Is your next robot a cobot?

I recently began looking into robots for an application and noticed other applications that also appeared suitable for automation.

No, our company is not looking to replace associates—the robots, in general, will be targeted for more mundane tasks such as machine tending, repetitive assembly and spray painting.

A couple of decades ago, I sold robotic thermal spray systems. We offered bright orange, 6-axis, articulated robots, which were effective for a variety of uses. Our applications required repetitively spraying hot metal or other materials onto parts, including anything from dental implants and hip replacement parts to jet engine components and centrifuges for use in the Canadian oil sands. Those robots always needed some sort of guarding, be it a light beam or actual fencing. In most cases, we provided soundproof rooms with dust collectors for the overspray.

Now, collaborative robots, or cobots, are available. A conventional robot requires guarding to prevent humans from entering its workspace and possibly getting injured. Cobots, on the other hand, generally do not require guarding, but users must perform a risk assessment for each application. The manufacturer of the cobot I’m looking at has sold thousands of them, 80 percent of which do not require safety guarding. This enables humans to work beside them on the shop floor.

In addition, the cost of a robot has dropped over time. Back in the day, my base price for a robot with a 10-kg payload capacity was around $90,000. The cobot I’m eyeing is around $46,000 for the same capacity. One with a 5-kg capacity is about $10,000 less, and is suitable for simple, repetitive-assembly operations. Even lower-priced cobots are available, though they sacrifice some accuracy.

My initial cobot application will be tending a vertical machining center with a rotary pallet changer. The operator will only have to set up the part and hit cycle start, freeing him to run another machine. We may incorporate an auto-door option to open and close the load/unload station, program the cobot to open and close the door or simply leave the door open because the machining station will remain closed. Another practical use for a cobot at our facility is painting finished assemblies—I know I wouldn’t want to stand all day hanging and painting them.

Acquiring a robot takes less time than in years past, when several days were needed to train an operator to program and use a robot. The cobot I’m targeting requires only a half day of training. Also, while delivery used to take several weeks, manufacturers now offer off-the-shelf cobots. I can literally order a cobot today and be in full production in about a week.

As previously stated, the goal is not to replace machine operators with automation. Instead, operators should be placed in positions with more responsibility. Back when automation and robotics began to be integrated, operators became cell coordinators, cell technicians or cell managers. Operators should stop performing mind-numbing tasks, such as deburring, part loading and unloading and assembling the same pieces for hours at a time. Let them perform more challenging activities while robots and cobots handle the drudgery without complaint.

[Editor’s Note: See the January issue of CTE for a feature article on cobots.] CTE

About the Author: Manufacturing engineer/project manager and a regular CTE contributor. Email: mderen1@wi.rr.com.