Safety Light Curtains

  • Greetings!

    Was wondering if anyone has any bad experience with light curtains used for a milling set-up.
    Light curtains are usually placed around 2meters from the robots furthest reach point.


    I wonder, will the dust and chips set off the light curtains?

  • AD
  • also beware that not all light curtains are created equal. some are not safety rated. and even some of the safety rated are not rated for applications using robot or press.


    i have seen laser scanners that are very sensitive to dust and trip even if no dust cloud can be observed.

    but light curtains are not relying on reflection, they use beam-through and are much more immune to particles in the air and lens contamination. the light curtain however requires proper alignment. i use SICK laser pointer tool for this, AR60

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

  • I've never seen a light screen tripped by weld slag spray or dust, but I have seen them tripped by birds flying through them, and sometimes by someone amusing themselves by tossing small bolts or nuts through them. And it's intuitively obvious that enough dust accumulating on the optics would eventually cause them to be tripped.


    To deal with this, most light screens have some tolerance for extremely brief interruptions, and many have a "size" tolerance. But these tolerances have to be very small to still qualify for safety.

  • @kimalia

    What are the regulations in your country? It would be very kind to answer this question?

    I wonder, will the dust and chips set off the light curtains?

    The breaking tip is the problem and not dust but 2m in my opinion is to short anyway


    What are you actually asking for:

    Distance is to short and flying bullets are deadly (I have seen a flying bullet and only a wall (steel and teflar saved our lives)

  • @ all:


    the problem is not the distance between you and the robot (2m is too short; you may be within a time slot of 1 or 2 s (not much distince) but you may get hurt by the bullet (after beeing dead you could say the distance was ok, but the bullet killed me - did this help?)


    In robotics safety is a very important issue: SAFETY FIRST

    If you want an alibi I would suggest using a safety carbet; it could be still deadly (do you care about this?) but at least you had some thinking about it

  • Thanks for the many answers. we decided on a basic fence enclosure instead.

    I was simply skeptical about the 2meters, that is why I decided to post. :)

    thanks again to you all.

    Edited once, last by kimalia ().

  • let me type this very slowly : what...is...your...country...? what.. is ...your... light ..curtain... model?


    each country has own standards and regulations. are we supposed to guess?


    in Canada machine guarding directive is CSA Z432

    robotic safety standard is CSA Z434

    etc.


    light curtains have different resolutions. spacing of beams is NOT the same. if you are using light curtain 2m away from hazard, chances are that is not going to be finger-safe model ...

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

  • although you "typed" that slowly, doesn't mean that we have to read it slowly... or does it? ;)

    my original question was - will the dust and chips set off the light curtains? (2m away from the spindle)

    why you want to talk regulations, i have no idea. i do not care for the regulations in this case.

    model name - sure, but it is not necessary anymore.

    nevertheless, the matter is settled, as you can see in the post prior to your ''slowly'' written post.

  • Is your milling application just for fun (private use) or industrial use?

    The regulations help to make the system more safe therefore you should care

    industrial use.

    I'm completely aware that there are regulations. in the EU and in the country that I currently reside in.
    But again, as previously mentioned. Regulations has nothing to do with this post, and is completely off topic.

  • The poster went with a Fence instead of light curtain so probably isn't concerned with light curtain regulations anymore. With Milling and chips flying, a light curtain may cause issues so not a bad decision.


    The only safety issue that may be of concern is if you are using a cutting tool that could lose an insert and go flying through a wire fence opening. Depending on the tooling used and fence material used that may or may not be a concern. If that is a possibility then you should use solid fencing such as sheet metal instead of wire mesh to prevent a person on the outside from being struck.

    • Helpful

    i do not care for the regulations in this case.

    Anyone in this line of work who says something like that has proven they should not be trusted with automated equipment. Either they don't know what they're doing, or have a callous disregard for human life.


