Can a Cobot Work Without a Safety Fence?
Yes, sometimes—but a cobot is not automatically a fence-free machine. An open collaborative workspace is acceptable only when a risk assessment covers the complete application: robot, end effector, workpiece, process, people and every operating mode. If the remaining risk cannot be reduced and validated with collaborative safety functions or other safeguards, physical guarding is still needed.
When can a cobot operate without a safety fence?
A fence-free layout can be considered when people need to share the workspace, foreseeable contact or approach hazards have been reduced to an acceptable level, the selected safety functions match the task, and the finished cell passes documented validation.
“No fence” does not mean “no safeguards.” The system may still need safety scanners, safe speed limits, monitored zones, protective stops, interlocks, guarding around local pinch points, process enclosures, safe tools and controlled restart logic.
What conditions must be true before removing the fence?
This is an early engineering screen, not a compliance approval. If any condition is unknown, treat the layout as unresolved until a competent integrator or safety professional evaluates it.
Examples include loading a fixture, handing over a part, inspection or cooperative assembly. If nobody needs access during automatic motion, a guarded layout may be simpler and more productive.
A rounded gripper handling a light carton is not the same hazard as a sharp cutter, heavy casting, hot part or energized welding torch on the same robot arm.
Safe speed, separation monitoring, force limiting, local guarding and control logic must perform with the actual payload, reach, fixtures, floor layout and operator behavior.
If crushing, impact, ejection, radiation, heat, fume or other process risk remains unacceptable, use physical guarding, a process enclosure or a hybrid cell.
Why is the complete application—not the cobot arm—the safety unit?
A collaborative robot can provide safety-rated functions that help an integrator design shared work. Those functions do not remove hazards added by the rest of the cell. The same arm can be suitable for an open carton-handling task and unsuitable for an open laser-welding task.
The risk assessment therefore follows the completed application through normal work, setup, teaching, clearing a jam, tool change, maintenance and foreseeable misuse.
Which collaborative safety methods can support an open workspace?
The correct method depends on how people and the robot interact. A real cell may combine several methods and conventional safeguards.
Power and force limiting
The robot system is designed and configured so that contact-related risk is controlled. Assessment must include the actual tool, workpiece, contact geometry, body area, speed and payload—not only the bare robot.
Useful when contact is reasonably foreseeable and can be reduced to the accepted risk level.Speed and separation monitoring
Safety-rated sensing tracks people and reduces speed or stops motion before the required separation is lost. The calculation depends on approach speeds, response time, stopping performance and measurement uncertainty.
Useful when production can continue at reduced speed while a person approaches.Hand guiding and monitored standstill
Hand guiding supports deliberate operator-controlled movement. Monitored standstill holds the robot stopped while a person enters the collaborative workspace. Neither means unrestricted automatic motion beside a person.
Useful for teaching, positioning, loading or inspection when the operating sequence is clearly controlled.Do not select a safety method by product label alone. Ask which hazards it controls, which hazards remain, how the safety function is configured, and what test proves that it works in the final cell.
When does a cobot still need physical guarding?
A fence, enclosure or local guard is often the clearer answer when contact consequences are severe, access is not needed during automatic production, or open-operation controls would reduce speed so much that the business case disappears.
Sharp, heavy, hot or energized loads
Knives, spinning tools, pointed fixtures, heavy workpieces, hot metal and energized process equipment can create hazards that low robot speed alone cannot control.
Common response: enclose the process or guard the hazardous portion while keeping safe loading access.Crushing, trapping and high-energy motion
A cobot can still pin a person against a wall, table, fixture or another machine. Long reach, high payload and unexpected approach directions can increase impact or trapping risk.
Common response: change the layout, remove pinch points, monitor separation or add fixed guarding.Hazardous process and lifecycle tasks
Laser radiation, welding arc, spatter, fume, flying chips and stored energy remain process hazards. Recovery, cleaning and maintenance may also expose workers differently from normal production.
Common response: process enclosure, interlocks, extraction, lockout procedures and controlled access.How should a fence-free cobot risk assessment be structured?
The assessment should be completed for the final application and documented through its lifecycle. The following sequence turns a vague “cobot is safe” claim into evidence an engineering team can review.
Identify who enters the space, why access is needed, where interaction occurs and which production advantage the open layout is meant to create.
Record payload, reach, speed, tool, part family, fixtures, floor space, utilities, shifts, access points and environmental conditions.
Cover automatic work, loading, teaching, cleaning, tool change, fault recovery, maintenance and foreseeable misuse.
Consider severity, exposure and the possibility of avoiding harm. Include robot motion and non-robot hazards from the process.
Start with safer design, then engineering safeguards and safety functions, followed by information, training and procedures.
Test the finished system, document results and define which changes require reassessment—such as a new gripper, payload, recipe, fixture or layout.
What must be validated before production starts?
