Conductive Ink TracesJune 14, 2006

Conductive ink, for example the Dow Corning PI-2000 series of Silver Polymeric Interconnect Materials, can be used to print conductive circuit traces. Generally, the ink is applied using a screen printing technique, with typical print thicknesses of 25 um to 40 um. Sheet Resistivity is specified in milliohms/square at a 25 um print thickness and varies from 8 to 81 for the currently available inks. For comparison, copper has a Sheet Resistivity of 0.68 milliohms/square at a 25 um thickness.

The Sheet Resistivity can be used to calculate the resistance of the printed traces as follows:

Resistance = Sheet_Resistivity*(Length/Width)*(Ref_Thickness/Thickness)

where "Ref_Thickness" is the thickness at which the "Sheet_Resistivity" is specified in the ink's data sheet and "Thickness" is the actual thickness of the ink you are printing.

The Calculator

Tips:

• Resistance per inch can be calculated by enter a length of 1 inch.

Required Inputs:

 Width mil mm um cm inch Length mil mm um cm inch Thickness mil mm um cm inch Reference Thickness mil mm um cm inch Sheet Resistivity milliohms/square

Results:

 Resistance Ohms

1. Satya - June 23, 2006

this is good …
If I have seen this site one year before!!!!!!!!!!! I became one the super PCB Designer in India now

2. Administrator - June 23, 2006

Satya,
I wish you all the success! With your enthusiasm, you wonâ€™t have any problem.

3. Satya - June 24, 2006

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leo.reddy@gmail.com

4. Jon - July 14, 2006

Can conductive ink be formulated with a resistance sufficient to generate heat? In other words, print a small heating element on a non-porous substrate such as cardboard or plastic sheet?

5. Administrator - July 14, 2006

Jon,
It sounds feasible, but it could be tricky. Depending on how much heat you want, the ink might start to flake or burn. I donâ€™t have the specifics on what type of inks would be best.

6. Jon - July 15, 2006

Thanks for the reply - who does have the answers? I only need 40 C for an hour or two, using 3 3V coin type batteries, so flaking should not be a problem.

7. David - September 11, 2006

Jon,

Yes you can use these inks for heating. 40C is no problem. We use them to heat

8. Josie - March 13, 2007

I am wondering using inks for heating to 40C, the total resistance of 0.8 ohm in total is good enough with 3.3 V voltage applied? What is the heat capacity of the conductive ink?

9. Brad - March 13, 2007

Josie,

You need to decide how much temperature rise you need and how much surface area you have. Then you can calculate the power needed. Per reference [1] page 13, in still air, the power needed is approximately:
Power = Temperature_Rise*Surface_Area/1000
Units: (cm, W, degrees C)
Then, find the combination of voltage, current, and resistance to get the power where:
Power = Current*Voltage
Voltage = Current*Resistance

[1] “Constructing Your Power Supply - Layout Considerations”, by Robert Kollman
http://focus.ti.com/lit/ml/slup230/slup230.pdf

10. James - April 15, 2007

I found a specsheet revised on April 1st, 2005 (http://mfc.engr.arizona.edu/safety/MSDS%20FOLDER/PI%202000%20Highly%20Conductive%20Silver%20Ink.pdf). I would recommend finding a recent specsheet (from Dow Corning) and reading it before use. Assuming it is authentic, the following may be relevant:

Section 3-Hazardous Decomp. Products: “Thermal breakdown of this product during fire or very high heat conditions may evolve the following hazardous decomposition products: Carbon oxides and traces of incompletely burned carbon compounds. Chlorine compounds. Metal oxides. Hexamethylene diisocyanate. Hydrogen Cyanide. Nitrogen oxides. Formaldehyde.”

Section-7 Handling & Storage: “Free isocyanate and MEKO may be released when this product is heated above 130 degrees C (266
degrees F).”

-Regards

11. Fred - July 9, 2007

Hi All,
I am looking to screenprint a heater with silver ink. Any ideas on resources to design the layout? I am in the screenprint industry and not a PCB designer or engineer.

Thanks,
Fred

12. scott - October 22, 2007

can you use these inks to arc like electrodes??
let’s say I have 50KV and I want to arc across 1.3 inch gap
will the inks burn off??

13. Brad - October 22, 2007

Scott,

That is really a question for the ink vendors, but I am guessing that there will be some burn rate for any electrode under those conditions. Also, be careful not to kill yourself!

14. lac - March 5, 2008