When off-the-shelf servoamps more than meet project needs, custom-designed amps might still be the better choice.
Factors and trade-offs
The cost benefits of custom amplifiers should always be weighed against the risks and associated costs that a custom-development program entails.
The most obvious factor is need. Need evaluates in terms of form, fit, function, and cost. Machine designers should ask whether an existing, off-the-shelf product can fulfill these needs in a costeffective manner or not. If the answer is yes, then there is no need to pursue a custom solution.
Efforts to develop a custom product are only worthwhile if there is sufficient volume. The word "sufficient" is purposely vague in this context, since it depends greatly on the product itself and on the forecast quantities. Some vendors may require a certain minimum forecast quantity, while others may look at the subject with a view for potential revenue. Both factors are relevant.
Cost is the most sensitive aspect of custom-development programs. In many cases, vendors may ask machine builders to bear some of the costs associated with product development and, thus, also carry some of the risk in the success of the project.
Risks from the vendor viewpoint are associated with developing a product for a particular customer. They typically seek mechanisms to cover that risk. Vendors commonly determine a midrange estimate as part of the process. The burden falls on the machine builder who argues that paying for something that does not yet exist puts money at risk.
One way to reach accord between vendors and builders ties the payment of development costs tightly to development progress. The machine builder typically specifies program milestones along which progress is measured and verified. This mechanism is also favorable to the vendor as it adds another dimension of control to the program and helps the vendor meet program goals.
Any custom-development program has an associated timeline. Once the machine builder concludes a custom design is right in terms of form, fit, function, and cost, then the last key in the decision process determines whether the product can reach its intended market in time. The machine builder must demand, and the vendor must provide, detailed development schedules in order for the machine builder to make informed decisions.
A mistake often made at this point is expecting the schedule to be completely accurate. After all, the schedule is being laid out for a product under development. There is always some measure of risk associated with this process. Designing custom products around existing building blocks reduces the risk to the schedule.
One other risk is that the product functionality may turn out differently than what the customer expected. A strong servoamplifier vendor as partner is key to mitigating this risk for all sides.
Risk is greater when developing new technologies or capabilities. A healthy and honest evaluation of scheduling risks is required to achieve the win-win situation both vendor and machine builder desire.