Custom CNC Milling: Process, Benefits & Role in Precision

Wondering what is cnc milling? It is a special manufacturing subcategory that utilizes machines that are controlled by computers to cut and form a material. These CNC milling machines are general can be of different sizes and with different axes and able to develop different parts with a lot of accuracy. Although CNC milling is usually used on hard materials such as stainless steel and titanium, it is also very useful when used on soft materials such as aluminum, plastics, and composites making it suitable for custom manufacturing.  Custom CNC milling provides tailored solutions, especially for designs that have flat and irregular contours. 

This article will discuss the custom CNC milling approach in manufacturing including, methods, benefits, tolerance standards, examples of custom parts, etc. 

Custom CNC Milling Explained

The use of CNC milling is most advisable if there is a need to produce small parts with special and complex shapes. It is done through a G-Code that directs the functioning of the CNC mill. This code is created by CAM software and it depends on the design of the part in question. The G-Code controls the motion of the tool head of the mill, the rate at which the tool has to rotate, to cut the workpiece, and how the tool and the workpiece will have to move. 

Custom precision milling

The degree of customization and the degree of sophistication depends upon the number of axes in the CNC milling machine; there are 3-axis, 4-axis, and 5-axis machines with varying levels of precision. Custom CNC milling costs can be optimal in the case of short production runs and when producing prototypes. The fact that custom CNC milling is capable of cutting through ordinary metals and complex alloys makes this service useful in several industries such as the aerospace industries, automotive industries, and medical equipment industries among others.  

Different Custom CNC Milling Machines

• 3-Axis Custom CNC Mills: Ideal for simple cutting and drilling operations which are more versatile and productive as compared to other operations. 
• 4-Axis Custom CNC Mills: It also includes the rotation around the X-axis which enables it to work through complex operations in the machining. 
• 5-Axis Custom CNC Mills: Offers the highest level of accuracy for the formation of complex shapes and patterns on the part to be formed. 

Benefits of Custom CNC Milling

The following are the benefits of custom CNC milling: 

Custom CNC milling is an affordable cnc mill process, used where accuracy, interchangeability, and versatility are called for. Custom CNC milling can be used in prototypes and small and large-scale production with various materials and tolerance. It also guarantees the accuracy of your custom components and the level of detail of the required design.

Precision and Repeatability 

Custom CNC milling is precise and accurate in terms of tolerance and each piece that is manufactured will be a replica of the other and this is very essential in areas such as aviation and health. 

Small allowable deviations for intricate shapes 

CNC milling is used in the fabrication of complex shapes with high accuracy and this means that there are few adjustments since the parts fit well in the assemblies.  

Versatility in Production-Grade Materials 

Custom CNC milling is versatile in terms of the range of materials it can work with, thus the manufacturer can select the most appropriate one depending on the application, it could be aerospace or medical application. 

Rapid Tooling and Manufacturing of Prototypes and Production Components 

Custom CNC milling is ideal for prototype and high-volume production because many of the parts can be produced and delivered the next day. The large volumes make the custom CNC milling to be cheaper, making it suitable for large-scale production with the same level of accuracy. 

Tolerances and Standards for CNC Milling in Custom Manufacturing  

CNC milling is one of the versatile technologies of machining that can be used to manufacture complicated parts with a higher degree of accuracy. To understand what CNC milling can do, one has to understand what it can and cannot do about part size, accuracy, and surface finishes. Below is a list of the most critical areas of custom CNC milling: 

Maximum Part Size for Custom CNC Milling 

CNC milling is suitable for large parts and the size of the parts that can be handled is usually up to 80” x 48” x 24” or 2,032 x 1,219 x 610mm. This capability helps the manufacturers to produce large and accurately machined parts that meet some specifications. CNC milling is capable of dealing with large projects in terms of size and is equally capable of providing high levels of accuracy regardless of whether the project is a machinery part, an automotive part, or an industrial equipment part.  

Distance Dimensions in Custom CNC Milling 

For parts produced by CNC Milling, the tolerance allowable for critical dimensions such as length, width, height, and diameter is normally within +/- 0.005”. This tight tolerance assists in keeping small dimensions such as position, concentricity, and symmetry in the products. This is particularly so for components that are to be fitted and joined with a high degree of precision or for components that are to be manufactured to fine engineering tolerances. 

