7 Tips to Save Money on CNC Machining Parts

A few things can influence the cost of CNC machining parts, such as the design, material, finishes, quantity, and lead time. Generally speaking, the most essential thing is how much time it takes to machine your parts, which can affect cost even more than the cost of CNC setup time, materials, or finishes.

The chosen materials and the design of the parts directly affect the machining time. Tolerance and part geometry also influence the CNC machining process, choices of machines, cutting tools, and CNC operators, which also affect the cost.

We would like to offer seven proven good tips for you to save money by optimizing your designs and making the most cost-effective choices.

7 Tips to Save Money on CNC Machining Parts

A few things can influence the cost of CNC machined parts, such as the design, material, finishes, quantity, and lead time. Generally speaking, the most essential thing is how much time it takes to machine your parts, which can affect cost even more than the cost of CNC setup time, materials, or finishes.

The chosen materials and the design of the parts directly affect the machining time. Tolerance and part geometry also influence the CNC machining process, choices of machines, cutting tools, and CNC operators, which also affect the cost.

We would like to offer seven proven good tips for you to save money by optimizing your designs and making the most cost-effective choices.

Try to Keep Everything Standard

The first tip is to try to make things such as threads, material choice, and tolerance requirements standard. Because standard things are easy to make, easy to find, easy to achieve, or easy to acquire. For example, if the geometry of a CNC-machined part is simple, the part will be easy to machine, and easy to inspect, thus saving a lot of labor cost.

Also choosing standard threads will save you some money because if the threads are non-standard, special tapping tools or even fixtures will be needed. Additionally, non-standard threads might be tricky to machine, as it’s always new for a prototype company. Sometimes it could take quite a few times for a non-standard part to be completed.

Some of the other benefits of using standard components include:

• Avoiding tooling investment
• Faster turn-around

Avoid Thin Walls

Wall thickness thinner than 0.794mm (1/32 in.) is known as thin walls. Avoiding deformation and fracture when machining a thin wall requires several careful passes, extending machining time and increasing costs. Thin walls can also cause chatter, slowing down machine speeds, which also leads to additional costs in machine and labor.

Use Tight Tolerances Only When Absolute Necessary

It will be quite costly if the design has many tight tolerances because it will increase a lot of machining time and more inspection time.

And tight tolerances are particularly difficult to achieve on the internal surfaces of your part, as machining holes and other cavities can develop burrs on the edges. These burrs require an additional step: deburring. Deburring is a manual and time-consuming process that also adds up to the cost of CNC machining.

Another note about tolerances is that the tighter tolerance you specify, the more labor will be involved, the more intricate your tools need to be used, and the more expensive the part will be.

If a place is not necessary to use tight tolerance, then we suggest the international standard ISO DIN 2768-MK. This standard tolerance works well for many features, so you should reconsider any tight tolerances you have and only specify tight tolerance when it’s necessary.

Keep a Minimum of Multiple Finishes

Finishes make a part more resilient to harsh environments or render a part more aesthetically. However, the more finish there is, the higher the cost is.

If you want to save money, consider choosing as-machined or no finish for a whole part. Only choose multiple finishes when it’s necessary.

Split Up and Bind Complex Parts

If you have an intricate part, for instance, the part has very complex geometries, the making of your part is probably very expensive, because it takes a lot of labor to program, and set up to machine the part. Sometimes it might need to use EDM to assist machining. All of these come at a cost.

Therefore, it is a good idea to split a complex part into two or more simple pieces, machine them separately, and then assemble them into one piece by gluing, or screwing.

Avoid Features with High Aspect Ratios

Parts with high width-to-depth ratios are difficult to machine. Because it leads to tool vibration and scrapes. As with many of the other details of machining, if it’s complicated to machine, it increases the cost.

To decrease CNC machining costs, it is only wise to design all geometries with a width-to-height aspect ratio that’s not over 4 and consider connecting them to a wall or adding support to increase stiffness.

Use Cheaper Materials

Generally speaking, with metal, the softer materials are cheaper to machine than harder materials.

First, the raw material is less costly. For instance, Aluminum 6061 is softer than Aluminum 7075, but the former is cheaper.

Second, harder materials such as steel are harder to machine, for they require more costly cutting tools, and the cutting tools are prone to wear and tear.

Seeking Help from a CNC Machining Expert

All in all, CNC machining is a great way to custom parts with great accuracy, precision, aesthetics, and speed. However, even with the most well-designed parts according to the above suggestions, sometimes the price is still beyond your expectations, especially without the assistance of a trusted manufacturing partner.