3D Capabilities
To design 3D parts in eMachineShop and to know what is possible, it helps to understand how the eMachineShop CAD software works.
The eMachineShop CAD software was designed to allow to make only parts that are economical to be manufactured. This approach saves you money and the software is easy to learn and use. This approach also reduces cost because the conversion from CAD to the CNC machine control program takes less time and you can get instant pricing.
Specifically, some of the eMachineShop CAD interface is based on the milling machine. The same CAD interface, with some minor variations, is also used for other 3D processes including: Casting, Rubber Molding, Plastic Injection Molding, Rapid Prototyping and others.
With the CAD approach based on the milling machine it helps to understand how a milling machine works. Although eMachineShop uses mostly CNC milling, a picture of a simple manual milling machine is shown here:
A milling machine looks somewhat like a drill press at first glance. A cutting tool protrudes down from a rotating spindle. A block of material is placed on a moving table below the cutter. While the cutting tool turns, a computer controls the vertical (Z axis) motion of the cutter and the horizontal (X and Y axis) motion of the block of material. The cutter is guided to move through the material, removing portions to create shapes. Additionally, the material can be turned to various orientations in the middle of the process and cutting tools of various shapes can be used. The cutter shapes directly supported in the CAD include (shown in side view):
The above tools are essentially round when viewed from the top. Referring to the above images from left to right:
- Plain endmill - used for most milling - creates walls with straight 90 deg edges and sharp corners at the bottom of recesses.
- Chamfer endmill - creates 45 deg bevels on the top (near) edge of a wall or recess
- Grooving endmill - creates rectangular grooves in side walls
- Ball mill - creates rounded edges at the bottom (far) edge of a recess
- Rounding endmill - creates rounded edges at the top (near) edge
- Angle endmill - creates walls at angles other than 90 deg
- and, not shown, a conventional drill
The eMachineShop CAD limits shapes to those that can be made by motion of the cutters vertically or X/Y motion of the material along straight lines or curves, but not simultaneous motion of all 3 axis, as doing so generally increases costs substantially and significantly complicates the interface. Knowing these capabilities and limitations allows you to determine what is possible and insures that the parts you design will be economical to make.
Many more shapes are possible using the revolve feature.
Examples of possible shapes include the parts shown on various pages of this web site such as the main gallery. You will see that a quite diverse array of shapes are possible.
Examples of shapes that cannot be modeled include those with complex curves such as statues, faces and computer mice, although there are tricks to achieve some complex curved shapes.
