Engraving is an ancient manufacturing technique with rich historical significance in human history. It has undergone incredible developments throughout history and has diverse and versatile applications, especially in art. Today, these developments have led us to CNC engraving, a process of considerable importance.
This article provides a detailed discussion on CNC engraving machining, its workflow and types. In addition, we will also address its advantages, material properties and applications.
What is CNC engraving?
Etching involves gradually removing a small amount of material from a surface along a defined path. The process leaves a visible mark on the surface of the substrate (part). CNC engraving is the modern version of engraving where automatic CNC technology guides the engraving tool with high accuracy and precision control.
Engraving processing is used in many areas such as decoration and signage. Furthermore, it is compatible with a wide variety of materials and is an economical process.
How does CNC engraving work?
Let's delve a little deeper into the world of printmaking and see how it works in an industrial environment. The CNC engraving workflow is as follows:
cad : First, a designer creates a preview of the engraving pattern using CAD software. The machinist must have a good command of CAD to be able to create complex patterns quickly and accurately.
CAM : Computer Aided Manufacturing (CAM) software is special software used to create programs for CNC engraving machine according to CAD design. The CAD/CAM engineer uses this software to select tools relevant to the engraving process, set process parameters, and define tool paths. Finally, the CAM software generates a G-code file written in a syntax that the CNC machine understands.
Set Up : Before starting engraving processing, a machine operator sets up the workpiece on the machine. During this process, positioning and leveling the part are important to avoid manufacturing errors.
CNC engraving : The engraving process finally begins. CNC technology is automatic, so technicians do not need to intervene much after a few initial procedures. Once the process is complete, the part is disassembled and the machine is ready for the next project.
Types of CNC engraving
Now we can learn more about the different types of CNC engraving processes. Although they all produce roughly similar results, they differ in many ways.
CNC rotary engraving
Rotary engraving uses a rotating cutting tool to remove material from the substrate. The cutting tool is similar to a normal machining tool and has groove-shaped cutting edges. Imagine how a drill rotates and cuts material thanks to its sharp edges.
The shape and size of the cutters are important because they create grooves that exactly match your shape. Common shapes include V-shaped and ball-end (rounded) cutters.
The CNC engraver has a special spindle to hold and rotate these rotary engraving tools. In general, CNC engraving is a high-speed process, with speeds up to 20,000 rpm. Furthermore, the cutting depth is in the range of 0.5 to 3 mm, depending on material properties and design requirements.
These features make CNC rotary engraving very versatile. It's also inexpensive and works with most materials.
CNC laser engraving
CNC laser engraving is fundamentally different from rotary engraving. In this process, a high-intensity laser beam heats the surface of the substrate to a temperature at which sublimation occurs (direct transition from solid to gaseous phase). This creates a depression in the surface.
The CNC laser engraving machine has a laser head to generate the laser beam. The movement of this head is controlled by CNC, making this process extremely precise and fast. Furthermore, laser engraving is very reliable and durable.
Finally, we would like to take a small detour to clear up a common misunderstanding between laser engraving, laser marking and laser engraving. Laser marking is quite similar to laser engraving, but has a much smaller indentation depth. Hence the word “brand”. Laser engraving is a completely different process that uses a chemical reaction to remove material from the surface. Compared to laser engraving, it is a low energy consumption process.
Diamond Drag Engraving
The name “diamond drag engraving” is pretty self-explanatory. This process involves dragging a sharp diamond tip over a surface to carry out the engraving process. As diamond is the hardest material known, it is an efficient engraving tool. Additionally, no tools are rotated during diamond drag engraving. The main material removal process is therefore scratching.
CNC diamond drag engraving is extremely accurate and fast thanks to precise control of tool movements. Furthermore, diamond's superior hardness makes it suitable for even the hardest metals.
Common materials for engraving processing
Engraving processing is a diverse process in terms of material compatibility. Because the mechanics are not very extreme and rely on basic cutting/burning operations, a wide variety of materials can be CNC engraved.
In the following sections, we will discuss the main categories of materials that a CNC engraving machine can easily process.
metals
Metals are typically the most common materials found in CNC engraving shops. Metal engraving is like a less complicated version of CNC milling, using the same CNC router and cutting parameters. In fact, most CNC machines have served as engraving machines at some point.
The same applies to laser engraving, which is not primarily about cutting the metal, but rather about engraving its surface.
However, metals are not always easy to machine and may require special tools such as coated cutters. Additionally, metals are also more expensive than other engravable materials such as plastics.
