Robotic Carton Palletizing Cell for End-of-Line Stacking

Why replace manual end-of-line stacking?

Motionwell Automation integrated automated palletizing robot systems for manufacturers in Singapore, replacing manual end-of-line pallet stacking with robotic automation. The systems use ABB industrial robots and 4-axis column palletizers, selected for payload capacity, reach, and reliability in high-duty-cycle applications.

Manual palletizing is the station where a line’s output meets a person’s endurance. Stack quality drifts across a shift, and a pallet that leans has to be re-squared before it can be wrapped or racked. Automating the last station also removes the lifting exposure that drives most end-of-line injury claims. The financial case is usually built the way we set it out in how to model warehouse automation ROI – labour hours are the visible input, but rework and damaged loads are often the larger term. This work belongs to our broader palletizing systems capability, and the cell-building side of it to robot integration services.

How is the cell designed?

Robot Selection

Motionwell selects palletizing robots based on application payload, reach, and cycle time requirements:

• ABB IRB 460: 4-axis palletizing robot with 110kg payload capacity and 2.4m reach. Capable of over 2,190 cycles per hour, making it one of the fastest palletizers in its class. Used for standard carton palletizing up to 25kg per case.
• Higher-payload platform: for multi-case grabs, full-layer picks, or individual cases above 30kg, the cell moves to a heavier palletizing platform. That selection is driven by case weight and layer pattern, not by a preferred brand.
• Robots are integrated with Motionwell’s standard Mitsubishi iQ-R PLC control architecture via EtherNet/IP, with the ABB IRC5 controller managing robot motion independently of the cell PLC.

Custom vacuum and mechanical gripper designs are engineered for each application. Typical grippers use Schmalz FXCB vacuum area grippers for carton picking, with Festo DSNU pneumatic cylinders for side-clamping when handling unstable or open-top cases.

Conveyor Integration

The infeed conveyor system uses Interroll drum motors driving 24V MDR (motor-driven roller) zones, providing zero-pressure accumulation upstream of the robot pick station:

• Powered roller conveyor infeed rated at 30 meters per minute from production line
• 3-zone accumulation buffer with SICK WTB4S photoelectric sensors for zone occupancy detection
• Carton squaring station with pneumatic side guides to ensure consistent pick position
• Reject lane with pneumatic diverter for out-of-spec cartons detected by upstream checkweigher

Carton presence, orientation and label facing are confirmed before the pick using the camera and lighting practice described on our machine vision inspection capability page. A mis-oriented case picked at speed is not a quality problem, it is a dropped load.

Layer Pattern Programming

Motionwell programs layer patterns using ABB RobotStudio offline simulation, verifying pallet stability and cycle time before deployment:

• Up to 50 stored patterns for different carton sizes and pallet layouts (1200x1000mm EUR and 1200x800mm standard pallets)
• Recipe-based changeover triggered by barcode scan or MES command, requiring zero mechanical adjustment
• Column, interlocking, and pinwheel pattern options optimized for pallet stability during transport
• Automatic pallet full detection via layer count and height sensor, triggering pallet conveyor indexing for stretch wrapper transfer

Safety System

The palletizing cell is enclosed with machine guarding panels and SICK M4000 safety light curtains at the pallet removal openings. Access doors use solenoid-locking safety interlocks. The safety circuit is designed to ISO 13849 Performance Level d, monitored by an ABB Pluto safety PLC. Performance level selection, muting of the pallet-exit light curtain and the LVD/CE test evidence are handled as part of our machine safety and compliance work.

Why choose a 4-axis column palletizer over a 6-axis arm?

4-Axis Column Palletizer Architecture

Alongside the articulated robot options described above, Motionwell also deploys 4-axis column-type palletizing robots for applications where the cost-performance ratio is the primary selection criterion. The 4-axis column palletizer uses a fundamentally different kinematic architecture from articulated robots:

The column design provides purely vertical lifting motion on J2, which is mechanically more efficient than the shoulder-elbow kinematics of articulated robots when the primary task is lifting cartons vertically onto pallets. The vertical column uses a ball-screw or rack-and-pinion drive with a counterbalance mechanism, reducing the servo motor sizing required compared to an articulated arm that must support the full payload at horizontal extension.

Performance Specifications

The repeat accuracy of +/-1mm is sufficient for carton palletizing where typical dimensional tolerances on the cartons themselves are +/-2-3mm. Chasing tighter placement accuracy than the carton itself holds is wasted money. The 6-10 carton per minute speed range handles most single-line end-of-line palletizing requirements. For higher-throughput applications requiring 12+ cartons per minute, Motionwell specifies the ABB IRB 460 articulated platform.

Heavy-Duty Linear Track for Extended Reach

For installations where a single palletizing robot must serve multiple pallet positions (for example, palletizing two or three SKUs simultaneously onto separate pallets), Motionwell mounts the column palletizer on a heavy-duty linear track. The track uses a rack-and-pinion drive system with hardened steel rails, providing:

• Extended working envelope spanning multiple palletizing stations along the track axis
• Positioning accuracy of +/-0.5mm along the track using an absolute linear encoder
• Travel speed up to 1.5 m/s between pallet positions
• Payload capacity rated for the combined weight of the robot, gripper, and maximum carton load

The linear track effectively multiplies the robot’s working area without adding a second robot. A single robot on a 6-meter track can serve three pallet positions with only a 2-3 second transit time between positions, which is absorbed into the natural pallet pattern cycle without reducing throughput.

