CNC Precision Machining Best Practices

A man holding up a sticky note that says " best practice ".

A man holding up a yellow post-it with the word "best practice" on it.

When thinking about best practices for CNC precision machining, it’s not just the process at the machine on the production floor that you should scrutinize. Producing the most optimal part in the least amount of time, at the lowest cost, while maintaining the highest levels of quality, means you need to consider the entire organization.

Starting with a full team of experienced professionals, United Scientific has implemented best practices throughout our company in the Twin Cities. Our methodology includes:

  • Creating prototypes
  • Designing for Manufacturability (DFM)
  • Maintaining an ISO 9001 certification and 99+% accuracy factor,
  • Customized inventory management
  • Fulfillment solutions

United Scientific will apply our full range of best practices to your next project. Contact us today and let us put our experience and expertise to work on your next CNC precision machining project.


CNC machining best practices start before any material ever hits the production floor. DFM is the first step in the optimally produced piece part.

DFM for machined parts starts with standardization:

  • reviewing the design for any simplifications,
  • replacing with standard parts wherever possible, and
  • reducing the number of individual components.

Material selection is next, determining the most cost-efficient material that will:

  • meet strength requirements,
  • handle the environmental conditions of the final part, and
  • meet functional needs such as being weldable, corrosive resistant, or heat treatable.

Also, whenever possible, choose material blanks in standard sizes rounding to the nearest 1/8 inch as smaller tolerances on starting blanks may require unique mill runs.

You should also consider the final part tolerances. The tighter the tolerances, the more time consuming and costly the machining process. Therefore, reviewing tolerances to allow for the maximum amount of variability while still maintaining a final working design will ensure the best value in your project.

Shop Floor

Now that you have optimized your design, it’s time to move the best practices to the shop floor. The main goals here are to:

  • minimize WIP,
  • minimize the number of touches to optimize the processes, and
  • eliminate variation.

You can achieve these goals with Lean manufacturing processes and some Six Sigma techniques.

Lean manufacturing tools can range from something as high level as Hoshin Kanri, where you align company strategy to middle management tactics in the form of action taken on the floor. Or it can be as straightforward as incorporating 5S into the workstations:

  • Sort
  • Set in order
  • Shine
  • Standardize
  • Sustain

Lean manufacturing works well as a best practice on the production floor.

While Lean takes out the excess waste in a product or process, Six Sigma takes out the variation.

One Six Sigma tool is utilizing run charts to establish upper and lower control limits for a machining process. Using process maps to define the workflow steps is another Six Sigma effort.

The point of implementing any of these best practices is so the manufacturing process can repeat regardless of shift, operator, or machine.

Business man holding a computer tablet. Background is out of focus, 4-high warehouse racking.

Supply Chain

Lean and Six Sigma are best practices not confined only to the shop floor. You should implement these best practices along the entire supply chain.

Sourcing and Procurement

Using swim lane diagrams to make sure the communication between functions is the most efficient and accurate every production step. This diagram is one way to implement Lean at the start of the supply chain.

Warehouse and Fulfillment

A critical best practice to incorporating Lean in the warehouse is minimizing steps and touches. If the most commonly used materials are located at the back of the warehouse, or moving materials to the production floor requires touching four different screens in the ERP software first, those moves require an excessive amount of time and overhead.

Locating the most commonly pulled materials, the least amount of physical distance from the production floor eliminates wasted steps.

Better yet, implementing a Kanban system ensures that materials are always available. A Kanban system pulls a standard quantity of the most commonly used materials whenever that item hits the low stock level value. This way, there is no downtime waiting on material moves.

To eliminate touches in the issuing process, determine how frequently the rest of the organization needs real-time inventory data.

Once the urgency of the inventory transactions is determined, utilize the most straightforward steps within the software, and complete the steps promptly within the defined time-frame.

Now, you’re assured that the rest of the organization has the most up-to-date information. Current information eliminates wasted time tracking down exact inventory levels or recalculating demand multiple times due to misaligned data.

