TheReg
Mechanical
- May 20, 2003
- 14
First thanks for any help..
We are using a bar of 2024-T3, approx 1-1/4" x 1-1/8" x 9" with male and female lug profiles, one per each side for mating parts.
Male width is .770 and slot depth is .231 and the female profile width is .780 and profile extrusion is .233 which should give a .010 interferance fit with urethane that has a shrink rate of 1.9%.
However, this is not acting like past parts...the above optimum mold temp is 220deg f.
The finished parts are .760 and .800 @ 220, respectively for male and female.
Is there a thermal calculation I can use to help determine the optimal dims to allow for and interferance fit. We machine our parts at 68deg f and the high and low of the ovens are 231/215.
Thanks
We are using a bar of 2024-T3, approx 1-1/4" x 1-1/8" x 9" with male and female lug profiles, one per each side for mating parts.
Male width is .770 and slot depth is .231 and the female profile width is .780 and profile extrusion is .233 which should give a .010 interferance fit with urethane that has a shrink rate of 1.9%.
However, this is not acting like past parts...the above optimum mold temp is 220deg f.
The finished parts are .760 and .800 @ 220, respectively for male and female.
Is there a thermal calculation I can use to help determine the optimal dims to allow for and interferance fit. We machine our parts at 68deg f and the high and low of the ovens are 231/215.
Thanks
