Assembly 101

Automotive Design & Production, August, 2005

What's happening on the plant floor? We asked Rodney Rusk, automotive industry manager, U.S. Electric Drives and Controls Group, Bosch Rexroth (www.boschrexroth.com; Hoffman Estates, IL) to take us through the issues facing OEMs as they weigh automation versus manpower, and determine the best way to share information from plant-floor equipment.

AD & P: What happened to the drive toward assembly plant automation?

Rusk: The automakers moved toward more automation in the hopes of producing vehicles faster, better, and cheaper by improving uptime and lessening the amount of manpower on their assembly lines. Unfortunately, in some cases, they locked themselves into only being able to do things a certain way because of the automation. They got the upfront savings they wanted, but any significant changes in what they were building resulted in reworking the machine or line. As a result, their long-term costs rose significantly.

AD & P: Is this the reason for the move to more flexible assembly?

Rusk: It's one of them. The shift we're seeing has manufacturers developing systems that--with the equipment they buy--gives enough flexibility to adapt to future changes with minor modifications to their assembly lines. In some cases, this means adding manpower because it is more adaptive than a machine built to certain specifications. For automakers, the biggest growth in manpower has been in powertrain production, where tweaks are made to a design almost every year. Automation flexibility, on the other hand, is critical in production of the vehicle structure where vehicle lifecycles run, on average, five years. However, after five years you don't want to throw away everything and start fresh, so you specify levels of flexibility in the machinery.

AD & P: What has this done to the purchasing process?

Rusk: It has become much more complicated for the OEMs because there are more variables to consider, including identifying vendors whose products are both forward and backward compatible. Beyond this, the three things OEMs should look for are: (1) the total machine design, (2) the manpower cost equation, and (3) upfront versus lifecycle costs for the entire line.

AD & P: What two topics are at the top of everyone's list these days?

Rusk: One is how the plant-floor equipment interfaces to the enterprise system. There is a global fight over how to transfer data from the proprietary systems automakers have built up over the years. There are champions for both the Profi-bus and Ethernet IP configurations, though I think the Ethernet will win in the end.

Nevertheless, we have to be ready for either one until there is a clear winner. Manufacturing has become much more reliable on a Windows-style software environment because it is more flexible and the programs are easier to use. However, it's also opened us up to virus exposure, software stability concerns, and trying to stay ahead of the curve to ensure that one thing they have done for one customer in the base program doesn't adversely affect us in future generations.

The other area of concern is safety. The safety concern includes knowing when machines are in safe-stop positions, and being able to protect humans from harm if they go into machines to do work. There is no overall global safety standard, and each region has its own philosophy on the subject. North American and Europe, in my opinion, are far ahead in trying to integrate safety into their machine designs because of the liability issues. Asia, where personal responsibility is expected, is beginning to push toward an industry standard safety protocol because of their move into North American and Europe with manufacturing facilities. It's not that they haven't thought of safety on their own, just that they have not thought of it in the same way. We're all going to have to come to some kind of consensus because companies like DaimlerChrysler and Ford view this as a differentiator for their suppliers.--CAS