Distribution and Logistics

Implementing standardized work in the distribution and logistics portions of the organization are also best practices that can lead to repeatable, auditable results. At United Scientific we have incorporated this best practice, as evidenced by an Independent ISO 9001 Auditor stating that we have one of the best internal audit programs ever witnessed.

This best practice culminates in United Scientific’s continuing ISO 9001 Certified status.

Person holding a touch screen control panel programming a mechanical machining arm.


You might think that a technology best practice is ensuring you invest more money in the latest equipment and software upgrades. There is some truth to that; however, it is more important to upgrade your processes and people first.

Never throw a piece of software or equipment at a problem thinking that is the solution. Put the process steps in place first and then implement a software solution or new machine to speed those steps or increase capabilities.

As for technology and equipment, that brings us to our last CNC Precision Machining best practice area — Human Resources.

Older gentleman wearing a light blue shirt and safety glasses setting up a CNC machine using an electronic control panel.

Human Resources

One final CNC precision machining best practice is to ensure that you have the most experienced and trained staff available. Continue providing training for your team, in all areas of your organization. You’ll keep their techniques and skills at the top of the industry standards. Everyone can benefit from this best practice.

When you need the best people, as well as the best practices utilized on your next piece-part production job, contact United Scientific. You can benefit from over 70 years of experience producing superior quality components at the highest accuracy rates around. Let’s put practice into action and be the best together.

The Basics of Aluminum Machining

A man in glasses is using a machine

Man wearing safety glasses closely watching milling machine drilling into a block of metal

Whether you must complete a production run of components or need a few prototypes created for testing, aluminum machining is often the first process that comes to mind for metal componentry.

Weighing in at around 170 lbs/cu ft, aluminum, and its alloys, are much more lightweight than the 490 lb/cu ft density of the average steel. Aluminum is soft, non-magnetic, and ductile.

Due to this lower density and increased workability, aluminum is much easier to machine than steel. It can, therefore, decrease machine time, which means an increase in productivity, and generate an all-around more affordable component.

Whether you already know which aluminum alloy to use or could benefit from some expertise in choosing the optimal material for your project, turn to the experts at United Scientific for your precision machined parts in the Twin Cities and surrounding areas.

Keep reading for some more of the basics of aluminum machining.

Chosing your aluminum

How you ultimately end up using your metal component will determine which type of aluminum you select. Some end-use factors to consider include:

  • Does it need to be welded to other parts?
  • Does it need to be resistant to corrosion?
  • What kind of forces will the part need to withstand?
  • Will the material be able to produce the required tolerances for the final part?
  • How complicated is the design?
  • Is the material the best option for all necessary fabrication process steps?

For example, what if welding your component to others is required in its final assembly? Welding is not feasible for many of the strongest alloys. So, 2000 and 7000 series alloys are not an option for this project, as they are not weldable.

Because the 2000 and 7000 series alloys have such high strength and a desirable response to heat treatment, they do make excellent components for the aerospace industry.

Let’s look at another option — alloy 5052. It’s acceptable for welding and has better strength. What truly makes alloy 5052 stand out, though, is its exceptional corrosion resistance, making it an excellent choice for marine applications.

United Scientific works with a wide variety of aluminum alloys for applications across industries ranging from aerospace to recreational equipment. Their experts can help you navigate the matrix of material characteristics to determine the best alloy for your needs.

A dozen different milling tools displayed with cutting edges pointing up

Choosing your tooling

Flute count and helix angle are two fundamental considerations when choosing aluminum machining tooling.

Flute count

Typical end mills for aluminum machining are usually 2 or 3 flute shapes. Higher flute counts do not evacuate chips effectively at faster speeds. However, since you can run aluminum at higher speeds and the alloys usually yield larger chips, the 2 or 3 flute configurations are the optimal choice.

Helix angle

Helix angle is defined as “the constant angle between the tangent to a helix and a generator of the cylinder upon which the helix lies.†This angle ranges from 30 – 45 degrees.

