In Mach3, LPT1 pin 12 input is used for the probe.
3D
Digitizing
Last updated on
Saturday, September 03, 2011 08:24:58 AM
Eastern US Time Zone
In progress
3D Digitizing Probe, Digitizing Movie
Basic 3D digitizing steps: probe, mesh point cloud, convert to appropriate file type, CAM to g-code & then CNC the part.
3D Probing Plug-in - download,
install, configure the plug-in under Mach3 Conf Menu.
Adds the 3D Probing tab to the right of Help. Creates an XYZ comma-delimited
txt
file.
Mach3 also has a Digitize Wizard but it is purportedly slower than the plug-in.
MachCloud - reads the 3D Probing
comma-delimited txt file & creates an XYZ point cloud that can be meshed from the
menu &
then saved as an STL file or just saved it as an STL file for use by
other meshing programs e.g., MeshLab.
Raw point cloud file structure can vary e.g., comma, tab, or space delimited.
Reading errors can result.
Convert meshed STL file (using any preferred method) into g-code for Mach3 with a CAM program e.g., FreeMill.
STL is a file
format native to the stereolithography CAD software created by 3D Systems. This
file format is
supported by many other software packages. It is widely used for rapid
prototyping & computer-aided
manufacturing. STL files describe only the surface geometry of a three
dimensional object without any representation
of color, texture or other common CAD model attributes. The STL format specifies
both ASCII & binary
representations. Binary files are more common, since they are more compact. An
STL file describes a raw
unstructured triangulated surface by the unit normal & vertices (ordered
by the right-hand rule) of the triangles
using a three-dimensional Cartesian coordinate system.
Mesh generation is the practice of
generating a polygonal or polyhedral mesh that approximates a geometric
domain. The term "grid generation" is often used interchangeably. Typical
uses are for rendering to a computer
screen or for physical simulation such as finite element analysis or
computational fluid dynamics. The input
model form can vary greatly but common sources are CAD, NURBS, B-rep & STL
(file format). Three-dimensional
meshes created for finite element analysis need to consist of tetrahedra,
pyramids, prisms or hexahedra. Those
used for the finite volume method can consist of arbitrary polyhedra. Those used
for finite difference methods
usually need to consist of piecewise structured arrays of hexahedra known as
multi-block structured meshes.
Computer-aided manufacturing (CAM)
is the use of computer software to control machine tools & related machinery
in the manufacturing of work pieces. CAM is the next
computer-aided process after computer-aided design (CAD),
as the model generated in CAD can be input into CAM software, which then
controls the machine tool.
Traditionally, CAM has been considered as a numerical control (NC) programming
tool, wherein two-dimensional (2D)
or three-dimensional (3D) models of components generated in CAD software are
used to generate
G-code to drive computer numerically controlled (CNC) machine tools.
In Mach3,
LPT1 pin 12 input is used for the probe.
3D Digitizing Probe
Shaft is ⅜" x 1.2", body is 1.8" diameter x 1.9" long & the
probe is about 0.24 diameter x 2" long with ⅛" ball.
The shaft can be removed & the probe tip replaced with a rubber-boot sealed
pedestal. The unit is then
mounted upside-down on the mill table in a setup that would be used for
automated tool length sensing.
Econo Probe instruction sheet.
Digitizing Movie
Click to see digitizing probe movie.
Another probe tip was constructed of stainless steel with a
10-24 thread.
A 2mm (0.078740") carbide tip from
a dial test indicator was
used for the tip. The tip is seated in a reamed hole & held in using Loctite red
#271.
Smaller ball tip mounted into the probe housing.
3D Digitizing Probe, Digitizing Movie