Posts By: CNC Masters


Cut Your CNC Manufacturing Costs with These Tips

Milling Metal Thanks to their ability automate machining processes and make them highly repeatable, CNC mills have helped to significantly reduce manufacturing costs in a wide variety of industries. That said, there are additional steps machine shops can take to reduce their CNC machining costs even further.

Today we’ll consider a few tips to help companies cut their CNC manufacturing costs and increase their profit margins.

Stay Away From Sharp Edges

Because CNC end mills are cylindrical in shape, it can be difficult (and expensive) to create sharp edges and precise 90-degree corners. Instead, make the radius of each corner as wide as possible, since larger tools can remove material more efficiently. If you need sharp edges for your product’s design, include an undercut at each corner so it can be more easily accessed by the end mill.

Choose the Right Material

You might think that you should always use the hardest available materials, such as stainless steel, but think again. These materials are expensive to machine because they are more difficult to manipulate. Consider turning to other materials, such as aluminum, which is typically the least expensive metal to use in CNC manufacturing.

Avoid Thin Walls and Features

Thin walls and features are more prone to breakage, which will inevitably drive up manufacturing costs. If your product design allows it, keep walls and features at least 0.02 inches thick.

Break Your Design Into Parts

It can often be less expensive to manufacture several discrete parts that fit together rather than milling a product out of a single block of material.

At CNC Masters, we’re proud to offer high-quality CNC mills and turning centers at prices our customers can afford. To learn more, feel free to give us a call at (626) 962-9300 or contact us online today!


Achieve Tight Machining Tolerances With These Helpful Tips

CNC End MillSo, you’ve reviewed the drawing with the engineers and designers. You’ve verified the dimensions and double and triple-checked the features. You’ve asked the team if they have any flexibility. You’ve explored every option, but alas that +/-0.0005 tolerance (or tighter sometimes) is correct. Now, you have to make the part. Here are some tips for maintaining tight tolerances.

Calibration

Machine maintenance is critical for the best performance. While CNC mills are designed to have minimal deflection, things move over time. It is a good idea to contact the manufacturer to service and calibrate machines annually. They can use specialized tools like the interferometers and laser calibration systems to ensure machines are in tip-top shape.

Warm-Up

A warmup routine might be standard procedure for any milling operation, but these routines are mostly designed to ensure the lubrication and bearings are warmed up. A high-precision operation should include a more aggressive routine to warm up all the internals. This exercise will minimize any dimensional changes that occur as the machine reaches operating temperature.

Thermal Stabilization

Thermal stabilization is different than warm up. While getting to operating temperature is essential, it is also vital for the environmental temperature to be stable. Shop temperatures might fluctuate throughout the day, or a specific machine might be near a vent, window or sunny spot. All these things can cause the workpiece or the machine to change dimensionally. Don’t forget to stabilize the material’s temperature too. If it is stored outside or in a cold room, it should be allowed to stabilize to an ambient temperature near the machine before starting.

Tooling

The right tooling is a necessity for achieving tight tolerances. Consider using radiused tools for rough cutting to reduce tool wear and allow for faster machining. Then use a sharp, square end tool for finishing. The tool should have the maximum number of flutes allowable. For holes, a reamer has better precision than a bit and leaves a fine polished finish.

For more helpful CNC milling tips, stay tuned for the latest updates from our blog or give us a call today to speak with a representative!


A Brief Explanation of Electrical Discharge Machining

Wire EDMElectrical Discharge Machining is a high precision machining process that uses electricity to cut metals. In fact, the metal being cut is never touched by a tool at all. Instead, a high-frequency electrical discharge basically disintegrates the metal to make a cut.

EDM involves molecular process that can be difficult to envision, so to help you understand how it works, check out this video of a lightning bolt cleaving a tree in half.

While this is not exactly how EDM works, it gives you an idea of what is happening on a molecular level. In a nutshell, EDM uses a graphite or soft metal tool as an electrode. The electrode is moved very close – within a hair’s width – to the part being machined. The tip is then loaded with electricity until dielectric breakdown – a spark – occurs. The spark’s corona causes material to vaporize, leaving a tiny cut in the surface only a few molecules deep. The process is repeated at a rate of 100,000 sparks per second and the cumulative effect is a cut through the metal piece.

