How to Reduce CNC Milling Costs? – Overview and Tips to Cut Your Expenses

Introduction: How Much Does CNC Milling Cost?

No matter whether you are a manufacturer looking to install new equipment at your facility, or a customer seeking to use a manufacturing process to obtain your desired product, all of us prefer saving costs wherever possible.

However, in today’s age of increased mechanization and competitiveness, both manufacturers and customers face the challenge of balancing the costs of production with the quality of product.

As simplistic as it may seem to you at first, there are several types of CNC milling costs incurred throughout a cycle.

Therefore, this article aims to provide you with a brief overview of the CNC milling process, followed by a discussion of the various types of costs involved and the factors on which they depend.

Tips to reduce these costs are then mentioned, followed by how milling services like Kemal offer affordable rates without compromising on quality.

CNC Milling Overview

Computer numerical control milling, often referred to as CNC milling, is a machining process that was first introduced in the 1960s. It replaced the milling machine, which had been in operation since the 18^th century.

It is one of the types of CNC machining, a broader term that also includes CNC turning and EDM cutting. Current research studies predict that the CNC machine market size will grow at a CAGR of 5.33% annually from 2023 to 2030, reaching a value of $153.8 billion.

A CNC milling machine uses multi-point rotary cutting tools, that are operated by computerized controls, to remove extra material from a workpiece.

The rapid rotation of the tools across a workpiece gradually removes excess material until the desired shape and geometry are obtained.

The CNC milling operation itself is preceded by the 2D or 3D design of the product using computer-aided design (CAD) techniques, the transferring of the CAD file into a computer-aided manufacturing (CAM) software, and the setup of the milling machine, its cutting tools, and the blank workpiece.

Types of Costs in CNC Milling

As the process requires several inputs and prerequisites, you will be interested in knowing the various types of costs associated with it. These will help you ascertain the price for CNC milled products. Here, we outline a few of them:

1. Material Cost

When determining CNC milling costs, you may start with the cost of the material to be operated on. Since milling is a subtractive process where your finished product contains less material than your starting workpiece, you should consider the cost of the material that will be machined off.

Two of the most common types of materials used are metals and plastics.

• Metals

Metals are used in CNC milling due to their hardness, ductility, and strength. Aluminium 6061 is one of the most common metals used due to its good machinability and affordable cost.

However, other metals, such as Brass C360 and Stainless Steel 303, are more expensive, which limits their use to large production volumes.

• Plastics

On the other hand, plastics are less expensive to operate on as their average bulk price is lower than that of metals. Their lower degree of hardness also means that they are able to be machined faster.

Plastics usually used in CNC milling include ABS, Nylon 6, and POM (Delrin). As you can see in the table below, they have almost the same cost as Aluminium 6061. Other plastics, such as PEEK, cost significantly more and, hence, should be used only when required.

Materials are usually purchased as sheets measuring 6” x 6” x 1”.

Before deciding on which material to buy, you should compare the cost per block of different materials:

2. Machining Cost

Since there are several types of CNC machines, it is hard to assign a single cost to all of them. The more complicated a machine’s operation is, the more expensive it will be. The table below summarizes these factors, along with their costs.

Although the machining cost per hour varies across different geographical regions, multi-axis CNC machines cost around three times more than 3-axis machines due to the more complex operations.

In addition to the type of machine and region, you must also consider the price of the CNC milling machine as well as the number of operating hours when calculating the cost.

Manufacturers usually factor this in by calculating the machine shop rate, which is found by dividing the purchase price of the machine by the expected number of operating hours per year (usually taken as 5,000 hours).

3. Labor or Service Costs

Although CNC milling is a mostly automated process, you may find it surprising that it also incurs several labor costs. These take place in the programming, setup, and post-processing stages of the operation:

• Programming

This part is considered to be the most expensive in terms of labor costs, as there are several experts involved. A designer makes a computer-aided design (CAD) file, which is then checked and improved by the manufacturing engineer, who advises on its reproducibility.

Finally, the programmer converts the file into a computer-aided manufacturing (CAM) file that can be fed to the CNC machine.

• Setup

Depending on the complexity of the part, the machine operator sets up the CNC machine to ensure that all requirements are met.

The setup costs are directly linked to the quantity of products to be machined, as producing a large volume divides the cost over a larger quantity.

• Post-processing

A CNC may or may not produce your desired end product. You may need to conduct further assembly operations, which incur extra costs. Transporting the product to the desired location also involves labor, thus adding more costs.

4. Equipment Costs

There are several types of machines available on the market. You should keep in mind that a CNC milling machine’s price depends on its size and complexity. You will find that smaller machines with relatively simple operations and axes are cheaper than larger ones with multi-axis operations.

Entry-level machines, such as the CNC 3018, cost less than $500. Professional CNC machines can cost as much as $100,000. Moreover, a 3-axis CNC mill ranges from $100,000 to $500,000, while a 5-axis mill costs more than $500,000.

