Stecker Machine Blog

6 Vital Questions for Finding a Great CNC Machining Partner

10/26/2023 | Scott Waak


You’re not asking for much. Reliable CNC machined parts and products that make customers happy. Simple, right?

What’s not so simple is finding the right CNC machining partner. One that understands your needs, has the right people and capabilities, goes the extra mile, and keeps its pencils sharp so the RFQ process results in accurate quotes.

Let’s see what an ideal CNC machine manufacturer looks (and acts) like. Here are the six most important questions you should ask when evaluating a potential CNC machining partner:

  1. “What are the CNC machine shop’s capabilities and size?”
  2. “What kind of customers and industries do you serve?”
  3. “What certifications have you achieved?”
  4. “Are you able to procure castings?”
  5. “Do you have an in-house engineering department?”
  6. “What sets you apart?”

1. “What are the CNC machine shop’s capabilities and size?”

Scrutinizing capabilities is an obvious first step. Can the CNC machine company deliver what you need today and in the future? High-end machining is only possible by using best-in-class CNC machining equipment: CNC machine cutting tools, CNC lathes, milling machines, robotics, AI CNC machining, and other equipment.

Find out what casting materials can be handled by this CNC machine shop. What types of iron (gray, ductile, austempered ductile)? Aluminum? Steel and/or stainless steel? Brass? Bronze? Are there reasons why the shop doesn’t handle certain materials?

As valuable as capabilities are, size does matter. You need to be sure your CNC machining partner has the capacity to handle your needs. Obviously, a company increasing its capabilities or expanding its facilities is a sign of growth and the ability to take on large projects to meet customer demand. Be upfront about what your needs are and challenge the shop.

2. “What kind of customers and industries do you serve?”

It’s a good sign when a shop has experience in various industries; it shows flexibility and a willingness to take on unfamiliar projects. Plus, it likely means that a CNC machine shop can run complex parts with long cycle times just as easily as it can run high-volume (and less complex) parts.

Ask about specifics and listen for industries that demand high-performance parts, such as agriculture, construction, military, industrial equipment, and automotive. If professionals in those industries have experienced success working with a CNC machine manufacturer, you probably will, too.

Lastly, inquire about that shop’s Tier 1 relationships. Nothing will give you more peace of mind than knowing this shop has extensive direct OEM/Tier 1 customer interactions.

3. “What certifications have you achieved?”

Capabilities? Check. Recent growth? Check. Various industries? Check. So far so good.

Another quality check that every worthy CNC machining partner handling should pass is having an ISO 9001-compliant quality management system (QMS).

Plus, the IATF 16949 standard — designed to be implemented as a supplement and in conjunction with ISO 9001:2015 — helps ensure that products consistently meet requirements and quality is routinely improved.

4. “Are you able to procure castings?”

High-end CNC machining shops value and respect the casting process. They know that, without casting, many intricate metal commercial and industrial products would be too complicated and too costly to produce.

Speaking of costly, did you know that design decisions can make up 70% of a product’s manufacturing costs? It’s vital that a part’s tooling and casting needs and costs are explored during the casting design stage. A strong partnership between the CNC machine shop, the customer, and the foundry offers cost-effective input on casting/machining designs.

A respected machining partner should help you compare both the advantages and disadvantages of different types of molding processes. Look for solid, long-term relationships with many quality foundries, meaning customers enjoy a reliable supply and the ability to hit deadlines.

Even better? Find a CNC machine manufacturer that owns the supply chain. If that shop takes responsibility for managing foundry relationships and reliably delivers completed machine parts, your life is much easier and worry-free.

5. “Do you have an in-house engineering department?”

A helpful engineering team – with numerous professionals of varied expertise – gets involved at a project’s early stages, helping develop the best possible part, efficiently and economically. The expertise these folks bring helps with design for manufacturability and creates a trusted partnership between the customer, the CNC machining contract manufacturer, and the foundry.

Quality in-house design teams provide designs/tooling quickly and cost-effectively, and can rapidly prototype a project for cast and machine tools. In addition, great in-house engineering departments have a continuous improvement team that stays on top of the latest technologies, identifying applications that could benefit customers.

6. “What sets you apart?”

This open-ended question may seem unlikely to separate one shop from another, but the answers you get should tell you something. Here’s what you want to hear:

“Tolerances.” Different materials and processes involve different standards. Your CNC machining partner should put a premium on how its precise processes meet tight tolerances to satisfy customers’ requirements and specs.

Knowing associations’ guiding standards is critical, too. For example, a CNC machine shop that works with aluminum die casting should know and follow Aluminum Association standards and the North American Die Casting Association (NADCA).

“Quality control.” While all reputable CNC machine shops check parts, some do more by combining their workforce expertise with automated audits to ensure consistency and accuracy. Some examples: CMM inspection, Millipore testing, Custom Gaging, High Accuracy Bore Gages, Hardness Testing, Surface Finish Testing, and Roundness Testing.

The best quality control is error prevention, so ask about poka yoking, which removes mistakes from the machining process and ensures a superior part. Plus, ask about the shop’s Manufacturing KPIs (Key Performance Indicators), which evaluate performance in order to make strategic adjustments.

“Our people.” OK, this may sound cliché, but take note of exactly why people are so valuable. When you hear phrases like “better communication,” “culture fit,” “good collaboration,” “schedules and deadlines,” and “customer feedback,” it lets you know that your goals become their goals. And, because they’re a valued partner, they’re more willing to work hard for you and give you extra attention.

Now, you have great questions to ask! Yet, if you’re unsure what’s next, read our guide: When Do You Know It’s Time to Work With a High-End CNC Machine Shop? which has insights for you when you may partner with a CNC machine shop. Click the link below for your copy.

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Scott Waak

About the Author

Scott pushes Stecker Machine forward. He brings a hands-on approach to a dual role of VP Procurement and Customer Relations . Scott has over 25 years of experience in the CNC machining industry, starting as a Machinist, and advancing to his current roles. He credits his success to hard work, dedication to manufacturing, and a drive for excellence.

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