilling.

To calculate the material removal rate (MRR), we use the formula MRR = cross-sectional area of the hole × feed rate × spindle speed. The spindle speed is not provided in the question, thus MRR cannot be directly calculated without this information.

The specific energy (U) is given as 0.275 hp×min/in³. To estimate the power (P) required for drilling, we would normally use the formula P = U × MRR. However, since MRR is not available, we cannot proceed with this calculation either.

Estimating the temperature rise at the tool-chip interface involves considering factors such as the heat generated by the cutting action, which is a function of the work done by the cutting force and the efficiency of the process, as well as how that heat is dissipated through the material and the tool. Without specific data on the cutting force and the efficiency of the process, along with the spindle speed for calculating MRR, it's not possible to estimate the temperature rise accurately. Nevertheless, one should take into account that aluminum has a melting point of approximately 660 °C (1220 °F), and any temperature at the interface approaching this value would be a cause for concern as it nears the melting point of the workpiece material.