Static Electricity Expertise

Hi Gary

Can you provide a little more detail so that others can chip in to help? 

Lisa

We have a process that produces deposition products (think small pieces of spaghetti) that is attracting a charge and causing issues with the process equipment. Because the process is registered then changing the process including product contacting materials of construction etc is not easy.

So what is happening in the process and what measures are already in place ?

Thinking of humidity controls, atmospheric ion generations, weakly conductive surfaces and so forth. If it really is spaghetti, then moisture content will be very significant.

Mike

Just to be clear...the product is not spaghetti and that is just to help describe what the product is like physically. My understanding is that this equipment is in humidity controlled area and that increasing RH has been explored. There are atmospheric ion generators being used and there are some dissipative surfaces for some parts of the process. I do not think any measurements have been taken of the static charge on the product itself.  

The charge on the 'not spaghetti' itself is probably quite hard to measure accurately, and in any case is a symptom, not  cause, and just recording that on its own may not be that useful.

Is the stage in the processing that is causing the initial charge separation clearly identified yet ? - Often measurements of potential can allow this to be narrowed down mostly coming from one  particular belt or roller or point where parts are peeled apart or something like that? That does not mean that production step can be eliminated of course,  but it does mean that the neutralization effort can be concentrated to the one area.

Mike.

I remember a situation once where high Nylon content carpet was the cause for static built up

presumably scuffing against footwear with insulating soles or trolleys with insulating wheels ? Certainly dissipative  (a few gigohms per square )floor coverings are very good start .  Then you can fit drag chains or brush contacts to mobile equipment so it remains in contact with the floor while being pushed about, workers can wear heel straps etc.

Mike.

Hi Gary

I recall that Southampton University was very active in electrostatics and see that Wolfson Electrostatics was spun-off in the 70's under Graham Hearn

https://grahamhearn.com/

Hi Gary, 

We had a similar issue with ESD causing circuit board failures causing product reliability issues. Had to perform a detailed process man and the use of a fish bone diagram to understand where exactly the ESD was introduced. 

Few factors to consider were the humidity levels within the working environment and the handling of part itself within various stages in production. We had introduced anti static ESD air ionizers with a combination of Anti Static PVC Strip Curtains at the respective sections within the process to mitigate this and the use of nitrile gloves & emphasising more of a clean room environment.