Tips for improving your CAD designs for CNC Machining

By: LoydMartin

CNC machining can be used to produce metal and plastic components that require drilling or cutting. It is a cost-effective and efficient way to make these parts. This manufacturing technology has seen significant improvements over the years. You can now make it according to your specifications via CAD software.

To ensure quick delivery to the market, you need to get your CAD design right. This will avoid revisions and rework. Revisions can be difficult if your model is not optimized for the chosen manufacturing process.

Tips to Improve Your CAD Designs for CNC Machining

These tips will help you improve your autocad design while making it more cost-effective and compatible with CNC machining.

Features for CNC Design

The CNC machine’s machining process is complicated if you add unnecessary features. It is best to thoroughly research the capabilities of the CNC machine before adding features that will not have any effect on the operation of the part.

Curved holes are one example of a feature that CNC machines, lathes, and drills can’t produce. If you are not adding these features to enhance the aesthetics of your product, you should remove it from the list.

Make sure you are accurate with depth-to-width ratios

Your CAD design will be vastly improved if you consider the cavity depth to width ratio. Tool hanging, chip evacuation difficulties, tool deflection and tool hanging can all be caused by deeper cavities.

Cavities that are six times larger than the diameter of the tool are considered deep. They must be at least four times the width dimension. A cavity 15 mm in width cannot be more than 60 mm deep.

Do not use tolerances excessively

It is important to maintain strict tolerances. However, excessive tolerating could increase machine time and expense. Different CNC machines have different tolerance standards. This means that if your dimensions are not within the tolerance range, the machine will automatically adjust to its standard tolerance.

To save time and money, tight tolerances should not be specified. To minimize the time it takes to machine, you must ensure homogeneous tolerances.

Radii when designing internal edges

Because most cutting tools are cylindrical in shape, the machining tool has difficulty creating sharp edges. When designing your CAD file, you should add radius to the inner edges.

You should design internal edges that don’t overstress the tool. This will help you to avoid damage to the CNC machining tool. You can achieve this feat by extending the radius of your milling tool by 130 percent.

Avoid redundant aesthetics

Consider the material to be removed and the process involved if you’re adding aesthetic features or producing parts that have visual appeal. Also, think about whether it is a 5-axis, 3-axis, or 5-axis machining process.

You can improve the accuracy of your CAD design by focusing on essential features. However, aesthetics can also be improved through certain post-machining processes.

Avoid designing thin walls

Research has shown that the stiffness of a material’s wall thickness correlates with its wall thickness. This means that thin walls could negatively impact the material’s stiffness. A reduced stiffness of the material would result in lower accuracy due to vibrations during machining. For plastics, the minimum wall thickness is 1.5mm and for metals it’s 0.794mm.

Don’t design small features

The minimum tool diameter for CNC machines is 2.5mm. This means that features smaller than 2.5mm are extremely difficult to machine. To produce small features, you will need specialized tools. This increases the machining time and costs. If they are not necessary, it is best to avoid too small features.

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