5 Easy Steps to Reverse Engineering With 3D Printing!

5 Easy Steps to Reverse Engineering With 3D Printing!

Reverse engineering (or back engineering) is a method used to understand an item and its interaction with various components. This can be quite helpful when you want to create your own version or copy of a common product with a 3D printer.

We are going to look at some things to consider when reverse engineering. Our primary focus of this article will be an automotive brake caliper and the processes we used to reverse engineer it into a 3D printable model for educational purposes. 

 

1) Get Your Tools Ready

There are a lot of tools that can be helpful when reverse engineering. Tools can range from Vernier calipers (aka. Digital Dial Calipers), rulers & 3D scanners to alternative measurement tools such as micrometers for inner & outer measurements. Another simple tool would be a pencil and notepad. You may want to keep notes on where the parts go, or to note some specific areas that you may want to look at later.

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In our initial design plans for reverse engineering the brake caliper, exact dimensions were not necessary and so we selected a pair of Vernier calipers as our tool of choice for this project. A good CAD program is also going to be very helpful. An excellent list of the top free CAD programs can be found on the Pinshape blog here. 

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A pair of calipers can start around $10+, but they should be a standard tool for all makers. Not only do they work well to measure your prints for reverse engineering, but they also serve to measure your filament to test for accurate and consistent prints.

 

2) Plan For Your Design & Print

It’s time to start planning out your design for 3D printing. Here are some key points to keep in mind: 

  1. What features of the product do you want to carry over to your design & print?
  2. Some products have complex shapes, is this something you can orientate & print properly? You may need to make a slight design change to allow for a better print.
  3. What areas will you need to create a tolerance in your design that’s acceptable to your printer?
    1. When working with a metal part, tolerances are going to be significantly smaller than what you can achieve with a desktop 3D printer. You will need to keep this in mind and adjust your design accordingly. Another community member, MakerClub goes into detail on tolerances in his article on Snap Fit Parts.
  4. Will you design your model to scale? If you need to scale your design up or down, check out this excellent scale calculator.
    1. Because the brake caliper is small enough to print, we were able to keep a 1:1 build scale. 

 

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Once you have your design planned out, it’s a good time to start taking measurements & notes. For the brake caliper we reverse engineered, we needed to start measuring seals, pistons and the bodies themselves. While taking notes during this step is important for consistency between your parts as some parts are quite complex and it may be tough to properly document your measurements. In this case, working in your CAD program while taking measurements may be a superior alternative.

 

3) Disassemble and Study – Understanding 

The most important starting point of reverse engineering is understanding the product you have in your hands. Since there is a number of interworking parts, you will want to check the interrelationships between the various parts. When disassembling the caliper, be sure to keep an eye on fit and feel of the parts. Tolerances will be a big factor in the print and design process. We will talk about that a little later in the article. Ensure that you have taken the time to fully understand the original Caliper, so you can cut down on any errors that may arise later in the design and printing process.

Having a strong understanding at the start will make the planning and design of your product much easier. As you can see, I started with a caliper that was already taken completely apart.

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In most cases the product you have will probably be pre-assembled. Your first step will be to start the disassembly process. Inspect each part and if there are moveable parts, move them until you have an understanding of how it works. In the above photo, the brake caliper has been disassembled and a note was made to where each part goes and how they work with each other. As you can see there are quite a few points of interest with the brake caliper that will need to be carried over to the computer design.

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4) Start Your CAD Work

Our choice for designing the brake caliper was to start out with a simple sketch. We designed the features of each brake caliper body within the initial 2D sketch. We were also able to cut the workload in half by only designing 1 half of each caliper body and mirroring the 2nd side. This is important if your design is exactly the same on each side. Mirroring the 2nd side is going to save you a lot of time and will ensure that everything lines up perfectly.

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The next step was to create offset planes at each key feature of the Caliper body. The original design sketches were then projected to their respective planes to create the thickness required.

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Once completed, all the other necessary design features that could not be done from the initial sketch can be added. For the brake caliper this would include the brake bleeder fittings and all the other parts to the caliper. After you begin 3D printing, you will start to see your 2D design transform into 3D. This is where you can see if there are any problems with the design.

Here’s a good example of how to project to surface on Fusion 360: 

Starting at the 6 minute mark

 

5) Choose Your Filament

Often when you replicate an item with a 3D printer,  you are not going to be able to print it in the same material as the original object. Another decision to keep in mind when designing your model is which filament you’re going to use. Of course, this depends on what you will use your model for. Will it be a display unit where nearly any filament will do or is your model going to be used daily and under various forces? This may require you to use a more robust filament that can withstand the wear and tear.

We designed this Brake Caliper model as an display piece that can be taken apart and re-assembled. We chose to print it with PLA and ABS.  Parts that require a little flex were done with ABS. The rigid parts that won’t need flex were done in PLA.

