Understanding CNC Fixtures: The Complete Guide

CNC machines are used in almost every machining process, helping to manufacture components. A CNC machine has various parts, among which CNC fixtures play a very important role.

Mostly the significance of CNC fixtures is ignored, but they are of significant importance. If you are inclined to learn about CNC fixtures and their working, this guide below can help you.

What are CNC Fixtures?

CNC fixtures are tools which help with the positioning and stability of the workpiece. They help to secure the workpiece at a fixed point so that it can be properly machined. It is a very important tool for machining the components accurately.

These CNC fixtures eliminate the need for human input to hold the workpiece in place. Moreover, these fixtures even move according to the process requirements for machining, along with the workpiece.

Applications of CNC Fixtures

CNC fixtures are used in almost every manufacturing process, including CNC machining. There are various functions performed by it in CNC-Fräsen, CNC turning, and CNC grinding. The two most important applications of CNC fixtures are discussed below.

Positioning

CNC fixtures ensure that the component maintains an accurate position with the machining tools during the process of machining. It even ensures that the components meet the required design specifications.

Clamping

After the workpiece is positioned, the CNC fixture holds it tightly so that it doesn't move, and this is done through clamping.

Types of CNC Fixture

There are various types of CNC fixtures, which are classified based on their purposes, machining processes, and power source.

Classification Based on CNC Machining Operations

The different types of CNC machining fixtures based on their machining operations are discussed below.

Milling Fixtures

CNC milling is a method of cutting which uses a computer program that helps cut the workpiece into desired shapes and sizes. The CNC milling process requires rotary table fixtures, fixture plates, indexing fixtures, T-slot, and vise fixtures for milling operation.

Turning Fixtures

CNC tuning is a process of machining in which the material in the workplace is cut by the cutter from the component. The turning fixtures used in CNC turning are composed of collets, mandrels, and faceplates.

Grinding Fixtures

The CNC grinding process uses a grinder to remove the material from the workpiece. It is used in the CNC-Bearbeitung process using fixtures like sine bars and centerless magnetic chuck.

Drilling Fixtures

Drilling fixtures include radial drills, drill jigs, and angle drilling jigs to create holes in the workpiece using CNC machining.

Boring Fixtures

CNC boring is the process of machining, which can increase the size of holes that are already drilled in components. It uses boring fixtures like boarding head fixtures and boring bars.

Classification Based On Their Uses

CNC fixtures are also chosen based on their use, and these are the following:

CNC Vise Fixtures

CNC vise fixtures are used to ensure high precision compared to the traditional vise. These CNC vise fixtures have an excellent power of clamping using a hydraulic screw mechanism. The internal mechanisms of vise fixtures have surfaces which are pushed against one another and increase the rigidity.

Angle Fixtures

Angle fixtures are used to hold workpieces from certain angles and are mostly opted in CNC machining processes like beveling, chamfering, and drilling at different angles. They are reliable and rigid and help with easy mounting of components.

Modular Fixtures

Modular fixtures are highly advanced types of fixtures which can be reconfigured and reconstructed to match the precise requirement. They have components that can be interchanged, and they can handle a wide range of components. It includes tooling plates, supports, and clamps.

Jig Fixtures

Jigs are very important machining tools which can guide the motion and position of the cutting tool over the component. These are used in drilling operations and consist of leaf jigs, plate jigs, template jigs, angle jigs, and diameter jigs.

Clamp Fixtures

Clamp fixtures are available in many sizes and types, and they hold the component with the help of screws and springs. The different types of clamps are step, hold-down, and edge clamps.

Universal Fixtures

Universal CNC fixtures are suitable to work with all types of workpieces and they can easily be adjusted. They have replaceable components which can easily match the workpiece and cater to versatile applications.

Classification Based on their Power Source

The CNC fixtures based on power sources are as follows:

Manual Fixture

Manual fixtures use screws and bolts so that the workpiece can be fixed manually. It is very easy to operate and design manual fixtures, and they are also very cost-effective.

Electrical Fixture

Electrical fixtures use electric motors for clamping and controlling the position of the component. These fixtures offer high precision and can automatically clamp the workpiece based on the programming.

