How to make a stencil on the CNC machine

Contents:

Stencils may be needed for various reasons, but most often they are required to paint only a specific area without applying paint to another. In this article, we will explain how to make a stencil on the CNC machine.

Where is it being used

Stencils may be used to design anything at home, including pots, notebooks, and walls. They are commonly included in children’s drawing books to assist them with bringing their thoughts to life.

These stencils can also be found in the beauty industry, specifically in manicure services, where professionals use them to create designs on nails.

Also stencils are used in spheres like:

• Wall decorations, graffiti, wall art, and other artistic purposes; 
• Furniture painting;
• Fabric custom design;
• Vases, glasses styling with special etching cream;
• Signs making and marketing goals.;
• Industrial marking on big shipping crates, barrels, etc.

Materials for stencils and how to choose

There are several criteria that determine the final choice.

1. Disposable or Reusable?

The chosen material determines how many times you can use your stencil.

• Those made from paper or thin cardboard are typically disposable.
• Stencils made from wood or plywood are more durable but can be damaged over time when used with wet paint.
• Another type of stencil is made from plastic, acrylic, and other harder materials, which tend to last longer.
• There are also stencils made from mesh fabric that can hold finer details, allowing for greater accuracy when painting intricate designs, and these are also quite durable.

2. Guiding Stars

Sometimes you need to place an image in a specific location or precisely in the center. For this, a mark can be made on the surface itself, but the stencil may cover it.

Therefore, the material can be chosen for its transparency. For example, acrylic, which you can easily look through, can be ideal for such needs.

3. Cleaning 

Don’t forget that if your stencil is reusable, it will need to be cleaned. Otherwise, the results may deteriorate with each use. As you might imagine, cleaning paint or other fillers off a stencil can be either difficult or easy, depending on the material it’s made from.

A stencil made of lightweight metal will be easier to clean than one made of wood, which can easily absorb staining substances.

4. The painted surface

Consider where you intend to apply the image using the stencil. If the surface is flat and straight, like a wall, there won’t be any issues. But what if it’s curved or angled? In such cases, you’ll need to choose a material that can bend; otherwise, you might encounter problems. Polycarbonate can be a good option in this situation, as it can be rolled and bent yet remains durable and reusable. Acrylic, on the other hand, won’t bend without consequences.

Of course, another approach is to create a stencil in several parts and use markers to align them, ensuring the design is straight. In this case, you can use any material, even rigid ones.

Which machines to use

All the materials mentioned above can be processed using laser equipment. CNC router machines can also process them. The choice depends on the size of your workpieces and the type of primary material.For cutting small stencils on the CNC machine, an equipment with a working area of 500×300 or 600×400 millimeters will be suitable.

Wattsan machines 0503 and 6040

Use the 0503 model for smaller layouts and items. This tabletop model can be used at home or in the workshop; it does not take up much space. It is both efficient and convenient. A 60-watt laser tube has been added to aid in the production of high-quality engraving results. This model can cut wood, plywood, and other materials up to 5–6 mm thick. It’s great for making stencils on the CNC machine!

The 6040 model is also a tabletop machine. It has a working area of 600×400 mm and features an 80–90W laser tube, which allows you to cut thicker, more durable stencils.

CNC routers 6090 А1 and М1

A router machine is also suitable for processing nearly all the same materials. For example, the 6090 A1 or M1 models can be used. However, items like paper, fabrics, and other particularly soft and sensitive materials cannot be cutted with a router machine. On the other hand, soft metals can be handled easily!

This model is equipped with a 1.5 kW spindle, which has a travel speed of 6,000 to 24,000 rpm. This allows for the processing of materials such as wood, MDF, plywood, plastic, acrylic, aluminum, paronite, etc.

For cutting thicker materials, a tube with greater power will be needed. For larger workpieces, Wattsan 1610 or 2030 machines are suitable. However, these are more appropriate for serious production settings. The same applies to larger router machines, which are not intended for home use.

Let’s make a layout

Arranging details

There are several important aspects to consider when designing a layout for cutting stencil on the CNC machine.

