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3D laser scanning / digitizing is a technology that captures the shape of physical objects digitally. Laser Design’s patented laser scanning technology will decrease your engineering costs, decrease time to market for your products, decrease material waste, and increase your product’s quality.
Laser scanning an object is a lot like spray painting an object. The laser projects points or a line of laser light onto a surface as if “spray painting” the object. The density of points can be controlled, either denser or sparser, depending on the speed at which the laser travels over the surface, the same as with spray painting where the slower or longer you spray an area, the thicker (denser) the coverage of pigment. Unlike painting, however, laser points do not stack on top of each other; they are regulated to a specific density for very uniform coverage.
And just like when you spray paint a part, the laser light needs to be directed towards the part so it covers all the surfaces that need to be captured. In order to make sure you don’t miss undercuts or otherwise blocked surfaces, you need to rotate the scanner to the specific area, such as inside holes. It is very difficult to spray paint into deep holes and the same is true of a laser scanner. It is unlikely to paint or scan the inside of a part if there is no access to it., however we can digitize hidden areas by casting a temporary splash or back-cast of the area and merge it with the prior scan data.
The primary advantages of laser scanning are:
• It is non-contact;
• It is extremely fast;
• It is highly accurate;
• It allows complete coverage of the part;
• It is very repeatable;
• Its Windows-based system makes it easy to use
Non-contact scanning allows fragile parts to be measured and makes the coordinate locations especially useful to CAD/CAM systems where splining or surfacing through true surface coordinates is desirable. The laser's high resolution and thinner beam also permit scanning highly detailed objects where mechanical touch probes may be too large or inconsistent (non-repeatable) to accomplish the task. Once true surface coordinates have been collected for an object, a single set of data can be used to generate roughing and finishing tool paths for machining, feed CAD/CAM and analysis software, drive rapid prototyping equipment, and allow "electronic archiving" of physical objects.
Laser Design's Surveyor family of 3D Laser Scanning Systems makes use of a laser sensor that is mounted to a 3 - 6 axis computer controlled positioning system or retrofitted to an existing CMM. We even have a portable model that sits on a camera tripod.
An object that is to be scanned is placed on the bed of the digitizer and our Scan Control software drives the laser sensor above the surface of the object. 3D coordinate locations on the surface of the object are recorded by the scanning system according to scan density and pattern parameters set by the user. These XYZ coordinate locations are stored in a file that can be converted to IGES or ASCII formats for input into nearly any CAD/CAM system or specialized point-cloud processing software on the market today.
The more automated systems have very easy programming features for covering the part geometry unattended. The process used by the machine can again be compared to what a painter would do to spray paint an object by sweeping back and forth across the part in a systematic method. The difference is the user does not have to hold the laser, but perform other duties while the scanner collects the data automatically.
Laser Design's technology uses Laser Triangulation, a precise method of 3D data acquisition. Laser triangulation is an active stereoscopic technique that computes the distance of an object with a directional light source and a video camera. A laser beam is deflected from a mirror onto a scanning object. The object scatters the light, which is then collected by a video camera located at a known triangulation distance from the laser. Using trigonometry, the 3D spatial (XYZ) coordinates of a surface point are calculated. The CCD camera’s 2D array captures the surface profile’s image and digitizes all data points along the laser.
In addition to XYZ positioning, Laser Design supports computer controlled object rotation and laser orientation. This allows scanning of virtually every side of a 3D object and eliminates the traditional problem of scanning undercuts. Laser Design's Surveyor Scan Control software includes powerful data manipulation tools which can blend data from multiple views together into a single data set with the use of tooling balls. Additionally there are several other CAD/CAM packages available in the market today that blend the data collected at different orientations into one complete 3D model using various powerful data matching algorithms.
The shape of that single "2D" profile is recorded by the digital CCD and subsequently, based on the calibration and look up tables of the lasers, a Z position is determined and stored for each pixel value by the software. This location along with the machine axes positions are used to compute the X,Y,Z coordinates of the points along that profile. Hundreds and thousands of similar profiles are thus collected as the probe sweeps over the object and the software stores this information into a database for later retrieval. Each profile comes into the database as a single polyline entity with points distributed along the length of the line. These polylines are displayed graphically on the computer screen as they are gathered.
Our 3D laser scanners are ideal for applications in Product Design, Inspection and Reverse Engineering. Our customers include nearly every industry imaginable. Automotive, aerospace, consumer electronics, medical, railroad, sports equipment, toy, jewelry and container manufacturers are all using our systems and endorse the technology. Two military branches and a leading manufacturer of space shuttle components also use our equipment. Companies in countries all over the world including Japan, France, Italy, Korea, Singapore, Spain, Brazil, China and India have also purchased systems and recognize that laser scanning is here to stay and will continue to define state-of-the-art manufacturing.
