The best results in terms of accuracy and quality of surface finish are obtained using contact RE systems. Contact systems have several fundamental advantages over noncontact systems: treatment of surfaces to prevent reflections is not required,
vertical faces can be accurately scanned, data density is not fixed and is automatically controlled by the shape of the component, time-consuming manual editing of the data to remove stray points is not required, postprocessing for cutting can be faster as surface offsetting may not be required, and very tiny detail can be accurately replicated.5
The contact systems’ touch-trigger probes can be used to digitize components when fitted to either a CNC machine tool or coordinate measuring machine. Analog probes operate at very high scanning speeds, with excellent accuracy and low contact force. This allows better machine finishing of parts and the ability to scan relatively soft materials. The scanning probes have been developed for the intricate scanning of objects such as coins, watermark dies and jewelry, where fine detail requires the use of very low contact force.
Once the data has been captured, the scanning software packages are used to produce mold and die cavities, CAM profiles and templates. Model variants can be produced by mirroring, scaling, rotating, translating and inverting. Once the scan manipulation is complete, the software enables the user to manipulate data and then create a CNC program or export the data to any of several CAD output file types.
3D Laser Scanning is a non-contact, non-destructive technology that digitally captures the shape of physical objects using a line of laser light. 3D laser scanners create “point clouds” of data from the surface of an object. In other words, 3D laser scanning is a way to capture a physical object’s exact size and shape into the computer world as a digital 3-dimensional representation.
3D laser scanners measure fine details and capture free-form shapes to quickly generate highly accurate point clouds. 3D laser scanning is ideally suited to the measurement and inspection of contoured surfaces and complex geometries which require massive amounts of data for their accurate description and where doing this is impractical with the use of traditional measurement methods or a touch probe.
Whatever the product, be it a car, hand drill or mobile phone, customers expect its tightly-toleranced parts to fit together and function perfectly and at the same time be of high quality and attractive design. But how do manufacturers ensure this level of precision without delaying the development and launch of the product? The answer is to digitise the 3D shape and features of the prototypes with a non-contact laser scanner mounted on a coordinate measuring machine (CMM) or articulated arm and compare the results to the original CAD designs.
Laser scanner based inspection of features in sheet metal.
It is much faster to inspect a part this way than to use a touch probe to take discrete measurements. With tens of thousands of points per second being captured by the laser and added to the point cloud, a complete inspection cycle is often between five and 10 times faster than tactile probing. Furthermore, with the latter technique it is impossible to know what is happening between two adjacent discrete points, so the data is very sensitive to imperfections in the geometry being inspected. Parts that have flatness and roundness errors, edge rollover or burrs are particularly problematic. Radius compensation error is a further difficulty with tactile probing. When a stylus makes contact with the edges of a hole, for example, radius compensation may result in unexpected measurement points if a neighbouring surface is touched first.
Contact scanners are in close contact with the scanned document. For example, flatbed scanners, documents will be placed in glasses.
Paper-fed scanners are also contact scanners. Just like working mode of printers, paper goes in and out.
Advantages of non-contact scanners:
1) Fast scanning speed. The contact type is mostly point-by-point scanning, while the non-contact type basically captures full page information directly. For example, it may take 1-2 minutes to scan a color image with a flatbed scan.
2) Versatile materials can be scanned. Not only it is able to scan a single page, it also scans curved materials such as books, objects, and files. Flatbed and paper-fed scanners can only scan single page documents.
Disadvantages of non-contact scanners:
1) Accuracy. This is a compromise between accuracy and speed. If the software algorithm is strong enough, lack of accuracy can be made up. However, the degree of remedy is limited by the human eye (can’t see difference from human eye).
2) The optical scanning element (camera) is affected by light. Different materials may work well, and reflections may also occur.
Contact scanners are in close contact with the scanned document. For example, flatbed scanners, documents will be placed in glasses.
Paper-fed scanners are also contact scanners. Just like working mode of printers, paper goes in and out.
Contact-based 3-D scanners work in a number of ways. One type has a carriage system and a control flat bed on which the object rests, while arms take measurements. Another type has articulated arms, and measurements are calculated from the joint angles of those arms.
3-D scanners are used for creating life-like images and animation in movies and video games. Other applications of 3-D scanning include reverse engineering, prototyping, architectural and industrial modeling, medical imaging and medical device modeling. 3-D printers can use data from 3-D scans to create physical objects.
Contact scanners are in close contact with the scanned document. For example, flatbed scanners, documents will be placed in glasses.
Paper-fed scanners are also contact scanners. Just like working mode of printers, paper goes in and out.
Advantages of non-contact scanners:
1) Fast scanning speed. The contact type is mostly point-by-point scanning, while the non-contact type basically captures full page information directly. For example, it may take 1-2 minutes to scan a color image with a flatbed scan, but CZUR ET16 Plus only takes 1-2 seconds.
2) Versatile materials can be scanned. Not only CZUR is able to scan a single page, it also scans curved materials such as books, objects, and files. Flatbed and paper-fed scanners can only scan single page documents.
Disadvantages of non-contact scanners:
1) Accuracy. This is a compromise between accuracy and speed. If the software algorithm is strong enough, lack of accuracy can be made up. However, the degree of remedy is limited by the human eye (can’t see difference from human eye).
2) The optical scanning element (camera) is affected by light. Different materials may work well, and reflections may also occur.