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My question is about the strength of the guard around a robot. We are building a machine that an operator will be within the reach of a robot. There will be a guard door with a interlock switch that is tied into the robot E-Stop. If the door is open the robot will stop. The problem is that the robot could break through the door guard. My question is, does the guarding system around a robot need to be stronger than any force the robot can apply or is it enough that the door interlock switch will trip if the door is broke through?

In your application, the guarding defines the restricted space. In that case, it definitely must be able to contain the robot motion. Even if the robot breaking through the door would generate a stop it is already too late. Any individual standing adjacent to the door would be struck by the door and the robot.

Lee Burk - Training Coordinator
l.burk@pilzusa.com

What are the current options for camera based, robot safety systems? Is there anything else besides PILZ SafetyEYE?

Not at this time. A competitive product was expected in 2009, but there has been no activity or news since late 2008.

Lee Burk - Manager, Training & Standards
l.burk@pilzusa.com

Do you forsee requirements for redundant valves in pneumatic systems or some similar impact on pneumatic systems in the upcomming release of R!A 15.06?

The safety-related controls performance requirements of RIA 15.06 is not limited to only electrical/electronic circuits. It applies equally to pneumatics and hydraulics. If your risk assessment requires Control Reliable performance, your valves will also have to be redundant and monitored.

Lee Burk - Manager, Training & Standards
l.burk@pilzusa.com

We have a number of die casting machines that are robot loaded and unloaded. The machines have light curtians on both the front (operator) area and side (robot) area. When the operators have to tilt the cope it breaks the front light curtians which e-stop the robot. To reset, the operator must hold an opto-touch and press a reset button together. I have been asked to add a bypass key switch for the front light curtians which will bypass only the front light curtians for the cope tilt. The robot would receive a cycle stop to finish it's task. The robot side light curtians would remain active and latch if broken e-stopping the robot. My question is if this is in compliance with the 15.06 standard?

Bypassing or muting the light curtain should only be accomplished by a safety-related circuit of equivalent performance. If your objective is to alleviate the reset procedure, I would suggest this can be accomplished by a request to enter function to allow the robot to complete the current task. After completion of the robot task, the robot can be placed in a safe state and the light curtain bypassed while tilting the cope.

Lee Burk - Manager, Training & Standards
l.burk@pilzusa.com

Regarding fixed barrier guards, what kind of impact from a robot would a fixed barrier guard have to sustain? In other words, if somebody is standing next to the fixed barrier guard outside the safeguarded space and the robot impacts fixed barrier guarding through some mishap how much deflection should fixed barrier guard allow to protect person standing next to it?

As Mr. Fryman has stated, if the barrier guard is the limiting device no deflection should be allowed.

Some standards, however, use a limit of 150 Newtons force for significant risk.

Lee Burk - Manager, Training & Standards
l.burk@pilzusa.com

What is robot interlock? How it will take place and what are its causes and remedies?

An interlock is a control function. A safety gate, for instance, may be interlocked either to prevent it being openned until robot motion has ceased or to cause cessation of robot motion if it is openned.

Lee Burk - Manager, Training & Standards
l.burk@pilzusa.com

Is there a safety standard available for using limit switches to limit motion of a six axis robot?

15.06 provides the requirements for safeguarding performance based on a risk assessment. This would apply to limiting the robot motion using "limit" switches as well. You'll have to look to the Euro standards for a specification for the actual switch device, however. In general, it should be positve acting, meaning the contacts are mechanically forced open.

Lee Burk - Manager, Training & Standards
l.burk@pilzusa.com

What do the standards say about distance between the entry/exit safeguarding into and out of a robot paint booth and the part?

Very good question as there are obviously potential crushing / shearing hazards at these points. Safeguardingsuch as light curtains with muting or profile gates should be provided to prevent access to these areas.

A good reference standard would be EN 349, SAFETY OF MACHINERY - MINIMUM GAPS TO AVOID CRUSHING OF PARTS OF THE HUMAN BODY

Lee Burk - Manager, Training & Standards
l.burk@pilzusa.com

I need to write a robotics safety policy for our company and need some direction or sample policies to go off of. Can I get some help or direction with this?

Suggest you try the OSHA web site. They have published Guidelines for Robotics Safety, STD 01-12-002. You can find it at

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=DIRECTIVES&p_id=1703

Lee Burk - Manager, Training & Standards
l.burk@pilzusa.com

I should have been less ambiguous in my question. Section 11.1 of RIA15.06:1999, it states in section (e) that fixed barriers shall require the use of tools to remove any fixed portion. Can a barrier be considered "fixed" if it has the ability to be locked? The key to the lock would only be available to trained maintenance personnel. In this sense, the key would be a tool. It would require a deliberate action by someone to gain access through the barrier.

Technically no, you are trying to stretch the definition. A lock and key is used only for movable guards. They provide simple and fast access. You are creating a gate in an otherwise fixed guard. Movable guards must be interlocked.

Lee Burk - Manager, Training & Standards
l.burk@pilzusa.com