• product design
• quality control
For a detailed account of various applications the laser scanned data is
being used for, visit Project News
Often times a part is built from the CAD model using molds, cutting tools, or assembling parts. However, once the part is “real,” how do you know it is within spec? In other words, how do you know if you part is correct?
3D laser scanning quickly creates an accurate digital model of a part which can be compared to the original design model to see where out-of-spec areas exist. This can save a lot of time and money because only those areas need to be corrected by retooling or redesigning.
Laser Design systems can accommodate items from as small as a
tooth all the way up to cars, aircraft, large buildings, and even oil rigs. The size of the part is not limited by the system, but rather by accuracy needs and time constraints. The size of the laser line is inversely proportional to its accuracy, so usually scans of large parts using longer laser lines are less accurate. However, even Laser Design’s longest-line laser, the SLP-2000 with an 8” laser line is amazingly accurate to within 127µm.
Surveyor Scan Control (SSC), Laser Design’s proprietary software which comes with all the Laser Design scanning systems, has two primary functions:
1. To move the machine in 3D space in order to physically adjust the laser probe over the object that is being scanned. SSC set up the scan so that the laser probe follows a pre-defined path in 3D space while scanning the part. The setup programming is entirely "graphical" and no code needs to be written. Moreover, SSC has powerful macro capabilities that allow the user to automate the scanning process as well as store and recall the scanning parameters in case the same or a similar part is scanned again.
2. To collect and edit the data from the laser. It organizes the 3D point coordinate information on each and every point collected during scanning and stores this information in a file on the hard drive. This file can be retrieved later for editing. The same coordinate system is valid during data-editing as in scanning. Typically the raw data collected from the system is de-spiked, filtered, and smoothed depending upon the quality of the data obtained and the application it is being used for.
Because Laser Design’s systems support computer-controlled object rotation and laser orientation, they are able to scan virtually every side of a 3D object and eliminate the traditional problem of scanning undercuts.
We offer several extremely powerful software packages available in the market today that can import data from our systems and use it for a desirable outcome. Through specialized software from Laser Design Solution Partners, the 3D laser scan can be easily compared to a CAD file, enabling deviations from normal to be graphically displayed. Other software programs allow NURBS surfaces to be applied to the scan data as well as STL and CNC tool path files. The choice of the software to use varies depending on the application and other circumstances.
Special surface finishes such as specularity and translucency can be addressed with various softwares such as Laser Design’s Point Cloud DeNoiser and SSC filters. However, refraction from water or glass limits the use of laser scanning.
The standard laser resolutions offered by Laser Design are 10µm and 25µm
although we have built custom systems with finer laser resolutions.
When considering any optically based measuring systems, it is important to realize that there is a difference between the terms resolution and accuracy. Resolution is simply the smallest change in distance that the sensor is capable of detecting, and is proportional to the point spacing along the laser line. Accuracy, on the other hand, describes how closely the measurements of the laser conform to the true dimensions of the object being measured.
LDI determines accuracy by measuring the position of a vertex target in multiple positions throughout the laser field of view. The true position of the target is measured using a high accuracy mechanical positioning base. Comparing the laser measurement to the true position value gives you the measurement error for each point. The accuracy of the laser is the total error bandwidth over all measurements within the entire field of view of the laser.
Naturally, the mechanical accuracy of the positioning system also comes into play when discussing accuracy. Our Scan Control Software accepts feedback from optional linear scales and supports the use of compensation tables that correct subtle mechanical inaccuracies inherent in any machine. The volumetric accuracy specifications in our literature are based upon our ability to digitize a ball-bar oriented several ways within the work envelope and have the measured length of the ball-bar vary by no more than the stated accuracy of the machine. A ball-bar is defined by the American Society of Mechanical Engineers (ASME) in their standards document, ASME B89.1.12M-1990, as a rigid bar to which a precision tooling ball is mounted on each end.
Much like a 35mm camera, the laser has exposure settings that need to be adjusted depending upon the nature of the object being scanned. In general, dark-colored objects require longer exposure settings than light-colored objects and longer exposure settings require the system to operate at slower velocities if data integrity is to be maintained. The point sampling distance requested by the user also affects scanning speeds. In general, we have experienced "real world" scanning speeds of 30,000 to 40,000 points per second although some situations may require slower scanning speeds and other situations may permit scanning at full scan rate of the probe which is 225,000 points per second. In all cases, laser scanning tends to be much faster than a CMM and somewhat faster than mechanical tracing systems.