    Most of the people you're interacting with in this thread have been in the field long enough to see people injured, or even killed, by the attitude you implied above. I've had two incidents where I came within millimeters of losing my life because someone else said "I don't care" and proceeded to act on that attitude. And if I'm honest, I can count 2-3 incidents where I was the one who got careless (due to fatigue or moving too quickly) and got lucky that no one got hurt as a result of my carelessness.


    So, saying "I don't care" on this subject is a very good way to get experienced people to stop helping you on the forum. Because we don't want to help you in injuring or killing someone. And if you "don't care," you will injure or kill someone, eventually. It's hard enough to avoid even when you follow every safety rule obsessively.


    And before you try to say we're taking an offhand comment too seriously: this is a topic where we cannot afford to have a sense of humor. If someone says "I don't care," we have to take it seriously, barring explicit clarification. And anyone in the forum who enables this kind of attitude is a candidate for banning.


    TLDR: there are damned good reasons we take this subject seriously. Respect that or GTFO.


    EDIT: I probably came across as rather intemperate, above. There's a reason for that. I literally just left an entire production line that was, apparently, designed&built by a Chinese company, to apparently no safety standard, and shipped to be installed and put into production in a North American plant.


    There was no safety. At all. The robots had their built-in pendant E-Stops, but those only stopped that robot -- nothing else. There was no lock on the gate, not even a latch -- anyone could walk into the cell, at any time, and everything would keep running. There was no place to lock out air, electrical mains, or other energy sources -- killing the 480V mains to one robot required going to the plant level main electrical box and turning off the breakers for an entire zone of the building. Every safety interlock on the robot was hot-wired. There was no "software" safety -- the PLCs were non-safety rated, there was no CIP-Safe on the Ethernet/IP network, and no safety options installed in the robot (hence, no safety-rated way to ensure the robot couldn't punch right through the fence if someone programmed it incorrectly). Adding even minimal safety to meet RIA 15.06 will require massive amounts of new hardware, and re-wiring everything.


    In the two weeks this line had been powered up for installation, they've already had two "near miss" events where someone teaching one robot was nearly hit by an adjoining robot that someone else had put into automatic and accidentally started.


    I've seen some pretty damn serious safety oversights in the past, but this was pure, high-octane nightmare fuel. I did a massive write-up, helped add some makeshift interim safeties using the non-safe I/O, and made it clear I would not hesitate to call the responsible authorities if this plant was put into production without addressing these issues.

  • SkyeFire


    when I said ''I do not care for the regulations in this case.'' it means that I do not want to talk safety regulations in this thread. This thread is and should only be about the fact if the chips and dust from milling can set off the light curtains at a distance of 2meters from the furthest maximum reach point.

    In the end, as previously stated I'm no expert. I am a buyer who wanted a answer to a simple question that was not answered, so I dumped the light curtains and took the less ''fancy'' rout and ordered a fence instead.

    The company I bought the milling robot module from makes sure that all regulations are met.

  • Quote

    ...wanted a answer to a simple question that was not answered

    not for lack of trying... and we did not get our own questions answered.

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

  • I'm completely aware that there are regulations. in the EU and in the country that I currently reside in.
    But again, as previously mentioned. Regulations has nothing to do with this post, and is completely off topic.

    so why you did ask?


    as I know in the EU you can't even use a fence, you have to use a bullet proof wall (unless you want to kill someone)

  • n the end, as previously stated I'm no expert. I am a buyer who wanted a answer to a simple question that was not answered, so I dumped the light curtains and took the less ''fancy'' rout and ordered a fence instead.

    This question was answered and you as owner have to go to jail if someone has died (at least in the EU)

    Think about that

  • This question was answered and you as owner have to go to jail if someone has died (at least in the EU)

    Think about that

    "so why you did ask?" - I didnt.

    If some can die from milling foam with a robot... then what about angle grinders, nail guns, drills, etc. ?

    Edited once, last by kimalia ().

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