Subtractive Manufacturing


Subtractive manufacturing can be performed manually by a machinist. More commonly it’s a highly complex process used by a CNC machine.

It is a decades-old practice with a demonstrated history of effectiveness in the prototyping process and manufacturing products. The goal for your project will determine if it is the correct process for your needs. 

 Subtractive manufacturing is like the process an artist uses to create a sculpture. The machinist or CNC programmer, like the artist, uses specialized tools to carve metal materials into the desired shape.   

The different techniques used by the craftsman or artist create the specific details requested by the client.

If you want to understand subtractive manufacturing further and whether it aligns with your needs, consider Glenn Metalcraft Inc. They are an industry leader with a customer service focus.

What is subtractive manufacturing?

CNC machine cutting example of subtractive manufacturing

Subtractive manufacturing is aptly named since it involves removing or subtracting materials to produce the end product. One method of implementing subtractive manufacturing utilizes a computer numerically controlled or CNC machine

The process begins with a rough slab or bar of material. Then, a machinist removes the excess until it reaches the final shape of the prototype or product being manufactured. You can imagine it like a sculpture. Your piece begins as a rough block but takes on a more complex shape through detailed carving. 

Subtractive manufacturing can be further broken down by the machines and manufacturing technologies used. 

Conventional machining uses three-axis cutting tools so that the block does not need to be manually flipped or turned. Conventional lathes, milling machines, and drill presses produce basic geometric designs.

Unconventional machining is ideal for working with brittle materials or producing more intricate and complex shapes. It uses a variety of processes to remove excess materials. This method can use a combination of mechanical, electric, thermal, or chemical methods to fashion the block into the desired shape.

What is the difference between additive and subtractive manufacturing?

CNC machine drilling example of subtractive manufacturing

The difference between additive and subtractive manufacturing is stated within their names. One method adds material; the other method subtracts material. 

Additive manufacturing involves adding material to create the desired part. Adding layers to the workpiece forms the designated object. 

Like a CNC machine, a 3D printer is programmed to create a 3d printed piece. The printer then builds up the shape from raw materials. Specific industries that utilize additive manufacturing include the medical and dental device industries. 

Subtractive manufacturing involves removing material from solid blocks to fashion the desired shape. Manufacturers can use it with many different metals, such as aluminum and brass. A machinist or CNC machine system will remove metal using drilling, milling, or turning. The process will clear away segment by segment until the result is your product or prototype. 

However, the two processes are not mutually exclusive. On the contrary, many manufacturers use both together to take advantage of each process’s unique advantages.

Advantages of subtractive manufacturing

CNC Machine Turning as an example of subtractive manufacturing

There are many advantages of subtractive manufacturing, so it has remained a popular production method after decades of use. 

Subtractive manufacturing usually results in much smoother surface finishes than the “stepped” surface, which results from using an additive manufacturing process. 

Why does the type of finish matter? If your product needs to slide, you will want the smooth finish that subtractive manufacturing provides. 

The texture matters if you use your prototype in your sales and marketing process. Your customers will be more likely to believe that your product is the right fit if it has the right feel. 

Computer numerically controlled systems are commonly utilized in the subtractive manufacturing process. First, the CNC software reads the design provided and instructs the CNC machine on creating the product. It then prescribes how to cut, drill, and channel your components. 

This level of automation means that larger-scale production can be handled with greater ease and less human involvement. 

The tools used in subtractive manufacturing are exact and can create intricate or tight geometric designs. These types of complex shapes may be otherwise difficult to mold or cast.

Subtractive manufacturing techniques

CNC Machine Abrading example of subtractive manufacturing

Many subtractive manufacturing techniques are used. However, the main approaches can be divided into three broad categories. Those are: 

  • Cutting, 
  • Machining, and
  • Abrading.

Cutting involves using saws, blades, or other such tools to remove excess material. 

Machining is when tools move around or across the raw material to shape it. CNC machining involves turning, milling, or drilling the item. 

Finally, abrading is when the raw material is sanded down or polished using an abrasive substance. 

The type of process used is dependent on the type of material used.  A manufacturer needs a deep knowledge of metals to apply those processes to create the right design effectively. 

Subtractive manufacturing examples

CNC machine being programmed by a manManufacturers can apply subtractive manufacturing in various industries, including medical, dental, automotive, aerospace, and agriculture.

From gears in an airplane engine to garden tools, subtractive manufacturing can produce many products. This manufacturing technique can even make jewelry! Glenn Metalcraft Inc. uses its decades of industry experience to create items that might otherwise seem impossible!

Subtractive manufacturing has earned its place as an effective fabrication process in most machine shops. Its long history has improved by adding automation and software to allow many additional applications. Moreover, its unique properties mean it can create tight geometric shapes with a smooth and polished finish. 

Hybrid Manufacturing, the Future of Subtractive Manufacturing

For a long time, subtractive manufacturing has been the go-to for detail and finish work because it’s simply the best method. But today, additive manufacturing gives us new shapes and structures possibilities.

The best of both worlds – additive and subtractive techniques combined on the same machine. This is what we call hybrid manufacturing. With this method, you can create a new part from scratch with 3D printing and then use CNC methods to finish it. 

With this technology, you can switch between methods as you please. For instance, start by 3D printing a layer of material, then use subtractive machining on it, and add another layer afterward. 

Why Glenn Metalcrafts Inc.?

Glenn Metalcrafts Inc. specializes in assisting the OEM industry in creating prototypes and manufacturing the products that build your success. Our company brings to the table decades of experience, advanced equipment, and the advice of metal industry experts. We manufacture products others would not even consider. 

