3D Digitizing
Last updated on Wednesday, March 10, 2021 05:52:35 AM Mountain US Time Zone

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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.

Find the Mach3 3D Probing Plug-in, then install & configure it
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
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

Econo-Probe. The shaft is 3/8" x 1.2", body is 1.8" D x 1.9" L &
the probe is about 1/4" x 2" with a 1/8" 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.

Centering Probe 1   Centering Probe 2


Econo Probe instruction sheet.


3D Probing (Alt-3) menu. The 3D Mach3 Probe Plug-in module.

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.

 

 

 
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3D Digitizing Probe, Digitizing Movie

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