Higher helix angles provide better surface finish and more effective chip evacuation. These properties make higher angles the preferred choice for aluminum finishing.

Resolving typical issues

Long chips, welded chips, and built-up edges are some typical problems associated with aluminum machining. They can be resolved with a few proactive steps.

Long chips

Long chips are problematic as they can get in the way and mar the surface of the finished part. They also pose a safety hazard to the machinist.

The simplest method of eliminating long chips is to change the speed and position of the cutting tools. An additional option can be to employ a chip breaker tool.

A 3-flute, chip breaker tool will leave a semi-finished surface but runs at increased speed and feed rates, allowing time for additional passes to achieve final tolerances.

Welded chips

Welded chips occur when aluminum chips produced during the machining process weld themselves to the flank of the cutting tool. These types of chips are very detrimental to the tooling itself, eventually causing breakage.

Controlling or changing the machining parameters, reducing the amount of heat generated during the fabrication, and making sure you are using the right materials for the process are all used to resolve this particular issue.

Built-up edge

Built-up edges are similar to welded chips, though in this case, the chip welds itself to the actual cutting surface of the tool. This build-up causes scratches to the machined part, an inferior surface finish, and can also ultimately end up breaking the tooling itself.

Similar to the solutions for welded chips, the proper use of coolant is one preventative step. The coolant prevents the materials from reaching a high enough temperature to weld together initially. Higher cutting speeds can be another solution.

Space shuttle still attached to boosters launched as viewed from above

Beyond aluminum

In addition to machining a wide range of aluminum, United Scientific is also proficient at fabricating parts using more exotic alloys such as Inconel and Hastelloy.

Inconel, although much harder to machine, retains its tensile strength up to 2,000°F and is corrosive resistant. These properties make it well suited for extreme applications such as securing the space shuttle’s solid rocket boosters to the launch platform. Inconel alloys are also replacing the steel in the main battery pack contactors at Tesla.

Hastelloy alloys are also highly corrosion resistant, yet still weldable. These alloys are resistant to many aggressive chemicals and acids and suitable for high-temperature and high-pressure wells.

These characteristics make Hastelloy alloys an ideal choice for the pharmaceutical and chemical processing industries and are being used in space shuttle engine components.

Choosing a CNC machining partner

Aluminum machining is a science, and here at United Scientific, we are “Scientific in Process, United in Purposeâ€. We have experts in design, prototyping, fabrication, and inventory management ready to help you and your business successfully fulfill its purpose.

Whether you already know what material to call out on your specifications or would like a second opinion in making sure you have created the optimal part in terms of cost and function, United Scientific will be your partner.

Contact us today to get started on your next fabrication order.

CNC Milling vs. Turning: What’s the Difference?

A man operating a machine in a factory.

Man standing in front CNC milling machine control panel adjusting dials

When you need an accurate, machined part for your project, factory, or product, you may not be concerned with which machines to use or how a CNC milling machine works. Your priority is obtaining the right part for your needs, in the quantity you need, the delivery date you desire, and with quality assurance on which you can count.

At United Scientific, we deliver on all of the above criteria with excellence. We also like to make sure that our customers are informed about all our fabrication methods so they can make an educated decision when choosing a manufacturing partner. Knowledge builds trust, and we strive to instill customer confidence through transparency in our operations.

Determining the right process for your part-making project results in the highest quality component at the lowest cost and on schedule. Today, we’ll look at an overview of the differences between CNC milling and turning — two divergent pathways to parts, but both with nuanced characteristics that make them the right choice for different applications.

We assist our customers with large and small-scale production projects and deliver your parts on time with 99+% accuracy. We serve a wide variety of sectors. Fill out our contact form today to get more information or request a quote from United Scientific for your next manufactured component purchase.

Analog to CNC

Part machining technology has come a long way in a few short decades. Before the advent of CNC applications, machining parts required a significant amount of manual control. A worker would steer a block of material around a fixed rotating or oscillating blade or would move the saw through the raw material on a fixed surface.

