Industrial PCs / PACs / PLCs

OEM builds flexible machines for demanding customers

Ehrhardt Combines User Input, Experience and Quality to Create Flexible Machines for Manufacturing Appliances, HVAC Units and Other Products

By Jim Montague

Variety might be the spice of life, but delivering it can be a headache. So if you need flexible machines that can make all kinds of new products and parts, it's vital to have an experienced builder that can provide all the innovations and quality you need.

"Our first job is to get our customers involved up-front and keep them involved in the design process, so we'll build a machine that does precisely what it's intended to do," says John Deibert, special machines business segment manager at Ehrhardt Tool & Machine in Granite City, Ill., just outside St. Louis. "This process is more important now because markets are demanding changes in the design, look and capabilities of many appliances, HVAC units and furnaces.  So instead of building a machine that produces one parts family for a furnace cabinet, our users need machines that can make more sizes and types of parts."

Ehrhardt designs, builds, assembles and tests tool and die, automated equipment and customized machines, mainly for users who need to punch, bend, form, weld and braze sheet metal. Most of its equipment is used to manufacture commercial and residential HVAC condenser units, heat exchangers, furnace cabinets and consumer appliances, such as washers, dryers, ovens, stoves and cooktops. It also builds leak-testing vessels and heat-exchange cells for forced-air residential furnaces.

Started by Willis Ehrhardt in 1937, the company operated during World War II and for decades after as a classic tool and die shop. In the early 1990s, Ehrhardt began adding automation and controls to its machines and sought to bridge its mechanical and electronic systems. "We wanted to be a one-stop shop for automation, controls and interfaces," Deibert says.

"So as part of the engineering group, I did the mechanics, Dave did the controls, and our philosophy was to combine them by taking an approach from the top on down. Fortunately, we had talented people and a team that could provide what customers needed, and we've been doing it for 20 years."

Deibert reports that Ehrhardt's machines and production lines use PLCs, PACs and HMIs from Rockwell Automation, Mitsubishi, Omron, Schneider Electric and GE Intelligent Platforms. These components and its machines are typically networked with EtherNet/IP. For its load aOmronnd testing equipment, Ehrhardt uses PC-based controls and LabVIEW software from National Instruments.

“EtherNet/IP is simple and easy for our users to understand, and it’s inexpensive,” Deibert adds. “We’re also doing remote diagnostics on critical equipment. Customers grant us access to their VPNs to monitor and adjust machines, but we're also looking at some Internet-based solutions."  

Besides involving customers, Dave King, Ehrhardt's senior controls engineer, adds that Ehrhardt's other driving force is quality and delivering a low cost of ownership to its users. "People might spend a bit more up-front, but they'll spend a lot less on a quality machine in the long run," King says.

"Now our machines can handle more patterns and make it easier for operators to enter data because our controls use more tag-based, portable software. This means operators can adjust recipes via on-screen fields for different parameters, which is simpler than typing in code. This is a lot like having reusable function blocks or a software library, which is more flexible than having to input a one-off ladder program for each machine." 


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