Undercutting effect

Surfaces of plastics may be provided with designs that can give a good grip or that can simulate wood, leather, etc. These types of surfaces should be specified in a manner that will not create undercuts to the withdrawal action from a mold. The undercut effect can be responsible for stresses and marring. A similar condition applies to lettering, and the location of such lettering should conform to smooth withdrawal requirements. 

Diameter) in PI-2555 Coating on Primed Ti Specimen Showing Undercutting Effect of a 10-volt Anodization. 

Alex Rosenberg I actually don t see how you can endorse those claims on the basis of the arguments that you gave in your paper, because the arguments you gave in your paper would undercut those claims as effectively as they undercut the claims made by evolutionary psychologists. 

Sykes M, Tredgold R. Restricted orbital undercutting. A study of its effects on 350 patients over the ten years 1951-1960. Br J Psychiatry 1964 110 609-640. 

Because of the proximity effect of surface diffusion, the flux from the regions adjacent to the neck leaves an undercut region in the neck vicinity.7 Diffusion along the uniformly curved spherical surfaces is small because curvature gradients are small and therefore the undercut neck region fills in slowly. This undercutting is illustrated in Fig. 16.3a. Because mass is conserved, the undercut volume is equal to the overcut volume. Conservation of volume provides an approximate relation between the radius of curvature, p, and the neck radius, x ... 

Heavily doped (>1018/cm3) n-type Si and poly-Si etch faster in Cl- and F-containing plasmas than do their boron-doped or undoped counterparts (103a, 105, 111, 112). Because ion bombardment is apparently not required in these cases, isotropic etch profiles (undercutting) in n + poly-Si etching often occur. Although the exact mechanisms behind these observations are not completely understood, enhanced chemisorption (103b, 111) and space charge effects on reactant diffusion (112) have been proposed. 

Whether or not a chemical process step has been successful is difficult to measure, since there are few on-line measurable electrical properties. For example, film thickness and grain structure of polycrystalline silicon can be measured after a deposition step. However, their effect on device performance might not show up until subsequent doping or patterning steps fail. Similarly, it is possible to measure etch rates on-line by laser interferometry, but the etch profiles must be checked by electron microscopy. Unexpected mask undercutting or undiscovered etch residues can result in subsequent contact and device lifetime problems. 

Straight portion of stem effective inside die bore Portion of punch stem which is undercut or made smaller than punch tip straight most common for lower punches in order to reduce friction from punch tip and die wall Complete set of punches and dies to accommodate all stations in tablet press... 

The effect of undercutting the sphere svirface just at the edge of the neck has been shown to have a major effect on the mechanisms of surface diffusion. 

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