Compaction data: density, springback, ejection and the Heckel line

Enter the die bore, the true density of the powder and the pellet mass, then one row per pellet. The pressure and the ejected height are needed; the other columns are optional and add springback, in-die density and the ejection stress. The example numbers are made up to show the format.

mm
g/cm³
g
mm
MPa
MPa
ejected pelletsat maximum loadfitted line, ejectedfitted line, at maximum load

Number of pellets

#Pressure, MPaP, MPaEjected height, mmh, mmEjected diameter, mmd, mmHeight at max. load, mmhmax, mmEjection force, kNF, kN

P pressure; h and d ejected height and diameter; hmax height at maximum load; F ejection force.

1
2
3
4
5
6
7
8

Density from mass and the ejected dimensions (the bore where no diameter is given); in-die density from the bore and the height at maximum load. Axial springback against the height at maximum load, radial springback against the bore. Ejection stress: peak ejection force divided by π × bore × ejected height, the die-wall area of a pellet of that height. Every row uses the one pellet mass. Heckel: ln[1/(1 − D)] = kP + A, Py = 1/k. Kawakita: P/C = P/a + 1/(ab), C = (h0 − h)/h0. Fits are least squares over the rows in the pressure range you choose. The line through the heights at maximum load uses one point per pellet; it is not the single-pellet in-die curve described in the guide. C from heights assumes the cross-section of the loose powder; on the ejected-height route the radial springback is ignored. The tool checks arithmetic and consistency of the entries; it does not say what values a powder should give, and parameters from different routes, dies or speeds are not comparable.