What comes to mind when you think of precision machined parts? Maybe what comes to mind is something like a super fancy surgical instrument, components of a space antenna, or even a jet engine. Precision machining is what produces many of the parts that make the world go round.

Honeywell APU - a Fictiv success story for precision machined parts

This guide will explain the basics of precision part machining and detail cutting-edge technological advancements.

We’ll also address some common issues in precision machining:

  1. Quality issues are common with precision machining. This may mean difficulty getting timely design for manufacturability feedback on your designs or receiving inconsistent parts or other issues. 
  2. It’s time-consuming to source and approve new suppliers for precision machined part, which takes time away from product development. 
  3. Finding someone who can do high-precision machining with excellent quality at rapid speeds is difficult. And slow machining slows down new product development, which reduces the number of design cycles in your timeline.

Shameless Plug: If you are looking for a manufacturing partner who can handle your precision machining needs at rapid speeds (up to 40% faster lead times vs. industry average), look no further than Fictiv. Get a free instant quote today to see for yourself!

What is a Precision Machined Part?

“Precision machining” is a term many manufacturers throw around to entice potential buyers and elevate their perception of their capabilities. But to truly understand what a precision machined part is, we need to review the definitions of precision and accuracy, two terms often used interchangeably and incorrectly. Both are related to quality, but they are not the same thing.

precision machined parts accuracy diagram

What is Accuracy?

Accuracy means how close to the targeted values something is; for example, how close the measurement is to the dimension. High accuracy means a measured value doesn’t deviate much from the desired value.

What is Precision?

Precision is the ability to replicate consistent attributes across many produced units (for example, hitting the same dimension when machining 200 parts). Precision is repeatability.

Pro-Tip: To learn more about precision vs. accuracy and how to improve the precision of your parts, check out Precision CNC Machining: How Can You Make Your Parts More Precise?

Precision Machined Parts

A Fictiv high-precision CNC machined part

Therefore, precision machined parts have the same dimension across many machined components. When a machine shop says they can hit your precision requirements, they can hit your dimensional requirements across multiple parts of the same design. 

Now, the ability to do this also means that a shop is more likely to hit your design’s accuracy targets/tolerance requirements — but technically, a machine shop can be capable of high precision without ever meeting accuracy requirements. 

You ideally want a precision machined part supplier who can meet both accuracy and precision requirements so you can make sure your parts are consistent and meet your design intent.

Fictiv precision machined parts platform snapshot

With Fictiv’s intelligent online platform, you can ensure no design requirement is left behind. Our platform seamlessly captures every design requirement with high precision, ensuring our highly-vetted manufacturing partners know exactly how to make your parts to spec. We provide tolerances as low as 4 microns, with a high level of repeatability, so you get accuracy, precision, and world-class traceability. To see all of our tolerance capabilities, check out this guide.

How are Precision Machined Components Made

Now that we understand the definition of precision let’s dive into how precision machined components are made. For a supplier to be capable of producing precision components, they must have processes and equipment to facilitate precision machining. 

A precision machine shop invests heavily in its quality control and management systems (some refer to the quality management system as quality assurance). The only way to meet precision and accuracy requirements is to start with a strong quality foundation. 

I have worked as an engineer supporting quality and even as a quality manager for manufacturing facilities — both with and without strong quality control or management — which taught me the importance of a strong quality foundation. At the companies without that foundation, I was left scrambling to support failure analysis efforts and navigate production delays while meeting customer specifications. Failures tended to be less common and less severe at companies with strong quality foundations, and when they did happen, they were mitigated faster.

A Ficitv high-precision CNC-machined part

Here’s a list of elements for a strong quality control and management system at a precision machine shop:

  1. A savvy combination of training and procedures provides precision machinists with the necessary resources to ensure parts are made correctly each time.
  2. A quality management system that’s been audited and certified to a standard, like ISO 9001 or AS9100 — facilitates reviews of quality policies, objectives, improvement efforts, and planning at set intervals, with expert oversight. 
  3. An organizational ethos of continuous improvement where employees understand how their work contributes to the overall precision of the produced product and how their work impacts the safety and application of each part. 
  4. Management that values quality and operates accordingly — even when quality issues arise and require corrective actions that cost the machine shop money
  5. A good measurement system using tools or techniques to check for errors (such as Gage Repeatability and Reproducibility, GR&R) that are analyzed regularly using equipment that is properly maintained and calibrated — it doesn’t matter how precise or accurate a part is if the measurement system and equipment determining precision or accuracy is inaccurate or isn’t being used correctly.

You may have noticed that some of these bullet points are requirements for an AS9100-compliant quality management system, and I did that on purpose! Following a standard is an important and useful tool with proven success.

Our Top Tips for Improving Your Precision CNC Machining

Based on our experience, here are some of the key elements of high-quality, precision CNC machining:

  1. Sophisticated preventative maintenance to keep all equipment in good working order — including rigid and balanced tooling that is properly maintained or replaced when needed.
  2. Highly skilled machinists — a state-of-the-art CNC machine still needs a capable operator.
  3. A collaborative, cross-functional approach to machining and manufacturing generally allows for quick and effective problem-solving.
  4. High-quality CNC machining equipment (usually multi-axis) with the ability to achieve tight tolerances.