To prevent the spark from simply conducting between the electrode and the surface, both are submerged in a dielectric fluid. Dielectric fluids are insulators that can rapidly quench an electrical discharge. So, in this case, once the corona forms, it is immediately quenched, but there is enough energy in the spark to allow the metal to vaporize. Check out the ETMM website for a more thorough description of the process.

EDM machines come in three varieties – wire EDM, sinker EDM and hole drill EDM.

In a sinker EDM, the electrode is a die that is moved into the part as material is removed. Wire EDM uses a thin conductive wire as the electrode, and the entire wire is moved into the tool along the cut direction. As the name implies, hole drilling EDM plunges a tubular electrode into a part to make very small and very deep holes in a part. In this case, the dielectric is inside of the electrode.

EDM is excellent for very high-precision parts and parts that must fit together perfectly, with no gaps. It is also used to machine metals that are hard to machine with traditional methods such as tungsten carbide, high strength titanium and hardened steel. The metals must be conductive to be cut with EDM.

Despite its precision and accuracy, EDM machining is also slow and expensive. Although EDM is commonly used in the aerospace and automotive industries, it is often reserved for lower-volume production where high levels of precision are critical. For most applications, CNC milling with conventional cutting tools offers a more cost-effective machining solution.


How Has CNC Machining Changed the Manufacturing Industry?

Machine ShopComputer Numeric Control (CNC) machining has been around since the 1940s. These days, with the help of computer aid design (CAD), high-speed automation and advanced production capabilities, CNC machining is a fully-integrated manufacturing technology. Since its introduction nearly 80 years ago, CNC machining has become a critical part of technology development. Let’s look at the ways CNC machining has empowered the manufacturing industry since its inception.

Speed

Before the advent of CNC machining, mills, lathes, drills and routers were run by operators. They would read a drawing and determine the best way to create the necessary features on the parts. A complex part might need to be remounted and reoriented by hand, and engineers had to include orienting features to ensure these operations maintained critical dimensions. This could be time consuming for both design and manufacturing.

Now, 3D modeling CAD files are read directly by CNC machines and a computer can automatically plan machining operations. An engineering design can include dimensional dependencies to maintain critical dimensions. Furthermore, advanced automated CNCs have articulating tables and heads to reorient parts and tools without ever unmounting a part. Rather than manually controlling each step in the process, operators can simply program CNC machines to interpret CAD files.

As result of computer integration and automation, more complex components are made faster than ever.

Repeatability

In addition to making components faster, CNC machining has enabled greater precision and accuracy as well. Since parts are not remounted and operations are carried out by a high-precision machine, errors are less likely to occur. The accuracy of the first part is largely dependent on the accuracy of the CNC machine itself. The precision from part to part is largely dependent on how constantly each part is initially mounted in the machine.

Better accuracy and precision allow higher-quality components to be made with less waste.

Scalability

CNCs also have advantages for scalability over traditional machining. Some machines can complete more than one operation at a time. And, they can run almost continuously, 24 hours a day.

Faster, more repeatable continuous operations mean greater quantities of parts can be made in a shorter period of time.

Turning Ideas Into Products

Probably the greatest impact CNC machining has had on manufacturing is its ability to take and idea and turn it into a product quickly. This has made CNC machining ideal for prototyping and testing early in the design process. Engineers and designers can come up with a new product concept, mock it up in CAD and have machined prototypes within days. This makes it possible to modify concepts or try alternatives with little risk, allowing them to fine tune a design before releasing it for production.

More prototyping contributes to the production of robust, well-tested and innovative designs throughout the manufacturing industry.

Interested in learning more about how a CNC machine can benefit your unique operation? Give us a call or contact us online to speak with the team at CNC Masters today!


Notable Differences Between CNC Turning and CNC Milling

CNC MillMilling and turning are everyday operations in a machine shop. Both techniques use a cutting tool to remove material from a solid block to make 3D parts. Removing material is what classifies them as subtractive manufacturing processes, but there are key differences to these operations.

Turning is an operation for a lathe.

The name ‘turning’ refers to the workpiece because it rotates about a central axis. The cutting tool remains stationary and is moved in and out of the workpiece to make cuts. Turning is used to create cylindrical parts and derivatives of cylinders; think of parts shaped like baseball bats, shafts, balusters and columns, for example.