A list of metals that can be CNC engraved:
- aluminum
- Steel and stainless steel
- gold
- Brass
- copper
- Silver
In addition to these common metals, harder metals such as titanium alloys can also be CNC engraved. In general, hardness is the most important property to pay attention to in CNC engraving because it defines how difficult it is to deform the surface. Therefore, for harder materials, experts recommend high-performance engraving cutters or spring-loaded diamond cutters.
Plastics
Plastics are another group of materials used in CNC engraving. The name “plastics” refers to a large group of polymers, most of which are compatible with CNC engraving. In general, thermoplastics are best suited for engraving due to their excellent thermal stability compared to other groups of plastics.
The plastics are compatible with CNC laser engraving and rotary engraving. However, for plastics, laser engraving is the most popular choice. It is fast, low maintenance and very accurate. However, in some cases there is an environmental risk, as some plastics burn and produce smoke, which requires adequate extraction from the system.
Plastic is also not completely unknown for rotary CNC engraving. Plastics are easy-to-cut materials that support very high cutting speeds and feeds. On the negative side, they sometimes form burrs and can soften during cutting, limiting productivity. Overcoming these disadvantages leads to excellent results.
Some common plastics for CNC engraving:
- Polyethylene
- Polystyrene
- polyamide
- Section
- nylon
- Polyurethane
Wood
Wood engraving can be used in various artistic areas, such as home decoration, gifts or luxury items. Wood is natural, soft, and generally the most affordable option among the materials we've discussed. Additionally, wood engraving is compatible with laser and rotary CNC engraving machines.
There are some tips you should keep in mind when engraving wood to avoid wasting time and money. Wood is an anisotropic material. This means that its properties are not the same in all directions. Instead, they vary slightly in grain orientation, nodes, and growth rings. So keep this in mind when choosing wood for engraving projects.
Additionally, moisture and oil content can negatively affect the effectiveness of a CNC laser engraver. Also, if you use a rotary engraving machine, be careful with wood dust.
Common types of engravable woods include:
- Softwood
- hard wood
- Ferry
- birch
- cork
Advantages of CNC engraving
The widespread use of CNC engraving is proof that it is a viable process with numerous benefits. In this section we highlight these benefits.
Precision and accuracy
High precision and dimensional accuracy are the defining characteristics of CNC technology. The same applies to a CNC engraving machine. Automatic CNC motion control allows for the creation of extremely precise engravings down to an impressive +/- 0.0025mm.
This level of accuracy is more than sufficient for most recording processing applications.
Time saving
In the past, when engraving was done manually, it would take artisans hours or even days to complete an engraving project. They used hand tools and relied on their human skills to engrave, which was understandably time-consuming.
The modern CNC engraving machine, on the other hand, is automatic and fast. Records with rapid advance and remarkable accuracy, producing results in minutes.
Adjustment
Using CAD/CAM software in CNC engraving allows for quick and easy customization of engraving designs. Users have the ability to make changes to their CAD designs and immediately implement them into the process.
This feature is extremely convenient for workshops specializing in rapid prototyping or multiple simultaneous projects. You can quickly fix errors or switch to a different design, increasing productivity.
CNC engraving applications
CNC engraving has countless applications across a wide variety of industries. Although we cannot cover them all, the most important ones are briefly explained below.
Sign Manufacturing : Traffic signs or advertisements are usually made by CNC engraving. They are durable and can withstand different weather conditions. Therefore, they are very suitable for this application.
Jewelry : Jewelers engrave items such as pendants and bracelets using CNC machines to create eye-catching designs or personalized text.
Industrial labeling : Almost all industries have markings for equipment, safety, instructions, etc. Engraving technology is a popular method for creating permanent, personalized industrial markings.
Awards and Trophies : Trophies are always good when your name is on them! Most likely this name was affixed thanks to a CNC engraving machine.
Concluding
CNC engraving is undoubtedly an important part of the modern manufacturing industry and offers a wide range of possibilities and applications. We can also appreciate the artistic patterns and useful signs/markings found throughout our surroundings. That's what print publishing brings to the world!
Common questions
What is the difference between engraving and etching?
Etching and etching involve the removal of material from the surface of the workpiece. However, both methods are based on different physical phenomena. Engraving is a mechanical process that removes material by cutting with a sharp tool. Etching is a chemical process in which material is burned onto the surface.
What software is used on a CNC engraving machine?
CNC engraving machines require CAD/CAM software to perform engraving tasks. The program allows the user to specify engraving geometry, select tool and cutting parameters, and tool path. Once completed, it generates commands that are passed to the machine controller.
What milling cutters or drills are needed for CNC engraving?
CNC engraving uses milling cutters or drills similar to those found on regular CNC machines. The most common type is the V-end mill with a solid carbide tip. Carbide cutters are also popular. Diamond tipped cutters are also used for harder materials. If the design requires a rounded surface, spherical end mills are used.
