Final answer:
Manual machines are preferable for custom or prototype work, small run jobs, or when machinist's hands-on control is valuable. The choice between manual and CNC machines depends on cost considerations and the nature of the work, with manual being favorable when machine costs are higher or flexibility is needed.
Step-by-step explanation:
Manual machines can be a better choice than CNC machines in certain situations. When individual custom pieces or prototype parts are needed, manual machining can be more cost-effective and quicker to set up than programming a CNC machine. Manual machines also offer a hands-on approach where the machinist has a feel for the machining process, which is beneficial for creating unique or artistic items. Moreover, for small run jobs or simple operations, the manual machine's flexibility and lower capital cost can be preferred.
In the realm of manufacturing, a firm's decision-making process often involves choosing between different production technologies to optimize total costs. If the cost of machine hours decreases, as in production technology 3, it may encourage the use of more machines and less labor, thus leaning towards automated CNC machines. However, if machine costs increase, as indicated in production technology 2, the firm might shift towards lower capital and higher labor inputs, potentially benefiting from the flexibility of manual machines.