Online CNC Milling Service | CNC Lathe Live Tooling and Production Parts

Overview

Our CNC Milling Service

What is CNC Milling

It uses computer-controlled and rotating multi-point cutting tools to incrementally remove material from workpieces and produce custom-designed parts or products. The process is suitable for machining a variety of materials such as metal, plastic, wood.

How Does CNC Milling Work?

The CNC milling process begins with the creation of a 2D or 3D CAD part design. The complete design is then exported to a CNC-compatible file format and converted by CAM software into a CNC machine program that instructs the movements of the machine and the movement of the tool across the workpiece. Before operators run a CNC program, they prepare a CNC mill by securing the workpiece to the machine's work surface (i.e., table) or workpiece fixture (such as a vise), and mounting the milling tool to the machine spindle. The CNC milling process employs horizontal or vertical CNC powerful milling machines - depending on the specifications and requirements of the milling application - and rotating multi-point (i.e., multi-tooth) cutting tools such as milling cutters and drills. When the machine is ready, the operator initiates the program through the machine interface, prompting the machine to perform the milling operation. CNC milling The creation of these aforementioned features requires a variety of different milling operations:

Surface milling
Face milling
Angular milling
Form milling
Profile milling
Gear milling, etc.

Other Benefits of CNC Milling

Since milling machines support the use of machine tools other than milling tools, they can be used for machining processes other than milling, such as drilling, boring, reaming, and tapping. Like most CNC machining processes, the CNC milling process uses CAD software to generate an initial part design and CAM software to generate a CNC program that provides machining instructions to produce the part. The CNC program is then loaded onto the selected CNC machine to start and execute the milling process.

Features of CNC Machining

Advantages

Rapid Turnaround

Using the latest CNC machines, Justway produces highly accurate, quick turn parts in as fast as 2 day. We also instantly quote CNC machined parts, cutting days off of your RFQ process.

High Precision Tolerances

Offers high-precision tolerances ranging from +/-0.001″ – 0.005″, depending on customer specs. We are the experts in making parts that are truly custom and ready to use.

Scalability

CNC Machining is perfect for prototyping and production production parts. Justway's massive scale can help you scale up from testing phase to production runs of 100,000 parts of more.

Custom Surface Finishes

Suitable for many different kinds of substrates, make your parts just the same as real products.

Material Selection

Choose from over 50 metal and plastic materials. CNC Machining offers a wide variety of certified materials.

Cost Saving

Low investment in tooling and preparation costs, economical for parts with simple structure.

Drawbacks

Structure Limits

CNC Machining is perfect for prototyping and production production parts. Justway's massive scale can help you scale up from testing phase to production runs of 100,000 parts of more.

Scale Effect

The unit cost and lead time will not be reduced as much as casted or molded parts.

CNC Milling Processes

3-Axis & 5-Axis Milling •Surface finishing •Lead times from 5 days

3-Axis CNC milling

The most widely used type of CNC milling machine. The full use of the X, Y, and Z directions makes a 3 Axis CNC mill useful for a wide variety of work.

4-Axis CNC machining

This type of router allows the machine to rotate on a vertical axis, moving the workpiece to introduce more continuous machining.

5-Axis CNC machining

These machines have three traditional axes as well as two additional rotary axes.

Maximum part size for 3-axis and 5-axis CNC milling

Size	Metric units	Imperial units
Max. part size for soft metals [1] & plastics	2000 x 1500 x 200 mm 1500 x 800 x 500 mm	78.7 x 59.0 x 7.8 in 59.0 x 31.4 x 27.5 in
Max. part for hard metals [2]	1200 x 800 x 500 mm	47.2 x 31.4 x 19.6 in
Min. feature size	Ø 0.50 mm	Ø 0.019 in

[1] : Aluminum, copper & brass

[2] : Stainless steel, tool steel, alloy steel & mild steel

Available materials for CNC machining

Here is a list of our standard CNC machining materials available through our online platform.

CNC Metals

Aluminum	Stainless steel	Mild, Alloy, Tool & Spring steel	Other metal
6061	304	Mild steel 1018	Brass C360
7075	316/316L	Mild steel 1045	Copper
5052	303	Mild steel A36	Titanium Gr5 (TC4)
2A12	430	Alloy steel 4140
	201	Alloy steel 4340
		Alloy steel 1215
		Tool steel D2
		Tool steel A2
		Tool steel D1
		Tool steel A3
		Tool steel S7
		Tool steel H13
		Spring steel

CNC Plastics

Plastic	Reinforced Plastic
ABS	PMMA (Acrylic)
ABS Flame Retardant	PEEK
ABS Transparent	Bakelite
Polycarbonate (PC)	FR4
Nylon 6
Nylon 12
Polypropylene (PP)
POM
PTFE (Teflon)
Polyethylene (PE)
Rubber

Custom Material

The materials available on the online system may not be exhaustive of all materials available on the market. If the materials you need are not listed on the order page, please select "custom" under the material menu, and our engineers will review and purchase.

Our standard surface finishes

Standard (As-Milled) (Ra 125μin)

The finish option with the quickest turnaround. Visible tool marks, potentially sharp edges and burrs would be removed by default.