5. Others

Other miscellaneous CNC milling costs are given below:

• Tooling costs

With the rotating tool constantly working to remove material, you may have guessed that while this is happening, the tools experience great levels of friction forces as they continuously come into contact with the workpiece.

The harder the material, the more the tools will wear, increasing machine costs.

• Surface finish

A product may still be required to undergo extra operations after milling to enhance its look as well as its resistance to the external environment.

These operations fall into the category of surface finishes, which, while increasing the life of the product, also increase machining costs.

What Are the Factors That Affect the Cost of CNC Milling?

1. Machine Size

Many types of CNC milling machines are available on the market. What suits you depends on what you need to produce. Smaller machines, while saving costs, cannot machine larger workpieces. Larger ones, in contrast, may be able to work on producing smaller parts, but this will result in a waste of money as you will not be utilizing them to their full potential.

2. Cutting Tolerances

Tolerances are the allowable amounts of dimensional variation in a part. While assigning higher degrees of tolerance results in a more accurate finish, it will cost you more to do so.

Hence, you have to make a tradeoff between the desired accuracy and the CNC milling cost.

3. Number of Axis

The number of axes a CNC milling machine has determines its complexity. While 3-axis machines are more affordable, their range of operation is limited to only three axes.

In order to produce parts with more complicated geometries, you must use multi-axis (5-axis or 6-axis) machines, which cost more to operate.

4. Milling Time

CNC milling machines are preferred over their traditional counterparts due to their superior speed of operation.

While they require a larger initial investment, this extra expenditure is significantly offset by their shorter milling times, which enable you to produce a greater volume of products in the same time period. This decreases the machining cost.

5. Type of CNC Machine/Mill

Horizontal, vertical, C-frame, double column, and double spindle are just a few of the many types of CNC machines you may find on the market. Due to their varying modes of operation, they incur different costs. As a general rule, the more complex a CNC machine is, the more costly it will be to operate.

6. Part Geometry

The rule regarding the complexity of CNC machines also applies to the complexity and size of parts. Parts with detailed geometries take more time to be machined due to the greater number of cutting tools and operations involved, and large workpieces require more material to be used, thus resulting in higher costs.

7. Production Cycles

Large quantities of parts use up more material, thereby increasing the total cost. But they also result in lowering the marginal cost of each unit of product as the fixed costs of equipment and tooling are distributed over a large number of parts.

8. Labor Costs

When we earlier discussed the CNC milling process, we mentioned some stages that require human involvement. These include the design, conversion, and setup phases.

Complex parts require skilled designers and operators to be manufactured, which means that such experts charge you more.

9. Tooling

Tools refer to the various components that come into contact with the workpiece during the fabrication process. They may be used for machining the material away, such as drill bits, end mills, and thread mills, which causes them to be used up gradually across numerous cycles.

Different parts necessitate different tools to be used. Hence, the tooling costs go up as the shape and dimensions of the part change. Conversely, other tools, such as clamps and dies, do not wear away and thus do not require replacing.

10. Lead Time

Lead time is the amount of time between the order date and the delivery date. Shorter lead times, which you can achieve by having all the necessary raw materials, experts, and tools at hand, result in lower costs as you waste fewer resources.

However, for specialized or customized parts, the time taken to deliver the product may be longer due to the extra tooling or labor costs involved, which increase the total CNC milling costs.

11. Raw Material Cost

The costs you incur due to raw materials depend on the specifications of your part, the tolerances, and the type of materials used. Good CAD design, strict tolerances, and using plastics rather than metals (if possible) result in lowering your raw material cost.

12. Power

Since CNC milling machines run on electricity, the0020high-power rating of the machine and unit electricity price contribute to higher electricity bills, which lead to higher milling costs.

CNC Milling Cost Calculators

All of the above-mentioned types of costs and the factors on which they depend can be used to establish the expected CNC milling costs even before you start designing the product.

This is useful for you since then you can determine whether or not it is financially feasible for you to use a specific milling service. Kemal’s experts can provide you with an accurate quotation by inspecting your design.

How Much Do CNC Milling Near Me Cost?

While you are looking for the milling services best suited for your requirements, you may also want to investigate various CNC shops near you.

Using your browser location, our CNC shop locator identifies several milling services in your area, so that you can compare their services, rates, and reviews to make a well-informed decision.

When making a decision regarding which milling service to use, you should take into account its location and timing, years of experience, quality and prices offered, its service record, as well as your design and material preferences.

In-Store CNC Milling Companies V.S Online CNC Milling Companies

Some customers prefer utilizing in-store milling services, while others choose online services. The choice you make depends on your requirements. Here, we will describe several aspects of both of these options.

In-store milling services are chosen mainly when you want to be personally involved with the process or when your part is relatively simple to fabricate.

Your product becomes more customized, as a result of your constant input and communication with the manufacturing company. Regular exchange of ideas, instructions, advice, and feedback enables short turnaround times and quicker delivery.

Payment options are diverse, and on top of that, you help to support your local industry. In-store options are especially useful for customers with small volumes or one-time orders. However, such options may have limited equipment and services.

