CNC Machining

CNC Machining (or Computer Numeric Control Machining) is a manufacturing process which uses a computer to automatically perform a set series of machining actions. CNC machining is widely used because of its ability for increased productivity and flexibility. CNC Machining is used by numerous companies in many industries for machining steel, aluminum and plastics.

Related to CNC machining is precision CNC machining, which refers to using CNC machining technology for very precise specifications that must be exact from part to part, and micromachining, which refers to CNC machining very small parts, often for the medical and dental industries.

CNC Machining Companies

  • 3D CNC, Inc. is a precision technology manufacturer specializing in precision tooling, wire EDM services, close tolerance component parts, automated manufacturing equipment, and prototypes.
  • Aaero Swiss, Inc. are experts in Swiss screw machining and precision CNC machining. They provide CNC milling, CNC turning, medical machining, micromachining and more. Aaero Swiss is located in Orange County, California.
  • Alpha Omega Swiss are innovators and industry leaders in CNC machining in Southern California. AOS is a full-service jobshop with the capabilities to perform all CNC machining projects. They specialize in machining a wide variety of materials.
  • Delmar Company is an expert in high precision  CNC machining of plastics including milling, routing and turning. They use state-of-the-art equipment to provide part, products and components of all types. Their CAD/CAM compatibility ensures that your designs are matched exactly.
  • Innovative Metal Designs (IMD Fabrication) specializes in CNC milling, turning, and machining, as well as a number of other services. IMD offers their custom stainless steel and aluminum machining services for all industries in Southern California.
  • JACO Machine Works has over 40 years of experience in CNC machining parts and assemblies for aerospace, high technology, and medical applications. They work with a range of materials including plastic and standard and exotic metals. They are NADCAP Certified and ITAR Registered.
  • Kurt Manufacturing is a national leader in CNC machining for close-tolerance parts and assemblies. They provide CNC machining services for the automotive, semiconductor, oil, aerospace, and defense industries. Kurt also provides a full range of industrial manufacturing solutions, including gear solutions, die casting, assembly, and more. Kurt Manufacturing is based in Minneapolis, MN.
  • Pendarvis Manufacturing is a metal fabrication company that provides precision CNC machining in California and metal fabrication services, from prototype short run machining to high volume machining and fabrication. Pendarvis’ staff includes certified welders offering MIG and TIG welding in addition to their machining services. Pendarvis works with nearly every kind of metal, including aluminum, stainless steel, and structural steel as well as a range of plastics.
  • Petersen Precision manufactures metal parts and provides tight tolerance CNC machining for complex, three-dimensional parts and components. They have over 35 CNC machining centers with high-speed spindle capabilities up to 30,000 RPM to accommodate intricate parts and tight profile tolerances.
  • Production Robotics has decades of CNC machining experience and specialized in complex precision parts, exotic materials, and volume production parts. Their machine shop uses sophisticated software, along with vertical machining centers, horizontal, lathes, and all the necessary support equipment to complete your most intricate projects. 
  • P&J Machining, Inc. offers precision machining services to produce a wide range of high quality components and assemblies for the aerospace machining industry. With over 40 years of experience in CNC machining, P&J was the first company outside of Boeing to make a Catia V5 part from only the model. They are based in Puyallup, WA.
  • SR Machining provides CNC milling, turning, and machining services to manufacture components for a wide variety of industries.

CNC Machine Manufacturers

  • Asset Liquidity International, Inc. sells end of lease and repossessed capital equipment and assists users in selling and marketing CNC machines and other equipment.
  • CMS North America is an industry leader in the manufacture and sale of CNC machining centers. They build and sell CNC equipment for a number of applications. CMSNA’s CNC machines include CNC mills, CNC routers, 5-axis CNC machining centers, and custom CNC machines.
  • CNC Masters provides high-quality, user-friendly CNC mills, vertical milling machines, lathes machines and milling machines at competitive prices. The company also offers prototyping designs for wood and metal milling and machining.

CNC Machining Video

This video demonstrates the CNC machining process in action. You can see a metal part being very precisely and progressively machined making use of high-speed CNC machines that can accomplish the kind of precision that humans could not and do it at speeds that no human is capable of.

CNC Machining History

Standard CNC machining occurs on 3 axes: a table that moves the part(s) being machined on the X and Y axes, and a tooling spindle that moves on the Z axis. Tool positioning is driven by motors through a series of step-down gears or, on newer machines, direct-drive stepper motors. Many modern CNC machines can operate 5- or even 6-axis machining programs, to ensure supreme precision and quality of the machined part(s).

Originally, machining equipment was operated by the use of handcranks and levers. In the 1940s and ‘50s, the first NC (numerically controlled) machining equipment was created. These early NC machines were based on existing tools, and automated their machining with motors whose movements were based on points fed into the system on punched tape.

Prior to NC systems, automated machining was possible with the use of cams, tracer controls, servos, and the like. However, these systems lacked the precision of NC machining. All were programmable to a degree, but this programming was primarily done manually, and couldn’t match the close tolerances needed for precise, repeated machining.

