The space issues can be solved by using belt-driven actuators. They are a simple, readily-available system capable of being outﬁtted with any controls or motor package so it can be conveniently integrated into an existing plant management software infrastructure. These can be easily designed in many conﬁgurations. The beneﬁts of utilizing belt-driving actuators can be shown by comparing two common examples based on a standard conveyor to palletizer setups that are used in many industries.
6-Axis Robot. A 6-axis robot can be used to build pallets of cases that consist of in-process or ﬁnished products. Cases stacked up to 60 feet require a standard pallet that measures 48 inches by 40 inches. A robotic arm with a minimum reach of 96 inches is required to account for the increased distance the arm has to travel in an arc. An arm this size can cost upwards of $50,000. Additionally, a 90-degree rotation requires roughly 200 square feet of ﬂoor space to pick up a case.
Aside from the space and cost estimates, there are several safety requirements needed for installing a robot on a manufacturing ﬂoor:
A multi-axis belt-driven gantry for the same application can occupy the same space as the conveyor and pallet. Taking into account the mounting structure and safety stroke of the actuators, this would account for up to 10 square feet of ﬂoor space and between $6,000 and $7,000 per axis, totaling in at $28,000 for a 3-axis, 4-actuator gantry.
Vertical Palletizer. A vertical palletizer can be used if the conveyor line is overhead. If the product isn’t transferred overhead, the machine needs a special inclined conveyor that requires larger motion components to move the product against the force of gravity. In most setups, the machine builds each layer of the pallet and lowers it while simultaneously building the next layer. The layers require rotating packages to form the correct pattern, a process that adds cost to the conveyor because it must be done upstream from the system. They must also be large and strong so they can hold the weight of a growing pallet. This snowball effect can cause some of these machines to cost up to $100,000 and they can take up 300 square feet of space.
A gantry similar to the ﬁrst example, with an additional vertical lift unit for an elevated conveyor setup, would cost roughly $35,000 and take up no more than 10 percent of the required space.