The Process of Preparing A CAD Model for CNC Milling

The ultimate aim of any CAD modeling project will likely be to produce a physical component based on your digital designs.

In the age of cutting edge machinery, using a CNC mill to make CAD creations come to life is increasingly common. So what are the steps you’ll need to follow to achieve this without hitting any stumbling blocks along the way?

Create a compatible version of the design

Whether you are using new or used CNC mill machines, the main barrier standing between your CAD model becoming a tangible reality is file compatibility.

CNC equipment is controlled via G-code, a tried and tested standard for operating the tooling which has been around for over half a century.

For most projects, you’ll either want to convert your CAD file into a STEP or an IGES format, both of which are widely compatible with machinery.

Of course if you aren’t handling the milling yourself, but are instead hiring a third party manufacturer to take care of this, then you might not need to handle the conversion process yourself. It’s worth checking the compatibility either way, before you finalize your design and prep it for exporting.

Conjure up technical drawings as an accompaniment

Another useful, although not strictly required, aspect of preparing a CAD model for CNC milling is a carefully labeled technical drawing.

You can use this to note down the specific parameters which relate to the component you want to make, not only factoring in things like the dimensions, but also making note of elements such as the surface finish you want.

When the part is being milled, the machinery operator will be able to refer to the technical drawing to ensure that everything is going to plan, and that no points are missed out in what can be a complex, multi-stage manufacturing process.

Another part of putting a technical drawing together is mentioning the tolerances you require. If you have very tight tolerances in mind, which go above and beyond the typical standards, then highlighting these clearly will be crucial.

Secure approval from those involved in the project

In the case that you aren’t the only person who’s working on a project, you’ll need to get your CAD model signed off by other team members and those with a stake in the finished product before you proceed with the milling process.

Because of the way that modern CAD software has been designed, sharing your creations is a breeze, and it’s also easy to collaborate and communicate so that any changes which are needed can be implemented without any issues.

Obviously if you are dealing with non-technical colleagues, then showcasing your CAD model in three dimensions is better than giving them access to complex plans that they might not be equipped to interpret.

Consider the variables & requirements

With your CAD model prepped and approved, you need to decide on a couple of other aspects that will impact the milling process.

First, you need to work out how many units you want to make, whether that might be one as a prototype, or several as part of a small production run.

Second, you need to pick the material that’s to be milled, and ensure that this is compatible with modern CNC machinery, as well as cost-effective for the purposes of keeping your budget in check and encompassing potential shortages.

Last, you have to think about how quickly you’ll need access to the finished part, and see whether this meshes with the lead times of any third party firm that you get involved.

With all this onboard, you should be well prepared for translating your CAD model into a milled component.

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