On the contrary, you normally choose online milling services when you want to take advantage of discounts on large orders. Economies of scale enable them to operate on a large scale, resulting in lower CNC milling prices as compared to traditional companies.

Furthermore, they offer a more accurate finish as a result of production-grade tools and stricter tolerances, allowing them to produce robust, complex parts that can be used in industries that follow stringent regulations.

They usually possess several advanced CNC machines, which makes them suitable if you need to manufacture numerous products with a high degree of variation.

Finally, they also have the experience of catering to a diverse international client base, so they are better suited to face any design, material, or production challenge that may come up.

9 Tips to Reduce CNC Milling Costs

1. Reconsider Material

Selecting the cheapest material that has all the relevant properties helps you cut the costs while achieving desired results.

Another important aspect for you to consider is the machinability of your material, as it directly affects the complexity of the process as well as the time required to machine it. This, in turn, affects your hourly rate for the process.

2. Optimize Design

A significant portion of the costs can be saved by incorporating several design optimizations in the initial stages of the process. You should try to design the product using simple geometric shapes and standardized parts.

Moreover, specify tolerance only when it is necessary. By doing so, the design will be simplified, leading to shorter processing times and, therefore, reducing costs.

3. Outsource a Trusted Manufacturer

Outsourcing the milling process to a reputable manufacturer helps reduce costs as you directly avoid material, machining, labor, equipment, and other costs.

However, the manufacturer does pass on their costs to you, which may result in a high bill depending on your manufacturer.

Manufacturers based in developed countries, including those in Europe, generally charge more due to the high standards of living prevalent in those regions.

On the other hand, Asian manufacturers, especially those established in China, provide you with a more reasonable alternative.

The expected charges for these regions are given below:

4. Get rid of unnecessary features

• Add a radius to the internal vertical edges

CNC milling tools have a cylindrical shape, which creates a radius when cutting the edge of a pocket. Costs can be minimized by adding a radius of a value greater than one-third of the depth of the cavity. If possible, try to use the same radius for all such edges.

• Limit the cavity depths

CNC cutting tools have a limited cutting length, and deeper cavities require more material to be machined, increasing the costs. Try to keep the depth of all cavities at four times their length.

• Limit the thread lengths

Longer threads necessitate special tooling, which increases costs. Therefore, design threads in a manner that ensures that their length is less than three times the hole diameter.

Threads with blind holes should have an unthreaded length of at least half the diameter added at the bottom of the hole.

• Specify tolerances only when required

Defining tolerances increases the machining time and manual inspection stages, thus raising costs. When not defined, the standard tolerance of ± 0.125 mm is usually used. You can also set a specific point, such as the cross-section of two edges, as a reference for all dimensional tolerances.

• Design holes with a standard size

Since holes with non-standard sizes require an end mill tool to be drilled, costs can increase.

For that reason, holes with diameters of less than 10 mm should be drilled in increments of 0.1 mm, while larger holes should be drilled in increments of 0.5 mm. The depth of the hole should be kept to less than four times its diameter.

• Avoid very thin walls

Thin walls are susceptible to vibrations, fracture, and deformation and, therefore, take more time and money to manufacture.

Hence, you should increase the thickness of such walls. It is good practice to design walls thicker than 0.8 mm for metal parts and greater than 1.5 mm for plastic parts.

• Avoid features with a high aspect ratio

Small parts with a high width-to-height ratio are difficult to machine with accuracy due to the vibrations they face. You can add bracing features or join such features to a wall to increase their stiffness.

You may also design such parts with an aspect ratio of less than four.

5. Reduce Cosmetic Finishes and Appearances

Sometimes, you want your product to bear text or lettering. While this may look great, it may also lead to extra milling costs, unfortunately. Adding extra surface finishing stages just to modify its appearance is, accordingly, best avoided.

6. Consider Part Size

Parts should be designed with dimensions 3 mm smaller than those of the available blank. To achieve high accuracy, some material may need to be removed from all edges of the part. For high production volumes, this may have a significant impact on material costs.

7. Reducing Design Complexity

The more complex a part’s design is, the more expensive it will be to design and then produce. Complex designs require multi-axis CNC machines, which increases their cost.

Try to split intricate designs into multiple simpler ones that can be milled on a regular 3-axis machine, and then assemble them to achieve the original complex part.

8. Increasing Production Volume

You may have heard of economies of scale, which refer to the cost benefits enjoyed by manufacturers due to high production volumes.

The more parts you produce, the lower the cost be, as the fixed costs, which occur regardless of the volume produced, are more evenly spread out.

9. Import From China

As stated before, the general costs in China are lower than those of developed regions due to economies of scale. To save on CNC milling costs, you can import the desired material from China at a cheaper rate.

FAQs:

Kemal: Your Ideal Solution for CNC Milling

At Kemal, we offer some of the best CNC milling services available on the market. With a qualified, dedicated team of experts to answer your every query, you can rest assured that all your fabrication needs will be satisfied.

Our experience catering to more than 2,000 companies across a variety of manufacturing services is a testament to our proficiency and customer trust.

Do reach out to us if you have any other questions.