Custom CNC Machining Parts: Everything you need to know
- Gavin Leo
CNC machines are very complex, and their uses can vary greatly depending on their application. CNC machines have been integral to the design of many modern manufactured goods, and there are many ways they can be applied to almost any project.
What is CNC Machining?
CNC machining is a process used to create high-precision parts. This process typically involves the use of computer-controlled tools, such as lathes and mills, to precisely cut, shape, and drill the material into the desired shape.
What Is a CNC Machine?
Let’s keep it simple. A CNC machine is basically a computer-controlled tool that cuts, shapes, drills, or mills materials like metal, plastic, or even wood. The full name—Computer Numerical Control—just means a computer is in charge of telling the machine exactly what to do. And it’s not just pressing a button. Every move, every cut, every angle is mapped out ahead of time using a programming language called G-code.
If you’ve ever used a power drill or a saw, imagine something like that, but way more precise. You can get tolerances so tight that the difference between parts is measured in thousandths of an inch. That’s part of why CNC machining has become such a go-to for prototyping—you can go from idea to physical part in days, sometimes hours.
Most shops today don’t just rely on one kind of machine, either. They’ve got full CNC milling setups, routers, lathes—you name it. And they’re all used depending on the shape, material, and level of detail needed. Say you’re cutting stainless steel for a custom bracket. You’re not doing that by hand. CNC does it cleaner, faster, and with fewer mistakes.
This whole process—what you might just call the manufacturing process—has come a long way. You can upload a design file, get an instant quote online, and have the finished part shipped out within a week. Some places even offer same-day options, depending on their lead times.
And this isn’t just for big industrial companies. Small businesses, individual engineers, even hobbyists are using CNC machines to build parts that feel like they came out of a high-end factory. The results speak for themselves: consistent, high-quality parts with repeatable accuracy.
Types of CNC Machining—What’s What and When It’s Used
Not all CNC machines work the same way. And depending on the function you need—cutting plastic parts, shaping titanium, or producing custom parts for an aerospace project—the setup can look pretty different. The tools may change, the direction of cutting may shift, and even the kind of material they handle can vary wildly.
If you’re new to CNC machining services, or just curious, here’s a quick breakdown of the most common types of machines in use today—and what they’re actually good for.
Vertical CNC Machines
These are kind of the workhorses of the industry. Most on-demand CNC machining services will have a few vertical machines in constant rotation. The tool approaches the material from above—great for working on flat surfaces or making detailed cuts in metals like aluminum or stainless.
You’ll see vertical setups used everywhere, from automotive parts production to general-purpose milling. They’re ideal for custom parts with a straightforward shape and good machinability. Whether you’re milling polyethylene or prototyping peek components, vertical machines usually get the job done.
One thing worth noting: Vertical machines are often easier to set up and a little more affordable than their horizontal counterparts. That makes them popular with shops that handle a mix of small-run jobs or prototypes that don’t require complex orientations.
Horizontal CNC Machines
This type of machine is built for power, speed, and precision—especially when working with tough materials or larger production volumes. The cutting tool attacks from the side rather than above, which makes chip removal more efficient and often improves surface finish.
Horizontal machines are a favorite in industries where efficiency matters, like aerospace and automotive. If you’re cutting titanium or processing a batch of high-precision cnc machined parts with tight tolerances, this is often the better choice. These machines can handle multi-face machining in fewer setups, reducing lead time and boosting consistency.
They also shine when dealing with sheet metal components that need high-speed, repeatable passes without sacrificing quality.
5-Axis and 3+2 Machining
When the part gets tricky—think complex curves, undercuts, or anything that needs access from multiple angles—you move into 5-axis machining. This isn’t just a machine with more bells and whistles; it’s a totally different level of capability.
These machines rotate on multiple axes, allowing the tool and part to shift dynamically. They’re essential for high-performance applications like turbine blades or orthopedic implants, where dimensional accuracy isn’t optional.
Because of that flexibility, shops can create more advanced custom parts without switching between fixtures or making manual adjustments. Yes, they’re more expensive, but the trade-off in quality and time saved often makes up for it.
If you’re working with tricky materials like peek, acrylic, or even dense plastic parts, 5-axis setups help maintain clean edges and tight fits—especially when you’re dealing with tight tolerances and need that high-end finish, possibly followed by processes like anodizing.
Other CNC Machining Techniques
Not everything gets cut with a spinning tool. Some CNC machining services rely on electric discharge or thermal methods for more specialized work.
Wire EDM uses a charged wire to cut conductive materials like hardened steel or titanium. It’s slow, but incredibly precise—ideal for intricate molds or small-run tooling.
Laser machining offers clean, contactless cuts on thin materials. It’s often used for delicate sheet metal parts or decorative finishes.
