Reverse Engineering
The Inspection Report. How it works

 

Notes on "Washer Cover Flap" case study 

 

The Reverse Engineering technologies represent today an indispensable instrument for cutting design times and obtaining high quality products.

 

The Reverse Engineering completes CAD/CAM and Rapid Prototyping technologies, therefore closes the DESIGN LOOP: concept development - design - engineering - production.

Three-dimensional scanners are able to digitize part surfaces for quality control purposes, comparing the physical model with the original CAD model and generating a measurement report able to highlight the dimensional discrepancies due to the production process.

 

In this case a car-bodywork component has been produced, in particular the washer cover flap of an high-performance vehicle, using Selective Laser Sintering technology and WindForm XT material.

 

 

Dimensional controls are usually performed using measurement instruments (calipers, height gages, thickness gages, coordinate measuring machines) which only manage to read some of the points and dimensions of the part being checked.

This results in shape defects (twisting, dimensional shrinking) being hard to detect and quantify.

 

The described rapid prototype has been, instead, digitalized by a Faro Laser Line Probe optical scanning system mounted on a Faro Platinum measuring arm.

The use of the 7 axes arm combined with the laser system allows to make contact measures or optical scanning at the same time, using the same reference system.

 

The result of the scanning process consists of:

• a point cloud accurately describing the object to be controlled
• a set of geometrical primitives (planes, axes, diameters, circumferences, etc.) captured by the probe

 

 

This information can then be used in CAD environment to compare the digitised prototype and the original mathematical model (inspection procedure).

 

By managing the entire quality control process in virtual environment, highly detailed measurement reports can be produced (colour-range mapping, cross sections, statistic error reports) with considerable time saving.

 

Finally, the quality control results are useful for correcting and improving the manufacturing process.

 

In the case of rapid prototyping, for example, building parameters can be optimised according to the shape and thickness of the parts to be made: all you have to do is build a first test prototype, perform the scan and then calibrate the rapid prototyping machine again according to the dimensions to be “offset”.