Orientation and Form Tolerances in Custom CNC Milling 

Orientation and form tolerance vary with the size of the part. For custom milled parts of up to 12 inches in size and smaller, CNC milling can achieve a tolerance of plus or minus 0. 005”. The angularity is maintained to the tolerance of ± ½ degree. In larger parts that are more than 24 inches, it is possible to find out the needed tolerance not in this standard, but in other standards or specifications. This ensures that even the large components have to be precise in terms of their dimensions and the angles they make. 

Custom CNC Milling and the Tolerances It Provides 

CNC milling is particularly useful in high accuracy with tolerances of +/- 0. 001″. It is particularly so for parts that must be accurately dimensioned and have specific tolerance requirements as to how they interconnect. It is defined by the drawing specifications and the usage of Geometric Dimensioning and Tolerancing (GD&T) symbols. This makes CNC milling suitable for the production of parts that need a lot of accuracy. 

Minimum Feature Size in Custom CNC Milling 

The accuracy of the CNC milling is typically to the extent of about 0. 020” (0.  50 mm). It may depend on the shape of the part and the material used to manufacture the particular part. However, the size of the intricate features and shapes that can be produced using CNC milling are small and hence it is ideal for detailed parts. 

CNC Milling of Special Threads and Tapped Holes 

CNC milling is also useful in the machining of threads; both the standard and the non-standard threads. In non-standard threads, there is always the need to refer back to the quote to ensure that all the requirements have been met. Whether it is according to the standard or the custom, the threading is precise and this makes the CNC milling suitable for the parts that require specific thread size or type. 

Surface finish in custom CNC milling 

Generally, the anodized CNC-milled parts are adopted as a standard surface finishing with an optimal roughness of 125 Ra or more. However, other additional finishing can be ordered at the time of quoting to fulfill some appearance or utility requirements. This makes it possible to be made to fit the requirements of the project as the project is being implemented. 

Edge Condition in Custom CNC Milling 

In CNC milling, the sharp edges are normally broken and deburred for safety and functionality purposes and this does not cost more. If a project requires the edges to be sharp then this must be stated on the design print. This makes it possible to meet all the design specifications and user requirements of the final part in cases where edge conditions are well communicated.

Related To: CNC Milling for Small Batch Production: Efficiency and Precision

Uses of Custom CNC Milling

The uses of custom milling are so widespread. Let’s discuss common uses of custom metal milling;

Custom Rapid Tooling 

CNC rapid tooling

CNC milling is ideal for rapid tooling because it can be used to produce the fixtures, molds, and other tools that are required in the manufacturing process. The versatility that is offered by CNC milling makes it possible to work with different materials hence making it suitable for developing tooling that fits a certain project. If you need special jigs or complex molds for your production line, then professional CNC milling services can offer the exact tools for your production line. 

Custom Rapid Prototyping 

Custom CNC milling is especially useful in rapid prototyping because the material used can be easily swapped and the parts can be produced in large quantities at a cheap and in the shortest time possible. Due to the accuracy that is associated with CNC milling, it is suitable for making prototypes that are very close to the final design before going for mass production. Custom CNC milling allows one to create prototypes that fit the project, and this leads to optimization of the design and development process and the time taken to complete the project. 

Custom End-Use Production 

CNC milling for end-use parts offers the highest quality, a broad range of materials, and high precision. This makes it suitable for use in manufacturing end products that require high accuracy and at the same time need to be strong. Whether it is low-volume or high-volume production, custom CNC milling can offer the parts that conform to the necessary standards of the application and offer the dependability needed in the finished product.