Waterjet machines? Those are for when heat can’t enter the picture. If you’re cutting polyethylene, peek, or even stone, waterjets can slice through it all without affecting the material properties.
Each machine and method has a role to play depending on the job. You’re not using a lathe to mill a turbine blade, just like you’re not pulling out a 5-axis setup to drill basic mounting holes in an acrylic panel.
CNC machining isn’t just about cutting—it’s about understanding the right function, the right tool, and the right material for the outcome you want. That’s how you get parts that aren’t just built, but built to last.
Custom CNC Machining Services: A Closer Look at Material Options
When you’re getting custom CNC machining services, choosing the right material is half the battle.
It’s not just about what’s cheapest or easiest to cut—it’s about how the part’s going to function under real-world conditions. Will it hold up to abrasion? Does it need chemical resistance? What kind of finishing options are you planning? And, of course, how does that all affect CNC machining cost?
Let’s walk through some of the most common (and most useful) materials shops work with—and what you need to know before choosing one for your next production run or prototype.
Aluminum
Aluminum is one of those materials that just works. It’s light, easy to cut, and ideal for high-volume runs where speed and cost matter. It also takes well to anodizing, which can protect the surface and give it a clean, finished look.
Whether you’re producing enclosures for robotics, brackets for automotive assemblies, or one-off custom parts, aluminum is a safe bet. It’s also great for parts that don’t need ultra-high tensile strength but still need to look polished and perform reliably.
Brass
Brass doesn’t always get the spotlight, but it’s fantastic for parts that require both function and form. It has excellent machinability and finishes up with a natural shine that makes it popular for decorative or exposed components.
It’s often used in turned parts, valves, or inserts where precision matters. And unlike steel, it won’t spark—making it safer for certain shop environments.
Steel
If you need strength, steel is where you start. It’s tough, durable, and holds up under stress, making it a staple in automotive, industrial, and construction applications.
During the machining process, it’s a bit harder on tools and takes longer to cut, but you get parts that can stand up to wear and tear. Steel also offers solid repeatability, so if your CAD model needs to be run over and over, it’ll deliver consistent results.
Stainless Steel
When corrosion resistance is non-negotiable—say for high-performance parts in harsh environments—stainless steel is the go-to. It’s strong like regular steel, but resists rust and chemical damage. That’s why it shows up so often in aerospace, marine, and medical components.
Keep in mind, it’s more expensive and harder to machine, so your CNC machining cost might jump. But for parts that need to look good and last, it’s usually worth it.
Copper
Copper is soft and conductive, which makes it perfect for electrical parts or thermal components. It’s often used in wire EDM or laser CNC machines for clean, detailed cuts.
Because it’s so soft, it machines easily—but it can deform under pressure, so tolerances have to be managed carefully. Still, for connectors, terminals, and heat exchangers, copper is hard to beat.
Plastic
If you’re looking for affordability, flexibility, and speed, plastics are tough to top. Materials like Delrin, acetal, polycarbonate, and Teflon (PTFE) are common in product development and prototyping because they cut easily and hold tight tolerances.
Different plastics offer different perks. Teflon has outstanding chemical resistance, while polycarbonate handles impact well. Acetal is great for strength and stability, and Delrin shines when you need slick movement and low friction.
Plastics are also ideal when you need to avoid heat or electricity. You’ll see them in bushings, gears, brackets—really anywhere you don’t need metal.
Carbide
This one’s a bit niche. Carbide is insanely hard and incredibly abrasion-resistant. You won’t use it for every job, but when you’re making cutting tools, wear plates, or high-performance inserts, it’s the right material.
It’s not cheap. And machining it isn’t fast. But when nothing else holds up, carbide delivers.
In the end, your material choice comes down to what the part needs to do. Does it need to survive high heat? Handle impact? Stay dimensionally accurate after 1,000 uses? Or maybe you’re just testing a fit and want the cheapest plastic part possible, shipped in a few business days.
Whatever your priority—tight tolerances, surface finish, price, or speed—there’s a material (and machining method) that fits. And when in doubt? Talk to your shop. They’ve likely seen it all and can steer you toward the best balance of function and cost.
Custom CNC Machining Services: A Closer Look at Material Options
When you’re done machining a part—whether it was made on a milling machine, during CNC turning, or even cut with EDM—you’re not really done. Not if it needs to look sharp, resist wear, or survive a harsh environment. That’s where surface finishing comes in.
For a lot of production parts, the finish isn’t just about aesthetics. It can change everything from corrosion resistance to how well a part fits in assembly. Different surface finishes also interact differently depending on the range of materials you’re working with, so choosing the right one isn’t always straightforward.
