A model number is not a specification

We maintain a verified database of several hundred robots, and building it taught us something worth passing on: manufacturers name their products by incompatible conventions, and the number in the name is often not what you think.

Here is a genuine example. Yaskawa names its handling robots by payload, so a GP180 carries 180 kilograms. Yaskawa also names its welding robots by reach, so an AR1440 is a twelve kilogram arm with a 1,440 millimeter reach. Same manufacturer, same catalog, opposite conventions. Anyone who assumes consistency across a single brand's lines gets it backwards half the time.

It gets stranger. Panasonic names arc welding robots by reach, and their TM-1600 carries four kilograms, less than the smaller TM-1400 which carries six. Reading that series as ascending capability is simply wrong. Cloos uses both conventions in one product family: in some series the QIROX number is the working envelope in centimeters, and in the PL series the same style of number becomes payload in kilograms. FANUC's CR-35iB carries fifty kilograms despite the thirty five in its name. Kawasaki's CL103N carries three kilograms, not one hundred and three. ABB's SWIFTI CRB 1100 carries four, because 1100 is a series number.

Two more patterns cause real design errors. ABB's YuMi and Kawasaki's duAro publish payload per arm, so a dual arm YuMi is half a kilogram per arm rather than one kilogram combined. And every delta robot manufacturer we have checked, including ABB, FANUC, Codian and igus, publishes the working envelope as a diameter rather than a reach. An ABB IRB 360-6/1600 has a 1,600 millimeter envelope, meaning roughly an 800 millimeter working radius. FANUC's own American site labels that diameter as reach while their Japanese catalog defines it correctly.

Then there is the assumption that bigger is bigger. Within a single family, higher payload often means shorter reach, because the mechanics trade one for the other. ABB's ten kilogram GoFa reaches 1,520 millimeters while the twelve kilogram version reaches only 1,270. KUKA's iisy 11 outreaches the iisy 15. Picking the higher payload model without checking reach can put an arm in a cell it physically cannot cover.

Finally, ratings themselves are not single numbers. Epson names by maximum payload while publishing a rated payload at roughly half, so a GX8 is rated four kilograms with an eight kilogram maximum. Gripper makers frequently publish a friction grip figure and a form fit figure that differ by half again. Güdel publishes gantry capacity in newtons rather than kilograms.

We are not telling you this to make equipment selection sound frightening. We are telling you because it is the reason we verify every figure in our database against the manufacturer's own datasheet, with a date attached, rather than trusting an aggregator, a reseller listing or a model name. When somebody quotes you a robot, ask where the number came from. If the answer is the model name, ask again.