Design finger, click, and press-fit joints
We often see laser-cut finger joints in various types of projects. It is an excellent way to create a 3D object using a 2D production technique by connecting two parts at an angle. There are numerous ways to make a connection, from screw connections to finger joints and even wedge connections.
These connections are useful when you want to turn a 2D object into a 3D object, such as an electronics enclosure, or when you have a sign that needs a stand. Connections can be either temporary or (semi) permanent.
What are finger, snap, and press-fit connections?
This is a collective term for a range of common connections that can be made through laser cutting. The different types of connections are briefly explained below.
Finger joints are a combination of fingers and notches on the edge of a material, these fingers interlock and provide the object with strength. This allows for the quick creation of complex 3D shapes from just sheet material. Depending on the complexity, one can choose to design the joints themselves or have them generated by software. A finger can also be completely enclosed, which is then referred to as a finger-and-slot joint.
This type of joint is held in place by friction between the fingers. If finger joints are well designed, it is possible to create objects that do not require glue to be assembled.
Snap joints are a way to secure a connection, providing a temporary or semi-permanent joint.This type of joint is used for projects that require more strength than finger joints or when the objects need to be disassembled.
Press-fit joints function similarly to finger joints, but the strength comes from the material properties, not the laser cutting tolerances. Press-fit joints come in many different designs/executions. The role of a press-fit joint is to hold the assembly together through friction, which is also the goal of finger joints; however, press-fit joints utilize the material properties in combination with the design instead of the cutting tolerances.
Finger Joint
Snap Joint
Press Fit
Above are some examples of joints. The best joint to choose depends on your project, material, and design. We often recommend snap joints because they are more versatile than other joints.
| Type of Joint | Advantages | Disadvantages | |
|---|---|---|---|
| Finger Joint | Unique aesthetics, well-suited for combining with adhesives | Joint depends on tolerances, not suitable for materials that cannot withstand point loads (e.g. | acrylic) |
| Click connection | Flexibly deployable in terms of shape and material. For temporary and semi-permanent connections | "bulky" compared to other connections | |
| Press connection | Virtually invisible connection | Not suitable for materials that cannot withstand point loads (e.g., acrylic) |
What should I consider during the design of different connections?
The precision of laser cutting makes it possible to produce connections in a reliable manner, however, there are some things to consider when designing finger, click, and press connections.
Designing finger connections
Designing finger connections is relatively simple but can be extremely labor-intensive depending on your design. We usually advise generating finger joints and incorporating them into your design. There are various software packages available, but you can also find different online tools to generate finger joints, such as for example BOXES.PY.
Although laser cutting removes very little material, it is important to consider the kerf if a tight fit is important. For most materials, this is 0.2mm per cut, and the exact kerf is specified per material. This means that the line of the object must be offset outward. For most materials, the kerf is 0.2mm, so each part should be compensated by 0.1mm.
For finger-and-slot joints, the thickness tolerance of the material must also be taken into account.If the hole is as thick as the material, it may happen that the material does not fit because it is on the thick side (even with the cutting loss of the slot). Therefore, always design your slot based on the highest values of the thickness tolerance.
Designing Press-Fit Connections
Press-fit connections are more challenging to design but provide a good result that is flexibly deployable. The easiest way to use snap-fit connections in your project is to make use of our templates.
Designing Snap-Fit Connections
Snap-fit connections are the most complex but provide the best result in terms of strength. They are complex connections in many different shapes and sizes that offer a strong grip but also make it possible and easy to disassemble an object.This connection works on the same principle as slot connections, only the finger is under pressure, allowing it to be inserted through the slot and grip firmly. Always test a finger joint and some variants to ensure that what you have designed also works in reality. To easily place a small order, you can use our online laser cutting service.
