Ensure Accuracy with these Tools
There are several instances when you may have a model that has to be precise. Whether you are prototyping a part, building the mechanical reproductions of a 3D Print for your classic car, or just want to ensure that everything is proportional, measuring tools within CAD Modeling program and then checking that model with 3D Printing tools will ensure that you have the best results.
Copying vs Bespoke Design
Measuring and tolerance, in a bespoke design, generally is a precise way of ensuring that the part is to the scale and dimensions that are needed for the printed part, be it a single print or a small batch. When such is needed, the precision of the part ensures the overall functionality of multiple builds and/or the partnering of the 3D Printed part to non-printed pieces. Copying is typically a bit rougher and usually involves a 3D Scanner, which although precise, does not ensure that the model have the same dimensions but rather only has the similar aesthetics to the model being copied. It is only the surface that is being modelled and not the full solid.
Before you Print (software measuring)
While there are some fine sculpting tools which will allow you to get high levels of details on the 3D models, not all of these focus on measurements and accuracy. They are more oriented to the aesthetics of the final print and lack the ability or functionality of precision building. There are a few programs which are recommended if you are prototyping or needing an accurate CAD Model for 3D Printing. The most popular of these are AutoDesk AutoCAD & Inventor and SolidWorks & CATIA by Dassault Systèmes.
When using these programs, ensure that your measurements are in the same unit and to the same level (For example: If you are measuring in metrics you should have the settings on mm to mm and not mm to m as that would cause for printing size problems).
What can you do if you can’t afford the “good” stuff?
While digital tools are by far going to give you the best accuracy, you can get a rough check of your measurements using standard cheap measuring devices. So long as you understand a little bit of math and know how to read a measuring tape, a protractor, a compass (the mechanical kind not the navigational type), and can convert metric to imperial and vice versa, you can at least measure to see if your print is close to the mark.
Measuring the size of your 3D Print
An industry standard measuring device would be the slide measuring tool. Usually referred to as a Vernier Caliper. This tool looks like a miniature crescent wrench but with two sets of jaws, one for measuring the outside of an object and the other for measuring the inside, and a probe at the end for measuring depth. Depending upon the model that you choose, as there are some which provide multi-decimal measurements and those which only provide to 0.1mm, you can get rather accurate readings of the print. Keep in mind that most Vernier Calipers are oriented to either imperial or metric, you will need to purchase the Caliper which best suits your needs. A good option is to pay slightly extra for a Digital Vernier Caliper, which can read both metric and imperial, like the one in the image below.
Another common tool for the 3D Print is the Micrometer. The Micrometer works by turning the ‘screw’ to open the clamp. The reader/measuring part of the Micrometer is typically the same part of the tool as the turning component to open or close the device. Micrometers are used to measure the thicknesses of objects, similar to a Vernier Caliper, but to a greater accuracy, often above 0.01mm. Due to this high level of accuracy, Mircrometers are also more expensive than a Vernier Caliper and therefore, one should consider how accurate they would like their tool to read before purchasing.
Use a Ruler
Say what you may about the common ruler, but it really comes in handy if you do not want to spend the money on the higher precision measurement tools. When using the common ruler, try to find one which has a cork back. The cork back allows you to make markings on the model and also limits inaccurate readings as the cork grips the surface better than metal (which is naturally slippery).
For large 3D Prints, you may also wish to use a T-Square or a meter stick ruler.
Do you need to measure your prints if your print is not for commercial purposes?
Whether you are building your model for commercial purposes or for a hobby, there needs to be a consistency to your methodology. And while the measuring of the print may be slightly time consuming, it does help to establish fundamentals and a good/professional workflow should you wish to go turn professional later on.