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Bead blast + Anodized color

Anodizing creates a corrosion-resistant finish. Parts can be anodized in different colors—clear, black, red, and gold are most common—and is usually associated with aluminum.

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Anodized

It creates a corrosion-resistant finish. Parts can be anodized in different colors—clear, black, red, and gold are most common—and is usually associated with aluminum.

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Electrically conductive oxidation

It creates a corrosion-resistant finish, the film produced by conductive oxidation is only 0.01-0.15 micrometers,

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Black oxide

Black oxide is a conversion coating used to improve corrosion resistance and minimize light reflection.

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Brushed

Brushing is a surface treatment process in which abrasive belts are used to draw traces on the surface of a material, usually for aesthetic purposes.

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Bead Blast

The part surface is left with a smooth, matte appearance.

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Spray painting - Matt paint

Spray painting: Using spray guns with air pressure to disperse into uniform and fine droplets and apply the painting to the surface of the object.

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Tolerances

We follow ISO 2768 standards for CNC Machining.

Limits for nominal size	Plastics (Coarse class (c))	Metals (Medium class (m))
0.5mm* to 3mm	±0.2mm	±0.1mm
3mm to 6mm	±0.3mm	±0.1mm
6mm to 30mm	±0.5mm	±0.2mm
30mm to 120mm	±0.8mm	±0.3mm
120mm to 400mm	±1.2mm	±0.5mm
400mm to 1000mm	±2mm	±0.8mm
1000mm to 2000mm	±3mm	±1.2mm
2000mm to 4000mm	±4mm	±2mm

Please clearly indicate tolerances for nominal sizes below 0.5mm on your technical drawing.

CNC Milling Design Guidelines

We have summarized recommended and technically feasible values for the most common features encountered in CNC machined parts.

1. Cavities and grooves

Cavity depth recommendation: 4 times the cavity width end mills have a limited cutting length (typically 3-4 times their diameter).
When the aspect ratio is small, tool deflection, chip ejection and vibration become more prominent. Limiting the depth of the cavity to 4 times its width ensures good results. Deep cavity milling: A cavity whose depth is greater than 6 times the tool diameter is considered a deep cavity. Tool diameter to pocket depth ratios of up to 30:1 can be achieved with special tooling (using 1 inch diameter end mills up to a maximum depth of 30 cm)

2. Inner edge

Vertical corner radius: ⅓ cavity depth (or greater) recommended.
Using the recommended values for inside corner radii ensures that the proper diameter tool can be used and aligns with the guideline for the recommended cavity depth. Increasing the corner radius slightly above the recommended value (eg by 1 mm) allows the tool to cut along a circular path rather than a 90°corner. This is preferred as it results in a higher quality surface finish. If a sharp 90°interior corner is desired, consider adding a T-shaped undercut rather than reducing the corner radius. Base plate radius recommended 0.5mm, 1mm or no radius; any radius will work. The lower edge of the end mill is flat or slightly rounded. Other floor radii can be machined using ball nose tools. It is good design practice to use the recommended values, as this is the machinist's first choice.

3. Wall thickness

Recommended minimum wall thickness: 0.8mm (metal), 1.5mm (plastic); 0.5mm (metal), 1.0mm (plastic) are both feasible. Reducing the wall thickness reduces the stiffness of the material, which increases vibration during machining and reduces the achievable precision. Plastics are prone to warping (due to residual stresses) and softening (due to increased temperature), so larger minimum wall thicknesses are recommended.

4. Hole

Diameter Recommended standard drill size: any diameter larger than 1 mm will work.
Use a drill or end mill to machine the hole. Dimensions of drill bits are standardized (metric and imperial units). Reamers and boring tools are used for finishing holes that require tight tolerances. For use up to ⌀20 mm, standard diameters are recommended. Maximum depth recommended 4x nominal diameter; typical 10x nominal diameter; feasible 40x nominal diameter. Holes with non-standard diameters must be machined with an end mill. In this case, the maximum cavity depth limitation applies and the recommended maximum depth value should be used. Holes deeper than typical are machined using special drills (minimum diameter 3 mm). Blind holes made with a drill have a tapered base (135° angle), while holes made with an end mill are flat. In CNC machining, there is no particular preference between through holes and blind holes.

5. Thread

Thread size minimum M2; M6 or larger recommended. The internal thread is cut with a tap, and the external thread is cut with a die. Taps and dies are available for cutting threads down to M2. CNC threading tools are common and preferred by machinists because they limit the risk of tap breakage. CNC threading tools are available for cutting threads down to M6.
Thread length minimum 1.5 x nominal diameter; recommended 3 x nominal diameter. Most of the load applied to the thread is carried by the few first teeth (up to 1.5 times the nominal diameter). Therefore, there is no need for more than 3 times the nominal diameter of the thread.
For threads in blind holes cut with taps (i.e. all threads smaller than M6), add an unthreaded length equal to 1.5 x nominal diameter at the bottom of the hole. When a CNC threading tool is available (i.e. threads larger than M6), the hole can run through its entire length.

