Heat staking machines

The riveting process creates irresolvable interlocking bonds. This is achieved by forming or reforming of thermoplastics. In most cases in this procedure only point-shaped or segmented joints are realized. In contrast to welding of two components there cannot be achieved hermetic joints.

A particular version of this procedure is the bonding of plastics with metals, textiles and cardboard. The method is frequently used for wooden decoration parts, into which a chrome decoration strip has to be embedded.

Properties:

• Welding of parts by forming or reforming
• Creation of a point-shaped or segmented joint
• Overlapping of the joint is necessary
• One of the welding partners must have a clearance hole

Advantages:

• Connections of dissimilar and similar plastics
• Bonding of plastics with metals, textiles or cardboard
• Cost-efficient assembly and welding technology

In contrast to ultrasonic riveting the thermal riveting can be used without any problems for metal/plastic connections, since no vibrating tools have contact to the metal sheets, thus the joint is not endangered. Particularly in critical plastics like POM or PA-GF which tend to embrittle in ultrasonic riveting, with thermal riveting a very high quality of joints can be achieved. This method is also very useful, if it is very important to avoid contamination of the parts by embrittled particles.

As a rule the hot form riveting is carried out in a one-cycle process. A heated riveting stamp forms the riveting head under pressure. After forming the stamp is shortly cooled down in order to avoid adhesion of the plastic material on the thermal riveting stamp. After this short cooling phase the riveting stamp is again moved above.

• Stamp sets down on the riveting dome
• Stamp stakes the riveting dome
• Stamp forms the riveting head
• Cooling of the formed riveting head
• Stamp lifts off

Advantages:

• cost-efficient process
• dissimilar materials can be bonded
• low mechanical influence on the part

Disadvantages:

• energy cost
• material adhesion in critical plastics
• process time longer than in ultrasonic riveting

Basic machine with frame, control cabinet, hydraulic aggregate and spreader

The spreader can be actuated hydraulically, pneumatically or by servo-motor. Our basic machine is designed for tooling exchange.

Advantage of this system: For future projects you need only a modular cassette for each product. The modular cassette is put into the machine by means of a tool transfer trolley, fixed and connected electrically as well as pneumatically via plugs with the machine.

All riveting stamps can be individually heated and their height and location can be set independent from each other. Various speeds and pressure stages can be set via the hydraulic system.

For an optimal riveting joint the following process parameters are important:

• melting time
• pressure
• speed
• holding and cooling time

Design of the riveting ribs/ riveting domes

The precondition for a high-quality welding joint is the professional conception of the riveting rib or dome. The riveting head is dependent on the design of the riveting rib or dome.

We will be pleased to support you in the elaboration of the welding concept for your plastic components.

Discover our current flyer with all the latest information on our systems - simply click here for all the details. Hot riveting