What is a Tight Tolerance Machine Shop?

Every industry requires a different level of precision for the parts they use. Some industries like the medical, aerospace, and automotive, require highly precise parts. If the parts aren’t kept within the specified tolerances, they become unusable. Many parts need to be within fractions of a millimeter to function properly.

A tight tolerance for parts is usually plus or minus 0.001 inches. If the parts are too small, there will be excess movement within the system, and if they’re too big, moving components can stick or grind.

A tight tolerance machine shop is a manufacturing shop that has the equipment, systems, and process required to produce highly precise components. These shops have highly skilled machinists who know how to use the latest machining equipment, and quality assurance teams who check the parts at various points during the machining process. Even with the latest technology, the people running the machines and checking the parts need to have the knowledge to maintain high precision.

At Spex, we use precision machining processes to manufacture metal and plastic parts and components. Our CNC machines can cut and drill parts within a 0.0002in tolerance. This is ideal for industries that require tight tolerances.

Quality assurance maintains tight tolerances

Spex is an ISO 9001:2015 certified machine shop. This means that our teams are required to maintain quality standards and make investments for continuous improvements.

During the prototype and set up phases, every part that’s machines is measured based on the customer’s part blueprint. Our team communicates with the customer to ensure the part specifications can be met. After that, a percentage of the parts are measured to ensure they’re within the specified tolerances.

Throughout the machining process, the cutting tools need to be checked and routinely replaced. When harder metals like stainless steel and nickel alloys are being machined, the cutting tools usually wear out faster and need to be replaced more often. Knowledgable machinists and high quality CNC machines helps maintain the tightest tolerances possible.

Industries that use tight tolerance parts

The industries that require tight tolerances usually involve moving metal components. These parts need to be exact so the assembled parts fit together properly. Tight tolerances are also needed when the parts experience high speed, pressure, and temperatures.

Tight tolerance parts are most commonly used in these industries:

• Aerospace
• Automotive
• Gas and Oil

These industries require parts that can withstand pressure and have longevity while maintaining the right tolerances. If essential parts wear out too quickly or are the wrong size, it can cause big issues.

They’re also needed for the defense industry and in medical machines. These industries rely on precision machined parts that meet very specific measurements and can’t fail. When an airplane or helicopter is flying, or a semi truck is driving down the highway in traffic, part failure simply isn’t an option.

Many of the industries that use tight tolerance parts also need complex part designs. Parts that are too small result in extra movement or vibrations, and parts that are slightly too big cause friction. Tolerances as tight as 0.00005 inches are common. As the parts are being machined and before they’re shipped to customers, they go through rigorous quality inspections.

To manufacture parts requiring such high levels of precision and accuracy, CNC machining is often the best solution. CNC machines can produce thousands of identical parts within the specified tolerances.

Challenges of tight tolerance machining

Tight tolerance machining stands as a testament to the pinnacle of manufacturing precision. However, achieving and maintaining these exacting standards is not without its challenges. Let’s delve into some of the complexities and difficulties faced by machinists and manufacturers in this domain:

1. Temperature Fluctuations:
   • Metal expands and contracts with temperature changes. In a high-precision environment, even minute fluctuations in temperature can impact the dimensions of a machined part. This is especially significant when dealing with tolerances in the thousandths or even ten-thousandths of an inch. To counteract this, many high-precision machine shops have climate-controlled facilities to maintain a consistent temperature.
2. Wear and Tear on Machinery:
   • The precision of tight tolerance machining relies heavily on the equipment’s condition. Over time, even the most robust machines experience wear, which can alter their accuracy. Regular maintenance, calibration, and sometimes replacement of parts or entire machines are necessary to ensure that they can consistently produce parts within the required tolerances.
3. Material Specific Challenges:
   • Different materials come with their own set of challenges. For instance, hard metals might be more wear-resistant but can be tougher to machine with precision. On the other hand, softer metals might machine easily but are more prone to deformation, potentially affecting the final dimensions of the part.
4. Quality Control:
   • With such tight tolerances, quality control processes need to be exceptionally rigorous. The challenge lies in ensuring every single part meets the required standards without significantly slowing down production.
5. Human Error:
   • While machines do most of the heavy lifting in a modern machine shop, human oversight remains crucial. From programming the CNC machines to final quality checks, there’s always a margin for error. Continuous training and stringent quality control procedures are vital to mitigate this.
6. Complex Part Designs:
   • As industries evolve, the parts they require become more complex. Intricate designs with hard-to-reach geometries can pose challenges for maintaining tight tolerances, especially when these intricate areas are critical to the part’s function.

By understanding and addressing these challenges head-on, tight tolerance machine shops like Spex demonstrate a commitment to precision, ensuring the delivery of components that meet the most stringent of standards.

Our machining capabilities

Spex offers a great range of tight tolerance parts and diverse material and design abilities. We have worked with customers in a variety of industries and work with engineers and product designers to manufacture the exact parts they need.

Our machine shop and industry relationships allow us to produce virtually any part, and use any material. The CNC machines we use allow for 100% customization of production, rapid prototyping, and ultra-precise mass production. Whether you need 1,000 custom parts, or 1,000,000 our machine shop can help maintain the quality and help you avoid supply chain issues.

CNC machines also allow us to run jobs 24/7. Modern CNC machines require very little human intervention which results in customers getting large orders quickly and efficiently.