Robotic palletizers

Palletizers are available in high-level, low-level, or robotic versions. In high-level palletizers, the case or product enters the palletizer via an overhead conveyor. In a low-level system, the case or product enters the palletizer at floor level or approximately 75-90 cm off the floor. Robotic palletizers generally operate at floor level and involve mechanical placement of the cases and/or rolls. 

Robotic palletizer systems have the abihty to orient the cases and to pick and place the trays, pads, and slip sheets. The robotic palletizers rate of operation will be considered too slow for most oil production lines. However, robotic palletizing systems will become more common for oil packaging lines based on the following issues ... 

The exact cutting to length of the rods/blanks in the green state is accomplished by external automatic high-efficiency sawing equipment cutting to a tolerance of 0.1 mm. The saw unit is fed by a fully-automatic robot pallet system. 

A robot often can be economically justified when the task of doing a certain packaging operation is an yzed in detail. For example, the palletizing of the fiber drums can be accomplished by human labor but work aids would be necessaiy in order to have acceptable production rates, reasonable operator fatigue, and a safe working environment. When the work aids are considered and their cost determined, the additional cost for providing robot capability is often of a small magnitude, which justifies its use to replace human labor. 

FIG. 21-53 Example of gantry-type robot having 4 axes which would he used for palletizing cartons or bags. Courtesy of C [Pg.1975]

FIG. 21-52 Fixed-position robot used for palletizing of corrugated fiberboard cartons. Robot is integrated with a personal computer using WINDOWS graphical-user interface. Courtesy of FANUC Robotics North America. Auburn HiU, MI.)... 

The using of multiple robots for loading a single pallet... 

Collection of molded components should be in sterile nonpaiticle shedding plastics. Robotic devices can be used to remove easily deformable components from the mold face and transfer them gently to receptacles. Wooden pallets should be avoided. There is no fundamental reason why injection molding processes should not operate in the total absence of personnel. The ideal is not often achieved. 

In the preassembly cell are automatic stations for pressing in different fastening nuts and screwing in several threaded tjolts. An industrial robot handles the frame parts. After removing the frames from the supply pallets, the robot brings the frame into a mechanical centering device for fine... 

The production line consists of two machines (Ml and M2), two robots (R1 and R2), and two conveyors. Each machine is serviced by a dedicated robot that performs the load/unload task. One conveyor is used to transport workpieces, a maximinn two at one time. The other conveyor is used to transport empty pallets. Three pallets are available in the system. Each workpiece is machined on Ml and then on M2. The machining time is 10 time miits on Ml and 16 time units on M2. The load and unload tasks takes 1 time unit. 

Load/Unload Stations Load/unload stations are employed to clamp/fixture parts on pallets before entering the system, and remove finished parts after their process cycle has been completed. These stations can employ human operators or robots to accomplish the task. 

The end effector could also be a magnet. The robot would energize the magnet to pick up metal objects and then shut off the current to release the object. An end effector could also be a syringe that dispenses liquids such as perfumes into bottles. Other end effectors resemble small forklifts designed to lift and move pallets. There are literally dozens of types of end effectors, each designed to handle a certain type of product. 

Feeding presentation of a component to the robot arm end effector in the correct orientation. Orientation can be achieved by vibratory/centrifugal bowl feeders, by receiving parts already orientated by the supplier in pallet, magazine or by escapement mechanisms for part feeding. 

When a part required for assembly is available within the manufacturing cell it is routed to an assembly station. Once the part arrives at the station, the robot is notified of its arrival by the host The robot moves the part from the pallet on the conveyor and places it in a fixture. Multiple parts/components may be required for an assembly. Assembly operations are carried out one step at a time. When assembly operations are complete, the host is notified and an empty pallet is requested. When the pallet arrives at the assembly station, the robot will move the assembled part onto the pallet. This sequence is repeated for each part to be assembled. 

In robot programming, positions are often expressed relative to local coordinate frame One reason is that it makes it easier to carry out changes. For example, if a robot has to pick several items from a pallet, it is best to express the positions in the coordinate frame of the pallet. If the pallet s position is changed, only the pallet s new position has to be entered, and the pick positions relative to the pallet can remain unchanged. 

A - GMF M-lOO ROBOT W1T KAREL CONTROLLER B - GMr S-IO ROBOT WITH A KAREL CONTROLLER C - PRATT VHITNEY MACHINING CENTER VlTH FANUC CONTROL D - PRATT VHITNEY LATHE WITH FAPT AND FANUC CONTROL E - ALLEN-BRADLEY expert VISION SYSTEM WITH TVG CAMERAS F - MITUTOYO COORDINATE MEASURING MACHINE G - ALLEN-BRADLEY PLC 5/25 H - MILL AND LATHE LIFT STATIONS I - palletized mill and LATHE STATIONS... 

A Karel controller is responsible for controlling the General Motors Fanuc (GMF) M-lOO cylindrical coordinate pick and place robot and the two palletizing stations for finished parts. The controller also communicates with the materials... 

Move to Load CONV pos 5 —Close robot hand —Pulse digital output 10 for 2 seconds to the PLC 5/25 to release the pallet from station... 

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