A chuck holds the workpiece centered on a rotating spindle. A base secures the cutting tool so it can move along the axis of the workpiece and in or out radially. Feeds and speeds come from the rate of rotation of the part, the radial depth of cut and the rate the tool moves along the axis of the piece.

Turning operations include OD and ID cutting and grooving, boring, treading and drilling. Since the cutting tool exerts a force on the workpiece perpendicular to its axis, it is crucial to support the piece to reduce deflection.

In milling operations, on the other hand, the cutting tool rotates while the workpiece is fastened securely to a worktable.

The cutting tool or the table can move orthogonally in the X, Y or Z direction for cutting. Milling can create more complex shapes than turning. It can even produce cylindrical shapes, but for cost effectiveness, those shapes are best left to a lathe.

In a CNC mill, a chuck holds the tool in a rotating spindle. The tool is moved relative to the workpiece to create patterns on the surface of the workpiece. Feeds and speeds are calculated based on the rate of rotation of the cutting tool, the cutting tool diameter and number of flutes, the depth of the cut and the rate the cutting tool moves across the part.

The limitation of milling pertains to whether or not a tool can access a cutting surface. Using longer and thinner tools can improve access, but these tools can deflect, causing poor machining tolerances, bad surface finishes and more wear and tear on the tool. Some advanced milling machines have articulating heads to allow for angular cuts and improved access.

Both turning and milling operations are useful for creating complex parts. The primary difference will be in the shape of the final part. For cylindrical parts, go with turning. For most other parts, milling works best.


Unique Advantages of Subtractive Manufacturing

Subtractive ManufacturingAdditive manufacturing, better known as 3D Printing, first started in the 1980s. Back then, it was a novelty concept reserved for advanced engineering research laboratories. In the 1990s, 3D printing made waves in the medical arena thanks to its ability to create custom medical devices. By the early 2000s, the open-source movement brought 3D printing into the homes of hobbyists and entrepreneurs During this time, people hailed it as the future of all manufacturing. It remains a promising technology, but subtractive manufacturing still offers many advantages over 3D printing.

Subtractive manufacturing techniques are those that remove material from a block to make a 3D part.

They are what we might call traditional manufacturing processes like milling, turning and even injection molding. Additive manufacturing processes, on the other hand, build up 3D parts by successively adding layers of material.

Although the cost for 3D printers continues to decrease, it’s still more expensive to 3D print many parts than it is to machine them. The printers themselves can be cost competitive, but the materials used in 3D printers are costly – especially if metals are involved.

Printing a part is a little bit like making pancakes – the first one usually gets tossed in the trash. This constitutes a waste of high-cost materials. Furthermore, 3D printers are more finicky and require frequent calibration and re-calibration when they’ve sat unused or when operators are swapping materials.

3D printed parts also require additional post-processing to achieve attractive surface finishes.

The additive component of the manufacturing process means pieces right out of a 3D printer have striations and stepped edges around radiuses. These surfaces require a subtractive manufacturing process to finish. Most subtractive manufacturing processes can produce finished surfaces.

Even if the striated surfaces of additive manufacturing is acceptable, 3D printer technology remains less reliable than subtractive manufacturing. High-reliability machines with good repeatability are expensive and require frequent maintenance while low-end devices typically cannot produce parts with consistent quality.

3D printing can be appealing for prototypes, but it is often limited to fit-and-feel prototypes. Because there are limited 3D printing materials available and the final mechanical properties are not always as good as those for machined parts, 3D-printed parts may not be robust or accurate enough for testing purposes. So, it sometimes makes sense to prototype with subtractive manufacturing processes and production materials instead.

Generally, subtractive manufacturing techniques are more familiar to designers.

Many designers even rely on certain functions that are common in CNC mills and lathes. For these folks, 3D printing can add cost for no discernible benefit. And with many machine shops capable of producing parts overnight using traditional techniques, the relative speed of 3D printing is rendered moot.

While additive manufacturing is attractive in some applications, good old milling, turning and molding are often better suited for the job at hand.


Essential Tips for Machining Aluminum Components

Machining AluminumCommon complaints among people new to machining Aluminum alloys include poor surface finish, gummy deposits on cut faces or tool edges, and a smeared appearance. All materials have different properties that require adjustments and care to achieve the optimal finishes.