Custom CNC Milling Materials 

As much as custom CNC milling is concerned, the material to be used in the process defines the outcome of the project. CNC milling can be done on any material and every material has properties that make it suitable for use in a particular application. Here are some of the most frequently used materials in custom CNC milling and their properties and uses: 

Aluminum Alloys

Aluminum CNC milling

Aluminum is one of the most frequently used materials because of its ease of machine, high strength-to-weight ratio, and corrosion resistance. Commonly used used custom aluminum milling alloys include: 

• Aluminum 5052: This type of aluminum is not easily corroded has high fatigue limit and is mostly used in marine and aerospace industries. 
• Aluminum 6061-T6: A general-purpose alloy that has adequate strength co-efficient used on the structural members. 
• Aluminum 7075 & 7075-T6: It is strong and is usually used in the aerospace industry where the parts are likely to serve the user for many years. 
• Aluminum 2024-T3: This material is strong has very good fatigue characteristics and is applied to aircraft parts. 
• Aluminum MIC-6: A cast plate with a low coefficient of variation in dimensions and is used in tooling applications. 

Bronze/Brass

Brass CNC milled parts 

Bronze and brass are very hard and do not corrode, they also have a very appealing look that makes them suitable for use in practical and aesthetic parts in custom CNC milling. 

• Brass C360: This one is so famous for its great machinability that it is used in parts that require fine working. 
• C932 M07 Bearing Bronze: It is very appropriate for use in bearing applications because of its high wear resistance and load-carrying capacity. 

Copper

Copper is one of the most used materials in custom CNC milling for electronics and other uses because of its conductivity and heat transfer characteristics. 

• EPT Copper C110: Owing to its high electrical conductivity it is used in electrical applications. 
• Copper 101: It has high ductility and is used in applications where high accuracy is required. 

Plastics

Plastic CNC Milling

Possibly, it’s easier to mill several plastic materials that are lighter than metals relatively easily on the cutting tool and possess good chemical stability. 

• ABS: A general purpose heat resisting thermoplastic with moderate impact strength and low shrinkage for use in tooling and finished parts. 
• Acetal (Delrin): It has high strength low friction and good dimensional stability and is used for the production of precision parts. 
• Nylon 6/6: It has good mechanical strength and wear resistance and is used in automotive and industrial parts. 
• Polycarbonate: It is also very famous for its high impact strength and for its optical clarity; it is used in armors and sights. 
• PTFE (Teflon): It has very good resistance to chemicals and the fact that it has low friction it is used where there is a need to lubricate. 

Steel/Titanium/Zinc

For steel/Titanium/Zinc or the more demanding applications where strength and durability are critical, custom CNC milling can use many steel grades, titanium, and zinc alloys. 

• Alloy Steel 4130, 4140: They are tough steels they have good wear resistance and they are used in the aerospace and automobile industry. 
• Stainless Steel 303, 304, 316/316L: It has excellent corrosion resistance and is employed in uses such as in medical instruments, food processing equipment, and marine equipment. 
• Titanium Grade 2, Titanium 6Al-4V: Valued for their low density and high strength, and for their corrosion protection; used in aviation and medical industries. 
• Zinc Sheet Alloy 500: This type has good formability and is applied in automobiles and construction. 

Custom CNC Milling Applications

Many industries employ custom milling to create several custom cnc milling parts for various uses;

Housings and Enclosures 

Custom cnc milling fabricates precise housing and enclosures for the protection of parts in the electronics, automotive, and aerospace industries. 

Brackets 

There are standard brackets in the market but for structural needs and precision, brackets are cut to order to suit the needs of an industry or structure. 

Fixtures for Manufacturing 

CNC milling services can be employed in the creation of accurate manufacturing fixtures that tightly grip workpieces in a bid to enhance accuracy during delicate manufacturing processes. 

Gears and Bearings 

The gear and bearing manufacturing needs a close tooth profile and tolerance that can only be accomplished by custom CNC milling. 

Medical Instrumentation 

Custom CNC milling of medical instruments and implants results in medical instruments and implants that are accurate, biocompatible, and have the required tolerance for use in the medical field.

Custom CNC Milling Services with Prolean Tech 

Order your custom prototypes and precision parts from Prolean Tech, a cnc milling china company. Our 3 and 5-axis custom CNC milling machines create precision parts from plastics and metals with an accuracy of up to 0.005 mm. We offer affordable prices to suit your budget and short turnaround, as short as one day. For your free quote and manufacturability check, just upload your CAD file. Choose Prolean Tech for complete cnc milling service solutions, material certification, and various finishings, so that you can get parts that are precise as per your requirements.