Though the principles of milling and turning haven’t changed much since the advent of the saw, milling machines have. CNC cutting technology relies on CAD programming in the design phase of your component.

The part designer then sets the cutting coordinates into G-Code that CNC machines can read and translate to blade, spindle, and bed movements in 3D space. A technician inputs the coordinates into the device and oversees the cutting process, checking for quality and accuracy along the way and in the end product.

This type of automation has revolutionized the accuracy and efficiency of tool cutting.

Read on for a more detailed look at two CNC (Computer Numerical Control) cutting processes, and which one is best for your project.

CNC mill cutting intricate angular pattern into a silver metal disk

CNC milling

Part-milling begins with a block of material, referred to as a blank, secured in place on a tool-bed. In CNC milling, the cutting or shaving blade attaches to a spindle. The spindle spins the tool rapidly and can travel in several axes, depending upon the machine capability.

To cut the part, the tool-bed moves the blank at different angles to the cutting blade to form the desired surfaces and shape the design. The spindle with the cutting tool can also shift to add further detailing capability.

A CNC machine technician enters coordinates into a computer controlling the bed position, and the bed moves in space to the same specifications with each part machined. The cutting blade could have a vertical or horizontal orientation, dependent on the part material and the forces involved in the cutting process for best efficiency and safety.

A CNC milling process works well for precision parts like enclosures, engine components, complex mechanisms, or other detailed cutting.

round metal chucks for lathe

CNC Turning

For parts that require fewer detailed cuts, CNC turning may provide superior and efficient cutting results.

A CNC lathe holds that block of material on a “chuck†and rotates, or “turns†it at high speed. In this application, the blank spins on an axis but remains stationary in space.

A computer-controlled blade contacts the spinning material and moves back and forth across the length of the raw material. The blade begins to carve the desired shape out of the block at specified intervals.

Before the advent of Computer Numerical Control, a worker turned the lathe and carefully shaved the cuts into the part with either a hand-held blade or a more massive cutting tool.

Today’s CNC turning machines can cut multiple parts on a variety of spindles. We can control rotation speeds with more accuracy for exceptional results. Different cutting tools and spindles can reside on the same machine, making the cutting process accurate, more time-efficient, and safer than ever before.

Fascinating fact: turning machines come in several different categories, depending upon the functions they perform and the type of parts best suited to the device. For example, Swiss-type turning machines turn and cut tiny parts for watches, medical equipment, and dental tools.

Further, some turning centers can turn up to four pieces on a standard lathe. Other lathes can machine two differing pieces simultaneously with specialized software.

Male worker leaning over CNC machine watching fabrication process

Which application is best for your project?

When deciding between CNC milling and turning to manufacture your parts, several factors can help you determine the best process:

  • Cost per part: When accuracy matters most, and your part requires many cuts to achieve a perfect fit, CNC milling may be the best option. Though the milling process may be more time-intensive, depending on the complexity of your part, it’s more cost-effective to get each piece correctly machined the first time.
  • Quantity: When you need larger volumes of parts that are a more straightforward design, CNC turning could be the more efficient option. You’ll benefit from controlled accuracy measures, so each piece conforms to the same precise specifications in the shortest time possible.
  • Multi-method part: If you require a highly complex designed piece, a blended application may be best, depending on the specifications for each part of the design.
  • Capacity: If you machine parts in-house in your manufacturing facility, you may need a separate machining partner for larger jobs or specialized parts. Choosing a protocol that allows you to scale up, down, or outsource your projects accordingly is paramount to successful results.

Choose an experienced, accurate CNC partner proficient in milling and turning

When the need to collaborate on your component manufacturing arises, choose a partner with comprehensive capabilities. At United Scientific, we support wide-ranging industries from aerospace to food processing and more.

Contact us today to customize your unique part-machining strategy. Our expert staff and industry expertise ensure cost-effective, accurate results with each client we serve.