Use reverse engineering to align the CAD world with the real world
Create and update CAD surfaces with digitized data
Reverse engineering generates a CAD surface model that precisely represents a scanned object. Reverse engineering is used everywhere work is performed manually on real objects and a CAD model is required for the subsequent process. In model manufacturing, design objects and vehicles modeled in clay are scanned and converted to CAD surfaces. In die manufacturing, manual changes to sheet-metal dies in the tryout phase are scanned, and the existing CAD model is updated based on the scanned data. CAD surfaces often need to be created for dies in which there was previously no CAD data.
How does Tebis reverse engineering work?
Tebis designers use reverse engineering to quickly create free-form surfaces based on underlying scanned data. In the same CAD file, they analyze and optimize the quality of the digitized data and then create a wire-frame model; and then the surface model is created based on that. They supplement the surface design created by reverse engineering using curve and surface methods from Tebis free-form technology. Using Tebis surface technology, a trained designer can quickly achieve free-form surfaces, even at Class-A quality. See also CAD surface quality.
These are the steps for using reverse engineering to generate high-quality CAD surfaces:
- Import STL data
- Analyze and edit mesh data
- Draw wire-frame model on mesh data
- Create individual surfaces in the wire-frame model
- Analyze surfaces
- Optimize surfaces
- Continue design work on the part
Always close to the mesh: Design intuitively using the wire-frame and surface models
Using the semi-automatic and interactive drawing functions, users create a wire-frame model based on the scanned object (mesh model), on which the degree and segmentation of the surfaces and the surface transitions are automatically controlled. The boundary curves of all individual surfaces are contiguous. Using the wire-frame model, you can define the layout of the surfaces and the qualities of the transitions to the adjacent surfaces. Tebis calculates the surface model completely automatically from the wire-frame model and the meshes. Changes made to the wire-frame model are automatically reflected in the surfaces. Using tolerance values, the user determines how tightly the wire-frame model and surfaces "adhere" to the digitized data.
Reverse engineering in die and mold manufacturing
Tebis reverse engineering quickly generates virtual twins of real forming and injection molding dies. Existing CAD data can also be
considered. In the following cases, reverse engineering is an extremely useful tool that yields significant time savings:
- Feedback of manual changes to the die from tryouts into the existing CAD model and ongoing work with a realistic, updated geometry
- Scanning drawn sheet-metal parts and providing it as the surface model for subsequent operations (e.g., trimming) and fixtures
- Generating surfaces based on FEM meshes from simulation systems
- Production of a second die set, e.g., for additional production locations
- Repair after die breakage
Reverse engineering based on simulation data
Mesh data from the drawing simulation can also be used as the basis for reverse engineering. The drawing system is first analyzed for curvature. The designer then generates the surface layout and fills the individual areas with four-cornered surfaces and N-cornered surfaces trimmed as desired. Method planners can very quickly obtain surface models in this way.
Updating CAD surfaces on manual changes
Die makers manually change dies in the tryout phase. This causes the CAD model to lose its validity. With reverse engineering, manual changes are scanned and conveniently imported into the CAD model file. This yields tremendous time savings for further optimization of the die and for duplicates.
Reverse engineering in design model making
CAD surfaces are the starting point for all design and manufacturing processes after model making. However, they are often not available, because the form is developed by manual design methods like clay models, or because the items are parts for antiques or art objects. With reverse engineering, you combine manual work and design technology and benefit from both worlds. You can create CAD surfaces for your physical models with very little effort.
Your benefits from the reverse engineering method:
- Quickly adapt a virtual CAD model to the real part
- High surface quality in a short time
- Generated CAD surfaces can be used immediately
- Large time savings in die manufacturing tryout and reproductions
- Large time savings during form development in design model making
The new process enables exactly the same dies to be quickly and efficiently fabricated and tried out for multiple locations at the same time. Our die manufacturers worldwide have benefited from this process. It allowed us to very quickly produce the dies for Mexico in a standardized process.
Roland Schöbel, head of machining, Wolfsburg die manufacturing, Volkswagen AG
Tebis enables a very simple and fast realization of reasonable extension designs to the scanned mesh data. It is a unique advantage that in Tebis you can combine meshes and surface elements extremely well and then mill them all at once using the CAM modules.
Christoph Schneeberger, responsible for die making at MS Design
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