Here is a comparison of 4 popular filaments that can help you choose the right material for your project. 

 

Conclusion

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Educational Brake Caliper by Chris Halliday

When reverse engineering an item for 3D printing, it’s important to have the appropriate tools along with a good CAD program and proper planning. One thing to always consider is the interaction between various parts as it will effect the final outcome of your 3D printed model. Orientation and filament selection are also important factors for the end product. With proper planning, you will be able to satisfy your curiosity and begin to take your ideas even further! 

 

F.A.Q 

You guys asked for more, so Chris answered a bunch of your questions to help you on your journey to reverse engineering! 

1. How do you take the measurements of the curved parts of the product with the calipers?

For the curved parts, I started with measuring the internal piston bore. I used the smaller jaws for this task, checking the measurement in a few locations and transferring it into the initial circle drawing on the 2d sketch. I basically started out gathering the easy measurements and transferring them to the 2d sketch so I would have good reference points. For the back side of the piston bore, the tricky radius part there is actually part of a circle here, as well before it flairs into the bleeder areas, so I was again able to measure the diameter and transfer it to the sketch.
 
The key is getting a good starting point and working from there.
 
2. Was any part of this 3D scanned?
 
Nothing was 3D scanned. I knew that for my end product, it wasn’t about copying the exact product. This was mostly due to not being able to capture every measurement perfectly with the calipers— they work great but not for everything. My end goal was to show caliper function and I could do this without the measurements being perfect.
 
3. How did you find the diameter of the holes?
 
The diameter of the holes were done with the small jaws of the caliper. I was able to reach all of the holes to get an idea on their sizes.
 
4. Were multiple versions 3D printed and compared to the original?
I had a couple failed orientation prints of the caliper bodies. Other than that, things went pretty well. The 3D printed parts were compared to the originals, but one must keep in mind that the end product— the 3D printed caliper— had to be modified to work properly with a printer and therefore, things like the wear plates, pad retainers, etc. have been modified from their originals to be better suited for 3D printing.
 
5. How close is the final version to original in terms of size, tolerances and other measurements?
 
In terms of size, the 3D printed caliper is nearly identical to within 1-2mm of the original caliper body. Tolerances are much looser in the design for 3D printing. While the original caliper has a piston diameter and piston bore diameter that are extremely tight, this wouldn’t work with my style of 3D printer. Adjustments were made to reduce piston size and such to allow assembly at the end of the print. Tolerances for the bleeders and fittings were also reduced to fit.
 

About the Authors

Brad & Chris Halliday

image10Born and raised on Vancouver Island, British Columbia, and yes, it really does rain alot!!!! Chris(left) got into 3D printing after the RepRap machines blew up the internet and the technology became accessible for hobbyists. Brad (right) quickly followed after getting his hands on a printer. Their natural curiosity got the best of them and they expanded into CAD design to start creating their own models. When Chris isn’t out rummaging through the woods playing photographer and historian, he can be found in front of Autodesk Fusion 360 designing the next print to come off of one of his Lulzbot 3D printers. Brad decided to make the trek out to Red Deer, Alberta 2 years ago and realized the potential of 3D printing. Having such common interests, they joined force. With their ideas and 3D printing tech, H2 Fabrications was created.

Facebook: http://www.facebook.com/h2fabrications

Twitter: https://twitter.com/h2fabrications

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Pinshape is a 3D printing community and marketplace where makers from all over the world can find and share their next great 3D print and help each other get the best results from their 3D printers.

  • sylvia_martinez

    Hi Brad & Chris,
    You make excellent points about how to reverse engineer for 3D printing. I know some of the teachers I work with might still be intimidated by the complexity of this caliper, so I wrote a post about how to choose good objects for 3D printing, even if the students you work with are young or beginning CAD users. Thanks for writing such a clear post that I could expand on! http://sylviamartinez.com/reverse_engineering_for_3d_printing/

  • Hi Sylvia, Sorry I have missed this post until now. I am just getting to see your article on your website, I like the way you have written it. Thank you for notifying us 🙂

  • I also wanted to make sure that the printing was parametric, so that I could make any adjustments to specific dimensions down the line. That approach proved to be useful when I had to reprint the part.

    Do you think that the tolerances would be good enough when working off of a scaled photo?

    Thanks for the tip though, I like Brad & Chris,as well.

  • Tolerances will be dictated by the accuracy of your printer and may need to be adjusted depending on print results @@disqus_RyJIbYyJGv:disqus

  • Thanks Chris.

  • This blog was… how would I say it? Applicable!! At last I have

    discovered something which helped me. Salud!

  • Glad to hear it @@kajalkulkarni:disqus