How to Select The Right Precision Machining Supplier

In recent years, some industries like the automotive are experiencing continuous growth and profits. Market demand for machined parts and precision machining parts is at an all-time high.

However, the difficulty is finding a shop that will actually deliver all that it promises in reality, and not just on paper.

In industries like aerospace, defense, and medical, finding a CNC parts manufacturer capable of delivering the necessary quality, fast and reliable delivery, and competitive price can seem an elusive combination.

however, as limited capacity among world-class precision machining suppliers, procurement professionals face major challenges to locate and source capable machining supply partners.

Procurement team often choose supply partners based on cost alone. But we would argue that capabilities, experience, and quality are as important as cost. These factors should be part of the decision criteria. So before moving forward with a CNC machining supplier, please ensure the following results meet company goals: capabilities, experience, quality, and costs.

Nowadays, some companies run large production with low cost, but some focus on lower volume with more options for customization.

Many modern CNC machining shops not only provide CNC machining service but also assembly, welding, plating, heat treating, painting. So procurement team should have a supply partner mentality, but not a supplier mindset when making a sourcing decision.

Questions to Ask When Selecting a Supplier

1. Capabilities

Procurement team should analyze every offering that a potential precision machining supply partner has the capacity to provide. One of consideration may be, “Does this offer provided meet all business needs and be without the risk of problems during production?” Following critical questions should be asked in a choosing CNC machined parts supply partner program.

What type of machining services can potential precision machining shop offer?

It is important for a procurement professional to understand the many types of machining processes that a potential supply partner can offer. It would help you know more about a machining partner and save production cost. When a certain design needs one type of machining, a supply partner can offer another cost-efficient type, it would help you be unique in your team. Some most common machining processes include: turning, drilling, milling, boring, broaching, grinding, planning, shaping, and sawing.

Do they work with your project’ s materials?

There are many different materials that can be machined, some supply partners specialize in different material types so it is important to know what they are good at. It is also important for the potential supply partner to understand all material variants and alternatives. Components are always designed in one region, sourced in another region. So it is also important to cooperate with a machining partner that understands material equivalents (EN, SAE, etc.).

What tolerances and precision can a CNC machining shop machine?

It is important to know the supply partner capability to machine to the tolerance you need. Not everyone can hit the precise tolerance that complicated components may require. So it is absolutely crucial to know exactly how tight the potential supply partner can go before being partners.

What machining services can be offered by potential precision machining partner?

Ask these referable important questions:

  • Can this machining partner provide finishing service for the machining part?
  • Can they assemble the parts required to a finished product?
  • Can they do positional tolerance inspection and other tolerance testing?

How do CNC machine shops ensure high tolerance work?

“Perfect” means machined parts will be within the tolerances specified which apply to straightness, hole size, outer diameter (OD), inner diameter (ID), and other shape specifications.

Because you can’t have one part compromising the quality of the assembled system in industries  such as medical, aerospace, or defense

A CNC machine shop should be a state-of-the-art facility with the latest equipment.

CNC machine shops should look for ways to continually improve and maintain tooling, check fixtures, upgrade to the latest, state-of-the-art equipment and acquire the highest quality materials.

Machined parts manufacturers should keep investing in automated inspection equipment, such as coordinate measuring machines (CMM) if they have enough capabilities.

Does machine shop have minimum part order?

Many machining production shops have large minimum part orders, which can be risky to procurement. Look for a service partner with small minimum part restrictions.

2. Quality

Ask potential supply partners about their knowledge about certification and industry regulations. If they have ISO/TS quality system certification. It is also important to ask potential partners how operations have continuously improved over the years to ensure it is more efficient and safe.


Experience matters much in automotive and medical industry. A procurement professional must ensure that the potential CNC machining supply partner has sufficient experience in order to avoid future costly mistakes.

4. Costs

Procurement team may always ask quotes from at least three qualified potential partners. But more factors should be considered.

Some companies might use higher quality material or more precise cutting tools, that is to say, fewer costly mistakes would occur in the future.

Some local machining shops offer higher prices because they offer more customized services or different machining processes.

While price is not as important as quality for industries such as aerospace, defense, and medical equipment manufacturing, if the choice is between parts manufacturers that on paper appear similar, it will become a determining factor when machined parts manufacturers offer similar on paper.


Procurement professionals should understand the full program costs but not just the short-term cost savings. Keeping above considerations in mind will help you choose the right CNC precision machining supply partner without mistakes.

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Get in touch with us

TopWio has factory equipped with CNC machining center, milling machines, turning machines, EDM machines, Grinding machines. We offer precision CNC machining service to worldwide customers in China. Whether it’s a big quantity order, or a 1 piece CNC Rapid Prototyping Project, we will treat it as our task strictly and deliver it as to your precise requirements, every time.

Send us your precision CNC parts/ turning parts machining needs today such as motor shaft parts as well as engine crankshaft accessories, please start reaping the benefits of cooperation! Get Quote!
Direct email: [email protected]

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