Ufuk Güneş Civelek 030050161 10th week

Round Rail

This system makes use of round rail or rod that provides the linear guide path for one or more bearing blocks to traverse along its length.The diameters of the rail are avaible anywhere from 1/8 up to 4 in and are found in lengths up to20 ft. This type of rail is typically not the same stock as what you would find at your local steel supplier, as it is precision ground to exacting tolerances. The rail itself can be mounted in either of two ways: end or continuous mounted. Let us first at the rail or shaft portion of this system with its avaible mounting options. After that, we will take a look at the bearing and mounting block options that are available.There are two basic types of bearing blocks used with round rail (open and closed).The bearing style will become a key factor when calculating the load capacitiesfor each of the mounting methods.
(Alan Overby,CNC Machining Handbook: Building, Programming, and Implementation,p.26)


Hybrid Roller Guide

Working on the same principles as the V-roller technology, some manufacturers use half moon profile rollers in conjunction with hardened steel rods embedded into base substrade.The hybrid roller system shown in fig is made by Pacific Bearing.
This system is only avaible as fully assembled units and comes in various sizes
and lengths.The components are not avaible individually.
(Alan Overby,CNC Machining Handbook: Building, Programming, and Implementation,p.26)



Isotrophy & anisotrophy

One aspect of material behaviour that we have not addressed yet except in passing is the influence of lack of isotropy.Recall that isotropy means that the material stiffnesses are identical or constant(iso) in all directions when observed or measured at a point.That is, if we look in different directions from the same point in the material, do we perceive different stress-strain behaviour in some way, shape or form? What's the level of that dissimilarity? That level is reflected in the types of anisotropy that are observed. If the material is simply called anisotropic,
then in every direction we look, we'll perceive a different behaviour.No behavioural characteristic is similar from one direction to another.We'll always see behaviour that's totaly different and without any symmetries in direction.
Transverse isotropy is a simpler lack of isotropy than anisotropy.For this class of materials ,there is one plane in which the beviour is the same in all directions, but perpendicular to that plane or transvewrse to that plane, quite a different behaviour exists.
Those dissimilarities in anisotropic metarial behaviour in different directions can be material nonliearities, they can be simply young's moduli being different in different direcitons, or they can be strength differences or all the foregoing.Thus, the anisotropy desciption does not necessarily mean we're dealing with material nonlinearity, but simply a difference in characteristic material behaviour, what ever that characteristic might be: nonlinearity, modulus, strength, orwhat have you.
(Robert Millard Jones,Deformation Theory of Plasticity,p.68)