Aluminum is a soft and ductile metal that has high thermal conductivity. The former means it cuts easily but creates long chips. The latter means it is susceptible to heat build-up. Following these tips when machining aluminum can help mitigate both these concerns.

Use the Right Cutting Tool

Although aluminum is soft and ductile, it requires a good cutting tool for best results. Don’t use high-speed steel or cobalt tools for this job; use carbide cutting tools instead. Also, it is sometimes better to use a tool with fewer flutes. Since Aluminum produces long chips, a tool with fewer flutes will allow chips to escape more easily. Using the right tool with the correct number of flutes will allow you to employ a broader range of spindle speeds.

Keep it Cool

As mentioned above, aluminum has a high thermal conductivity. It gets hot when cut, and that heat can build up fast. This, in turn, can result in a finish with a smeared appearance, workpiece warpage, and leading edge build up (that gummy problem). Proper coolant flow will move chips away from the cutting zone and keep the cutting surfaces properly lubricated.

Horsepower is Your Friend

While aluminum may be softer than other metals, it is still a metal and machining it requires a great deal of power. If your machine can’t keep up with the power requirements for a cut, it will result in chatter and deflection. It may be necessary to use horsepower “derating” in feed and speed calculations when using smaller, lightweight machines for aluminum milling.

A Note on Chip Management

Aluminum’s high ductility results in long unbroken chips that can quickly build up around a tool. This can cause tool breakage, leading edge buildup (more gummy problems) and heat buildup (that smeared finish). When cutting aluminum, be vigilant about cleaning chips. Whether it is with a fixed air blast system, high coolant flow rates or chip conveyors, chip removal should be integrated into your process.

Aluminum is ductile, lightweight, thermally, and electrically conductive with excellent strength characteristics. With a few adjustments to machining techniques, it can be a great material for many parts and projects.


Up in Flames: Fire Precautions for Milling Combustible Materials

CNC SparksFlint on steel coupled with some easily-combustible kindling makes for a cozy fire. That combination is just one of the tricks up a scout’s sleeve for survival. However, that same formula can spell trouble when milling woods, plywood, or even plastics. Fast-moving metal tools cutting against combustible materials can result in a not-so-cozy fire on a workpiece, in piles of cuttings and shavings, or in a dust collector.

CNC fires are not only costly, they are dangerous and potentially deadly. To mitigate the potential risks associated with machining combustible materials, here are four tips to help you prevent machining fires.

Know Combustible Materials

For a fire to start, there needs to be a spark and an oxygen source. For it to catch, it needs fuel. In the context of CNC machining, that fuel is a combustible or flammable material. Wood, plywood, and paper materials are common sources of fuel. Plastics are also excellent fuel sources – after all, they are made of petroleum. However, as outlined by OSHA, dust is also a common source of combustible fuel, including metal dust. With this in mind, it’s wise to adhere to fire prevention procedures no matter what material is being machined.

Check Feeds and Speeds

Maintaining proper feeds and speeds is important for addressing all sorts of machining concerns, from poor surface finishes to improper tool wear. So, it should be no surprise that using proper feeds and speeds is a beneficial for fire prevention as well. Incorrect feeds and speeds can increase friction, which in turn generates heat. With materials like wood, it’s also essential to adjust the cutting depth so you’re not cutting into the spillboard to prevent heat buildup.

Don’t Dwell

A spinning tool sitting and dwelling can generate a great deal of heat in a short amount of time. That heat buildup can quickly reach the point of combustion and spark a fire. In addition to potentially burning a workpiece, that hot spot can easily ignite chips or dust. Smoldering dust and chips can carry flames into collections systems, causing a fire to spread.

Have a Fire Safety Plan

Any shop’s safety plan should include fire response procedures. Fire extinguishers should be readily available, in an accessible location, and in proper working condition. Some operations, especially those handling a large number of flammables or generating a significant amount of dust, should consider a fire suppression system, facility alarms, automated emergency call systems, and evacuation procedures. Even for small or single-person facilities, a fire response plan is critical.

The good news is, machining combustible and flammable materials can be safe and easy as long as the risks are mitigated with proper precautions.


Benefits Of The CNC MAX Milling Machine

CNC MAXAt CNC Masters, we’re proud to produce some of the some of the best tabletop milling machines on the market. One of these tabletop machines, however, is a different breed from the rest.

The CNC MAX sets itself apart from the pack with its versatility and ease of operation.

