Stylus is one of the most important parts in a cmm because it´s in contact with de surface of the piece tomeasure.
First of all, im going to talk about materials:
The most used materials are the Ruby, Silicon Nitride and Zirconia.
Ruby is the best materialand its used in all applications, except in two ones:
-heavy duty scanning applications on aluminum (where we use Silicon nitride)
-heavy dutyscanning applications on cast iron (where we use Zirconia)
Lets talk about types of styli:
-Straight Styli: it’s the most common styli , its very used becauseof its simplicity and accuracy
-Star Styli : A star styli is used to inspect internal points ; it is used because it minimizes the need to move deprobe.
-Pointer Styli: It has lower accuracy because they are designed for the measurement of forms, points,,,
-Ceramic Hollow ball styli: They are ideal forprobing deep features.
Rules for choosing a stylus
To get the best accuracy, we should follow these instructions:
-keep styli short: the more itbends, the lower accuracy
-minimize joints: a join introduces potential bending points
-Keep stylus balls as large as possible : larger ball allows largerstem diameter
Stylus for Faro Arms:
They are portable teams , which are made of tungsten carbide stem to increase the resistance in all conditionsNaming Protocol
M2: size of the screw top
STY D2R: type of stylus
L20 : stem length
d1.4 SS: material and diameter of the steam ( stainless steal)