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then heated at a rate of 2 o C/min until the required deflection is attained. Since stress divided by strain is the modulus of the material, another way of stating this result is to say that the DTUL is the temperature at which a material achieves a certain modulus. In 1978, Michael Takemori presented a paper at the SPE ANTEC where he calculated the modulus associated with the DTUL. As most people who have looked at a data sheet know, DTUL can be measured at a stress of 66 psi (0.455 MPa) or 264 psi (1.82 MPa). The ISO method rounds off this higher stress to 1.80 MPa and then adds a third stress level of 1160 psi (8.00 MPa). The modulus asso- ciated with 66 psi stress was calculated by Takemori to be 29 ksi (200 MPa) while the modulus associated with the 264 psi stress was calculated to be 116 ksi (800 MPa). Takemori did not comment on the higher stress of 1160 psi introduced by ISO because it did not exist at the time he wrote his paper. But if it had, he could have easily shown that the associated modulus would have been approximately 510 ksi (3520 MPa). Which modulus and DTUL stress level should be used for esti- mating ejection temperature, and why? And what are the chances that a property (DTUL) that has nothing to do with the engineering properties of a polymer is somehow related in a scientific way to the temperature at which a part molded from that material can be ejected without undergoing an unacceptable degree of post-mold distortion? Takemori went on to show that the DTUL test incorporates a measurement of short-term creep. The sample is placed under constant stress for the duration of the test. This test may last anywhere from 30 min for a material such as a PP copolymer to over 2 hr for a reinforced PEEK or PEK. For the entire duration of that test, the sample is under constant stress and the measured deflection is therefore continually increasing independent of the effects of the increasing temperature. This means that if the sample is left under stress for a sufficient period of time, it will deflect the required amount to signal failure without any need to increase the temperature of the sample. The quantitative relationship between the estimated cycle time and factors like wall thickness, thermal diffusivity of the material, and temperature of the melt and the mold will be elusive. Screenshot of Loader Control Screenshot of Dryer Control K now How