Industrial Robotics
How Many Cases per Minute Can a Palletizing Robot Really Do?
Realistic palletizing throughput by robot type, with the arithmetic behind cases per minute, why layer picking beats single picking, and where the pattern costs you cycles.
A conventional six-axis palletizing robot handles 10 to 20 cases per minute single-picking, and 25 to 45 when it picks a full row or layer at once. Dedicated four-axis palletizers reach the upper end of that band with less energy, and the honest limit is almost never the robot: it is the infeed, the pattern, and the time spent slip-sheeting and changing pallets.
The arithmetic behind the rate
A single-case cycle is pick, lift, traverse, place, return. For a typical layout with a 1,400 mm traverse and a 600 mm lift, a 150 kg class arm needs roughly 1.2 s to 1.8 s of motion each way, plus 0.4 s to 0.8 s for gripper actuation at each end. That lands at 3.2 s to 5.2 s per case, so 11 to 18 cases per minute.
Picking multiple cases changes the equation completely. If the infeed presents a row of four cases and the gripper takes all four, the same 4.5 s cycle now moves four cases, and the rate rises to about 53 per minute at the gripper. In practice the infeed cannot always fill a full row, and squaring the row costs time, so 25 to 45 per minute is the realistic band.
| Configuration | Cases/min | Typical payload | Constraint |
|---|---|---|---|
| Collaborative arm, single pick | 5 to 9 | 16 to 30 kg | Speed cap and reach |
| 6-axis, single pick | 10 to 20 | 80 to 240 kg | Motion time per case |
| 6-axis, row pick | 25 to 45 | 160 to 300 kg | Infeed row formation |
| 4-axis dedicated palletizer | 25 to 45 | 160 to 700 kg | Infeed and pattern |
| Layer gantry | 60 to 120 | layer | Layer forming time |
| Bag palletizing, 25 kg sacks | 8 to 16 | 50 to 100 kg | Settling of a soft load |
The three costs nobody quotes
- Pallet change. An unbuffered station loses 15 s to 40 s per pallet. At 30 cases per minute and 60 cases per pallet, that is a 2-minute build interrupted by a 30-second stop, which is a 20 % throughput loss. Two-position stations or a shuttle remove it.
- Slip sheets and interlayers. Each sheet costs 2 s to 5 s including the vacuum cycle. On an 8-layer pallet that is 16 s to 40 s per pallet, comparable to the pallet change itself.
- Pattern complexity. Interlocked and pinwheel patterns require case rotations. Each 90-degree wrist rotation adds roughly 0.3 s to 0.6 s, and on a 60-case pallet with half the cases rotated that is 9 s to 18 s.
The gripper decides the ceiling
Palletizing gripper choice sets both the pick count and the reliability, and it is where most throughput is won or lost.
| Type | Handles | Cases per pick | Weakness |
|---|---|---|---|
| Vacuum cup array | Sealed cartons, cases | 1 to 6 | Fails on porous or wet board |
| Fork or clamp | Cases, trays, bundles | 1 to 4 | Needs clearance between cases |
| Bag gripper | Sacks, soft packs | 1 to 2 | Slow settling, dust |
| Combination vacuum and clamp | Mixed case sizes | 1 to 4 | Mass and complexity |
| Layer head | Full formed layer | whole layer | Requires layer forming station |
Vacuum performance on corrugated board is the single most common surprise. Recycled board with high porosity, cold storage condensation and print varnish all reduce the achievable holding force, sometimes by half. Testing with the actual board grade, in the actual ambient conditions, is the difference between a design that works in June and one that drops cases in January.
Sizing the cell honestly
- Take the line rate in cases per minute, at the peak, not the average.
- Add pattern overhead: roughly 10 % for rotations on interlocked patterns.
- Add sheet handling: seconds per sheet times sheets per pallet, divided by pallet build time.
- Add pallet change unless the station is buffered.
- Divide the required rate by the achievable cases per pick to get robot cycles per minute.
- Compare against 12 to 18 cycles per minute for a six-axis arm. If the answer exceeds that, you need multi-pick, a second robot or a layer solution.
Frequently asked questions
How many cases per minute can one robot palletize?
Roughly 10 to 20 single-picking and 25 to 45 when picking a row or layer. Dedicated four-axis palletizers sit at the upper end, and layer gantries reach 60 to 120 by placing an entire formed layer at once.
Is a four-axis palletizer faster than a six-axis robot?
Usually slightly, and it is more energy efficient, because it keeps the load level mechanically instead of coordinating wrist axes. The trade is flexibility: a four-axis machine cannot tilt, so it cannot handle angled placement or non-palletizing tasks.
Can a collaborative robot palletize?
Yes, at 5 to 9 cases per minute, which suits end-of-line stations with modest rates. Full pallet coverage generally needs the 20 kg class at about 1,750 mm reach, or a shorter arm on a lift column.
What limits throughput most often?
The infeed, followed by pallet change and slip sheets. A robot placing 40 cases per minute averages the line rate if the conveyor only delivers 22, and unbuffered pallet changes can remove 20 % of theoretical output.
Why do vacuum grippers drop cases in winter?
Condensation and cold board reduce the seal quality, and recycled corrugated is more porous than virgin board. Test the gripper with the actual board grade at the actual ambient conditions before committing to a cup layout.
Sources
- World Robotics 2025, industrial robotsInternational Federation of Robotics, handling as the largest application category
- ISO 9283, manipulating industrial robots, performance criteria and test methodsCycle and velocity definitions used for the throughput arithmetic
- ISO 10218-1:2025, Robotics, Safety requirements, Part 1International Organization for Standardization, requirements applying to palletizing cells