The Case for Rapid Prototyping

The prominent factor in creating successful machines is not the technology, but the experience and expertise of the people who specify, design, and build them

 

As a controls engineer for a company that designs and builds custom automation equipment, many of the clients I work with are under continued and intense pressure to reduce time-to-market for new products. To do this, they often need to produce limited quantities of a new product in a production-representative setting, but cannot commit to full production lines for products and/or processes that are not yet fully understood. That's when our clients come to us to rapidly design and build prototype equipment.

Here are a few of the key client requirements and expectations for rapid prototype equipment:

* Strict Schedule Requirements: The speed at which a new product can be introduced to the marketplace frequently will determine the success or failure of the product, so the pressure to meet production deadlines with the equipment can be high.

* Minimize Risk: The equipment must function right out of the gate, as there's rarely an opportunity to rework a faulty design. The costs to a client from a missed equipment delivery milestone could dwarf the entire cost of the equipment.

* Future Scalability: The word prototype implies that the client's product design and processes may not be in its final form, so the equipment should be capable of being easily modified or expanded to meet future needs. In many cases the client will want the flexibility to modify the equipment in-house.

* Compatibility with Existing Infrastructure: Most large manufacturing companies have controls standards that include the component vendors and even the technology to be used.

* Complete Documentation: Clear, concise documentation helps minimize training time for production and maintenance personnel.

All this is a tall order with the reality of balancing time and budget constraints. Therefore, what are the design principles we use in evaluating the potential technologies for use?

We start by incorporating proven, off-the-shelf components. In addition to reducing risk, the design cycle can be significantly shortened.

A good working relationship and communication between the client's technical people and the machine provider's engineers is key. As a machine provider it's our responsibility to ensure the client is made aware of all opportunities, options, and tradeoffs that will ultimately determine machine performance, flexibility, schedule, and price.

Using new technologies can insert unneeded risk, but because of the processes involved, sometimes they cannot be avoided. Again, the decision between balancing risk and performance should be addressed by the client and the machine builder together. We are often driven to new technology when required by the application, but we will not drive the application to the new technology. Several technologies such as system simulation, vision systems, 3-D solid modeling, and highly integrated systems have given us a tremendous boost in delivering on time and in step with client need.

Reusing proven subsystem designs has the potential to reduce risk and schedule. New software applications allow for portable control routines, and increased hardware integration allows for greater modularity and flexibility. Customization to reduce cost and optimize performance is often not possible due to time restraints.

Using general-purpose tools such as robots, servo motors, and graphical user interfaces to provide more flexible and adaptable machines can increase the initial cost, but the schedule and modification costs will often be decreased.

Considering software flexibility in the design process can yield significant benefits. Systems that can be modified through software rather than hardware or mechanical means can reduce modification and ownership costs in the long run.

Using open standards such as DeviceNet, IEC 61131, ActiveX, etc., increases compatibility with other systems and decreases integration time. This highlights the necessity that a machine's hardware and software design be based on non-proprietary standards.

Obviously, each job is unique. There are no absolutes. What works in one application may be completely wrong for another. However, by using our experience and the combined intellectual capacity of our staff, we can choose techniques, components, and technologies that best meet our client's specific requirements.

After interviewing our clients and reviewing our own processes for this column, I found that the prominent driving factor in creating successful machines is not the technology, but the experience and expertise of the people who specify, design, and build the actual equipment. In the end, clients may not notice or even care about the technology used to create their equipment. However, they always care that the new equipment helps them get a job done in the most cost-effective and productive manner. Combining the creative use of new technology with practical, proven engineering concepts results in equipment that consistently meets or exceeds our client's expectations.

Roger Bates is a controls engineer for DWFritz Automation, a full-service automation systems design/build firm located in Portland, Ore. You can reach him at

rbates@dwfritz.com.
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