Conductive Ink Traces June 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.
Tips:
- Resistance per inch can be calculated by enter a length of 1 inch.
- If cookies are enabled, the form will return to its previous state upon your next visit, so your unit preferences etc. will persist.
Required Inputs:
| Width | ||
| Length | ||
| Thickness | ||
| Reference Thickness | ||
| Sheet Resistivity | milliohms/square |
Results:
| Resistance | Ohms |
- Posted in : Calculators, Electrical Engineering, PCB
- Author : Brad
Comments
this is good …
If I have seen this site one year before!!!!!!!!!!! I became one the super PCB Designer in India now
Satya,
I wish you all the success! With your enthusiasm, you won’t have any problem.
Brad
Thanx for ur reply/encouragement…
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my id is
leo.reddy@gmail.com
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?
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 don’t have the specifics on what type of inks would be best.
Brad
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.
Jon,
Yes you can use these inks for heating. 40C is no problem. We use them to heat
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?
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
Brad
[1] “Constructing Your Power Supply - Layout Considerations”, by Robert Kollman
http://focus.ti.com/lit/ml/slup230/slup230.pdf
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
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
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??
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!
Brad
Hi - I’m trying to learn about this stuff. In your formula, please explain the thickness and reference thickness
If my logic is correct, Reference thickness, you’re refering to the thickness spec on the ink supplier’s data sheet. Correct me if I’ m wrong.
lac,
Good question, and you guessed it right. I added the definitions into the text of the post above. Thanks!