Day one of commissioning: payload and reach are checked, the comparison table picks the right tier. The first cycle runs—and the part slips two centimeters above the tray. The gap is usually the hand, not the arm.
Your end effector (EOAT: fixtures, grippers, vacuum cups, adapters, and custom nests) is the last interface between the task and the robot flange. Answer three questions before you open any catalog: what must this station do, what takt do you owe, and what does the part look like—can it be gripped, can it be sealed for vacuum?
Pick the category first: three common paths
Gripper path — when there is a face to clamp
Edges, shafts, bosses with a clear grasp surface. Before you order, write down: single vs dual grip, jaw stroke needed, parallel clamping in a narrow gap or not. Gripper mass and extension add directly at the TCP—and belong in your payload and reach ledger.
Vacuum path — when the surface is flat and sealable
Panels, glass, smooth metal plate. Write down: vacuum build time in seconds, whether slotted or porous surfaces hold, whether vent-to-release will eat takt. Valve stack, bracket, and cup mass and length count at the TCP too.
Custom fixture path — when profile locates the part or changeover is rare
Tray nests, irregular parts, one flange shared across stations. Write down: locating only vs locating plus clamping, changeover frequency, and whether parts arrive from conveyor or tray.
Floor example: 40 mm plastic bottle into a case
Round body, smooth surface, 6 s takt—many teams default to a gripper. Small contact patch on a cylinder slips easily; when the line allows, vacuum is often steadier if build time stays under ~1 s and fits the beat. Irregular bottles or case nesting may need a nest fixture first, then vacuum or grip. Pick the path, then the brand.
If your part looks like this → start here
Shaft, frame, or reliable grasp faces → gripper path; verify stroke and clamp force
Flat and sealable, vacuum allowed → vacuum path; verify build/release inside takt
Complex shape located by profile → custom fixture; then decide on clamping
Four things to align before you quote EOAT
Flange and interface — will it mount
Most cobots use ISO 9409-1 flange. Tell your supplier: flange size, bolt circle, how many tool I/O lines you need (grip open/close, vacuum on/off), and whether signals land in the robot cabinet or PLC.
Action time inside takt — will it finish in time
Put open/close or vacuum on/off into the beat budget. In a 6 s cycle, 1.2 s jaw close is part of the move—not a surprise after commissioning.
Process and compliance — allowed on your floor
Food, medical, cleanroom, or contact-sensitive surfaces may restrict lubricants, materials, or particulate. Put that in the EOAT spec up front.
TCP mass and extension — match payload and reach
Finalize gripper/vacuum/adapter/custom plate total mass and farthest extension here. Have not validated payload and reach yet? Read: https://roooll.com/en/insights/guides/choose-right-payload and https://roooll.com/en/insights/guides/how-to-calculate-cobot-reach
One page for your integrator (copy-paste ready)
Part: size, material, unit weight, photo or sketch
Motion: pick/place direction, stroke, takt target (seconds per piece)
Path bias: gripper / vacuum / custom fixture (or “TBD on site”)
Interface: flange type, tool I/O count needed
Constraints: install space, clean/food/medical rules if any
Attachments: floor photo or CAD screenshot
Buy off-the-shelf when it covers the job; pull in an integrator when geometry is tight or takt has no margin.
Next step
Browse Roooll end-of-arm accessories (grippers and fixtures): https://roooll.com/en/accessories/grippers
Put payload, reach, and flange fit in one comparison table: https://roooll.com/en/selector/comparison
Need to narrow paths by application first? Start with the Product Advisor: https://roooll.com/en/selector/advisor
Have sample parts or a station sketch? Share them—we will help validate real constraints: https://roooll.com/en/contact