First, consider the details. It’s advisable not to include too many small ones. Why? No matter how good and high-quality the stencil is, with multiple uses, paints or other materials you’re using may clog in the very small fragments, causing you to lose those details. The final result might even turn out poorly. Thus, it’s simply a waste of time during the production of the stencil.

When designing the layout  for cutting stencil on the CNC machine, keep only the parts of the stencil that you consider essential, and remove those that you can do without. Also, remember that leaving a large gap might be just as bad as having too many little ones. A precise balance, depending on the intended purpose, is essential for making the right stencil.

Don’t Burn Bridges

Sometimes, you need to have bridges in the design to keep parts from falling out. For example, the inner parts of letters like “b,” “d,” “o,” or certain numbers, as well as elements within illustrations.

However, don’t make these bridges too narrow, as they may break, especially if the material is thin, fragile, or soft. More robust materials, like metal, allow for thinner bridges.

It’s also important to consider their placement: if you plan to use the stencil in a vertical position, the bridges should either be on top or on both sides of the necessary part.

Edge size

The image or text you want to apply is enclosed in a “frame,” which can vary in thickness. Sometimes this frame is made thick to prevent excess paint from creating unwanted marks, while other times it is made deliberately thin, using the overpainted areas as part of the design.

It all depends on your preferences and the concept, which should be considered during the layout stage.

Vector

Don’t forget that your design must be in vector format. If you create it as just an image, the machine won’t understand what you want it to do. Also, check at this stage to ensure that all necessary lines are closed and single.

Settings

In this section, we will provide some general recommendations for processing various materials on laser and router machines for cutting stencil on the CNC machine. However, please keep in mind that everything can be quite individual, and sometimes settings require additional adjustments depending on the power of the tube or spindle, the type of bit used, or the material itself.

Laser machine

Paper and cardboard

For cutting  stencil on the CNC machine from these materials, a tube with a low wattage, such as 50W, is sufficient. The general cutting parameters can be as follows:

• Speed: 150 mm/sec, Power: 15-20W. For intricate cutting, it is preferable to adjust the parameters as follows: Speed: 30 mm/sec, Power: 10 W.
• The air assist should be minimal, between 0.2 and 0.5 atmospheres. It should not be completely turned off to avoid damaging the lens. It is not recommended to increase the air assist too much, as the lightweight material can be blown away. However, when cutting cardboard, you can set it up to 1 atmosphere.

Acrylic

Here’s an example of settings for 3 mm acrylic:

• Using a 60W tube: power: 65%, speed: 16 mm/sec;
• Using a 90W tube: power: 65%, speed: 20 mm/sec;
• We recommend setting the airflow to 0.5 atm. Less might be dangerous for the lens.

CNC router machine

Acrylic

For processing acrylic, special plastic-cutting bits are used. These include single-flute and sharp bits, or o-flute bits. It’s also important to use an upcut bit to ensure that all the chips are lifted out, preventing accumulation inside the cut and reducing the risk of melting.

The necessary settings are:

• Spindle speed: 15,000–18,000 rpm or 6,000–9,000 rpm
• Feed rate: 2000–2500 mm/min or 3000 mm/min
• Depth of cut: This depends on the bit. For a 3 mm bit, you can remove 1-2 mm per pass. For a 5–6 mm bit, you can remove 4-5 mm per pass.
• Cutting direction: climb (parallel flow)

Wood

Wood processing can be more complex due to the different characteristics of various wood species. However, there are some general guidelines to make a stencil on the CNC machine.

• Typically, wood milling is done at high spindle speeds, usually between 18,000 and 22,000 rpm.
• For working with wood, spiral bits with diameters ranging from 3.175 mm to 6 mm are recommended. They should be single-flute or double-flute bits.
• The maximum depth of cut depends on the wood species and the bit diameter; the larger the bit, the deeper the cut can be.

Conclusion

1. Stencils are still widely used, and their production may be a little tricky. To make them of good quality, you need the correct equipment, layout, and settings.
2. For stencil production, CO2 laser or router machines may be used. The question is about the required size, which is based on the size of the workpiece.
3. To create a stencil on the CNC machine, while making the layout, you should: decide which details stay and which are going to be deleted; where to make special bridges; what size edges are going to have.
4. The setting should be chosen carefully based on the material you’re going to cut the stencil on the CNC machine from.