Rennco LLC: Rennco LLC: Plug and bag simplicity

Plug-and-play is the intent for Rennco’s E-Pac™ bagger, which plugs into a standard 120-volt AC outlet. It also combines for users the usually mutually exclusive aspects of simplicity and sophistication.

“It’s radically different for us,” says Robin Thurgood, vice-president of engineering at Rennco.

The difference is electronic motion control in place of the pneumatic controls of Rennco’s previous offerings. The E-Pac operates without air.

The improved version features an “intelligent” human/machine interface from Xycom Automation that integrates the machine’s control. The model LT Series H-ADT HMI eliminates the need for a separate programmable logic controller, thus eliminating a box located on the backside of the machine.

“The HMI integrates a touchscreen operator interface, a programmable logic controller, servo control, and analog control,” says Thurgood. “It allows us to build a machine more rapidly, yet with much less wiring. It uses a lot of plug-in cabling rather than point-to-point wiring. And there is only one program for all functions of the machine.” Programming is done using LT Editor, a de facto controller programming language; all basic operations are mouse prompted. The HMI offers 32 input/output points.

Tool-less changeovers

The bagger features two servo drives, one that operates the sealing jaws and a second that operates the film advance. Servo control of major adjustments has eliminated mechanical parts and assemblies that were previously used.

The electronics also helps on changeovers. “It gives us a lot of flexibility, rather than the ‘unbolt this and move it over to that hole’ approach,” notes Thurgood. “The machine is truly tool-less when it comes to changeover.”

The servo components also allowed Rennco to use lighter sheet metal construction. Thurgood says that they are also making fewer electrical connections per machine and more plug-in connections. It is also ergonomically designed for operator ease, and is in fact shorter in height than prior models, an attribute especially welcome in certain markets outside the United States.

The general-purpose machine is designed to package notebooks, video cassettes, paint rollers, dental supplies—anything that goes into a bag, says Thurgood.

It was also crucial that the machine remain easy-to-use, adds Thurgood. He says that simplifying the operator controls and the ease of film threading means users can be more effective more quickly.

It operates at a rate of 30-35 bags/min, though Thurgood says if someone can throw products into it faster, such as tennis balls, then the machine can bag faster.

Assembly is faster due to the simplified electrical system, which does not use a main electrical enclosure as previous models did. Also not having to assemble and install a pneumatic control system has saved time and expense. The sum of factors combines to reduce assembly time by at least 30%, according to Thurgood.

What all this means for users is a selling price 20% lower than a comparable machine. “That, along with ease of use, are the chief benefits for this new machine model,” says Thurgood.