BAH!! How do I detect a weld nut?!?!


2015-07-24 09.04.44
Specialty nut detection sensors failed from mechanical damage or heat from close proximity to welding

In automated manufacturing, part quality issues are a weekly discussion and this continues to be true in most weld shops across North America. One of the more common issues that I encounter in discussions with customers involves nuts being welded to a part.
Nut problems seem to come in a variety of frustrations:

  • upside down
  • no nut present
  • wrong position
  • wrong nut
  • two nuts

There are many different sensing technologies that have been applied or attempted over the years for weld nut detection and each has its pros and cons. In my travels I have personally encountered technologies like machine vision, mechanical plungers, inductive proximity sensors, photoelectric sensors, specially designed “nut sensors” and linear position sensors, to name a few.  The biggest complaints I hear about different technologies is either they are unreliable/unrepeatable or they aren’t rugged enough to survive a hit from big metal parts or they can’t take the heat of close proximity to welding.

Repeatedly we have found two technologies are finding success for tough weld nut detection applications in two different parts of the production process.

  1. Post Process Check Stations – Mechanical Contact with PlungerProx sensor.  This sensor uses a spring loaded pin sized for the proper nut to detect presence, is easily repairable (if necessary) and has the ability to adapt to a wide range of nut threads and diameters.
  2. In-Process Check on Pedestal Welders – weld-nut-detect-btlLinear position feedback on the height of the weld gun can provide exact measurements and feedback on the status of the weld nut from presence to orientation of the nut.

I acknowledge that every nut and every application are different.  I regularly see the key to success is to test and discuss with your local sensor guy about the best technology for the situation.  If you are interested in discussing a particularly difficult application please connect with me on Linked-In or Twitter @WillAutomate.

Stop Industrial Network Failures With One Simple Change


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.

2013-08-19_Balluff-IO-Link_Mexico_Manufactura-de-Autopartes_healywBy 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