Pneumatic Fixture

Pneumatic fixtures allow the clamping of the workpiece using compressed air. It is opted to reduce the cycle time, and by air pressure, the clamping force is adjusted.

Magnetic Fixture

Magnetic fixtures use magnetic fields to hold the workpiece. They are suitable when it is difficult to clamp the workpiece using conventional methods. These workplaces can be held magnetically and hence offer an unobstructed process of machining.

Hydraulic Fixture

Hydraulic fixtures use hydraulic fluid for clamping the workpiece. These fixtures can exert huge force, which ensures enhanced stability and is suitable for heavy machining processes.

Vacuum Fixture

Vacuum fixtures use vacuum suction to secure the component. The workpieces that are compatible with the vacuum fixtures are those that have an irregular and flat shape.

Considerations for Custom Fixture Design

Some important considerations to be done when choosing a custom fixture design are as follows.

Define the Design Requirements of Your CNC Fixture

The design requirement for the CNC fixtures must be clearly specified. This includes clarifying your goals like timing, accuracy in production, and cost for the intended fixture design.

Gather Relevant Information from the CNC Shop

The next thing to consider is collecting relevant information about the materials the CNC fixture has to work with. It helps to analyze the specifications and capabilities that a custom CNC fixture must have to hold that workpiece.

Create More Drafts for CNC Fixture Design

CNC fixtures are versatile and can be used for a wide range of workpieces. However, the design of the fixture needs to be innovative enough to work with different shapes of components. Hence, it is important to create multiple drafts featuring varied designs.

Pick the Best CNC Fixture Idea

Once you have created a design for a CNC fixture, you need to assess its pros and cons for your project. It helps you analyze if the design is the best option for your application or not. Factors like cost of manufacturing, tooling and life of the fixture play a vital role here.

Optimize and Implement the Preferred CNC Fixture

The last thing is optimizing the design of the fixture and finalizing the plan of production. Make sure to consider expert advice here so that the right fixture is developed.

Advanced CNC Fixture Techniques for Machined Parts

CNC machining has progressed like anything, and the use of advanced CNC fixtures has made it possible to carry out machining processes in a highly automated way. Some of these fixtures are as follows:

Robotic Fixture Loading

Robotic fixture loading saves a lot of time that is spent in loading and unloading workpieces. These fixtures consist of robotic arms which can automate the process of loading and unloading for the entire product batch.

CNC Fixture Monitoring

Monitoring is the process in which the CNC fixture uses modern techniques. Some fixtures use sensors for different locations, and the CNC fixtures are monitored. Aspects like clamping forces, precise fixture location and part validation are monitored.

Fixture Damping

Damping is a method in which the machining vibrations are suppressed, as this can cause problems in the components. Some CNC fixtures are equipped with damping materials that absorb the machining forces and keep the components stable.

Get Your Custom CNC Fixtures at DEK

Wir bei DEK use CNC machining processes consisting of different methods. If you are on the hunt to get a CNC fixture customized for your projects, you can get in touch with us. Our team of engineers will provide you with an excellent CNC fixture equipped with all the relevant features you are looking for.

Schlussfolgerung

The accuracy and precision of manufacturing components through CNC machining rely a lot on the CNC fixtures. Hence, the selection of the right fixture in terms of power, purpose and machining process is crucial. As you have read above, you must now be aware of the aspects associated with CNC fixtures and this will help you in all your upcoming projects.

FAQs

How is a CNC fixture different from a jig?

CNC fixtures and jigs differ from one another in terms of function. A jig is meant to guide the movement of the cutter, whereas a CNC fixture secures and holds the workpiece.

How to choose the right CNC fixture for my application?

When choosing the CNC fixture for your application, you need to analyze factors like shape, dimensions, machining processes, and materials associated with the workpiece.

What type of workpieces can CNC fixtures hold?

CNC fixtures can hold different types of workplaces like irregular shapes, round plates, and cylindrical ones.

Are CNC fixtures interchangeable between different CNC machines?

CNC fixtures are interchangeable because of their standard geometric features. In very rare cases, it might not be possible if the specifications of the machine differ or if the fixture is customized.