Techniques and Technical Infrastructure


Friction Spot Joining (FSpJ)

Goushegir Technique Description

Since its introduction in 2009, Friction Spot Joining (FSpJ) has shown high performance in producing polymer-metal hybrid structures. Therefore, this technique is being investigated to join lightweight alloys such as aluminium and magnesium with high performance engineering thermoplastics and composites. For this reason a friction spot welding / joining machine (RPS 100) is employed. Briefly, the metallic partner is plasticized and deformed due to the generated frictional heat and applied force. A metallic nub is created which is inserted into the composite. Simultaneously, a thin layer of polymer matrix is molten, and displaced around the joining area. The joint is formed after consolidation of the polzmeric molten layer. These are the two main phenomena responsible for joining mechanisms.

The term "joining" is used to differentiate spot joints where a sharp interface is present (minimal or absent atomic or molecular diffusion), such as in hybrid polymer-metal joints, while "welding" is used for joints without a discontinuous transition between joining partners (presence of diffusion mechanisms), such as "polymer-polymer" or "metal-metal" spot welds.

Read more about principles of Friction Spot Joining (PDF) (328 KB)

Friction Spot Welding (FSpW)

Amancio Technique Description

The Friction Spot Welding (FSpW) is a new technology for producing similar and dissimilar overlap joints in thermoplastic and thermoplastic fiber-reinforced composites. As thermoplastic fiber reinforced composites (TPC) are difficult to weld or bond by traditional joining processes, there is an open niche to be filled by the research and development of alternative joining technologies.The main improvement of FSpW over the Friction Stir Spot Welding (patented by The Welding Institute – TWI, England) is the absence of a keyhole in the spot seam; this usually leads to higher joint strengths due to reduction of the geometrical notch effect of the keyhole.

Read more about FSpW of thermoplastics and composites (PDF) (187 KB)

Friction Riveting (FricRiveting)

Blaga Technique Description

Friction Riveting (Fricriveting), is an innovative joining technique for polymer-metal hybrid structures, developed and patented by the Helmholtz Zentrum Geesthacht in Germany. In this process, polymeric parts are joined by a metallic rivet; the joining is achieved by mechanical interference and adhesion between the metallic and polymeric joining partners. During the process, a rotating cylindrical metallic rivet is inserted into a polymeric base plate. Due to the local increase of temperature, a molten polymeric layer is formed around the tip of the rotating rivet. The local temperature increases leading to the plasticizing of the tip of the rivet. While the rotation is being decelerated, the axial pressure is increased, the so called forging pressure is applied and the plasticized tip of the rivet is being deformed and anchored in the polymeric plate. The technology is adequate to produce overlap riveted joints between metal-polymer, metal-composite and composite-composite connections.

Read more about principles of Friction Riveting (PDF) (74 KB)

Injection Clinching Joining (ICJ)

Abibe Technique Description

Injection Clinching Joining (ICJ) is a new joining process for hybrid structures, composed of one thermoplastic-based partner and a metallic or thermoset partner. The principle of the process is to produce joints through heating and deformation of a thermoplastic element (such as a cylindrical stud) integrated in the polymeric partner, which is previously inserted in a through hole (cavity) of a metallic/thermoset component, therefore creating a rivet from the structure itself. Spot joints created by ICJ process are tight and with good mechanical anchoring due to the cavity profiles on the metallic partner. ICJ is a potential technology for secondary and tertiary structures in automotive and aircraft applications.

Read more information about principles of ICJ (PDF) (242 KB)

Ultrasonic Joining (U-Joining)

Eduardo Techniques

Ultrasonic joining (U-Joining) is a new direct assembly technique developed by Helmholtz-Zentrum Geesthacht (patent EP 3 078 480 A1). U-Joining uses ultrasonic energy to join fiber-reinforced thermoplastics to surface-structured metallic parts, for instance produced by metal injection molding (HZG’s patent EP 2 468 436 B1). Ultrasonic vibration and pressure create frictional heat at the materials interface, which softens the composite matrix and allows the reinforcement (structured on the surface of the metallic part) to penetrate the composite. As a result, a metal-composite hybrid joint with improved out-of-plane strength is achieved.

Read more information about principles of U-joining (PDF) (261 KB)


Addjoining Aa2024 Cf-pa6

The AddJoining concept (German patent application number DE 10016121267.9) uses a new and unique approach to produce complex hybrid parts, by combining the principles of joining and polymer additive layer manufacturing (ALM) to produce layered metal-polymer hybrid structures. This is an important contribution to the state-of-the-art in additive manufacturing. AddJoining has potential to overcome the main limitations of production time of state-of-the-art manual lamination techniques, allowing for the production of future composite-metal layered structures with high-specific strength (Rm/density), tight dimensional and damage tolerances.

