CNC Milling Service
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How CNC milling works
Looking something like a drill press, a milling machine uses a cutting tool that moves in all three dimensions, removing material to achieve the desired part shape. The cutting tool usually rotates about an axis that is perpendicular to the table that holds the material to be cut. 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.
Some common cutter shapes include:
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 edge of a wall or recess
- Grooving endmill - creates rectangular grooves in side walls
- Ball mill - creates rounded edges at the bottom edge of a recess
- Rounding endmill - creates rounded edges at the top edge
- Angle endmill - creates walls at angles other than 90 deg
- and, not shown, a conventional drill
Material is usually removed by both the end and the side of the cutting tool.
Although setup tooling is mainly software, custom jig tooling is often required for workholding.
Milling has several advantages over other manufacturing processes. It is cost effective for short runs. Complex shapes and high dimensional tolerances are possible. Smooth finishes can be achieved. CNC milling can produce almost any 2D or 3D shape provided that the rotating cutting tools can reach the material to be removed. Examples of parts include engine components, mold tooling, complex mechanisms, enclosures, etc.
This machining process can handle most rigid materials including most metals: Aluminum, Stainless Steel, Copper, Steel, Brass, Titanium, Sterling Silver, Bronze, etc.; hard plastics and other materials: Nylon, Acetal, Polycarbonate, Polystyrene, Acrylic, Fiberglass, Carbon fiber, PTFE, ABS, PVC, etc.
Cost reduction options include reducing the amount of material removed, limiting complexity, avoiding intricate features and making shapes that are easy to hold.
Design Considerations for CNC Milling
- Providing corner radius of 10% or more of wall height is ideal.
- Avoid flimsy shapes.
- Provide shapes that are practical to hold during machining, such as straight edges.
- As the milling process applies pressure to the material, weak shapes are difficult to machine, such as long thin shapes and thin walls.
- Generates a cut surface with a visible pattern resulting from the rotation and movement of the cutter.
If you need online CNC milling services we are one of the most capable and affordable sources and we can get the job done right. Download our Free CAD software today and design your custom part or convert an existing file. Order online for ultimate speed and convenience.
About our service
eMachineShop offers a unique approach to providing CNC milling services. We provide special free CAD software that allows you to easily draw your part or convert an existing design. The software then provides instant expert feedback about your design and helps you correct any issues to ensure a smooth trouble-free process. It then gives an instant price - saving you from waiting for quotations. And finally the software allows you to order your custom parts online with just a click - at prototype or production quantities.
We stock a wide variety of materials, use state-of-the-art machines and diligently follow all design specifications. We continually strive to improve and optimize our processes and maximize customer convenience. Our customers range from inventors to businesses to government agencies. We are focused on quality and customer service.
Get started today - design, price and order your custom parts through eMachineShop.