I had the pleasure to analyze ESD testing data for shoes in a big electronics plant. I was shocked to see that the operators on average spent 15 min daily on waiting for failed tests to pass and on re-testing.
Does anyone else have experience about this and on the causes of the tests causing problems?
This can happen, espesically with shoes worn for the first time or when the outside enviroment is cold.
The shoe works with a person by developing a “sweat” layer through the sock. If the sock is thick, it might take a few minutes for that connection to be made. If it is cold outside, it may also take some time for the person’s foot to warm up enough to create the sweat layer.
Some shoes work better than others, heel straps have the same issues but can be placed right next to the skin. Some companies allow the shoes to be worn home so that by the time they get to the site, the sweat layer has already been made.
The experience seems to be that new shoes generally work well but after a while people start experiencing problems. Especially in the mornings it can take a lot of strolling before the shoes pass. Are we experiencing more than our share of problems or is this a typical behavior of ESD shoes?
I would not say this is typical. It is usually the first time takes the longest than it is shorter times the more they are worn. I don’t know why this is occuring.
Maybe someone else can comment on this.
Actually the perception was that it’s not really an issue but I heard muttering every now and then from the operators and decided to take a closer look on the data. The guesses from management on the magnitude of the problem were 100x off.
My experience is that in the morning the shoes is not warm up jet and are dry, that´s way you also see this 15 min waiting time. In north (Sweden) we have these issue during winter when we have less humidity, our winter climate is dry and many electronics company suffer this issue during winter but not in summer when we have higher humidity.
But this can also be a case of poor quality or that the shoe is old.
So I suggest that you check,
1, The humidity in your facility?
2, The condition of the shoes, age, worn etc.?
3, Does the employees use the same shoes outdoors? (Clean shoes = better conductivity)
One add more. See what employees use as insoles inside shoes. I found many people exchanged into new one shoe insoles, directly from market (without dissipation properties, insulative at all). For better comfort.
Hi!
That´s a problem I have experience due to the fact that I use special insoles for feet issue. It´s important too talk too your employment that they have to use right type of insoles. One option is that you check whit your supplier if they have options.
On suggestion if there are no options, consider using copper tape. Put the tape on top of the insert and wrap it around the insert to connect to the sole. Copper tape is very conductive and very thin but durable. Being thin usually does not cause any discomfort.
I ordered the esdokay strips. They work like charm. The problem seems to be the resistance between the insole and shoe. It needs to get moist from the wearer in order for the test to pass. The esdokay strips address this exact interface. Now more than 50 operators use them. The test fails have dropped dramatically.
Greetings of the day from India to all the members on this forum and welcome to Insula and Jhilner 
to the community.
Regret for greeting them late as I am seeing this link quite late and missed to see earlier.
Well, already our ESD Guru JK Sir and other expert members have given sufficient suggestions. But , I would just like to add a few lines from my side as a passion to enjoy exchanging of ideas on this wonderful platform provided by ESDA.
**1. Basically per both global ESD control standards any EPE need to undergo a stringent PQ test at controlled conditions to ensure its eligibility/acceptance to use it as an EPE in an EPA . **
**2. Majority of the resellers /mfrs do not have either adequate knowledge on the PQ test methods or facility for the same .and just give a compliance certificate to the global standards just checking only the Surface resistance of any material with a 10/100 v SR meter without any setup but test at ambient conditions. Because in most of the cases the ambient conditions would be 40-70% Rh and temperature 20-28 degree C which makes most of the insulative items too make pass in the dissipative range and issue certificates and customers too blindly accept it with trust. But , when put into use and when the Rh% goes down, in many EPAs the issue of the EPE failing does arise and it is a fact even today. **
3. Especially in case of consumables viz; All personnel grounding aids and all the packaging items I suggest all users to insist the supplier to supply each lot of material with a detailed PQ report and a pass certificate w.rt to the relevant test methods but just not a one line certificate mentioning Conform and comply with std xxxxx.
4. The current both stds mention (from 2007 itself) that any EPE used for ESD control shall have the inherent property for static dissipation irrespective of the environmental conditions. Well Rh% does influence for a better ESD control but not a mandatory condition as it may lead to ambiguity in their test results when measured at very low rh% maintained at EPAs.
**5. The problem cited by you and similar problems does occur and seen regularly even in most of the ESD facility certified units as this ESD Facility Certification has now become a fashion and easily available without proper Trg.- without proper Product qualification reports- without proper compliance verification- and no process assessment **
**6. Follow the ESDA global standard properly and make use of your investment worth .
Thank you