Laser Scan data is used to create a digital model of the item scanned. The model can be either non-parametric (dumb) or parametric. While a parametric model will be more time-consuming and more expensive to construct than a non-parametric model, it will pay dividends later on if many changes are required.
A non-parametric (or dumb) model is described by trimmed surfaces without the underlying dimensional parameters. To edit or change a “dumb” model one would have to recreate new surface patches by hand for all of the change areas. This can be very involved and must be re-done each time a new change to the model is required.
Non-parametric or “dumb” models are mainly used for:
1. One-time applications (where the model will not be changed later on)
2. Reference geometry for accessory design
3. Parts with large areas of free-form shapes
A parametric model is made by combining base features (often 2D sketches) that are specified by simple dimensional parameters. While each base feature is relatively simple in nature, a complex model can be produced by combining these features. Changes can easily be made to the parametric model by altering the dimensions of the features. A correctly constructed parametric model would then use this built-in “intelligence” to automatically rebuild itself to these new parameters.
The most common reasons for needing a parametric model are:
1. Being able to change the model quickly and easily
2. Easily creating dimensioned 2D drawings of a model
3. Quickly and easily creating similar parts with different dimensions (i.e. brackets, bolts, etc.)
Of course these lists are only a few examples of reasons for using a parametric vs. non-parametric model. The best solution depends on your application of the data. To determine the best way to solve your 3D modeling challenge, contact us.
The Laser probes employed by our scanning systems use a diode based class II laser. It has a very low power output with ratings at less than 1mW and a 670nm wavelength (visible red spectrum). It utilizes passive beam spreader and has no moving parts. Class II lasers are still ocular hazard, but viewing time in order to do the damage to the eye is significantly longer than for instance for a class III laser.
Although used in a variety of inspection applications, laser scanning is not intended to compete with the micron accuracies of some CMMs. However, Laser Design’s Surveyor ZS series scanners combine the mechanical accuracies of a CMM base with laser scanning, plus a touch-probe option.
As a rule, CMMs are better suited to measure geometric parts where basic dimensions, hole locations, diameters, flatness and roundness measurements are required for accept/reject types of applications. Laser scanning tends to be better suited for 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 a touch probe. Also laser scanning comes into play for picking fine features that are inaccessible to a touch probe.
By combining non-contact laser scanning with traditional contact measurement in the ZS systems, Laser Design offers the convenience and efficiency of both worlds.
Laser Design has different processing software to meet whatever your requirements are for export, depending on your compatibility and accuracy needs. Typical outputs are inspection reports, CAD models, surfacing, comparisons, and deviation reports.
Laser Design offers Quick Start Training that prepares a new user for using
Surveyor Scan Control for scanning and data editing. Advanced training is also provided for experienced users. For further information and a training schedule, contact us.
We can deliver many types of file formats--whatever kind of file customers need for their applications:
• Raw point cloud data when a customer has their own CAD software that can create models from point cloud data (ie Geomagic, Rapidform, Imageware,…) or CAD system that can import point clouds for reference purposes.
• Polygonal models (PLY and STL formats) typically used for making rapid prototype models or for carvings/engravings with fine or sharp details where the STL file is directly machined using special CAM software to create CNC machine code. There are also some software packages that use polygonal models (FEA, animation, rendering packages, etc.)
• Surface models (IGES and STEP formats) This is the workhorse file format for reverse engineering. Provides a precise and complete 3D model that most CAD/CAM/CAE systems can import and utilize. Excellent for manufacturing, documentation, and design analysis. If them main purpose of the reverse engineering process is to replicate the physical model exactly as it exists this is the best and least expensive file format to use. This format does not provide parametics or design history and surface editing by pulling surface or edge curves is limited. If the part design needs to be modified or part variations created (beyond mirroring, scaling, or simple cuts or feature additions) this may not be the best format.
• Solid models (parasolid model) Provides a generic solid model with out history. This format allows for importing complete, water tight, solid models into any package that can accept the standard parasolid solid model format.
• Native files with the complete design history This reverse engineering file format provides the same model information as if the model was created from scratch in that native CAD system. The parametrics and design history provides for fast and easy editing and design variations after the creation of the original model from the scan data. While native solid models provide the greatest editability of the model they also can cost 2 to 3 times what a standard IGES or STEP file would cost to create from scan data. This premium price can generally not be justified if design changes of the initial model are not needed afterwards.