John T. Parsons is generally considered the creator of NC machining. In the 1940s, while working on helicopter part designs for Sikorsky Aircraft, he used increasingly complex point data sets to machine the parts. After a series of improvements to existing, manually-operated machining equipment, he devised a fully-automated machine that would eliminate the possibility of human error and boost production speeds. In 1949, Parsons received funding from the US Air Force to create his automated NC machining equipment. Despite numerous revisions, Parsons’ design still produced parts that needed additional manual working.

Parsons and the USAF then teamed with the Servomechanisms Laboratory at MIT to further refine the original design. Whereas Parsons’ design simply made a large number of drill points to create the desired part, the MIT team adjusted the system to make cuts between the points, resulting in much smoother lines which required little to no additional working. MIT and the Air Force then formed a joint venture, leaving Parsons out of the remaining development processes. However, Parsons was able to secure a US patent for his designs in 1958.

MIT spent several years improving the NC machine’s design, and in September 1952 gave its first public demonstration. The completed machine could achieve tolerances within 0.0005 inches. It was an incredibly complex system, however, requiring five refrigerator-sized cabinets to house the motors and digital reading components. The total cost was $360,000 (just under $3 million in 2011 dollars). The machine was ultimately ill-suited for production, but was used to create a number of prototype parts to demonstrate the potential of the technology involved.

Air Force funding for NC machine projects ran out in 1953. The Giddings & Lewis Tool Machine Company quickly took up funding for the burgeoning technology. In 1955, several departing members of the MIT team founded Concord Controls, a commercial NC company backed by Giddings & Lewis. After further development, Concord Controls created the Numericord NC controller. Instead of punch tape, the Numericord used magnetic tape to relay signals to the machine’s tooling mechanisms. The use of magnetic tape lead to greater versatility of the technology. Further developments lead to far less complex controllers. Concord Controls’ Numericord “NC5” machine went into operation at G&L’s factory in 1955, creating precision dies for aircraft skinning presses.

At the same time, competing companies were creating their own NC machines. Monarch Machine Tool developed an NC lathe, and Kearney & Trecker’s Milwaukee-Matic II was capable of changing its own cutting tools under numeric control. Both were shown at the 1955 Chicago Machine Tool Show. The performances of NC machines at this show were met with glowing reviews, and they clearly demonstrated the benefits of the technology: reduced costs, improved quality, faster production, and increased productivity. However, despite these advantages, NC technology was slow to catch on in manufacturing. Ultimately, the US Army built 120 NC machines and leased them to various manufacturers to help popularize the technology.

In the late ‘50s, NC machining became CNC machining with the introduction of coded computer programming language that, even in its early stages, was able to reduce the time required to produce the machining instructions and machine the part from eight hours to just 15 minutes. Multiple entities were creating different CNC programming languages during the same period, including MIT (part of the “Whirlwind” computer’s development), Ross and Pople (what later became APT), and Patrick Hanratty, working with GE and G&L (PRONTO for the Numericord system). By 1963, these programming languages had undergone multiple revisions and each had been accepted as the “standard” by various organizations. Total CNC machining language standardization was not completed until 1968, when APT became the internationally recognized standard under USASI X3.4.7. With continuing improvements in computer technology, APT programming accounted for one-third of all computer use at large aviation companies by the mid-1960s.

Over the course of the 1960s, the price of computer technology dropped significantly. In the 1970s, the microprocessor was introduced, further reducing the cost of CNC implementation and improving the performance of CNC machines. And, with the creation and development of CAD technology during the 1950s and ‘60s, CNC machining became widespread throughout the manufacturing industry. The increased automation made possible by CNC machining changed manufacturing dramatically. Considerable improvements in quality, consistency, flexibility, and productivity were achieved, with far less involvement by machine operators required.

While most CNC machining up to that point had been aimed at high-end markets, such as aerospace, the economic downturn of the early 1970s lead to an increased demand for lower-cost CNC machines for various industrial applications. German and Japanese firms quickly stepped up to this challenge, causing US-based CNC machine manufacturers to fall behind in sales.

These low-cost machines made CNC machining possible for a number or lower-profit industries, furthering the reach of the technology. Further derivations of CNC machine programming and equipment have, over time, made personal and DIY CNC machining possible. This, in turn, leads to hybridization of personal and industrial CNC technology, making it possible for those without professional CNC training to implement CNC machining in large-scale manufacturing and production.

Modern CNC machining utilizes ever-evolving technology. While much has stayed the same, and many CNC machines are not much different than MIT’s original 1952 prototype, there are constant improvements being made to every part of the CNC machining process. Most notably, CNC programming languages have strayed widely from the APT “standard,” with hundreds or even thousands of specialized and customized programming variations being used throughout the CNC machining field. The programming technology continues to progress, with new systems and plugins similar to smartphone apps being created on a regular basis.


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