PES Blog: Reverse Engineering and Replacement Parts for Classic Vehicles
The challenge of maintaining classic vehicles
A key challenge for the owners of classic cars is maintaining them, both in terms of bodywork and mechanical components. Modern engineering technologies, such as reverse engineering can help ensure that your prized vehicle can enjoy a long future automotive life.
The ability to find highly engineered, quality, replacement spare parts is an important aspect of this challenge, as is the availability of engineering drawings for components, especially in cases of high value and rare vehicles. The difficulty of this task increases exponentially for older and rarer vehicles, especially where the original manufacturer may not still exist.
Reverse Engineering – combining technology with traditional engineering
The key to the accurate reproduction of parts is through reverse engineering. This is the process of taking an existing part, reproducing the geometry, creating a 3D CAD model and then producing a manufacturing drawing and re- manufacturing the part as it was originally intended.
There are a number of technologies used to support the reverse engineering process and these can be applied dependent on:
- The level of accuracy / tolerances required
- Complexity of the part to be re-engineered
- The manufacturing process and materials
- Physical accuracy to ensure it replicates the original part to the finest detail, including imperfections where identified.
- The brief and of course the budget.
Where accuracy and tolerances are not crucial the parts can easily be manually measured and then the part built as a 3D model in CAD. This is not possible if the part has crucial internal features and the part cannot be dismantled to expose these features.
Using Reverse Engineering Technologies to support Classic Vehicle Restoration
As we have mentioned manual data capture can be carried out on very simple, non-crucial parts. The challenge comes when a greater level of accuracy is required, as design engineers now work in terms of microns. Below are some of the technologies that can be applied.
1: 3D Scanning
Scanning is a very accurate data capture technology for reverse engineering that can capture data, using light or laser sources. The scan will capture an image in a ‘point cloud’ format on any surface visible to the scanner. Depending on the scanner and scanning process selected the data can replicate the part up to very fine tolerance +/- 2 microns in a controlled environment.
The point cloud data creates a mesh from millions of points, and once the data has been downloaded into the CAD software, 3D CAD models and manufacturing drawings can be produced from this data.
Scanning can only capture data from surfaces visible to the scanner, however these system can be combined with other processes, including reconstructing the missing features in CAD from manual measurement.
Scan data can also be used for quality assurance as the data can be used to check the CAD model against the original scan to ensure absolute accuracy.
2: Computed Tomography (CT Scanning)
Where internal detail is crucial and not accessible through disassembling of the part then CT scanning can be used. This is a very similar process from the CT scanning carried out in hospitals and is an excellent system for capturing external and internal features that can be used to create 2D or 3D CAD models.
As with all systems there are limitations, including:
- The physical size of the part.
- Thickness of the material.
- The cost can also be prohibitive for low value parts.
All the above technologies and processes can be combined to deliver the best result.
The key thing to remember is that once the data is collected, it should be classed as an investment, as once it is in a digital format it can be archived and used whenever required. The archived data can be used to create 2D and 3D drawings, manufacturing drawings or to output data files for machining.
Replacing worn parts for my classic?
In most cases this is not a problem. Most parts are worn to some extent. A 3D CAD model of the old part can be re-created using the scan data or original drawings if available. Then, by measuring the interconnecting parts, the 3D CAD model can be changed to assure the new part provides a perfect fit.
One of the key benefits for reverse engineering from CAD and the digitised data is that you can manipulate or change the data once it has been captured. For example: If you had a broken gear or part that is part of a mechanical system, that has seen some mechanical wear over the years, a ‘new’ worn part can be modeled, manufactured and assembled back into the original system, allowing to fit and work perfectly.
Are tolerances an issue?
The key question to ask is ”How accurate does it have to be?”. A good design engineer will talk you through all the reverse engineering options and the appropriate manufacturing process will be a key part of this. E.g parts to be forged will have accurate and radius set to specific tolerances for that process.
Modern Design Engineers and machines now work in microns, however the original parts would not have been produced to the tolerances that can be produced today.
