Its tough enough getting a new piece of machinery built and working. Turning out the same product reliably can be a challenge. Even something as simple as a V belt becomes a lot more complicated when you have to turn parts out by the thousands or tens of thousands.
Getting it done on time and in budget are basic requirements of the challenge. Over the years the only thing I have learned is that things always take more time and cost more than what was planned. Good planning rarely eliminates mistakes or discovering an unforeseen problem late in the project that can jeopardize the whole effort.
The fix, if there is one, is building some slack in the project work plan. So if it is at all possible, plan for 10 percent of the time and money to be set aside for contingency. This will allow room for corrections to take place within the project plan and help prevent delays to the project deliverables.
Among many competing priorities in machine development, one that is rarely discussed is life expectancy. Machine life expectancy is more subjective because component selections are not simple and straightforward. Many decisions will be based on judgement and experience rather than on an explicit technical basis.
Something simple like a pulley may be perceived to be more durable if made of steel instead of aluminum. But that component decision will increase the load mass. The increased load will then require a larger motor and drive to power it. And there are hundreds of similar choices that have to be made just like this.
Sprocket and chain mechanisms are generally indicated when high loads are being powered. But in a situation where high life expectancy or reliability are involved, may be preferred over belts and pulleys.
Mechanical components of this type are subject to significant variations in cost versus life expectancy. The basic metallurgy of parts will impacted. In one project, the balancing of load versus durability lead to the use of titanium. The increased cost of the material was offset by reduced cost in the motor and drive solution.
Plating and coating of parts can be a significant opportunity for improved life. Nickel plating has excellent performance in low friction, corrosion resistant coatings. There are a number of hard Teflon coatings that can be used for reducing friction.
The life expectancy question is also connected to the maintenance cost of equipment. For new machine designs, the maintenance issues are largely unknown and are part of the learning curve. But the reliability of any piece of equipment is a huge issue. And a lot harder to engineer in a systematic way. But always worth the effort.