What Sets Precision CNC Machining Equipment Apart From Other Machining Equipment?

a high-precision CNC machine

A good way to think about precision CNC machining is if your supplier always meets your accuracy requirements, your parts will be precise enough for the application. So, if you always get highly accurate measurements for parts within the allowable tolerance range, you will inevitably achieve high precision. 

High-precision CNC machines are capable of position accuracy down to the millionth of an inch and repeatability down to the ten-thousandth of an inch because they:

  1. Are rigid enough during operation — from the work table to the fixturing and the tool head — to meet tight tolerances without problematic chatter or deflection. Read our article Tool Balancing: Our Top 5 Tips to learn more about the ramifications of a lack of balancing and rigidity in a CNC machining setup. 
  2. Use a linear measurement scale system with tight tolerances and can read small dimensions down to microns.
  3. Are capable of achieving high tool rotation speeds, up to a few ten thousand RPMs.
  4. Operate in multiple axes to reduce the need for re-fixturing, which can cause errors in positioning or machining.
  5. Have automatic tool changers, reducing the potential for human error in tool changing. 
  6. Use dampeners and other methods that reduce the adverse impacts of vibration on the precision of the finished parts.
  7. Have linear roller guides with zero clearance in all axes to enable higher accuracy.
  8. Use a system of sensors, feedback mechanisms, and intelligent programming to compensate for any raw material defects and ensure correct part positioning and accuracy of material removal.

Protip: A note about precision from one of my favorite textbooks (Shigley’s Mechanical Engineering Design): “Excessive precision on the part of the designer may seem like an easy way to achieve functionality, but it is a poor design choice in that it limits the manufacturing options and drives up the cost.” 

A good general rule is to simplify designs to save time and money!

Common Precision Machined Components

Precision machining is an optimal choice for many industries and applications — whenever your part plays an important functional role or is assembled with other components, precision CNC machining is the best choice for manufacturing.

Examples of precision-machined aerospace parts include:

  • Engine components
  • APU components
  • Thermal management system parts
  • Flight control equipment
  • Battery components
  • Lighting system parts
  • Valves and sensors
  • Electrical connectors and components

Examples of precision-machined transportation parts include:

  • Engine components
  • Transmission components
  • Radiators
  • Battery components
  • Lighting system parts
  • Valves and sensors
  • Electrical connectors and components

Examples of precision-machined medical industry parts include:

  • Surgical instruments and tools
  • Screws, plates, and other implantable hardware
  • Non-implantable hardware
  • Components for storage and transportation of tissues or cells

Precision CNC machining is also utilized to manufacture components for the following:

Best Materials for Precision CNC Machining

Copper precision CNC machined part

Precision machining can be carried out with metal and non-metal materials.

Pro-Tip: When sourcing materials, ensure you get materials per your required specifications and request a material certificate with your parts.

Some Popular Metallic Materials for Precision CNC Machining Include:

Some Popular Non-Metallic Materials for Precision CNC Machining Include:

Recent Advancements and the Future of Precision Machining

Advancements in Tooling for Precision CNC Machining

Advancements in tooling materials, coatings, and geometries expand the capabilities of precision machining and the durability of tooling, which reduces the potential for missing precision requirements like critical dimensions due to tool wear or failure.

CNC Tooling Coatings

Common coatings for CNC tooling include titanium and/or carbide, which increase wear resistance and hardness of the tool’s surface. Recent advancements include coatings with incorporated nanocomposites or nanolayers to improve tools’ wear resistance and coefficient of friction. These nanomaterial coatings also prevent crack propagation of the coating, which would otherwise compromise the base material of the tool. 

Coating technology has also improved to allow for thinner coatings with the same wear resistance/hardness properties — thicker coatings create more rounded tool edges, which reduces their cutting ability for materials like stainless steel and aluminum (although it may be fine for carbon steel and cast iron). 

New coating technologies like physical vapor deposition allow for a homogenous, thin coating with excellent mechanical properties. These methods can be performed using various coating materials, such as a titanium, nitrogen, and aluminum combination (TiAlN).

Robotics, Programming, and AI

AI, robotics, and simulation technologies are also being used in every industry, and  precision CNC machining is benefiting from these advancements, too:

  1. Sophisticated software can predict, optimize, and verify machining in real-time to reduce accuracy mistakes, handle raw material deviations, and provide in-process feedback for on-the-fly optimization of operations. Among the most prominent benefits are cutting tool feeds and speed optimization, reduction in step-by-step machine verification, seamless integration of CAD/CAM interfaces, and toolpath efficiency. 
  2. CNC machine tending with robotics increases efficiency and reduces workforce costs. It also allows technicians and engineers to focus on bigger issues or productivity gains projects. 
  3. IoT machine monitoring and connectivity collect and feed extensive data to machine learning algorithms that analyze operations to make them more efficient and ensure machines are functioning optimally.
  4. Dynamic monitoring and feedback loops allow for real-time adjustments to compensate for vibration, thermal deformation, and accuracy changes, enabling precision without rework.

Fictiv is your operating system for custom manufacturing and your ultimate precision CNC machining service. 

The accessibility, convenience, and enhanced communication of our platform, combined with fast turnaround times, customization, and material options, make us the right choice for precision CNC machining services. Add in the skill and knowledge to help you scale from prototypes to production seamlessly, and you won’t find a better production partner than Fictiv!

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Choose Fictiv for all your precision CNC part manufacturing needs. Sign up for a free account and see how beneficial our CNC machining services can be for you!