What is CNC Milling, advantages and disadvantages?

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What is CNC Milling, advantages and disadvantages?

What is CNC machining used for?

What is Milling and What is milling used for?

CNC Milling or manual milling is a precision machining process used to process prismatic parts. A milling cutter with a rotating cylindrical tool head and multiple flutes is usually called an end mill. It can move along different axes and is used to machine long and narrow voids, grooves, and outer contours. The machine tool for milling is called a milling machine, and the CNC milling machine usually refers to computer numerical control milling. 

It is a mechanical machining process along with drilling, turning, and a variety of other cnc machining processes, meaning that material is removed from the workpiece via mechanical means, such as the actions of the milling machine’s cutting tools.   

This article focuses on the milling , outlining the basics of the process, and the components and tooling of the CNC milling. Additionally, this article explores the various milling operations and provides alternatives to the CNC milling process.

Milling Machine Definition

What is Milling Machine? The milling machine mainly refers to a machine tool that uses a milling cutter to process various surfaces of a workpiece. Usually the milling cutter mainly moves by rotation, and the movement of the workpiece and the milling cutter is the feed movement. It can process planes, grooves, various curved surfaces, gears, etc.

A milling machine is a machine tool that uses a milling cutter to mill a workpiece. In addition to milling planes, grooves, gear teeth, threads, and spline shafts, milling machines can also process more complex profiles. The efficiency is higher than that of planing machines. It is widely used in machinery manufacturing and repair departments.

How does mill machine work?

The milling machine is a machine tool with a wide range of uses. It can process planes (horizontal planes, vertical planes), grooves (keyways, T-slots, dovetail grooves, etc.), gear parts (gears, spline shafts, sprockets), Spiral surfaces (threads, spiral grooves) and various curved surfaces. In addition, it can also be used to process the surface and inner hole of the revolving body and cut off the work. When the milling machine is working, the workpiece is mounted on the worktable or the indexing head and other accessories, and the milling cutter rotates as the main motion, supplemented by the feed motion of the worktable or the milling head, and the workpiece can obtain the required processing surface. Due to the multi-edge intermittent cutting, the productivity of the milling machine is high. In simple terms, a milling machine can be a machine tool for milling, drilling and boring workpieces.

What is 3 axis CNC Machining

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CNC Milling Machining Operations

What is the CNC milling machine used for? CNC milling is a machining process suitable for producing high accuracy, high tolerance parts in prototype, one-off, and small to medium production runs. While parts are typically produced with tolerances ranging between +/- 0.001 in. to +/- 0.005 in., some milling machines can achieve tolerances of up to and greater than +/- 0.0005 in. The versatility of the cnc milling process allows it to be used in a wide range of industries and for a variety of part features and designs, including slots, chamfers, threads, and pockets. The most common types of CNC milling operations include:

  1. Face milling
  2. Vertical milling
  3. Profile milling

01: Face Milling

Processing plane. Face milling is the most common type of milling used for milling planes parallel to the tool face. The milling cutter is often installed on the spindle. To complete face milling, you can use a tool with a certain diameter, so that the workpiece can be processed in one stroke, or you can use a milling cutter of the type that requires several strokes to complete the workpiece.

[face milling cnc milling 

02:Vertical milling

Process approximately 90 stepped surfaces. This kind of milling is somewhat similar to face milling, but the angle of the circumferential cutting edge plays a decisive role. If a part of the workpiece to be machined is a 90° shoulder, this tool can only be used. The side of the tool (entering angle) is parallel to the axis of rotation. This milling is also called step milling, shoulder milling or end milling.

[vertical milling cnc milling 

03:Profile milling

Machining a special-shaped surface (curved surface).

profile milling cnc milling 

Other Milling Machine Operations: Plain milling; Angular milling; Form milling ; Straddle milling; Gang milling; Gear cutting; 

Since cnc milling machines support the use of other machine tools besides milling tools, they can be used for machining processes other than milling, such as drilling, boring, reaming, and tapping.

Advantages and disadvantages of cnc milling machine

CNC Milling Machine: The CNC milling machine has high efficiency in mass production, good processing consistency and stable quality. However, the price is high, and programming takes a lot of time when the processing quantity is small, which is not economical.

advantages and disadvantages of cnc milling machine

The 4 main advantages of cnc mill machine: 

1. The number of tooling is greatly reduced, and complex tooling is not required for processing parts with complex shapes. If you want to change the shape and size of the part, you only need to modify the part processing procedure, which is suitable for new product development and improvement.

2. The processing quality is stable, the processing precision is high, and the repeat accuracy is high, which can meet the high-quality processing requirements.

3. The production efficiency is higher in the case of multi-variety and small batch production, which can reduce the time of production preparation, machine tool adjustment and process inspection, and reduce the cutting time due to the use of the best cutting amount.

4. It can process complex profiles that are difficult to process by conventional methods, and even process some unobservable processing parts.

CNC milling is an automated process that reduces the need for human labor, and it has many advantages. However, CNC Milling Machining also has some disadvantages that are worth mentioning such as the cost of cnc milling machine tools is expensive and requires a high level of maintenance personnel. 

The 3 main disadvantages of cnc mill machine: 

1. One of the main disadvantages of CNC milling machining is that it can be very expensive to purchase the equipment needed to do this type of work.

