Back when I worked in the tier 1 automotive industry we were always trying to find time to break into our production schedule to perform preventative maintenance. The idea for this task was to work on the assembly machines or weld cells to improve sensor position, sensor and cable protection and of course clean the machines. As you all know this is easier said than done due to unplanned downtime or production schedule changes, for example. As hard as it is to find time for PM’s (preventative maintenance) it is a must to stay ahead and on top of production. PM’s will not only increase the production time, but it will also help maintain better quality parts by producing less scrap and machine downtime due damaged sensors or cables.
If you have read any of my previous posts you have probably noticed that I refer to the “pay me now or pay me later” analogy. This subject would fall directly into this category, you have to take the time to prevent machine crashes and damaged sensors and cables on the front side rather than being reactive and repairing them when they go down. It has been proven that a properly bunkered or protected proximity sensor will outlast the machine tooling when best practices are executed. It’s important to take the time and look at the way a sensor is mounted or protected or acknowledge when a cable is routed in harm’s way.
PM’s should be an important task that is part of a schedule and followed through in any factory automation or tier 1 production facility. In some cases I have seen where there is a complete bill of material (BOM) or list of tasks to accomplish during the PM time. This list will help maintenance personnel and engineering know what to look for and what are the hot spots that create unplanned downtime. This list could also indicate some key sensors, mounting brackets and high durability cables that can improve the process.
For more information on a full solution supplier or products that can improve and decrease downtime click here.
Whether it’s through preventative maintenance or during planned machine downtime, reducing downtime is a common goal for manufacturers. Difficult environments create challenges for not just machines, but also the components like sensors or cables. Below are three tips to help protect these components and reduce your downtime.
Cables don’t last forever. However, they are important for operations and keeping them functional is vital. An easy way to help reduce downtime and save money is by implementing a “sacrificial cable” in unforgiving environments. A sacrificial cable is any cable less than two meters in length and placed in situations where there is high turnover of cables. This sacrificial cable does not have to be a specialty cable with a custom jacket. It can be a simple 1 meter PVC cable that will get changed out often. The idea is to place a sacrificial cable in a problematic area and connect it to a longer length cable, or a home-run cable. The benefits of this method include: less downtime for maintenance when changing out failures, reduced expenses since shorter cables are less expensive, and there is less travel for the cable around a cell.
A second way to help reduce downtime is consider your application conditions up front. We discussed some of the application conditions to consider in a previous blog post, but how can we address these challenges? Not only is it important to choose the correct sensor for the environment, but remember, cables don’t last forever. Choosing the appropriate cable is also key to reducing downtime. Welding environments demand a cable that weld beads will not stick to and fuse the cable to the sensor. There are a variety of jacket types like silicone, silicone tube, or PTFE that prevent weld debris from accumulating on the cable. I’ve also seen applications where there is a lot of debris cutting through cables. In this case, a stainless steel braid cable would be a better solution than a traditional cable. Fitting the right protection to the right application is crucial..
A third tip to help reduce your machine downtime is to simply add protection to your existing components. Adding protection, whether it is a protective bracket or a silicone product, will help keep components running longer. This type of protection can be added before or after the cell is operational. One example of sensor protection is adding a ceramic cap to protect the face of a sensor. You can also protect the connection by adding tubing to the cable out version of the sensor to shield it from debris. Mounting sensors in a robust bracket helps protect the sensor from being hit, or having debris cover the sensor. There are different degrees of changes that help prolong operations.
Metalforming expert, Dave Bird, explains some of these solutions in the video below. To learn more you can also visit our website at www.balluff.us.
Applications where sensor contact is unavoidable are some of the most challenging to solve. Metal forming processes involving over travel can also damage or even destroy a sensor causing failure and expensive unplanned downtime. Manufacturers often try to remedy this with in-house manufactured spring loaded out-feed mechanisms but those are expensive to make by experienced tool and die personnel who have more important things to do . Over the years, I’ve seen this as a pervasive problem in the stamping industry. Many of these issues can be solved with the use of a simple yet effective sensor actuator system known as a plunger probe.
Plunger probe solves a few key issues in Progressive stamping:
The flexible trigger/actuation point is fully adjustable to meet sensitive or less sensitive activation points, not possible with “fixed” systems with substantial “over travel” built into the design.
It is fully self-contained (minimizing any risk of sensor damage and resulting unplanned machine down time).
The device can be disassembled and rapidly cleaned, reassembled, and placed back in service in the event that die lube or other industrial fluids enter the M18 body that can potentially congeal during shut down periods.
However this can sometimes be the easy part of the project. Many times a great sensor solution is identified but the proper controls inputs are not available or the control architecture doesn’t support analog inputs or network connections. The amount of time and dollar investments to integrate the sensor solution dramatically increases and sometimes the best poka-yoke solutions go un-implemented!”
