3D DESKTOP CNC MACHINING & RAPID PROTOTYPING OVERVIEW
Traditional 3D Machining & Rapid Prototyping
Computer numeric controlled (CNC) cutting machines (routers or mills) are often seen as large expensive items that only manufacturing companies use. These machines are often hundreds of kilograms in weight and are usually bolted to concrete factory floors.
If an accurate physical prototype of a computer generated model is required the two main avenues are to CNC machine them in a workshop or go to rapid prototyping (RP) bureaus. Costs can range from a few hundred dollars to thousands of dollars depending on the size and complexity of a model. Sometimes a number of models are required before a product is approved.
For small models and concept designs, there is now an office based low cost CNC prototyping alternative that fits on a desk or workbench - a desktop 3D printer. RP systems are heading towards desktop models as well. The advantage of desktop systems is that they allow low cost and rapid turnaround of prototypes in a variety of materials. You can now make a 'draft' model in the office to ensure everything is correct before proceeding to the more expensive traditional CNC or RP prototypes.
What can you do with these CNC and RP systems?
The Roland range of desktop and benchtop CNC machines have working areas from 152mm x 101mm x 60mm up to 650mm x 450mm x 155mm. The materials that can be machined range from plastics, model making foam, epoxy resins and wood for the smaller machines, to light alloy metals such as aluminium and brass for the larger machines. This allows users to prototype a wide range of parts in different materials and sizes in an office environment, with a fast turnaround time.
These compact CNC systems include accessories such as a 4th axis and workholding devices for fast securing and removal of workpieces. The result is a versatile range of office or small workshop based CNC machines that are easy to use and inexpensive to maintain. Easy to use software supplied with Roland's CNC machines means you do not need to have lengthy training before using these CNC systems. The software is so easy to use that even high school students are using Roland's desktop CNC machines. For industrial users or for those wishing to progress to more advanced machining, the Roland range of machines are G code compliant and are therefore able to be used with industry leading computer aided manufacturing (CAM) software such as Mastercam, Surfcam, CAMWorks, VisualMill and Machining Strategist among many others.
RP systems can be used to make complex parts, hollow parts and working parts such as thin walled plastic prototypes with small intricate details in a single piece, something that CNC systems are usually unable to do. Wax parts suitable for lost wax casting can also be made from RP systems.
Users of CNC and RP systems include designers making quick foam models for concept evaluation, patternmakers producing molds and prototype models, jewellers making patterns and molds, doctors making wax radiation therapy devices, bronze foundries making molds and patterns and orthodontists making modern braces.
How do you use desktop machining and RP systems?
Today's desktop machining systems simply plug into your computer and power outlet. Whether you are a home user or industrial user a range of 3D CAD and CAM programs exist to meet your needs. The computer power required to operate 3D CAD/CAM systems and desktop machining systems need only be a standard home computer. Industrial users with complex parts should use faster computers with more memory and better graphics cards.
In Europe, Asia and America, desktop machining and small RP systems are in widespread use across many industries. The computerised workflow has significantly reduced product development times. For industry specific information on machining go to the 'Case Studies' page.
Types of Desktop CNC and Rapid Prototyping Systems
There are a variety of CNC systems and RP systems, each with its own advantages and disadvantages. As a result one machine type is not always the best solution, but together they can meet most prototyping needs.
A four page extract of a benchmarking study conducted in the USA by T. A. Grimms & Associates comparing a Roland MDX-650 CNC mill and layered prototyping machines is available for download. The full report is available from the Roland website link below.
The following lists some of the common types of prototyping systems. For the SLS, FDM and STL systems, they operate on the principal of building a model in layers by adding material gradually. Layer thickness varies for each technology and even for different models within each technology. CNC systems operate by cutting material away from an existing block of material. CNC systems can cut into metals, plastics, woods and resins.
For more information please visit our 'Links' page and follow the links under Prototyping Systems.
1. Selective Laser Sintering (SLS)