Most selection mistakes are made in the first ten minutes, when a payload and a reach are picked from a catalogue before anyone has looked at the part. The robot then works, but it works at the edge of its envelope, and every later change — a second gun, a longer hose package, a taller hanger — costs a model change. This is the sequence we use before quoting.
Step 1 — add up what the wrist carries
Payload is not the weight of the gun. It is the gun or bell, the atomizing and fan air lines, the paint and solvent lines with paint in them, the trigger valve, any in-arm mixer, and the bracket. On a 2K application with an in-arm mixer, the difference between the gun weight and the real wrist load is substantial.
The GR and SR families cover 5, 8, 10, 12, 15 and 16 kg at the wrist. Pick the class above your calculated load, not the class that just fits — the margin is what absorbs a later change of applicator.
Step 2 — measure reach from the mounting point, not the part
Reach is a radius from the robot base. What matters is whether every point to be coated lies inside that radius at a workable gun angle and gun-to-part distance, with the arm not folded into itself. A 2 m part does not need a 2 m reach; depending on where the robot stands it may need 2,700 or 3,200 mm.
Our range runs from 1500 mm (GR6150-1500, for small irregular parts in compact booths) to 3750 mm (GR6100-3800, for long parts and full car-body sides). Between them, 2,700–2,900 mm covers most bumper, cab and body-side work from a fixed base.
Step 3 — decide how the robot is mounted
| Mounting | When it is the right answer | What it costs you |
|---|---|---|
| Floor | Standard case; parts within one reach radius | Floor space inside the booth |
| Wall or shelf | Narrow booths, conveyor passing close to the wall | A pass-through and a certified wall interface |
| Inverted / overhead | Coating from above, or clearing the conveyor | Structure, and harder access for maintenance |
| On a 7th axis (linear track) | Parts longer than one reach; several stations served by one robot | Track cost per metre, plus Ex-rated motors and cable carriers inside the booth |
Step 4 — check cycle time before you check price
Cycle time decides the number of robots, and the number of robots decides the budget. The inputs are the coated area, the film build, the fan pattern width, the overlap, the gun speed and the number of coats — plus the time lost to color change and to moving between faces.
Freeze the hanger design and the parts per hanger before this calculation. In one truck-wheel project, switching from one wheel per hanger to two changed the robot selection three times; the hanger is a customer decision that silently rewrites the robot specification.
What we need from you to do this properly
- Part drawings or dimensioned photographs, including the deepest recess that must be coated.
- Booth internal dimensions and the conveyor or hanger arrangement, with speed if it is a moving line.
- Paint system: 1K or 2K, solvent or waterborne, number of colours, required film build.
- Required output — parts per hour or jobs per hour — and the shift pattern.
- The hazardous area classification your safety engineer has assigned to the booth.
Frequently asked questions
Can one robot serve two booths?
Yes, with the SR portable series, which is designed for exactly that: a movable base, so one robot is wheeled between shared booths for small batches. For continuous production, a robot per booth or a robot on a linear track is the normal answer.
How much reach margin should I keep?
Enough that the arm is not working at full extension on any point of the part. Full extension costs you speed, path accuracy and the ability to reach the same point at a different gun angle later.
Do I need to know my film build before selection?
Yes, because film build and fan width set the gun speed, and gun speed sets the cycle time. Without it we can confirm reach and mounting but not the number of robots.
Request a quote Send drawings and we check the selection before quoting.