Eliminating Hazards with Safety-Focused Engineering: 5 Questions Every Engineer Must Ask When Designing Automated Equipment

Thursday, October 27th, 2011

“The design looks great, and I’ve met all of the productivity requirements…. Now, what parts need guarding?”

As a design engineer, safety tends to be an afterthought. Guards and safety lockouts are usually considered after all of the design requirements are met. In some instances, safety isn’t addressed until the equipment is built and undergoes testing.

Taking this approach can lead to equipment redesign if simple guarding isn’t good enough. Below are 5 simple questions to ask yourself the next time you design a piece of equipment to ensure a safe and effective product.

How could the equipment fail?

When we talk about equipment failing, it doesn’t have to mean a catastrophic failure with explosions and mass destruction. It could be as simple as a chain breaking under a peak load or a photoeye failing to read the product. To eliminate personal injury and equipment downtime, engineers must use redundant designs to act as a backup plan in the event of a failure. Elevator emergency brakes that engage when a cable fails are a perfect example of this practice. Hard mechanical stops to limit over travel of specific components or a safety mechanism that acts as a backup plan are ways that you can protect against equipment failures.

How will the equipment react to a loss of power?

Power losses are unpredictable and always seem to come at the worst time. Equipment must be designed to safely power down and come back online when power is cycled. Sensor selection is key when designing around power loss. Normally open (NO) and normally closed (NC) sensors allow the engineer to select the fail-safe mode for a piece of equipment. For more information about NO and NC sensor selection, visit AllAboutCircuits.com.  Other sources of energy, such as pneumatics and hydraulics, must also be taken into consideration in the event of a power loss with appropriate measures made to release stored energy.

How will the equipment be treated by operators?

This article is too short to tell some of the stories that are the purpose for this rule. Unless you have been an equipment operator or a maintenance technician (or had one of your designs destroyed by one), this is can be a very difficult idea to wrap your head around. I can only give you a few pieces of advice to steer you in the right direction. If it looks like a step, it will be stepped on. If it is designed to hold 100 pounds, at some point it will see 200. Every limit will be tested and every parameter could be changed. Try your best to anticipate the real-life environment your equipment will be in for the next 20 years.

Could the hazards be removed with a better design?

It still stands that the best way to guard around a hazard is to eliminate the hazard entirely! Instead of placing a guard over a pinch point, is it possible to redesign the equipment to eliminate the pinch point? What about the component that you are worried might fail and cause a safety issue? Can it be replaced with something more reliable or possibly removed completely? Think outside of the box to provide a safe alternative and you might find a more cost-effective approach staring you right in the face.

How do we ensure the equipment is used properly?

Operating instructions, safety manuals, warning labels, and instruction plaques are the last line of defense in protecting against hazards. You have worked hard to provide the safest design you can, and now is the time to communicate the potential hazards to people who will work around your equipment every day. Don’t overlook things like warning stickers or labels. These are simple additions that instruct the operators of dangerous machinery.

By applying these 5 tips, you can provide safety-focused equipment to your customers that will never be mistaken for a safety afterthought.

Low Cost Sortation Equipment Doesn’t Have to Mean Low Throughput

Tuesday, September 20th, 2011

When it comes to automating product sortation, businesses have many types of equipment they could invest in to meet their requirements–some simple, some much more complicated. A few of these options include:

• Shoe Sorters
• Narrow Belt Sorters
• Activated Roller Belt Conveyors
• Cross Belt Sorters
• High Speed Paddles
• High Speed Pushers
• Pivot Wheel Diverters
• Tilt Tray Sorters

Often times, conveyor system designers get caught up in using complex sortation equipment with scanners, cameras, etc. These systems take a heavy amount of controls programming and initial testing to be successful and perform the sortation needed.

Unfortunately, more programming and testing typically leads to greater risk for both the supplier and the end user because there will be more work up front to get the system running properly and more chance for maintenance issues down the road.

With those issues in mind, why not start with the basics and see where that gets you? For example, a pneumatic pusher can sort at roughly 40 cartons per minute, which isn’t slow by industry standards, and the controls are simply a single input from a product photoeye and one output from the programmable logic controller (PLC) for extending the cylinder.

Another way to simplify the sortation process is through the use of Intralox activated roller belt (ARB) conveyor. Diverting in multiple locations on either side of a conveyor is often done using a shoe sorter, but the process can be simplified by using ARB conveyor instead.

One of the biggest advantages of using ARB conveyor versus a shoe shorter is there are less moving parts, meaning less downtime for maintenance and repair. We have hit rates of 120 cases per minute utilizing this Intralox belt and the solution has a smaller footprint than that of a system utilizing a shoe sorter.

Try not to get caught up in the bells and whistles of fancy sortation equipment. Invest only in the equipment that will get the job done and get it done well. Sometimes that equipment will be complex, but many other times, keeping it simple will be the best way to go. Remember to start with the basics and move to more complex solutions only if the challenge warrants it.