The CNC MAX tabletop milling machine is the first mill of its kind to have true ball screw accuracy in not one or two, but all three axes. It is built durably and precisely, with a cast-iron body, sliding dovetail ways and tapered gibs on the square column. These features give the machine superior accuracy, repeatability and alignment.

One of the best attributes of the CNC MAX mill is that it offers the performance capabilities of larger CNC mills in a more compact package.  

Thanks to its flexibility and user-friendly design, this mill can be a great investment for manufacturing plants, machine shops, research institutions, high schools, universities and even small business owners who want to save money by machining their own components.

The CNC MAX mill is compatible with ordinary PCs running a Windows 8 or 10 64-bit operating system, and a convenient “teach mode” allows the machine to automatically write each line of a tool path as the operator manually jogs each axis with a mouse, keyboard or optional handheld keypad. As such, amateur machinists can easily mill simple parts on the CNC MAX without the need to learn specialized CAD programming languages.

More experienced operators, meanwhile, can enjoy many of the same features they’re accustomed to finding on larger, more expensive CNC mills.

The CNC MAX mill is proudly manufactured and assembled right here in America, combining both American-made and imported parts that allow us to offer competitive pricing while retaining a high degree of quality and durability. All of our milling machines come with a one-year hardware warranty against manufacturer defects, and they undergo a rigorous quality assurance and pre-shipping inspection upon purchase. Our USA-based customer support team is also available to answer any technical questions you might have about the CNC MAX mill for as long as you own the machine.

To learn more about the CNC MAX tabletop milling machine or any of the other products we offer at CNC Masters, feel free to give us a call or contact us online today!


Use a CNC Mill to Create Your Own Printed Circuit Boards

Printed Circuit BoardElectrical engineers and technicians often use breadboards for prototyping and testing circuit designs. Breadboards are typically plastic plates with grids of spring-loaded receiving holes for inserting wires and components. While breadboards are great for quickly mocking up circuit layouts, they have several drawbacks. They are large, so they easily don’t fit into mechanical housings. They can get cluttered, which makes it difficult to chase down defects on complex layouts. Since they are not soldered, they are also not very robust.

For these reasons, designers are often eager to have Printed Circuit Boards (PCBs) manufactured as early in the design process as possible. A PCB is a flat board with conductive lines called traces on its surface for electrically connecting electronic parts and components.

Unfortunately, between tooling costs, high prices for low quantities, slow turnaround times and limits in redesign flexibility, a small manufacturing run for a PCB can be prohibitive. As a result, some designers have turned to milling their own PCBs using in-house, engraving CNC machines.

In order to mill a PCB, a wiring diagram must first be translated into a CAD model.

Since CAD modeling is an important step in product design, creating models early is an excellent habit for product development. Next, these models need to be translated to the CNC programming language G-code with a CAD/CAM translation software. Once the G-code is generated, you are ready to mill a circuit board.

There are a few things to keep in mind when milling PCBs.

  1. Drill, Mill, Cut: There are three processes for creating a PCB. First vias (holes for components) are drilled. Second, the clearances for the traces are milled. Finally, the board is cut to shape.
  2. Tooling: Each process should use the appropriate tools. Drills for holes; endmills, either square or v-tipped, for trace clearances; and endmills for shaping.
  3. Machine Performance: There are a variety of small CNC machines on the market with significant differences in built quality. Some are preassembled, while others require assembly on-site. The stiffness and build quality of the machine will dictate how accurately and precisely it mills. A lower-quality machine does not necessarily mean it can’t be used for prototyping PCBs, it just means you may need to account for larger trace clearances, use deeper cuts or use larger tooling.
  4. PCB Materials: Circuit boards consist of a copper layer bonded to a composite substrate that is often made of a flame-retardant material. FR-4 is one of the most popular substrates in use today. It is a glass-filed, epoxy resin. That glass fill makes the material highly abrasive, which will result in fast tool wear. Precautions should also be taken to avoid inhaling FR-4 dust, which is hazardous to one’s health.
  5. Finishing: The copper layer is prone to oxidization, which can diminish its electrical performance. So, once your PCB is milled and the components are soldered in place, it is important to coat the copper. Luckily, a quick coat of nail polish can address this issue.

Interested in milling your own PCBs with a CNC machine? Give us a call or contact us online to find the machine that’s right for you today!