1 The individual sheets of cut plywood are clamped together before being machined.
2 View showing the machined internal structure before the external surface is cut.
– Can be used on virtually any material.
– Designs can be cut straight from CAD files.
– Highly adaptable for cutting intricate and complex shapes.
– Not suited to high-volume production.
– Can be slow.
Volumes of production
CNC cutting is best suited to one-off or batch production because of the slow progress rate.
Unit price vs. capital investment
No tooling, just the expensive time for cutting and the creation, using CAD, of the three-dimensional data.
Speed
The speed is determined by several factors, including the material, the complexity of the form, and the surface finish that is required.
Surface
Good, but may require some post finishing, depending on the material.
Types/complexity of shape
Virtually any shape that can be conceived on a computer screen.
Scale
From small components to huge objects. CNC Auto Motion in the US, for example, is one of several companies manufacturing monster-sized machines having more than 50 feet of travel, with 10 feet of vertical-axis travel and a gantry measuring 20 feet across.
Tolerances
High.
Relevant materials
CNC technology can be used for cutting a wide range of materials, including wood, metal, plastic, granite, and marble. It can also be used for cutting foam and modeling clay (see typical products).
Typical products
Ideally suited for making complex custom-made designs such as injection-molding tools, die cutters, furniture components, and the highly crafted, complex forms of handrails. It can also be used, in automotive design studios, for rapid prototyping of full-size cars in foam or modeling clay.
Similar methods
Laser cutting (p.46) when the laser is mounted on a multi-axis head is possibly the closest method.
Sustainability issues
As the machines have excellent accuracy the amount of wastage produced as a result of faulty parts or errors is minimal. Additionally, the layout of parts to be cut can be designed effectively so that there is minimal excess material. Depending on the material, waste can be reused or recycled.
Further information
www.demakersvan.com
www.haldeneuk.com
www.cncmotion.com
www.tarus.com
Electron-Beam Machining (EBM)
Product |
customized tri-flange implants |
Materials |
titanium |
Country |
Sweden |
Date |
2005 |
This titanium hip-bone plate illustrates the spattered surface that is a common result of this process.
Electron-Beam Machining (EBM) is a versatile process that is used to cut, weld, drill, or anneal components. As a machining process, one of its many advantages is that ultrafine cuts can be made with such high precision that they can be measured in microns. EBM involves a high-energy beam of electrons being focused by a lens and fired at extremely high speeds (between 50 and 80 percent of the speed of light) onto a specific area of the component, causing the material to heat up, melt, and vaporize. The process needs to occur in a vacuum chamber to ensure that the electrons are not disrupted and thrown off course by air molecules.
– Highly accurate.
– There is no contact with the material being cut, so it therefore requires minimal clamping.
– Can be used for small batches.
– Versatile: a single tool can cut, weld, and/or anneal at the same time.
– A disadvantage compared with laser cutting (see p.46) is that it requires a vacuum chamber.
– Laser cutting can be just as effective for less accurate machining.
– High energy consumption.