A Perspective View of the MODCON System
In this paper, a system of computer programs for the geometric description of hot forgings is outlined. The system is known as the MODCON system which stands for MODular CONstruction. The MODCON system allows quite complex forging shapes to be produced from relatively few input instructions. The forging geometry is defined as a series of volumetric modules which are then merged together during generation of the N.C. tape necessary to machine the finishing-cut EDM electrode for the whole forging cavity. The system can also be used for the roughing cut of the EDM electrode before the finishing cut stage as well as for generating cross-sectional data which serves as input to subsequent preform design systems. The system represents a considerable saving in time and cost over current methods involving conventional pattern making for the copy milling of electrodes.
Low Cost CAD/CAM System for Machine Parts
A CAD/CAM system known as the MODCON(1,2,3) has shown to be useful for producing machine parts such as rocker-lever, connecting-rods, etc. In spite of the usefulness of the MODCON system, it suffers the inherent disadvantage of a batch system and therefore does not interact with a MODCON user wishing to design a machine part. An interactive CAD/CAM system is now proposed which is conceptually similar to the MODCON system. The proposed system is implemented on a microprocessors based machine which includes a central processor, a numerical data processor and another processor for I/O. This low-cost/high-power machine enables a designer to interactively design a machine part to his satisfaction before a N.C. paper tape is produced for manufacturing purpose.
Phase diagram and magnetic properties of the diluted fcc system NipMg1-pO.
Starting from Ni and Mg nitrates, about 20 samples of ${\mathrm{Ni}}_{\mathit{p}}$${\mathrm{Mg}}_{1\mathrm{\ensuremath{-}}\mathit{p}}$O samples (with 0.06\ensuremath{\le}p\ensuremath{\le}0.86) were prepared and x-ray-diffraction studies showed the samples to have the NaCl structure with the lattice constant fitting the expression a(p)=4.2115-0.0340p \AA{}. Temperature-dependent magnetic-susceptibility (\ensuremath{\chi}) studies of the samples were carried out between 1.8 and 600 K using a superconducting-quantum-interference-device magnetometer and N\'eel temperatures ${\mathit{T}}_{\mathit{N}}$'s were determined from the peak in \ensuremath{\partial}(\ensuremath{\chi}T)/\ensuremath{\partial}T. The variation of t=${\mathit{T}}_{\mathit{N}}$(p)/${\mathit{T}}_{\mathit{N}}$(1) vs p is compared with that of ${\mathrm{Co}}_{\mathit{p}}$${\mathrm{Mg}}_{1\mathrm{\ensuremath{-}}\mathit{p}}$O. For both systems, the variations for pg0.31 are found to fit the predicted values for a simple-cubic Heisenberg antiferromagnet and a theoretical basis for this anomalous result is advanced. The experimental percolation threshold ${\mathit{p}}_{\mathit{c}}$=0.15\ifmmode\pm\else\textpm\fi{}0.01 and for ${\mathit{p}}_{\mathit{c}}$p0.31, \ensuremath{\chi} below ${\mathit{T}}_{\mathit{N}}$ shows irreversible behavior for the zero-field-cooled and field-cooled cases, suggestive of spin-glass-like behavior also observed in other diluted fcc antiferromagnets, such as ${\mathrm{Co}}_{\mathit{p}}$${\mathrm{Mg}}_{1\mathrm{\ensuremath{-}}\mathit{p}}$O and ${\mathrm{Eu}}_{\mathit{p}}$${\mathrm{Sr}}_{1\mathrm{\ensuremath{-}}\mathit{p}}$Te. It is suggested that the differences in the t-vs-p variations for p0.31 in ${\mathrm{Ni}}_{\mathit{p}}$${\mathrm{Mg}}_{1\mathrm{\ensuremath{-}}\mathit{p}}$O, ${\mathrm{Co}}_{\mathit{p}}$${\mathrm{Mg}}_{1\mathrm{\ensuremath{-}}\mathit{p}}$O, and ${\mathrm{Eu}}_{\mathit{p}}$${\mathrm{Sr}}_{1\mathrm{\ensuremath{-}}\mathit{p}}$Te may be related to the differences in the ratio of the next-nearest-neighbor to nearest-neighbor exchange constants in these systems.