The myth of the paperless society has long ago been debunked. It’s very possible that the use of paper, for many requirements, has actually increased over the last several years. With the acceleration in computer power, more reports, spitting out a variety of information, can be generated faster and in more detail. And now that almost every household has a personal computer with a desktop printer, the demand for printer and copier paper continues to grow.
Typical machine designs for the making and wrapping of reams of paper previously included a lot of cams and cam boxes. Cutting, slicing, stacking, adjusting, wrapping, and delivery involved a lot of continuous, intermittent, and reciprocating motion. Most of these elements were mechanically linked and driven by a primary power source. While the concept worked, it was a complex design and limited in speed.
A manufacturer of paper reams decided it was time to eliminate all the mechanical timing linkages. They approached us with a plan to integrate servo motors and gearheads to provide independent direct drive to all the operations. But, it wasn’t as easy a transition as some may think.
While many servo motors were up to the task, the gearhead was another story. The operation required up to 150 start/stop cycles per minute. This type of dynamic application would destroy most gearheads. Proper torque calculations were critical and a design that could hold up to the constant pounding was a necessity.
When our customer approached us with this challenge, we knew that a custom automation solution with a Servofoxx servo gearhead was the appropriate choice. They needed right-angle designs in a couple of different configurations and ratios, all of which were available to satisfy this tough application. In this case our series SKP2 and PSK2.
The Servofoxx provided several features that achieved the performance required. The low backlash was a must, to keep the reciprocating motion on target. The precision gearing kept transmission error to a minimum. The dual support planet shafts optimized bearing load sharing, and the widely spaced output bearings provided the radial capacity required.
The motor input assembly, which includes a flexible coupling, was a crucial element in guaranteeing maximum torque transmission and reduced gear wear. Many gearhead designs, which have a fixed motor connection, lock the sun gear in place. Inherent misalignments assure uneven load sharing between the planet gears. With a flexible motor connection, the sun gear is allowed the micro-movements necessary to guarantee perfect load sharing. This is important, especially in highly dynamic applications, to reduce wear and noise, and increase efficiency.
For the right-angle models, ground spiral bevel gears were incorporated. The precision bevels shared the loads over more of their tooth surface, drastically reducing wear and increasing shock capacity.
Most servo gearheads utilize aluminum mounting plates and bearing housings. With highly dynamic reciprocating motion, bolt holes and contact surfaces can wear rapidly, causing lost motion and lubrication leakage. With an all-cast iron construction, the Servofoxx was able to provide the superior torsional rigidity required.
There are many other types of applications, other than paper converting, that have high cycles. These include any machine that has high feed rates, such as bottling, packaging, part processing, metal converting, and others. When high cycles are present, peak torques are more prevalent, putting extra demands on mechanical components. But, when properly applied, many mechanical components can stand up to the challenge. It’s picking the right product for the job that determines success or failure.
While there are many servo gearheads on the market, few were appropriate for this application. Avoiding a misstep in selection is one of the main advantages of working with DieQua. We have the widest range of servo gearhead technologies available and the experience and expertise to help choose the right one for the job. Contact us for custom automation solutions and more.
