Determination of micro geometric standard parameters of squeeze casting

The geometric characteristic parameters of rough surface are determined by iso12085 standard program.

F. Robbe Valloire discussed this method in detail. The surface profiler commonly used in the market is used to measure the profile curve of rough surface. Then, the corresponding geometric parameters, i.e. roughness parameters and waviness parameters, can be obtained by filtering the contour curve of rough surface with standardized program.

(a) Rough surface contour curve (b) local enlarged drawing

When the profile curve of rough surface is known, the peak and trough of the profile curve can be well determined. For rough surface contour processing, the contour curve is divided into different “motif”, which is defined as the part between two peaks of the contour curve. The geometric features of “motif” labeled I are shown in Figure 1.

The conditions of merging the two “motifs” are given by the standardized program. According to these conditions, the roughness parameters and waviness parameters of rough surface profile curve can be calculated.

In the horizontal direction, the operation factors A and B should be used to separate the roughness parameters and waviness parameters. The recommended values of a and B are obtained from the manual drawing of about 36000 pairs of milling, turning, boring and grinding parts evaluated by French experts.

In this paper, two rough surfaces are involved, the casting surface of A356 aluminum alloy and the die surface of H13 steel. The contour curves of the two rough surfaces are measured by the surface profiler dektak150. Their contour curves are shown in figures 2 and 3.