Custom CNC Machining Services: Machining, Turning, and Milling

CNC (computer numerical control) machining is an essential manufacturing process used to produce highly accurate custom parts from metals, plastics, and other materials. CNC machining services utilize multi-axis machines and advanced cutting tools to shape raw material blocks into finished components based on digital design files. The key services offered are milling, turning, and specialty machining operations. For businesses needing precision prototyping or production runs, partnering with an experienced CNC machine shop can provide access to a versatile, scalable solution for manufacturing complex parts.

CNC machining employs programmable machine tools like mills and lathes that are controlled by computers. The machines follow coded instructions that direct the movement of cutting tools and parts to shape the material precisely. Instead of manual operators, the process is automated for higher speed, reliability and accuracy. Common CNC machines include vertical mills, horizontal mills, and turning centers. Advanced 5-axis machines offer even greater flexibility to handle complex geometries. The programs controlling CNC equipment are generated from 3D CAD models using CAM software.

Compared to alternatives like 3D printing or injection molding, CNC machining provides:

- Higher accuracy and repeatability, typically within 0.005 inches

- Ability to produce stronger, more durable metal and plastic parts

- Parts with fine surface finishes and crisp details

- Capability to machine a wide range of materials like aluminum, steel, titanium, plastics, composites

- Scalability from a few prototypes up to high-volume production

- Cost efficiency for medium to high production runs

With turnaround times in days or weeks rather than months, CNC machining enables rapid manufacturing of custom parts.

Milling is a fundamental CNC machining process where rotating cutters remove material from a stationary workpiece. Flat, square, and irregular shapes can be produced using a variety of milling tools. Parts are secured to the machine's bed while the cutter is fed against the surfaces to be machined. Common types of milling include:

- Face milling - Cutting flat surfaces into the workpiece

- Peripheral milling - Cutting along an open edge to create slots, grooves, shoulders

- Pocket milling - Cutting enclosed cavities into flat surfaces  

- Form milling - Shaping complex 3D contours 

CNC mills provide excellent control over depth of cut, feed rate, and speed for optimizing toolpaths. Multi-axis machines allow angular and curvilinear features to be machined in a single setup. Milling produces highly precise parts for industries like aerospace, medical, mold-making, and more.

Turning is a machining process in which cylindrical parts are rotated against a cutting tool to produce Precision turned parts including shafts, pins, bolts, and disks. On a lathe, the workpiece spins at high speeds while the cutter feeds against it to cut away excess material. Common turning operations include:

- Facing - Smoothing ends of a cylinder 

- Turning - Reducing diameter as cutter moves along axis

- Boring - Enlarging internal diameters

- Grooving - Cutting grooves into and around circumference

CNC lathes offer automated, high-volume production. Bar feeders can continually supply fresh material. Live tooling allows milling operations during turning for complex parts. Precision turning is ideal for automotive, aerospace, medical, and electronics applications.

Specialty CNC Machining Services

In addition to basic milling and turning, CNC shops can provide other value-added services:

- 5-axis Machining - Simultaneous multi-axis cutting for complex parts

- EDM (Electrical Discharge Machining) - Removing metal via electrical sparks  

- Laser Cutting - Precision cutting sheet material with a laser beam

- Waterjet Cutting - High pressure waterjet cutting through various materials

- CNC Grinding - Fine abrasive grinding for smooth finishes

- Heat Treating - Altering material properties like hardness via controlled heating

- Anodizing - Electrochemical surface finishing for corrosion and wear resistance

- Welding - Joining plastic or metal components together

- Assembly - Putting together machined components into final products

Partnering with a full-service CNC machine shop allows access to a diverse range of secondary operations for a complete manufacturing solution.

Key Factors in CNC Machining

To produce quality machined parts efficiently, there are several key factors to consider:

Raw Material Selection

The starting material's composition and properties like hardness significantly impact the machining process and parameters. Aircraft grade aluminum alloys, for example, require much more careful handling than steel.

Tolerancing 

Design drawings must specify required dimensional tolerances based on the application. More stringent tolerances (+/- 0.001 in) require slower speeds and fine-tuned setups. 

Surface Finish

The desired surface smoothness is specified by maximum Ra or RMS roughness values. Finer finishes require polished cutting tools and proper speeds and feeds.

Complexity

Highly complex geometries with thin walls or delicate features need careful programming and toolpath generation. Multi-axis machines and skilled operators are a must.

Quality Control

CMM inspection, testing prototypes, material certs, environmental controls and other checks ensure CNC parts meet specifications consistently.

Leveraging experience and technology, the best CNC machining services optimize every project for quality, efficiency and reliability.

Benefits of Outsourcing CNC Machining

For companies without in-house machining capabilities, outsourcing CNC services offers many advantages:

- Access to advanced equipment like 5-axis mills without capital investment

- Skilled machinists and programmers to run complex parts correctly

- Flexibility to have short prototype runs or scale to larger production

- Focus internal resources on core competencies rather than manufacturing 

- Confidence in on-time delivery of quality parts that are ISO compliant

- Cost efficiency from a provider's economies of scale

The right CNC machine shop becomes an extension of the client's team, providing expertise and capacity to manufacture precision components.

CNC machining services enable businesses to produce highly accurate custom parts from metals, plastics and other materials. Milling and turning form the core capabilities for shaping parts to specifications. By leveraging multi-axis CNC machines, skilled technicians, quality systems and secondary processes, machining services provide a fast, flexible solution for prototyping and production needs. Partnering with an experienced machine shop gives access to world-class manufacturing capabilities.