The Tooling Section of the Metal Processing Workshop is responsible for providing dedicated tooling systems for...

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The Tooling Section of the Metal Processing Workshop is responsible for providing dedicated tooling systems for each workshop in the factory. There are two lathes, two milling machines, a drilling machine, a surface grinder, a cylindrical grinder, a CNC wire cutting machine and an EDM machine in this section. Unfortunately, the main motor of one of the milling machines broke down over the last weekend and could not be repaired within a week. At 7:30 AM today (Monday, June 13), the Tooling Section received an urgent task to produce a set of new assembly fixture for the assembly workshop, which mainly consists of the following parts: (1) base plate, (2) vertical bracket, (3) middle plate, and (4) cover plate. The processing sequence and working-hours required for them are as follows: (1) Base plate: First, mill the upper and lower planes with the milling machine, which takes 3 hours. Then drill 4 big holes on the drilling machine, which takes 2 hours. Then send it to the surface grinder to finish the upper and lower planes, which takes 5 hours. (2) Vertical bracket: First, use the milling machine to mill its front plane, which takes 2 hours. Then 12 holes for jointing the plates will be drilled on the drilling machine, which takes 4.5 hours. Then go to the surface grinder, and it takes 3 hours to finish the front plane. (3) Middle plate: It takes 3 hours to mill the upper and lower planes with the milling machine first. Then two positioning holes will be drilled on the drilling machine, which takes 1.5 hours. Finally, it takes 8 hours to cut the contour line of the cavity on the CNC wire cutting machine to match the back casing of the portable monitor. (4) Cover plate: It takes 3 hours to mill the upper and lower planes with the milling machine first. Then drill 4 large holes on the drilling machine, which takes 2 hours. Then send it to the surface grinder to finish the lower planes, which takes 3 hours. The working hours of the Tooling Section are: 8:00 AM to 12:00 AM, 1:00 PM to 5 PM, and 6:30 PM to 9:30 PM, Monday to Saturday. The Section Head has set the highest priority for this new fixture task, hoping to complete the machining of the required parts as soon as possible. Assume that all machines (except the broken milling machine) and operators are available from 8:00 AM Monday. Please determine the sequence and schedule of the machining operations for the four parts. When is the earliest time that four parts can be finished so that the fixture assembly can start? The Tooling Section of the Metal Processing Workshop is responsible for providing dedicated tooling systems for each workshop in the factory. There are two lathes, two milling machines, a drilling machine, a surface grinder, a cylindrical grinder, a CNC wire cutting machine and an EDM machine in this section. Unfortunately, the main motor of one of the milling machines broke down over the last weekend and could not be repaired within a week. At 7:30 AM today (Monday, June 13), the Tooling Section received an urgent task to produce a set of new assembly fixture for the assembly workshop, which mainly consists of the following parts: (1) base plate, (2) vertical bracket, (3) middle plate, and (4) cover plate. The processing sequence and working-hours required for them are as follows: (1) Base plate: First, mill the upper and lower planes with the milling machine, which takes 3 hours. Then drill 4 big holes on the drilling machine, which takes 2 hours. Then send it to the surface grinder to finish the upper and lower planes, which takes 5 hours. (2) Vertical bracket: First, use the milling machine to mill its front plane, which takes 2 hours. Then 12 holes for jointing the plates will be drilled on the drilling machine, which takes 4.5 hours. Then go to the surface grinder, and it takes 3 hours to finish the front plane. (3) Middle plate: It takes 3 hours to mill the upper and lower planes with the milling machine first. Then two positioning holes will be drilled on the drilling machine, which takes 1.5 hours. Finally, it takes 8 hours to cut the contour line of the cavity on the CNC wire cutting machine to match the back casing of the portable monitor. (4) Cover plate: It takes 3 hours to mill the upper and lower planes with the milling machine first. Then drill 4 large holes on the drilling machine, which takes 2 hours. Then send it to the surface grinder to finish the lower planes, which takes 3 hours. The working hours of the Tooling Section are: 8:00 AM to 12:00 AM, 1:00 PM to 5 PM, and 6:30 PM to 9:30 PM, Monday to Saturday. The Section Head has set the highest priority for this new fixture task, hoping to complete the machining of the required parts as soon as possible. Assume that all machines (except the broken milling machine) and operators are available from 8:00 AM Monday. Please determine the sequence and schedule of the machining operations for the four parts. When is the earliest time that four parts can be finished so that the fixture assembly can start?