Glenn Metalcrafts Inc. builds solid relationships and grows alongside its customers. It is selective in its clientele to achieve the right fit. Reach out today to find out how Glenn Metalcrafts Inc. can make your manufacturing idea a reality.


Subtractive Manufacturing

Subtractive Manufacturing : Answering Some FAQs

Simply put… Additive manufacturing adds material, and subtractive manufacturing takes it away. Both are used for prototyping and are practical for large-scale production. These processes have different fundamentals but are beneficial in conjunction with one another.

If you have questions about subtractive manufacturing options, consider Glenn Metalcraft Inc for guidance. We are experts in robotic welding, punching, automated machining, and waterjet cutting. Our engineers are available to support you through product manufacturing.

Today, we’re going to answer some FAQs about subtractive manufacturing.

What Is Subtractive Manufacturing?

A good analogy for subtractive manufacturing is a sculptor making a statue. Sculptors start with a big block of stone or wood and gradually chisel away at it. Eventually, they have a finished sculpture.


Subtractive manufacturing is an umbrella term for machining and material removal processes. The process starts with solid blocks, bars, rods of plastic, metal, or other materials.

The “subtraction” takes shape by removing material through cutting, boring, drilling, and grinding. It involves cutting, hollowing, or taking parts out of a block or sheet of a material, such as a metal.

Subtractive manufacturing is performed manually or by computer numerical control (CNC).

With CNC versions of subtractive manufacturing, a virtual model designed in CAD software serves as input for the tool. Software plans are combined with user input to generate paths to guide the cutting tool through the part geometry.

These plans tell the machine how to make necessary cuts, channels, holes, and any other features that require material removal. They take into account the speed of the cutting tool and the material’s feed rate. CNC manufacturing tools produce parts based on this computer-aided manufacturing (CAM) data, with little or no human assistance or interaction.

Subtractive manufacturing creates 3D objects by successively cutting small pieces of material away from a solid block of material.

Subtractive manufacturing helps create metal parts for prototyping, manufacturing tooling, and end-use parts. These processes are ideal for applications that require tight tolerances and geometries that are difficult to mold, cast or produce with traditional manufacturing methods.

Subtractive manufacturing offers a wide variety of material and processing methods. Softer materials are, of course, much easier to cut to their desired shape but will wear out more quickly.

What Are The “Pros” Of Subtractive Manufacturing?

CNC machining can produce more substantial parts with better tolerance and smoother finishes than additive manufacturing techniques. This is especially true of intricate features such as threaded holes. Additionally, extremely durable metal parts are produced using CNC machining.


What Are The “Cons” Of Subtractive Manufacturing?

CNC machining can require substantial set-up time. For this reason, subtractive manufacturing may be too expensive for anything but high quantities of parts.

What Is The Difference Between Additive & Subtractive Manufacturing?

Since we defined subtractive manufacturing above, let’s look quickly at additive manufacturing before comparing the two.

Additive manufacturing is synonymous with 3D printing or any process by which 3D objects; built by adding material, layer by layer. Modern 3D printing has always been beneficial for rapid prototype development, but it is starting to impact the manufacturing world.

So with additive manufacturing processes, adding material, layer by layer, and subtractive manufacturing conversely removes material to create parts. While these approaches are fundamentally different, subtractive and additive manufacturing processes are often used side-by-side due to their overlapping range of applications.

Is It Always A Choice – Subtractive vs. Additive Manufacturing?

While there are fundamental differences, subtractive and additive manufacturing are not mutually exclusive. The two are often used side-by-side or at different product development stages in manufacturing.

For example, the prototyping process often utilizes both additive and subtractive techniques.

Additive technologies are typically better suited for small pieces and highly intricate or complex designs.

In later stages of the development process, when larger batches are required, subtractive processes become more competitive.

Larger, less complicated manufacturing pieces lend themselves to subtractive manufacturing. Due to the myriad of choices in surface finishes and the speed of the process, subtractive manufacturing is often the choice for fabricating finished parts. As metal 3D printed components can be cost-prohibitive, subtractive processes are a better choice for metal parts for all but the most intricate creations.

In today’s manufacturing world, subtractive and additive processes often complement each other in tooling, jigs, fixtures, brackets, molds, and patterns. Manufacturers often opt for subtractive metal processes for higher volumes or pieces subject to more extreme mechanical strain and stress.

It is utilizing additive and subtractive manufacturing in tandem in a hybrid approach that is key. The process allows product designers and today’s manufacturers to combine the versatility and quick turnaround times of additive manufacturing with the strength of subtractively-produced parts.


What Are Some Subtractive Manufacturing Techniques?

  • CNC machining. This broad term refers to turning, drilling, boring, milling, reaming. It’s ideal for hard thermoplastics, thermoset plastics, soft metals, and hard metals (industrial machines).
  • Electrical discharge machining (EDM). This subtractive manufacturing process is ideal for hard metals.
  • Laser cutting. Laser cutting is ideal for thermoplastics, wood, acrylic, fabrics, and metal (like industrial machines).
  • Waterjet cutting. With or without abrasives, waterjets can cut almost any materials, including plastics, hard and soft metals, stone, glass, composites, and even food!

What Are Your Takeaways About Subtractive Manufacturing?

Here are the key points our FAQs went over. Subtractive manufacturing:

  • Removes materials from an object.
  • Can be done manually or by a CNC machine (computer numerical control).
  • Uses computers to aid machine processes, such as drilling or milling.
  • Is ideal for bigger parts and metal parts.
  • Can be a relatively fast set-up process.

GMI crafts the highest quality parts that others say are too complicated or too difficult. Our expert craftsmen and their equipment work within tight timelines and tolerances to meet customers’ specifications. We handle robotic welding, punching, automated machining, and waterjet cutting. Contact us for information about our subtractive manufacturing options.