Cobot vs Conventional Case Packing and Palletizing

Define the physical job before comparing robot types

Case packing and palletizing are different tasks. Case packing places product into a shipping case; palletizing places cases onto a pallet in a pattern. A cobot arm and a conventional cell can each do either task, but the constraints differ. Start with the case: length, width, height, filled weight, closure type, surface friction and center of gravity. Then record the pallet pattern, tier count, slip sheets, stretch wrap and pallet exchange method.

Separate steady demand from peak demand. A line that averages 900 cases per hour but peaks at 1,300 needs a design point and a buffer strategy. Also list changeovers per shift, SKU count and whether operators will share the cell space. These facts decide more than the robot payload rating.

• Case dimensions and filled weight for every SKU in scope.
• Closure type, case surface and center of gravity.
• Pallet footprint, pattern, tier count and load height.
• Pallet exchange method, stretch wrap and slip sheets.
• Changeovers per shift and the case families that share a pattern.

Convert demand into a gross rate and a pallet cycle

Divide the hourly case target by 60 to get the required net cases per minute. For a hypothetical planning model, divide that rate by an assumed efficiency of 0.90 to estimate the required running rate. Define which losses that efficiency includes so exchange, wrapping and faults are not counted twice. Cases per pallet divided by net cases per minute gives the required average interval between completed pallets, not necessarily the active filling time at one station. Model each station's filling and exchange cycle, including operations that overlap. Consider accumulation or another pallet position where interruptions would otherwise prevent the required output.

Treat these as planning estimates. Confirm rate with a timed trial using representative cases, not a brochure rating. State the efficiency assumption and test it.

Worked example: one line, two automation shapes

Hypothetical example, not a quote or benchmark. A line needs 1,200 cases per hour. That is 20 cases per minute. At a planned efficiency of 90 percent, the gross design rate is 22.2 cases per minute, because 20 divided by 0.90 equals 22.2. Assume a cobot cell is rated at 8 cases per minute on this case and pattern. Three cobot cells provide 24 cases per minute gross on paper. That covers 22.2 only if the infeed can split cases evenly and the cells do not wait on each other, which must be verified in a trial. Assume a conventional cell is rated at 30 cases per minute. One conventional cell provides 30 cases per minute gross, also covering the need.

In the same hypothetical example, assume each pallet holds 48 cases. At 20 cases per minute net, the system must complete one pallet every 2.4 minutes on average, because 48 divided by 20 equals 2.4. If three cells receive equal shares and each builds its own pallet, each cell must complete a pallet every 7.2 minutes on average. A single palletizing cell must meet the 2.4-minute interval. These intervals include losses; they are not active filling times. Verify exchange duration, overlapping operations and buffer capacity for each layout before deciding whether either design meets demand.

When a cobot cell fits

Consider a cobot proposal for a pilot line, secondary station or application with frequent changes, but verify its actual rate, changeover procedure and safeguarded footprint. Shared space and manual intervention require evaluation of the complete application, not reliance on the cobot label. Check reach, cycle path and the manufacturer's load limits for the case, end effector and all carried equipment, including applicable center-of-gravity and inertia limits. Have qualified personnel assess safeguarding for the complete cell.

• Lower sustained rate with acceptable cycle margin.
• Demonstrated pattern or SKU changes within the required changeover time.
• A proposed footprint that accommodates all required safeguards and access.
• Simple case geometry and a gripper that can hold the filled weight.
• Operators available for replenishment, pallet exchange and fault recovery.

When a conventional cell fits

Evaluate a conventional cell against the required sustained rate, case range and interfaces with conveyors, pallet dispensers and stretch wrappers. Define safeguarding, safety controls and the operating envelope through qualified application-specific assessment. Compare demonstrated changeover time and engineering scope rather than assuming a fixed trade-off by robot type. Confirm performance across the agreed case weights, dimensions, patterns and closure conditions.

• High sustained rate with little pattern variation.
• Few SKUs and long runs.
• Space for guarding, conveyors and pallet storage.
• Controls and maintenance support available.
• Clear interface with upstream case packing and downstream stretch wrapping.

Use a hybrid design when the bottleneck is uneven

Hybrid designs can separate tasks. A cobot might pack cases while a conventional palletizer handles the pallet pattern, or a conventional case packer might feed a cobot palletizer. Evaluate both proposals against the actual product and rate requirements. Finite accumulation can absorb temporary rate differences, but sustained average output must remain balanced. Consider phased trials while defining interface requirements for the complete line before committing to either cell.

Keep interfaces simple. Define who clears jams, who changes the pattern and how the line restarts after a stop. A hybrid cell with unclear ownership can lose more time than a simpler design.

Decision table for cobot, conventional and hybrid cells

Use this table to frame the engineering questions. It is not a substitute for a timed trial with representative cases.

Validation and acceptance checklist

Build a factory acceptance test and a site acceptance test around the real job. Run the line at the gross design rate for a sustained period, then repeat with the heaviest case, the lightest case and the most awkward pattern. Time changeovers and fault recovery. Confirm that guards, interlocks and stop functions follow the site risk assessment. For packed load performance, define whether the objective is screening or prediction and select a distribution test method with that objective in mind; ISTA guidance notes that protocol choice depends on the test objective and knowledge of the distribution environment. The checklist below is Teal's editorial planning framework; the cited sources cover only specific underlying principles.

• Record actual case dimensions and expected dimensional variation for every SKU for equipment design. Record pallet footprint and load height separately. Maintain carrier-rounded shipping dimensions separately where applicable.
• Record filled case weight and compare it with the maximum gross weight on the Box Maker's Certificate or the case maker stated limit.
• Confirm gripper or clamp force does not damage the case or product.
• Run at gross design rate with representative cases.
• Test every pattern and changeover in the agreed range.
• Time pallet exchange, stretch wrap and restart after a jam.
• Verify accumulation does not create unstable or damaged cases.
• Review guarding, interlocks and emergency stops with qualified safety personnel.
• Select appropriate packed-case and unitized-load tests based on the distribution environment and test objective. Consider trial shipments as an adjunct to laboratory testing, not an automatic substitute.
• Document accepted rate, efficiency and open limitations.

Scope limits and what to confirm

This guide is a planning framework, not a robot selection, safety certification or cost estimate. It does not set guarding distances, risk levels or acceptance thresholds. Those require a site risk assessment and qualified engineering. It also does not determine carrier, marketplace or customer packaging requirements. If a channel program applies, confirm eligibility, testing and labelling in your own agreement. Automation can change how cases are handled, so revisit the packed load validation after any change to case, pattern, stretch wrap or pallet.

Use the arithmetic to frame questions, then validate with trials. A cell that meets a rate on paper can still fail on changeover, jam recovery or case damage.

Questions about case packing and palletizing automation selection