Safety Options for Robotic Systems

Sep 24, 2017

​There are very specific safety parameters to follow when integrating the robotic automation system. Items such as fencing, arc glare shield, and dividers will help to increase worker safety. Contact experts today to get started with the safety options.

Safe­ty equip­ment is an essen­tial part of any robot­ic sys­tem or work­cell to ensure the pro­tec­tion of your work­ers while your robot is in motion. There are a vari­ety of safe­ty options on the mar­ket today that will keep work­ers safe – phys­i­cal bar­ri­ers like fenc­ing, arc glare shield, and dividers, as well as invis­i­ble bar­ri­ers like light cur­tains and area scanners.

Safety features for robot systems

Fenc­ing, Arc Glare Shields and Dividers

These are the most com­mon safe­ty option. Fenc­ing pro­vides a phys­i­cal bar­ri­er that clos­es off the area around the robot itself, allow­ing peo­ple to see the set perime­ter of the work cell or sys­tem. These cages are sev­er­al feet tall, and their design depends on the appli­ca­tion and how much area needs to be safeguarded. 

Fenc­ing may also be cov­ered with cur­tains to keep debris from being thrown out­side of the perime­ter of the work cell or sys­tem. Some cur­tains pro­tect against debris and oth­ers pro­tect from arc glare. The bril­liant light present dur­ing an arc weld­ing process can cause eye irri­ta­tion or reti­nal dam­age if it is observed for long peri­ods. Weld­ing cur­tains pro­tect your eyes in a way sim­i­lar to a pair of sun­glass­es. Arc glare cur­tains, like Wil­son Spec­tra cur­tains, are avail­able in shades of yel­low, orange, grey and brown, and they are usu­al­ly fixed to the three sides of the work cell fenc­ing. This safe­ty option will absorb, fil­ter and scat­ter the light from the arc weld, reduc­ing the glare and improv­ing the work­ing envi­ron­ment for every­one in a weld­ing shop. 

Unlike arc glare shields, which are par­tial­ly trans­par­ent, met­al dividers work in a dif­fer­ent capac­i­ty to pro­tect a worker’s eyes from the impact of arc glare. When a 180-degree index­ing table is fixed inside the sys­tem, it will have a tall, ver­ti­cal met­al divider fixed in the cen­ter of the table, which blocks the robot oper­a­tion from the oper­a­tor. This not only pro­tects the eyes from arc glare, but also weld spray. 

Robot Area Scanner safety feature

Light Cur­tains and Area Scanners

Fenc­ing tends to have three sides, with one area open for load­ing parts. This area needs a dif­fer­ent set of robot­ic safe­ty options, like light cur­tains or an area scanner. 

Light cur­tains have an emit­ter and receiv­er that are lined up across from each oth­er. Once the light cur­tains are lined up and func­tion­al, they send an invis­i­ble beam across the area and give the robot a sig­nal that it is okay to oper­ate. If this area is invad­ed, the light cur­tains send a sig­nal to the robot to stop. This is caused by a break in the fence cir­cuit between the robot and the light cur­tains. When the fence cir­cuit is bro­ken, the robot can still be moved with a teach pen­dant.

SICK makes a vari­ety of light cur­tains used by Robots​.com in sev­er­al of their work cells and robot sys­tems. Accord­ing to SICK, safe­ty light cur­tains are a cost-effec­tive way to pro­tect the access point for your robot sys­tem entry point. They come in sev­er­al dif­fer­ent sizes, from com­pact to robust, and even have dif­fer­ent resis­tance variants. 

An area scan­ner is sim­i­lar to light cur­tains. How­ev­er, instead of hav­ing one spe­cif­ic area where light is trans­mit­ting from an emit­ter to receiv­er, an area scan­ner is one small device that is can scan an entire area. SICK also makes area scan­ners, and their scan­ners are pro­gram­ma­ble, allow­ing com­pa­nies a high lev­el of per­for­mance that can work for a vari­ety of appli­ca­tions. Since they can be pro­grammed, area scan­ners have a high­er lev­el of ver­sa­til­i­ty than light cur­tains, because they can have a more pre­cise area mut­ed out (a load­ing zone for exam­ple), mak­ing it eas­i­er to load and unload parts in a par­tic­u­lar sys­tem or work cell.

Emer­gency Stop (E‑Stop)

Emer­gency stop, or e‑stop, is a func­tion that is used in case of emer­gency. There are usu­al­ly one or more e‑stop but­tons around a robot­ic work cell or sys­tem, and these but­tons cause the robot to stop motion imme­di­ate­ly. Unlike the fence cir­cuit, when the e‑stop cir­cuit is bro­ken, the robot is unable to be moved at all, even with the teach pendant. 

When­ev­er some­thing breaks the e‑stop or fence cir­cuit for a robot sys­tem, the safe­ty reset light will come on. This light is usu­al­ly locat­ed at the oper­a­tor sta­tion. Once you have cor­rect­ed the safe­ty sit­u­a­tion, the oper­a­tor can press the safe­ty reset but­ton and then press start to resume oper­a­tion. If the safe­ty sit­u­a­tion has not been cor­rect­ed, the reset will not work, and the sys­tem will not work until the sit­u­a­tion is corrected. 

Safe­ty equip­ment, like that, fea­tured above, is required under the OSHA direc­tive regard­ing robot­ics. OSHA Direc­tive STD 112002 states that one or more of these safe­ty meth­ods, be it bar­ri­er guards or elec­tron­ic safe­ty devices, shall be pro­vid­ed to pro­tect the oper­a­tor and employ­ees from haz­ards of oper­a­tion, such as fly­ing chips, sparks, rotat­ing parts, etc. While this is a typ­i­cal reg­u­la­tion for all machin­ery, there are oth­er reg­u­la­tions from OSHA and oth­er orga­ni­za­tions that are geared direct­ly toward robots. 

In 2012, the Robot­ics Indus­try Asso­ci­a­tion (RIA) com­plete­ly reassessed and rewrote their stan­dard prac­tices for safe­ty when deal­ing with indus­tri­al robot­ics. One of those changes was to the func­tion­al safe­ty guide­lines for robot­ics. Basi­cal­ly, accord­ing to RIA R15.06:2012, com­pa­nies must per­form risk assess­ments on their inte­grat­ed sys­tems and work cells and ensure that they are out­fit­ted with a func­tion­al safe­ty design to reduce risk to users. This can incor­po­rate one or many of the prod­ucts list­ed above. 

Dif­fi­cul­ty choos­ing the right safe­ty options for your sys­tem? Call us at 8777626881 or fill out a Con­tact Form here to get in touch with a specialist. 

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