How To Cut Costs on Machined Components

Choosing the right material is a crucial factor when considering the cost of CNC machined components. The material you select should strike a balance between the required properties and the cost constraints of your project. Aluminium, for example, is lightweight, readily available, easy to machine, and relatively low-cost compared to other options.

Plastics are also lightweight, have a high rate of material removal, and are generally low-cost. However, these savings can sometimes be offset by minimum order requirements, longer lead times, and the challenges of machining to tight tolerances. So, while plastics can be an affordable choice, it's important to weigh these factors against the specific requirements of your project.

Designing your part to align with standard stock sizes of plate, bar, or tube can help reduce material waste and overall CNC machining cost. Using standard sizes means less excess material needs to be removed during machining, which also reduces cycle times.

You can find common stock dimensions for most materials on our Material Resources page.

It's vital to think about the most appropriate tolerance for your machined part. By thinking about where tighter tolerances are necessary, and where more open tolerances can be applied, it's possible to reduce run time on the machine and cut costs. Being selective with tolerances is a simple but effective way to influence the cost of CNC.

For example, if you are machining a shaft that will be inserted into a tube, there will be a certain tolerance that will allow for the two components to function properly together when assembled. If the size difference between the two components is small, a tighter tolerance will be required. If close fitting isn't required, a smaller shaft could be machined and a wider tolerance applied.

Another possibility would be leaving some faces 'as stock', a particularly good option for components that are part of an assembly where some or all faces will be hidden. This would allow a smaller billet of material to be purchased and less machining time too. Both approaches contribute to reducing overall cost of CNC machining without impacting function.

Some faces or sections of a component may not be customer facing and therefore the surface finish could be relaxed to Ra3.2µm or greater. This would allow the machinist to take greater care on customer-facing surfaces or those that need a higher spec finish. Less important faces can be machined more quickly, saving time on the machine and reducing unit cost.

Taking machined features into account early in the design stage can make a significant difference to the cost of CNC. Simplifying features wherever possible helps reduce programming, tool changes, and machining time. Below are a few areas where smart design can deliver cost savings:

Ordering in larger quantities can help reduce the unit cost of CNC machined components. This is because setup time, programming, and tooling costs are spread across more parts, improving overall efficiency. Options like call-off orders or scheduled deliveries can also support cash flow while taking advantage of volume pricing.

Placing a bulk order upfront allows your supplier to optimise production planning and reduce downtime. If you have clear visibility of future demand, this can be a smart way to keep your CNC machining cost under control. Always discuss quantity-based pricing and stocking options with your supplier to maximise savings.

Minimising the number of times a part needs to be repositioned or re-fixtured during machining helps reduce cost and lead time. Each setup introduces additional handling, alignment checks, and potential for error, all of which add to the overall machining time. Designing parts that can be machined in fewer setups makes the process more efficient.

Features should be grouped logically where possible to allow machining from a single orientation. Multi-axis CNC machines can also be used to access multiple faces without manual repositioning. For turned or round parts, reviewing your design considerations for cylindrical components can help reduce unnecessary complexity and improve machinability.