Palletizing Robot Cost Versus a 6-Axis Solution

The 4-axis column palletizer with linear track typically costs 30-50% less than an equivalent 6-axis articulated robot solution for standard carton palletizing applications. The cost savings come from three factors:

1. Simpler mechanical design: Four axes with direct-drive column lift require fewer gearboxes, bearings, and structural castings than six-axis articulated arms.
2. Smaller servo drives: The counterbalanced column design and purely vertical lifting motion reduce the motor torque requirements compared to articulated robots that must support payload at varying arm extensions.
3. Simpler programming: 4-axis palletizing requires only position-rotation paths without the complex singularity avoidance and joint-limit management needed for 6-axis robots in confined palletizing cells.

Motionwell recommends the 4-axis column architecture for straightforward carton palletizing up to 200kg, where the application does not require the dexterity of 6-axis motion (such as bag palletizing, multi-face label application, or palletizing into constrained spaces). That 30-50% is a comparison between two architectures, not a price. The absolute number for a cell like this one comes from the case list rather than from a catalogue: case rate and SKU count set the robot class and the pattern work, case condition sets the gripper, and stack height decides whether a lift column or a 7th axis has to be added. Those drivers are set out on our palletizing systems page.

Constraints and trade-offs

Four axes instead of six. The column architecture costs 30-50% less for the same carton job, and the saving is structural rather than negotiated: fewer gearboxes, smaller servos because the counterbalanced column lifts vertically, and simpler paths with no singularity management. What is given up is wrist dexterity. Bag palletizing, applying labels to more than one face, and dropping cases into a constrained space all need the sixth axis. If any of those appear in the product roadmap, the saving is a false economy and the articulated platform is the right starting point.

Vacuum area gripping rather than mechanical clamping. Vacuum releases faster, marks nothing and adapts to different case footprints by zoning the pad. It fails on open-top cases, wet or dusty board, and unstable loads where the top face lifts away from the contents. Those applications get pneumatic side clamps added, which slows the cycle and adds a mechanism that has to be re-taught per case size.

One robot on a linear track instead of a second robot. A track lets a single arm serve three pallet positions with 2-3 seconds of transit absorbed into the pattern cycle, so throughput is unchanged. The trade-off is availability, not speed: a track fault, or the robot itself, takes all three pallet lanes down at once. Two robots on fixed bases fail independently. Where a stoppage on one SKU cannot be allowed to stop the other two, buy the second robot.

Placement accuracy matched to the carton, not to the robot. +/-1 mm was accepted because corrugated cases hold +/-2-3 mm on their own dimensions. Specifying a tighter arm would raise cost with no effect on stack quality.

Related work

This project demonstrates Motionwell’s robotics integration for the warehouse and intralogistics industry, and end-of-line cells like this one commonly sit downstream of consumer product and pharmaceutical packing lines. A related material-flow project is documented in the AGV fleet warehouse case study, and buyers weighing suppliers may want our checklist on choosing a system integrator.

To size a palletizing cell, send us your case dimensions, weights and line rate.

Frequently Asked Questions

What robots does Motionwell use for palletizing?

ABB industrial robots and 4-axis column palletizers, picked on case weight, reach and required rate rather than on brand. The ABB IRB 460 is a 4-axis palletizing arm with 110 kg payload and 2.4 m reach, rated above 2,190 cycles per hour, used for standard cartons up to 25 kg per case. Column palletizers cover 100-200 kg payload across a 2-3 m working radius at 6 to 10 cartons per minute. Multi-case grabs, full-layer picks and cases above 30 kg move to a heavier platform. Jobs needing wrist dexterity, such as bag palletizing or labelling more than one face, start from a 6-axis arm.

Can the system handle multiple product sizes?

Yes. Up to 50 layer patterns are stored on the cell, covering different carton sizes and both 1200x1000 mm EUR and 1200x800 mm standard pallets. Changeover is a recipe call triggered by a barcode scan or an MES command, with no mechanical adjustment. Patterns are built in ABB RobotStudio offline and simulated for pallet stability and cycle time before they run on the floor; column, interlocking and pinwheel arrangements are selected per product for stability in transport. Vacuum area grippers adapt to different case footprints by zoning the pad, while cases needing pneumatic side clamps have to be re-taught per size.

What throughput can palletizing robots achieve?

Throughput depends on carton weight, size and pallet pattern. A 4-axis column palletizer runs 6 to 10 cartons per minute, which covers most single-line end-of-line work. Applications needing more than 12 per minute move to an articulated platform such as the ABB IRB 460, rated above 2,190 cycles per hour. Infeed matters as much as the arm: the powered roller conveyor feeds at 30 meters per minute into a three-zone accumulation buffer, so the robot is not paced by upstream gaps. Where one robot on a linear track serves three pallet positions, the 2-3 second transit is absorbed into the pattern cycle.