Which Linqstat product is right for pressure sensors?

A ques­tion came in to us recent­ly about the right elec­tri­cal­ly con­duc­tive plas­tic for pres­sure sen­sors, which we felt was worth answer­ing publicly.

The min­i­mum thick­ness suit­able for pres­sure sen­sors is 4mil, but the 6‑mil and 8‑mil thick­ness­es are more com­mon for pres­sure sensors.

Question for Pressure Sensors

The ques­tion that was asked was from a design­er that was design­ing a fair­ly large pres­sure mat with a sen­sor matrix. He was try­ing to fig­ure out the min/max/typical sheet resis­tance for our MVCF and VCF (Mid-Lev­el Con­duc­tive Film vs Low-Lev­el Con­duc­tive Film) prod­ucts. The web­site and the datasheets have con­flict­ing infor­ma­tion. Also, he would also like to know what the vari­abil­i­ty of sheet resis­tance in a sin­gle roll is. Would the vari­abil­i­ty be low­er when using thick­er films?

Answer for Pressure Sensors

Although, we are a lit­tle embar­rassed to admit it, he was right. Over the past 6 months, we have been updat­ing and rec-clas­si­fy­ing our range of vol­ume-con­duc­tive sheet­ing. The rea­son for this is because our cus­tomers have asked for more spe­cif­ic con­duc­tiv­i­ty ranges with tighter tol­er­ances. You can read the post here that talks about tighter spec­i­fi­ca­tions on LINQSTAT vol­ume-con­duc­tive plas­tic for more details.

As a result of this, we have just updat­ed our LINQSTAT Con­duc­tive Plas­tic Sheet­ing Overview page, which has the most cur­rent infor­ma­tion. All the infor­ma­tion on the web­site and in the tech­ni­cal datasheets has been updat­ed to reflect this information.

As far as the vari­abil­i­ty goes, it is about 10% roll-to-roll due to the dis­tri­b­u­tion of con­duc­tive filler, but is inde­pen­dent of the thick­ness. (the vol­ume resis­tiv­i­ty how­ev­er is of course thick­ness depen­dent). Where the thick­ness plays a role and is par­tic­u­lar­ly impor­tant for pres­sure sen­sor appli­ca­tions. The thin­ner sheets are less sen­si­tive to pres­sure changes than the thick­er ones (because essen­tial­ly by reduc­ing the thick­ness, you increase the con­duc­tiv­i­ty). The min­i­mum thick­ness suit­able for pres­sure sen­sors is 4mil, but the 6‑mil and 8‑mil thick­ness­es are more com­mon for pres­sure sensors.

I am not sure whether you need the 50,000 ohms per square or 10,000 ohms per square prod­uct for your appli­ca­tion, but typ­i­cal­ly the larg­er the pres­sure sen­sor, the less con­duc­tive the film needs to be. You could still use the more-con­duc­tive mate­r­i­al, but then you are pay­ing for con­duc­tiv­i­ty that you don’t nec­es­sar­i­ly require.

CAPLINQ is a spe­cial­ty plas­tics sup­pli­er offer­ing a range of LINQSTAT brand­ed con­duc­tive mate­ri­als includ­ing our broad range of elec­tri­cal­ly con­duc­tive plas­tics and anti­sta­t­ic tapes and films. If you have any ques­tions, please don’t hes­i­tate to con­tact us if you have fur­ther ques­tions on using con­duc­tive plas­tic for pres­sure sensors.