Contact us today to discuss your project and to determine the best output format.
When this question is clearly understood and addressed, GKS can provide optimal results for every customer. Unfortunately, reverse engineering is a process and real parts as-manufactured never exactly match the unambiguous design; there are always some variations which can be shown in an inspection report.
If a customer’s end result wishes have not been made explicit, GKS metrologists can sometimes make educated guesses based on experience as to what areas are kept “as-built” and which are corrected to “design intent.” On simple shapes such as flat surfaces and straight edges, this is not difficult to infer. However, as complexity of the part increases, options for “design intent” also increase exponentially and we can no longer able to figure out what is needed without customer input.
Providing the appropriate results boils down to knowing what the customer will be using the data for. For recreating the part exactly as it is, then a surface model of the as-built part is the most cost-effective option. If the customer wants to bring the part back to its original design intent specs, make modifications, or redesign it, then an editable solid model would be a better solution. The results of laser scanning run along a continuum of relatively simple to extremely complex.
At GKS we always ask customers what they will be doing with their CAD files so we can provide them with the correct level of complexity and file format to keep the project costs down.
GKS metrologists can quickly and accurately scan all kinds of complex, free-form polymer parts with our Laser Design high-accuracy non-contact laser probes, creating a 3D point cloud with millions of XYZ coordinates. This complete data set is edited down into a data file that represents the detailed shape of the part in three dimensions. Depending on a customer's needs, we can make a solid model of the polymer part, ready for reverse engineering or design applications, or generate an inspection report to compare its measurements against a set of as-designed dimensions in CAD.
Class A surfaces are CAD surfaces resulting from specialized CAD modeling tools and techniques used when the ultimate design goal is the visual appearance and appeal of a product. Applications include automotive/ vehicle bodies, consumer goods, or any design project where industrial design impacts the consumers appeal for a product.
Class A surfacing experts are few and far between. Our experienced staff at GKS Engineering Services includes four class A surfacing experts to meet our customers' most complex and diverse class A surfacing needs.
Depending upon the measurement task at-hand, GKS metrologists will determine and utilize the most appropriate measuring tool for the job. Whether the required measurement tolerances involve microns or meters, the GKS team will use a combination of 3D laser digitizing, CMM layout, vision-system inspection, surface finish testing, and surface plate tools to deliver measurement data of the highest quality and reliability. We are your one-stop-shop for all of your dimensional inspection needs!
Scan Density is a measure of how close together the 3D coordinates are in the data point cloud. Laser scan densities are measured in microns. Generally speaking, the greater the scan density, the more accurately the scan data captures the surface shape of the part, which is why non-contact laser scanning is so useful in precisely defining geometry.
It can capture the entire surface of free-form, irregular shapes, with millions of data points, instead of just a few specific surface landmarks that contact measuring technologies typically record.
Not necessarily. Class A surfaces are seamless and smooth, so they are good for editing in CAD. However, B surfaces may actually be more accurate for creating a complex mold. They are made up of very precise surface patches which reflect the exact shape of the part even if the patches don't align perfectly. The level of continuity varies depending on the accuracy of the data, the processing of the boundary lines, and the modeler's effort. However, B surfaces are also quicker and less expensive to create. And you can count on GKS to make your B surfaces as accurate and seamless as possible.
It depends on the intended use of the model. While a parametric model will be more time-consuming and expensive to construct than a non-parametric, it will pay dividends later if many changes are required.
Common reasons for needing a parametric model: Ability to change the model quickly, create dimensioned 2D drawings of a model, create similar parts with different dimensions (i.e. brackets, bolts). Non-parametric or "dumb" models are mainly used for: One-time applications (where the model will not be changed), reference geometry for accessory design, parts with large areas of free-form shapes.
These lists are only a few examples of reasons, the best solution depends on your application of the data. To determine the best way to solve your 3D modeling challenge, give us a call.
This is a very typical problem for manufacturers. Since many manufacturing steps can lead to "as-built" parts falling away from the CAD model's "as-designed" specifications, FEAs performed on the original CAD model are not valid. GKS often scans manufactured parts to generate a CAD model that represents the true geometry of the completed part. The model created from 3D laser scan data provides an accurate as-built model on which to conduct the tests, yielding more accurate results predicting stress locations for the product.
Often customers need a specific kind of output that depends on their application of the scan data. "Imaging" refers to the point cloud data exported into a polygon model, usually as an STL file. This type of file is often used in graphics applications such as simulations, analyses, and rapid prototyping. "Modeling" refers to 3D applications where a solid model is required to reverse engineer a part or mold.
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