2. Another disadvantage is that there can be a lot of downtime when using CNC milling machines. If a machine needs maintenance or there’s a problem with one part of the machine, then all work will stop until the issue is resolved.

3. Finally, one more disadvantage to note about CNC milling machining is that not all materials are suitable for this type of machinery, which means you may have to do some trial and error before you find what works

Support software for CNC Milling

Like most of CNC machining processes, the CNC milling process uses CAD software to produce the initial part design and CAM software to generate the CNC program which provides the machining instructions to produce the part. The CNC program is then loaded to the CNC machine of choice to initiate and execute the milling process.

Material options for milling machine

CNC Milling can machine verity of metal and plastic materials including of aluminum, steel, brass, titanium; and ABS, PC, NYLON; also workable for

  • Elastomers
  • Ceramics
  • Composites
  • Glass

Outlined above are the basics of the CNC milling process, various CNC milling operations and their required software, materials which workable for cnc milling, and some of the considerations that may be taken into account by manufacturers and machine shops when deciding what kind of CNC milling  or other machining is the most optimal solution for their particular machining application.

How much are milling machines and other cnc machines cost?

CNC machines are expensive, but they produce high quality output. The price of cnc machines varies depending on the model and the quality of the machine. A basic cnc mill can cost around $2,000 while high-end ones can go up to $100,000.

Categories of CNC Machines and their Price Ranges

CNC Machine Category

CNC Machine Cost (US Dollars)

Entry Level Desktop CNC Routers like the 3018s 

$150 – $500

Hobby CNC Router Machine

$1,000 – $3,000

Small CNC Lathe Machines like Sherline and Taig

Less than $5,000

Entry-Level 2-axis Lathe Machines

$15,000 – $50,000

Professional CNC Machine

$50,000 – $100,000

Entry-Level 3-axis Mill (VMC)

$50,000 – $100,000

Production CNC Lathe Machines like Doosan and Okuma

$50,000 – $300,000

Production 3-axis CNC Milling Machines

$100,000 – $500,000

Production 5-axis CNC Milling Machines

Over $500,000

Source: https://www.scan2cad.com/blog/cnc/cnc-machine-cost/

How much does CNC milling cost for custom machining parts?

CNC milling is a type of machining that uses computer-controlled machines to transform raw materials into finished goods. The cost of CNC milling depends on the type of material, the complexity of the design, part size and the expertise of the operator.

The cost for a custom machining part can range from $150 to $25,00 or more. While some companies offer their own CNC milling services, other companies outsource their work to suppliers and manufacturers who specialize in CNC machining.

CNC Mill costs are typically measured by hours and the price per hour is calculated by multiplying the hours with the tool set up cost and dividing it by $150 to start. For example, it may cost $15 per hour to produce a simple gear with a 3-axis motion but it could cost $20 per hour to produce a gear with 4-axis milling machine.

If you don’t have enough budget for your custom machining part projects, especially you only need 1 pcs or couples for a simple machining part, you can choose a manual milling machine to make it for saving set up cost and usually it can start from as low as $50, because manual milling doesn’t require program and the machine cost is much lower than a 3-axis cnc milling machine.

How to reduce cnc milling cost?
How to reduce cnc milling cost?

How to reduce cnc milling cost?

The cost is always priority for either small or big business, everyone want to find the balance between cost, quality, timing, and service, so how to recuce cost for your custom maching parts when with cnc milling? Let’s have a look at details then you may find out it’s much simple than you think:

01: Raw material

The cost of raw material is much different, when you understand what’s the main functions and where will be used of your products, you can easy to find out the best and economical material for making your parts.

For example, when we considering stainless steel or aluminum to make the parts, we can easy to find out aluminum material price is much cheaper than stainless steel, and aluminum is much easier to be machined than stainless steel, which means the total machining cost of aluminum machining is much cheaper than stainless steel machining.

So choose a right raw material can save your cnc milling cost to start.

02: Machine type

As a professional cnc machining manufacturer, 3Q Machining can help you to choose right machining machine to save cost without downgrade quality, manual milling machine is most suitable for simple design parts with small volume quantity, because it doesn’t need program that can save set up cost a lot, and 3+1 axis cnc milling machine cheaper than 4 axis cnc milling machine, so choosing a right machine can save your money.

03: Location

When you are urgent to get the part, or the part size is very big, that you should considering source a cnc machining shop where nearby you to save time and save shipment cost.

But when you are looking for purchasing big volume projects, and the prices to make the parts are high in your area, you should considering outsource in different areas, for example, you can choose to outsource cnc machining service in China manufacturer, which can save the whole cost and acquire high precision quality parts.

04: Quantity and Forecast

Make accurate forecast is very important for your projects in a long term business, that you can save time to waiting for the parts, also save time to machining the parts.

CNC milling and other cnc machining service have set up cost every order, that means you need to pay the set up cost every time even the order is small, and the more quantity you order, the cheaper price per unit you will pay, the per unit machining part price has much different when it is 1~10pcs with 100~500pcs

There are more ways to reduce cost for your cnc milling parts, such as surface treatment, dimension tolerance, packaging etc. you can contact 3Q Machining team to get more technique support to get a instant quote to check how much to make your custom machining parts.

Author: Mose Li

Author: Mose Li

Director of Project Engineering at 3Q Machining

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