Validation must use the installed cell and agreed test conditions. A robot brochure, simulation or supplier statement is not proof that the completed application is safe.
| Validation area | Evidence to collect | Failure boundary |
|---|---|---|
| Safety functions | Configured safe speed, position, space, stop and reset behavior; safety-related control architecture; change protection. | The function is not safety-rated, not configured as assessed, or can be bypassed without controlled authorization. |
| Stopping and separation | Measured response and stopping performance under the specified payload, speed and operating conditions; sensor coverage and uncertainty. | The required separation cannot be maintained for the tested approach path or foreseeable entry. |
| Contact risk | Defined contact scenarios, test method, calibrated equipment, actual tool and workpiece, and results for relevant body regions. | Measured or foreseeable contact exceeds the accepted criteria, or trapping cannot be ruled out. |
| Tool, part and process | Secure gripping, retained parts, guarded sharp points, controlled heat/radiation/fume and verified failure behavior. | A dropped part, sharp edge, hot surface or hazardous process remains accessible at unacceptable risk. |
| Human tasks | Observed loading, unloading, teaching, cleaning, jam recovery and maintenance using the planned work instructions. | A normal or foreseeable task requires workers to defeat safeguards or enter an uncontrolled hazard area. |
| Restart and fault recovery | Manual reset location, clear field of view, unexpected-start prevention, emergency stop response and recovery sequence. | The system can restart with a person in the hazard area or recovery creates a new uncontrolled hazard. |
The exact acceptance criteria must come from the applicable standards, local law and the project risk assessment. They should be agreed before factory and site acceptance tests.
Can a cobot welding or laser cell run without a fence?
The robot arm may support collaborative motion, but welding and laser processing add hazards that must be controlled separately. This often leads to a hybrid or enclosed cell even when the cobot itself can work near people.
Laser welding and laser processing
Collaborative speed or force functions do not contain hazardous optical radiation. The design may need a process enclosure, interlocks, beam-control measures, suitable viewing protection, extraction and controlled access based on the actual laser class and application.
- Assess direct, reflected and scattered optical radiation.
- Include the workpiece, fixtures, openings and failure conditions.
- Validate interlocks, process stop and restart behavior.
- Control fume, hot material and fire risk.
Arc welding and thermal processes
An arc-welding cobot can expose workers to ultraviolet and infrared radiation, spatter, hot metal, electrical risk and fume. A low-speed arm does not reduce these process hazards to an acceptable level by itself.
- Screen arc radiation and contain spatter.
- Provide source-capture fume extraction.
- Control torch, wire, gas and hot-part hazards.
- Plan safe loading and recovery access.
A practical hybrid layout: keep the hazardous process enclosed or guarded, then use the cobot’s flexibility for setup, changeover or loading outside the active process. This can preserve useful access without treating collaboration as a substitute for process protection.
How do the main cobot safety standards fit together?
Use the editions and legal requirements that apply to the installation location. Standards support the engineering process; they do not replace local regulatory review or application-specific judgment.
Provides the general machinery risk-assessment and risk-reduction method across relevant lifecycle phases. ISO states that the edition remains current while a replacement is under development. Official ISO page.
Covers safety requirements for the industrial robot itself as partly completed machinery. Application hazards—including welding and laser processes—must still be addressed during integration. Official ISO page.
Covers integration of industrial robot applications and cells, including design, commissioning, operation, maintenance and decommissioning. It focuses on the completed system rather than the arm alone. Official ISO page.
Supplements ISO 10218 requirements and guidance for collaborative industrial robot systems and work environments. ISO lists it as published and marked for revision. Official ISO page.
The current U.S. national standard adopts ISO 10218 Parts 1 and 2 with U.S. modifications. A3 notes integrated collaborative guidance and updated terms including “monitored standstill.” A3 publication notice.
For U.S. workplaces, OSHA’s robot-system guidance emphasizes task and application risk assessment, worker involvement, stopping performance, force and pressure, tools, workpieces and process hazards. OSHA Technical Manual.
What should you ask the cobot integrator before ordering?
A credible proposal connects each safety claim to a defined configuration and acceptance test. Ask for the evidence while the layout, cycle time and commercial scope can still be changed.
Do not accept “collaborative robot” as the entire safety argument. The integrator should explain what makes the application collaborative and what happens when conditions change.
- Who is responsible for the application risk assessment, validation report and final technical file?
- Which collaborative operating method is used in each phase of the cycle?
- Which tool, payload, workpiece, speed and fixture configuration was assessed?
- What stopping, separation or contact tests will be witnessed during acceptance?
- Which hazards require local guards, scanners, interlocks or a process enclosure?
- What cycle time is achieved with the final safety settings—not with safeguards bypassed?
- Which changes require reassessment, and who is authorized to approve them?
- Which standards, local requirements and customer rules define acceptance?
Choose an open, hybrid or guarded cobot cell
The best layout is the one that controls the actual risk while meeting access, quality and production targets. “Fence-free” is not automatically safer, cheaper or faster.
When an open collaborative workspace makes sense
Typical fit: low-hazard handling, inspection or assembly with controlled payloads, suitable tools and clearly defined human interaction.
When a hybrid cobot cell makes sense
Typical fit: open or monitored loading combined with guarded automatic motion, local pinch-point protection or an enclosed laser or welding process.
When a guarded cobot cell makes sense
Typical fit: high-speed production, heavy or sharp parts, trapping points, hazardous processes, or applications with no need for access during automatic motion.
Continue from safety screening to application design
Use the next guide that matches your project stage, then validate the proposed layout with the actual parts, process and production conditions.
Sources and technical boundaries
This guide explains the decision logic at a practical level. The project team must confirm the applicable requirements and acceptance criteria for the actual location and machine.
- ISO 12100:2010 — machinery risk assessment and risk reduction.
- ISO 10218-1:2025 — industrial robot safety requirements.
- ISO 10218-2:2025 — industrial robot applications and cells.
- ISO/TS 15066:2016 — collaborative industrial robot systems and work environments.
- Association for Advancing Automation — publication summary for ANSI/A3 R15.06-2025.
- OSHA Technical Manual, Section IV, Chapter 4 — industrial robot system safety guidance.
Send the workpiece, material, process, payload, target cycle time, layout and operator tasks. Oceanplayer Laser can help define a practical system concept for further risk assessment and validation.