Founded in 1994, Arnold Machine Inc. (Tiffin, OH) manufactures automated assembly equipment for the automotive, appliance and heavy equipment industries.

Recently, it landed a contract with an automotive parts supplier to build an automated system to assemble a component with three separate parts.

Among other requirements, the customer demanded that an operator be able to load up to six sets of parts and then leave the machine to run unattended. Floor space was also tight, because the machine had to be integrated into a larger workcell. Finally, because the customer's program volume and duration were not going to be especially large, the budget for the new system was extremely limited.

Although engineers at Arnold Machine knew a rotary indexing machine would satisfy most of the customer's criteria, such a system would be too big for the allotted floor space. An in-line cam or servo-indexing machine, on the other hand, would have easily solved the space problem, but it would have been too expensive for the project's small budget.

To solve the problem, Arnold Machine went with a lower-cost pneumatic indexing system from conveyor manufacturer Northstar Industries Inc. (Tiffin, OH). The resulting 8-foot-long system, employs a series of 8-by-6-inch pallets, each equipped with a single nesting fixture. The conveyor is long enough so that a number of nests are exposed for loading at the same time a number of the other nests are inside the machine being processed.

The system's heavy-duty frame serves as a solid base for mounting assembly tooling, and its $20,000 price tag proved instrumental in bringing the project in under budget. The system's operating requirements are simple: three solenoid valves and six inputs. With a positioning accuracy of 0.003 inch, the conveyor is precise enough for a material-handling robot to unload the finished product with ease.

Northstar Industries' line of indexing conveyors is available in widths from 6 inches to 12 inches and lengths from 4 to 10 feet.

For more on automated assembly systems, call 419-443-1818 or

For more on conveyors and indexing systems, call 419-455-9258 or