“Sometimes the best poka-yoke solutions go un-implemented!”
Many of our customers are finding that the best controls architecture for their continuous improvement processes involves the use of IO-Link integrated with their existing architectures. It can be very quickly integrated into the existing controls and has a wide variety of technologies available. Both of these factors make it the best for integrating Poka-yoke or Mistake Proofing due to the great flexibility and easy integration.
Download this whitepaper and read about how a continuous improvement technician installed and integrated an error-proofing sensor in 20 minutes!
It’s the worst when a network goes down on a piece of equipment. No diagnostics are available to help troubleshooting and all communication is dead. The only way to find the problem is to physically and visually inspect the hardware on the network until you can find the culprit. Many manufacturers have told me over the past few months about experiences they’ve had with down networks and how a simple cable or connector is to blame for hours of downtime.
By utilizing IO-Link, which has been discussed in these earlier blogs, and by changing the physical routing of the network hardware, you can now eliminate the loss of communication. The expandable architecture of IO-Link allows the master to communicate over the industrial network and be mounted in a “worry-free” zone away from any hostile environments. Then the IO-Link device is mounted in the hostile environment like a weld cell and it is exposed to the slag debris and damage. If the IO-Link device fails due to damage, the network remains connected and the IO-Link master reports detailed diagnostics on the failure and which device to replace. This can dramatically reduce the amount of time production is down. In addition the IO-Link device utilizes a simple sensor cable for communication and can use protection devices designed for these types of cables. The best part of this is that the network keeps communicating the whole time.
If you are interested in learning more about the benefits that IO-Link can provide to manufacturers visit www.balluff.us.
I am seriously excited about the new Smart Light. It will revolutionize how we automate and interface with people working in the manufacturing environment. If you didnt watch this video… you need to watch this video.
Even if you don’t know what a stack light is, you will want one of these for your discotec to light it up!
Operating on the open communication protocol IO-Link that I have discussed in previous posts, I think this single part number will improve the factory for:
an operator wanting to know when to refill a feederbowl, position a part, or empty a full output bin
a maintenance guy needing to know what cell is causing the machine downtime
a plant manager wanting to know the machine output, speed, productivity
If you are a manager at any level of a manufacturing facility, I hope you are aware of the dangers of arc flash. For those who are not aware, “an arc flash, also called arc blast or arc fault is a type of electrical explosion that results from a low-impedance connection to ground or another voltage phase in an electrical system.” Typically this does not occur in 120V situations, but can occur in 480V+ installations if proper precautions are not taken. Employees can be severely injured or even killed when an accident occurs while working with these kinds of electrical systems. There are many standards like OSHA, IEEE and NFPA that regulate these types of situations to provide a safe working environment for the employee. In addition to those standards, I would propose two simple changes to controls architecture and design to help limit the exposure to working inside an electrical cabinet.
In typical sensors all you get is ON or OFF… we just hope and assume that the prox is working, until something doesn’t work properly. The part is seated but the sensor doesn’t fire or the operator can’t get their machine to cycle. This can sometimes be tricky to troubleshoot and usually causes unplanned interruptions in production while the maintenance teams attempt to replace the sensor. On some recent customer visits on the east coast, I have had a number of interesting conversations about the customer’s need to collect more information from their sensors; specifically questions like:
How do I know the sensor is working?
How do I predict sensor failure?
How do I know something has changed in the sensor application?
How do I get my sensor to provide adaptive feedback?
How do I plan preventative maintenance?
How can I increase the overall equipment throughput?
Recently Hank Hogan published an article in Control Design titled “Sensor, Diagnose Thyself.” (To be honest, I really wanted to steal his title for my blog entry.) I think Hank did a great job dissecting the key benefits of smart sensors and the amazing things you can do with them. Utilizing the technology IO-Link (that we have discussed in many past Blog Entries), sensors can communicate more with the controller and provide more data than ever before.
Some of the key points that I really thought are useful to maintenance and engineers at end-user facilities or machine builders:
Being able to detect and notify about pending failures; for example a photoeye’s lens is dirty and needs to be cleaned.
A failed sensor needs to be swapped out quickly; IO-Link allows for the smart sensors settings to be cloned and the swap to be executed super fast.
Configure a sensor before installation; program with your laptop: sample rate, response time, measurement settings, on/off switch points, anything!
One platform can be used for many sensor types; this gives familiarity to a single interface while using multiple sensor types and technologies.
In the future sensors in a wireless cloud would self-heal; this is an amazing concept and if we can figure out the price for radios and batteries to make it cost-effective, I think this could be a game changer someday.
But all that being said, it really comes down to the total cost of ownership doing it the standard sensor way versus the smart sensor way. I think you will pay more upfront in capital but down the line there will be less cost in maintenance and downtime.