Special machine time shortage is a scenario when a special machine is required (for a key or non-optional operation) and its usage demand is much more than its availability hours. For example, the vehicle keys these days are laser-cut to a specific combination for enhanced vehicle security. Imagine if the manufacturer of the car keys has only one laser cut machine that takes about 5 minutes to laser-cut the pattern on a key. However, it takes only one minute to complete the other operations on the raw key (say, printing vehicle brand, putting it in a ring, etc.). In this case, the laser-cut machine is the bottleneck to the production and for a large enough order (more than 288/day in this case) we are bound by the machine. In this case there is a shortage of time on this special machine and we cannot exceed the production.
There are some solutions to the problem of special machine time shortage. We can bring in additional special machines to distribute the time over more machines. We can also try to increase the efficiency of the machine to reduce the time consumption per unit product, thereby freeing up additional time. Another solution is to increase the price of machine use, thereby putting some deterrent on machine time usage.
More detailed solutions are not possible without further information, however these generic solutions may provide you with some ideas to tackle the problem of special machine time shortage.