Read more information about principles of AddJoining (PDF) (1,1 MB)

Technical Infrastructure

T805 Bobbin Tool FSW robotic system

140617 Wmp Www T805 Bbt Maschine Foto

Siemens 840D control
5 axes
positioning accuracy ±50µm
repositioning accuracy ±10µm
max. acceleration 2G
max. velocity 90m/min
max. forces:
vertical : 45000 N
horizontal: 10000 N

HZG Flexistir Bobbin Tool FSW system

140617 Wmp Www Flexistir Maschine Foto Frontal

six motor controlled axes: table, portal, gap (BT-mode), secondary table, y-positioning and tilting
one manually adjustable axis: tool angle +/- 5°
two fully independent spindles (BT-mode): pin and upper shoulder

bobbin tool welding head:
-up to 20Nm per Spindle
-0-2000 RPM
-up to 4kN gap-force

steel welding head:
-up to 80Nm
-up to 40kN down force

3D piezoelectric force sensors:
-measurement of X,Y and Z forces acting on the tool
-torque measurement
-1D piezoelectric force sensors
-measurement of gap-force (BT-mode)

HZG FSW gantry system

140701 Wmp Www Gantry Maschine Foto Iso

axial Force (z): 80 kN
side Force (y): 15 kN
force in welding direction (x): 20 kN
bi-directional rotational speed of the Spindel: 3500 rpm
spindle torque continous / max.: 190 Nm / 340 Nm
tool tilt angle: between -3° and +3°
welding speed: up to 160 mm/s
max. working space (x, y, z): 2350 mm x 250 mm x 800 mm

measurement and control:
-axial force
-rotational speed

-horizontal forces
-spindle torque

T9000 FSW robotic gantry system

140617 Wmp Www T900 Robgant Maschine Foto Frontal Fischauge

electric actuators
rotational speed of spindle up to 6000 U/min
axial forces up to 60 kN
radial forces up to 20 kN
dimension of workspace 6m x 2m x 0,8m

measurement and control:
-axial force
-roational speed of spindle

-horizontal forces
-torque at spindle

HZG RPS 100 friction spot welding system

140630 Rps100 Wmp Www Foto Frontal

rotational speed between 500 and 3000 rpm
max. spot diameter 12 mm
max. weld depth 10 mm

measurement and control:
-axial force
-rotational speed at spindle
-tool travel of pin and sleeve

HZG RPS 200 friction spot welding system

140617 Wmp Www Rps200 Maschine Foto Perspektivisch

stroke of welding tool: 10 mm
welding force: 35 kN
torque: 60 Nm (90 Nm for 15 s)
bi-rotational speed of tool elements: 3300 rpm
work area: 1000 mm x 500 mm
mass: 4,7 t
stroke of weld head: 300 mm
clamping force: 40 kN

measurement and control:
-torque at pin
-torque at sleeve
-clamping force
-intrusion force pin
-intrusion force sleeve
-travel pin
-travel sleeve

HZG friction surfacing- / HFDB- system

140617 Wmp Www Ras Maschine Foto Perspektivisch

axial force: 0-60 kN
spindle speed: 0-6000 rpm
spindle torque: max. 200 Nm
stiff and robust design
work space: 0,5 m x 1,5 m x 0,3 m
consumable rod diameter: max. 30 mm
consumable rod length: max. 300 mm
flash cutter device

measurement and control:
-forces in spatial direction
-spindle torque
-spindle rotational speed
-displacement in x-, y- and z-axis

HZG (small) RSM friction riveting system

Rsm 400

-spindle speed 6000 up to 24000 rpm
-axial forces max. 15 kN
-stroke max. 50 mm

measurement and control:
-axial force
-rotational speed

HZG (large) friction riveting system

140617 Wmp Www Fricriveting Maschine Foto Perspektivisch

tri-axial control concept (automatic operation)

spindle: RSM 410 Harms & Wende
-drive max. 21000 rpm
-max. axial force 24 kN
-max. torque 20Nm

work piece magazine for 20 rivets
backing plate 1000 x 1500 mm

3D piezoelectric force sensors
-measurement of X, Y and Z forces
-torque measurement

integrated position sensor

FEI Quanta 650 FEG Scanning Electron Microscope

140617 Wmp Www Sem Quanta 650 Foto Frontal

high resolution Schottky field emission

vacuum modes
-high vacuum, HiVac (10^-2-10^-4 Pa)
-low vacuum, LoVac (10-200 Pa)
-extended vacuum mode, ESEM (10-4000 Pa)

accelerating voltage : 200 V to 30 kV

stage control: eucentric position

Analytical system: Energy Dispersive Spectrometer, Electron Backscatter Diffraction

Assistant unit: Navigation Camera, Quick Loader

External device: Vibration Isolation Controller Unit, Magnetic Field Compensation system, and Uninterruptible Power Supply

Miscellaneous: Beam Deceleration, Concentric solid-state Backscattered detector (CBS)