Assignment task: In the welding operations of a bicycle manufacturer, a bike frame has a flow time of about 12.55 hours. The time in the welding operation is spent as follows: 2 hours waiting in front of the cutting machine for the batch to start, 1 hour waiting for the setup of the machine, 2 hours waiting for the other pieces of the batch to go through cutting, 1 minute at the cutting machine, and 3 hours waiting for the transfer to the welding machine, Then, at the welding machine, the unit spends 1 hour waiting in front of the welding machine for the batch to start, 2 hours waiting for the setup of the welding machine, 0.55 hours waiting for the other pieces of the batch to go through welding, 0.35 minutes at the welding machine, and 1 hour waiting for the transfer to the next department.
Determine the exact flow time. What is the value-added percentage of the flow time?