Robot repeatability describes returning to a commanded condition consistently under specified conditions. It is not the same as absolute positioning accuracy, continuous-path performance, or the quality of a completed weld. Treating these as interchangeable can make a specification seem to prove much more than it actually does.
In this Article
- Four different questions
- Worked example: repeating the wrong location
- More axes do not change the meaning of quality
- What belongs in a useful application review
Four different questions
| Term or requirement | The question it addresses | What it does not establish alone |
|---|---|---|
| Repeatability | How consistently can the robot return under the stated conditions? | Whether the target corresponds to the actual joint |
| Positioning accuracy | How closely does the achieved pose match the intended pose? | Suitability of the welding process |
| Path behavior | How does the system follow the required movement? | Acceptance of the resulting weld |
| Weld acceptance | Does the completed joint meet the applicable requirements? | That every untested variation will behave identically |
Use the manufacturer's definition and test conditions for any published specification. Do not assume figures from different sources describe the same conditions or can be compared without context.
Worked example: repeating the wrong location
Imagine a robot repeating a programmed seam while incoming assemblies are located differently from the reference used to teach it. The motion may be repeatable even when it no longer corresponds to the actual joint.
This is a conceptual example, not a statement about a particular robot's measured error. It shows why consistent part presentation, appropriate programming, and any application-specific correction strategy belong in the complete method. A tighter robot specification does not by itself resolve a displaced workpiece.
More axes do not change the meaning of quality
The seventh joint in a Kassow arm adds configuration freedom. That can help maintain a useful tool approach around an obstruction. It does not make axis count a weld-quality certification or prove that a seven-axis arm is inherently more accurate than every six-axis arm.
Likewise, a six-axis robot can be part of a method that produces acceptable welds. The comparison should establish the required access and process capability, rather than infer acceptance from one robot specification.
What belongs in a useful application review
Confirm the intended path on the actual arrangement, then evaluate the weld using the relevant acceptance basis. Record the workpiece conditions and variants included. If additional sensing or correction is proposed, verify its configured scope rather than treating its name as unlimited compensation for variation.
The useful production goal is a repeatable method for accepted work. That includes the robot, the welding process, and the work presented to both. Seven-axis access can be one part of that method, but it should be credited with the geometric capability it actually provides.
Related Reading
- Why Manufacturing Consistency Is Becoming the Competitive Advantage in 2026
- Cobot Welding Fixtures: What to Plan Before Automating a Weldment
Discuss Your Welding Application
Works Cited
Kassow Robots. "7 Axis Collaborative Robot Arm: KR Series." Kassow Robots, https://www.kassowrobots.com/products/7-axis-collaborative-robot-arm-kr-series. Accessed 14 Sept. 2026.
TWI. "Robotic Arc Welding." TWI, https://www.twi-global.com/technical-knowledge/job-knowledge/robotic-arc-welding-135. Accessed 14 Sept. 2026.