## Metric Formula  for the Deposit Stress Analyzer System:

CALCULATIONS: (For Thickness)

The deposit stress is compressive if the resist is on the outside of the Test Strip legs.

The deposit stress is tensile if the plating is on the outside of the Test Strip legs.

It is necessary to know the total units or increments spread between the plated test strip leg tips from both sides of the center line on the measuring block scale and the average deposit thickness in order to calculate the deposit stress. If the deposit thickness cannot be determined by actual measurement, it can be calculated as follows:

T =              W                   = cm

.               D (7.74 cm²)

T = deposit thickness in cm

W = deposit weight in grams,

D= Density of the plated material, g/cm³ (Table of Density Values for the D)

A = surface area in square centimeters. Since the plated surface area on a test strip is 7.74 square centimeters, the formula for nickel thickness can be shortened as follows:

Note: If using x-ray for thickness it would = T after the deposit thickness is known and the number of increments spread between the test strip leg tips has been determined, the deposit stress can be calculated thus:

Calculate the Deposit Stress:

S = UKM÷3T                          where:                 S = kg/cm²

U = number of increments spread (See Table B for conversion),

T = deposit thickness in cm,

K = the test strip calibration constant will be labeled on each lot of test strips,

M= the modulus of elasticity of the deposit ÷ by the modulus of elasticity of the substrate material (See Table A).

TEST STRIP MATERIAL RECOMMENDED PLATING CONDITIONS FOR PLATING See table 2 page 8 of DSA Brochure

Note: If the test conditions cause the test strip leg tips to spread beyond 20 units, reduce the deposition time and the deposit thickness for the test to improve accuracy.

FOR PN: 1194 – COPPER–IRON ALLOY 0.00508 cm thick (deposit stress from 105 to 10194 kg/cm²)

DEPOSIT STRESS M value for nickel plating M = 1.715 The correction factor for the difference in the modulus of elasticity between the deposit and that of the substrate = EDeposit ÷ ESubstrate = 2110813 ÷ 1230797 = 1.715 kg/cm².

FOR PN: 270NI – PURE COLD ROLLED NICKEL 0.0011 INCH THICK  (deposit stress from 14 to 4218 kg/cm²)

DEPOSIT STRESS M value for nickel plating M = 1.0000 The correction factor for the difference in the modulus of elasticity between the deposit and that of the substrate = E Deposit ÷ E Substrate = 2110813 ÷ 2110813= 1.0000 kg/cm²

TABLE A                                        (Values for M)

 Test Strip Material 1194 270NI E Substrate 1,230,797 2,110,813 Stock Thickness, cm 0.00508 0.002794 Metal E Deposit Value M M Cadmium 562,883 0.4573 0.2667 Cobalt 2,528,896 2.0547 1.1981 Chromium 2,151,601 1.7481 1.0193 Copper 1,121,688 0.9114 0.5314 Gold (Soft) 787,221 0.6396 0.3729 Nickel 2,110,813 1.715 1.0000 Palladium 1,193,068 0.9693 0.5652 Platinum 1,743,715 1.4167 0.8261 Rhodium 3,660,781 2.9743 1.7343 Sliver 774,984 0.6297 0.3671 Tin 414,820 0.337 0.1965 Zinc 984,026 0.7995 0.4662

E Substrate= modulus of elasticity of the substrate material (test strip material).

E Deposit = modulus of elasticity of the plating deposit.

M= modulus of elasticity of the E Deposit ÷ modulus of elasticity of the E Substrate

Table B   (U factor conversion) (*English is the increments spread on the Deposit Stress Analyzer)

Note:  If the increments spread is 6.5 the Metric would be 1.1598

 English Metric English Metric English Metric 0 0 8.5 1.5172 17 3.034 0.5 0.0891 9 1.6066 17.5 3.1236 1 0.1782 9.5 1.6957 18 3.2129 1.5 0.2675 10 1.785 18.5 3.3025 2 0.3569 10.5 1.8741 19 3.3914 2.5 0.4452 11 1.9635 19.5 3.4807 3 0.5353 11.5 2.0528 20 3.5688 3.5 0.6247 12 2.1419 20.5 3.6595 4 0.7138 12.5 2.2308 21 3.7486 4.5 0.8031 13 2.3206 21.5 3.8377 5 0.8917 13.5 2.4097 22 3.9273 5.5 0.9816 14 2.4991 22.5 4.0161 6 1.0707 14.5 2.5882 23 4.1057 6.5 1.1598 15 2.6773 23.5 4.1951 7 1.2497 15.5 2.7667 24 4.2842 7.5 1.3388 16 2.8558 24.5 4.3735 8 1.4279 16.5 2.9454 25 4.4629