Here’s a breakdown of the most common surface treatments we see in custom CNC machining services, and why you might use one over the other.
Anodizing
If you’re working with aluminum or titanium and want durability and color, anodizing is often the go-to. It’s an electrochemical process that adds a layer of oxide to the part—enhancing corrosion resistance and allowing you to add color without paint.
Different voltage levels, dye types, and application times affect both how deep the color goes and how thick the protective layer is. You’ll find anodized parts in everything from automotive components to consumer electronics. Bonus: It doesn’t just look good—it holds up in high-temperature environments too.
Painting
Sometimes you just need color, plain and simple. Unlike anodizing, painting adds a top layer rather than changing the metal itself. It’s versatile, works on most metal parts, and allows for more variety in finish and texture.
A typical workflow? Clean the part (usually with IPA or a degreaser), apply a primer, then follow up with your base coat and either a lacquer or clear coat. It’s simple but requires good prep and quality control to get a smooth, long-lasting finish.
Polishing
Polishing takes your part from rough-cut to mirror finish—or at least something close. It’s especially useful for parts that were rough milled or show tooling marks after machining.
Whether done by hand or machine, the idea is to reduce scratches, smooth out imperfections, and improve the overall surface finish. On small part sizes, it can be fast and effective. On larger production parts, it’s usually done mechanically to save time. Some shops even combine polishing with rapid prototyping for smoother prototypes that are closer to final product appearance.
Brushing
This one’s more utilitarian. Brushing doesn’t add color or a glossy finish, but it does clean up a part that’s been sitting in the shop covered in oil, dust, or debris. It’s often done by hand for simple geometries or with mechanical scrubbers for more complex shapes.
Think of brushing as prep work. It doesn’t stand alone as a finish for most high-end parts, but it’s useful if you’re doing further coating or assembly and need the surface clean and ready.
Electroplating
If you’re looking for added protection—and maybe a little more shine—electroplating adds a super-thin layer of metal (like copper or zinc) over your part. It’s not just decorative. It helps with wear, improves corrosion resistance, and boosts conductivity in some applications.
It’s often used on electrical housings, decorative trim, or parts where a little extra durability goes a long way. It works well on complex geometries too, which is helpful when your CAD file includes details you can’t reach with traditional coating tools.
Sandblasting
Sandblasting is basically power-washing your custom CNC machined parts with fine grit. It smooths out rough spots, removes burrs, and gives the surface a more uniform texture. It’s especially helpful if your part came off the machine with tiny nicks or unwanted tooling lines.
This method also preps metal for secondary coatings—like paint or plating—by giving them something to grip. And it’s fast. On larger parts or weird geometries, it’s often more efficient than hand polishing.
Why choose The CNC Machine Factory in China?
When you’re sourcing machines for volume production or upgrading your machine shop, reliability matters. The CNC Machine Factory in China has built a strong reputation for delivering high-quality equipment that simplifies the machining process—whether you’re working on a single workpiece or running non-stop batches.
Their tools are designed to handle demanding production needs while offering flexibility across different materials and finishing techniques, including powder coating. Every unit is manufactured under strict ISO 9001 standards, so you’re not just getting speed—you’re getting consistency and traceability.
They also understand time is money. That’s why they’re known for fast turnarounds, responsive support, and pricing that makes sense—especially if you’re scaling up. Whether you’re setting up a new facility or adding capacity to keep up with orders, their machines deliver where it counts: precision, durability, and dependable performance right out of the crate.
Frequently Asked Questions
Q: What’s the difference between CNC machining and injection molding?
Injection molding is best for high-volume production, especially when you need thousands of identical plastic parts made from materials like ABS or POM. It requires upfront tooling but delivers low per-part costs.
CNC machining, on the other hand, doesn’t require molds—making it a better choice for low- to mid-volume projects, tight deadlines, or parts that need high precision and strong material options like aluminum or PTFE.
Q: Is 3D printing a better option than CNC for prototyping?
3D printing is fast and affordable for early-stage concepts, especially when testing form or fit. But if you need prototypes that mimic real-world durability or require high strength, CNC machining gives you better results. It’s also more accurate when you’re preparing for full-scale production.
Q: What is DFM and why should I care?
DFM stands for Design for Manufacturability. It’s the process of tweaking your design so it’s easier—and cheaper—to produce. A part that looks perfect in CAD might be impossible or inefficient to machine. Good DFM improves manufacturability, reduces errors, and makes it easier to introduce automation into your process.
Q: Can CNC machining handle complex geometries?
Yes, CNC is excellent for complex parts with tight tolerances and smooth finishes. Whether you’re working with soft plastics like ABS or harder materials like PTFE, CNC machines can produce consistent, detailed results across small and large batches.