Whilst tolerances are no longer a challenge, in most cases, you do need to consider the level of accuracy that you may wish to reproduce, especially with consideration to your budget.
In many cases ‘practical manufacturing accuracy’ is not a challenge to produce the replacement part, to operate, as intended, within its designed environment, however on a number of occasions the accurate reproduction of the part is demanded to ensure it is fully representative of the original including any defects.
What is Optimisation or Enhancement of an original classic part?
Once you have the data in a digital format you can choose to optimise the performance of any part using modern technologies. This can be for a number of reasons, including:
- Improved durability and sustainability
- Increased performance
- Insurance; when using the part outside of its intended performance envelope
During the optimisation process, whether through the introduction of new materials or manufacturing techniques the design can be put through a number of ‘virtual’ simulations before manufacture to ensure greater reliability of the optimised part. Such simulation software includes Computational Fluid Dynamics (CFD) or Finite Element Analysis (FEA).
What can I do with the 3D data from my Classic Vehicle?
Data capture of any pre digitised engineering, especially if it is rare, unique or a valuable asset is crucial; more so if no original technical & manufacturing drawings exist.
Data Archiving details of my Classic Vehicle
Once the data has been captured it can be stored indefinitely in a data archive until required to ensure your classic and its constituent parts will always be available, to preserve the detail and design of a vehicle from body panels to engine components.
Advantages of having digitised data of your Classic Vehicle
- Providing machine shops with standardised drawings
- Classic car groups can create a digital archive for its members and the data can be purchased at a subsidised rate or accessed directly when required.
- Using the data to manufacture multiple runs of one common part as part of a classic car group.
- Using the data to restore a vehicle after a racing accident etc. E.g. Body work can be accurately reproduced by a professional fabricator if they have the drawings produced from the digital data.
- If you have a failure whilst on tour or due to attend a classic race meeting. The data can be used to have a new part manufactured immediately, therefore speeding up the process.
- CAD drawings can be updated or modified whenever required to accommodate any updates or changes to the vehicles design.
- Having the same part produced again to enable repeatability and equality.
- CAD drawings are provided in digital format and can be printed and shared without diminishing quality.
Insurance of having a digital archive of your classic vehicle
One great advantage to having a data archive of your classic would be that if it was ever stolen, the data of the vehicle or individual parts can be used to aid identification and recovery.
Can I get a part made to order for my Classic?
If you do not already have data for the required part, it can be sent through to the design team and reverse engineered using the agreed applied technology. The data will then be manipulated in CAD to produce a model. From this model drawings can be produced and your part can then be manufactured.
How can Rapid Prototyping help in classic restoration market?
Rapid prototyping is a very advanced technology that if applied correctly can be used in the optimisation and manufacturing process, and to save costs. One application is for ‘space claim’ confirmation. If you have a part that will be expensive to manufacture, however you are unsure how it will fit in the space in which it will operate, you can ‘grow’ the part in plastic and review it before committing to full manufacture.
Advantages of using 3D CAD for a Classic vehicle
There are numerous advantages of creating the car part in a 3D CAD package including:
- Valuable and rare classic car drawings can be reproduced in a digital format to ensure the original technical drawings remain in mint condition.
- Changes to the CAD model and designs are much faster compared to 2D.
- The 2D drawing updated automatically.
- 3D CAD allows for tolerance checking, interference checking etc.
- 3D models can be sent directly to CNC machines, to guarantee quality and high repeat-ability.
Veteran, vintage and classic car restorers have requirements for a vast diversity of parts. Holding these in stock is very inefficient. With a CAD model these parts can be made to order. 3D can also be used as an aid to visualise the finished component.
Reverse engineering offers opportunities in the continued support of classic engineering pieces to ensure our engineering heritage is preserved and maintained. These new technologies have proven to save time and money, when used as part of a planned engineering maintenance process.
Please view the services we can deliver and if you would like to discuss your particular project or wish to understand how we can offer you a solution for your classic then please contact us for a chat or drop us an e-mail with your enquiry.
Copyright; PES Performance Ltd, 2014
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