6. Text

Recommended font size is 20 (or larger), 5mm lettering Engraved text is preferred over embossed text because less material is removed. A sans-serif typeface (such as Arial or Verdana) that is at least 20 point in size is recommended. Many CNC machines have pre-programmed routines for these fonts.

FAQ's

What is CNC machining?

CNC machining is a modern manufacturing technique that utilizes programmable software and computer-controlled equipment to create complex parts and products from a wide range of materials such as metal, plastics, and wood.

With CNC (Computer Numerical Control) technology, the manufacturing process is highly automated and precise. The process begins with a CAD (Computer-Aided Design) file, which is converted into a set of instructions in the form of G-code. This code is then sent to a CNC machine, which follows step-by-step instructions to produce the desired part or product.

CNC machining has revolutionized the manufacturing industry by increasing productivity, improving accuracy, reducing waste, and allowing for complex shapes and designs to be produced with high precision. It is used in a variety of industries, including aerospace, automotive, electronics, and medical devices.

What are the benefits of using CNC machines?

The benefits of using CNC machines are:

1. Enhanced precision: CNC machines can produce highly precise and accurate parts with tolerances as low as 0.0002 inches, which is not possible manually.

2. Increased speed: CNC machines are automated and can run 24/7, thereby offering faster production time for large volumes of parts.

3. Consistency: Unlike manual production, CNC machines produce parts that are identical in terms of size, shape, and quality consistently.

4. Reduced labor costs: CNC machines require less manual labor and supervision, which saves labor costs and improves overall efficiency.

5. Flexibility: CNC machines can be reprogrammed easily to create different parts without the need for complex tool changes.

6. Ability to work with a wide range of materials: CNC machines can work with a variety of materials, including metals, plastics, wood, and composites.

7. Improved safety: CNC machines can run automatically, which reduces the risk of injury for workers and provides a safer work environment.

8. Reduced waste: The precision offered by CNC machines reduces the material waste and scraps generated during the production process.

What types of materials can be used with CNC machines?

CNC machines can work with a wide range of materials including metals, plastics, wood, composites, ceramics and more. The types of materials that CNC machines can work with depend on the specific capabilities of the machine, the tooling options available, and the type of work being performed. Here are some examples of materials that can be used with CNC machines:

1. Metals: CNC machines can work with a variety of metals, including steel, aluminum, brass, titanium, copper, and more.

2. Plastics: CNC machines can work with various types of plastics such as polycarbonate, acrylic, nylon, ABS, PVC, and more.

3. Wood: CNC machines also perform operations on hardwood, softwood, plywood, and MDF board.

4. Composites: CNC machines can work with glass and carbon fiber composites, Kevlar, and other composite materials.

5. Ceramics: Machinable ceramics can also be used with CNC machines like porcelain, alumina, zirconia and other materials.

It's important to note that different CNC machines will have specific requirements for the materials that can be used. The feed rate, chip load, and spindle speed will vary depending on the material, so it's essential to understand the material properties and choose the appropriate tools and settings for each job.

What is the difference between CNC milling and CNC turning?

CNC turning and CNC milling are both processes used in CNC machining, but there are some significant differences between the two.

1. Operation: In CNC turning, a stationary cutting tool is used to remove material from a rotating workpiece, whereas in CNC milling, the cutting tools rotate and move across the stationary workpiece.

2. Geometry: CNC turning is more suitable for creating cylindrical shapes such as bolts, nuts, pipes, and shafts. CNC milling is better suited for more complex geometries such as pockets, slots, and complex shapes.

3. Tooling: Turning tools are generally simpler and more robust, while milling tools are more complex and can have more cutting edges.

4. Materials: CNC turning machines are mostly used for turning materials such as round bars, billets, and blocks, while CNC milling machines are used for a wide range of materials such as metals, plastics, wood, and composites.

5. Speed: In general, CNC turning is faster than CNC milling, as the tools are shorter and the process is simpler.

6. Cost: CNC turning is usually less expensive than CNC milling, as the tools are simpler and less expensive.

In summary, CNC turning is best suited for creating simple cylindrical shapes, while CNC milling is better suited for creating more complex geometries. Both processes have their advantages, and the choice between them will depend on the specific requirements of each job.

What is the maximum size of parts that can be machined with CNC machines?

The maximum size of parts that can be machined with CNC machines depends on the size and capacity of the machine being used. CNC machines come in various sizes, and they have different work envelopes that dictate the maximum size of parts they can handle.

Small CNC machines are ideal for small and intricate parts, while larger machines are used for bigger parts. Generally, the maximum size of parts that can be machined on a CNC machine ranges from a few centimeters to several meters.

For example, a small benchtop CNC milling machine may have a work envelope of around 300mm x 300mm x 200mm, while a larger vertical machining center may have a work envelope of 2000mm x 1000mm x 1000mm. In comparison, large gantry-style CNC machines used in the aerospace industry have a work envelope of over 30 meters in length.

It's essential to consider the size and weight of the parts being machined and the capabilities of the CNC machine when selecting a machine for a specific job.

CNC Machining Case Study