The cost of turning and milling

With CNC turning and milling, there are no fixed costs that can be universally applied to different machining projects. The cost of a CNC machining project is determined in part by several factors. Since cost is an essential consideration in most projects, it is recommended that you understand these factors and the extent to which they affect cost. This article will help you understand the key factors that determine the cost of CNC machining and optimize your project to get the most out of it.

Factors affecting the cost of CNC machining

The main factors affecting the cost of CNC-milled parts can be categorized under equipment, materials, design, production volume and finishing operations.

Equipment and machinery

Equipment costs are factored in before machining begins. However, they are setup costs and affect the cost of the project. The more expensive it is to purchase, operate and maintain a machine, the more expensive the parts manufactured with the machine will be.

How do you choose the type of CNC machine?

CNC manufacturing involves various machining operations. These include drilling, boring, turning and milling. Most of these are performed on a CNC lathe or CNC milling machine. Another issue is how efficient the machine itself is. CNC machines have evolved tremendously over the years. Early NC and CNC machines are nothing compared to the highly sophisticated modern CNC machines in use today. Modern machines are faster and much more efficient. In the long run, this speed makes part production cheaper.

How do you choose the tooling?

The cost of milling tools also affects the total cost. The tool material, coating and geometry all affect this cost. For example, carbide tools, which are harder, more heat-resistant and can withstand extreme speeds, cost twice as much as tool steel tools.

Why is CNC milling more expensive?

Milling machines typically cost more than lathes because they have more complex moving parts; are more difficult to set up, operate and maintain; and are capable of more complex operations. CNC milling is therefore generally more expensive than any other operation. Milling machines are of different types, with different levels of complexity and capacity. The more axes a milling machine has, the more expensive it becomes. Modern CNC machines usually have three or five axes. Although 5-axis machines can more accurately and quickly handle highly complex geometries (thus requiring less machining time), they tend to be more expensive than their 3-axis counterparts.

Setting cost

Setup costs cover costs incurred in preparation for the actual machining. All CNC-machined parts begin as a 3D model. The 3D model is designed by design experts using Computer Aided Design (CAD) software. The resources required to produce a 3D model make up a significant portion of the setup cost. Setup costs also include design optimization and Computer Aided Manufacturing (CAM) preparations for producing the parts using appropriate CAM software.

Materials

How the price of material affects the cost of CNC machining?

The material from which a part is made is one of the most important cost drivers. There are several costs associated with a material to be machined. The most important of these is the cost of the material itself. Materials are priced differently, with prices determined by their availability, desired properties and overall production costs. Metals tend to be more expensive than other materials. The chart below shows the relative prices of some commonly used engineering metals. Keep in mind that metal prices fluctuate and exact prices may vary by country. The prices in the chart below are relative.

The machinability of the material, a key factor

In addition to material cost, machinability is another important cost determinant. Materials with low machinability cost more time and effort to machine, and in the world of CNC machining, time is literally money. The cost of a machined part is directly proportional to the time it takes to machine it. Difficult to machine materials also consume more resources, such as coolants, electricity and milling tools. At Batchforce, we offer a wide range of materials, including aluminums, metals and plastics. You’ll find a complete list of the materials we offer, along with their descriptions.

Design and geometry

Improve CAD designs for CNC machining

Part design and geometry have a significant impact on cost. It is a rule of thumb that the more complex a part is, the more expensive it will be to produce. Very complex parts may require more sophisticated machinery. They also require more machining time, multiple fixtures and settings, more resources and more accurate inspection. All of this affects the cost of parts. In milling, there are certain parts and designs that inevitably increase costs. These include sharp inside corners, thin walls, deep cavities, non-standard tapped holes and engraving. These and other cost-ineffective features we have compiled significantly affect costs and should be avoided unless absolutely necessary. In addition, certain design specifications, such as surface roughness or tolerance options, may require multiple checks and inspections. Also, large parts are logically more expensive to manufacture because they require more raw materials, resources and manufacturing effort and time.

Production volume

Reduce costs through series production

The unit cost for a set of identical parts decreases significantly as the number of parts increases. This proportional reduction in cost results from the elimination of repeated installation costs. CAD design, CAM preparation and machine setup are handled once for all parts to be manufactured. Using data from our plaform, the chart below compares the unit cost and number of units for the part in the image above, made of aluminum EN AW-6061 / 3.3211 / Al-Mg1SiCu.

The graph above proves that the cost per part is inversely proportional to the number of parts manufactured. The cost per unit for a production volume of 1000 is about 88% lower than the cost of a single piece.

Finishing level

CNC turning and milling produces parts suitable for machining. However, certain applications require parts to undergo post-treatment such as heat treatment, surface finishing and coating to improve their functionality, properties and aesthetics. All of these increase the price of a part.

Cost of CNC machining with the Batchforce platform

At Batchforce, we understand how difficult it would be to analyze each of these numerous factors to get an estimated cost for your project in advance. For every factor you want to change, you have to redo your calculations to get a new estimate. That’s why we developed our platform that calculates the cost of a project within two business days. All you have to do is upload your model and select the desired specifications (material, finishing, tolerances, number of pieces, etc.).