Böllhoff and DELO have developed a new fastening system called ONSERT that allows for quick and reliable bonding of fastening elements. There are two variants, ONSERT basic and ONSERT plus. ONSERT basic bonds threaded bushes to sheets, circuit boards, and housings using heat-curing or dual-curing adhesives. It provides advantages like preventing leaks and allowing fastening elements to withstand heat without being visible. ONSERT plus bonds fastening elements coated with transparent adhesive to injection molded parts, reducing sink marks and allowing new design possibilities. Both variants offer short curing times, standardized elements, and suitability for automated processing.

1. Quick and process-reliable bonding
of fastening elements
0250/07.02
ONSERT
A joint project between

2. An efficient connection
Technological progress, reduced development times, legal changes, etc. result in new requirements on the
fastening and assembly technology.
As a result, Böllhoff, as a specialist in mechanical joining technology, and DELO, as a specialist for intelligent
bonding technology, have together developed a new fastening system. The most important factor was process-
reliable curing of adhesives with ideal cycle times as well as geometric designs of fastening elements.
The ONSERT technology is the result – quick and process-reliable bonding of fastening elements. The innovative
joining technique provides ideal preconditions for manifold applications in different areas. Currently, there are two
variants – ONSERT basic and ONSERT plus.
ONSERT basic
Principle and idea
Böllhoff and DELO developed a threaded bush which, regarding geometric design, is provided with a sufficient
bonding surface area due to an enlargement in diameter in the lower area. The cavity in the contact surface
ensures that reproducible layer thicknesses in the adhesive layer are maintained and that the adhesive wets
the complete component surfaces.
ONSERT basic can be bonded to sheets, printed circuit boards and plastic housings with heat- or dual-curing
adhesive systems.
Advantages
■ Prevention of leakages and overlaps on the back
■ Fastening elements do not become apparent on
the visible side through heat input during laser
welding or soldering
■ High fitting values and compensation of impulsive
stress
■ Connection to freeform surfaces
ONSERT plus
Principle and idea
The ONSERT joining technique is a real alternative, not only for particularly small but also for large wall thicknesses.
If a housing with material accumulation is produced by injection moulding, visible shrinkage (sink marks) often
occurs after cooling down – this problem can be avoided with ONSERT plus.
ONSERT plus allows quick, form-closed bonding on optimised fins on the corresponding component. As an
alternative to bosses produced with the original mould, the system provides new design possibilities due to
subsequent joining.
Fastening elements, such as well-proven AMTEC® thread inserts, are coated with transparent plastic (adhesive
boss) and are then fitted using light-curing adhesive systems. Adhesive bosses can be produced in various
designs, e.g., with internal threads, bolt threads, ball bolts or snap-on fasteners.
Advantages
■ Reduction/prevention of sink marks
■ Shorter injection cycles
■ Easier tooling concepts
■ Standardised elements
■ Suitable for semi-automated and fully
automated processing
■ Short curing times (< 5 sec)
Adhesive Substrate Release force
Fmax in [N]
DELO-MONOPOX aluminium 114
AD066 stainless steel 120
DELO-MONOPOX aluminium 241
AD295 stainless steel 442
DELO-DUALBOND aluminium 188
AD420 stainless steel 181
600
500
400
300
200
100
0
DELO-PHOTOBOND DELO-PHOTOBOND DELO-PHOTOBOND
GB VE57288 PB493 PB437
Tensile strength [N]
unaged
afteraging
unaged
afteraging
unaged
afteraging
•
168 h at +40°C/100% r.h.

3. 2
3
Process description
ONSERT basic
1. Dispensing
The one-component, heat-curing acrylate or epoxy resin adhesive DELO-MONOPOX
is dispensed onto the housing, e.g., from the Euro cartridge.
Dispensing is carried out from the Euro cartridge pressure tank DELO-XPRESS 911
via a constricted tube valve. The pressure tank is controlled with the control unit
DELOMAT.
2. Joining
The fastening element is joined onto the housing.
3. Curing
DELO-MONOPOX adhesives are either oven-cured (e.g., 20 min at +130°C),
induction-cured or cured using a thermode (typical curing time approx. 30 s each).
As an alternative to DELO-MONOPOX adhesives, you can also use
DELO-DUALBOND products with combined light and heat curing. The adhesive is
dispensed in such a way that a fillet is created. A DELOLUX curing lamp results in
quick fixing within seconds (< 5 s). Afterwards, the areas inaccessible to light are
cured by heat (e.g., 3 min at +130°C).
ONSERT plus
1. Dispensing
The one-component, UV- and light-curing acrylate adhesive DELO-PHOTOBOND is
applied to the bar.
The adhesive is dispensed with the pressure tank DELO-XPRESS 951 via up to four
constricted tube valves from the one litre container. The control unit DELOMAT is
used for control.
2. Joining
The adhesive boss is joined onto the plastic plate.
At least one joining partner – in this case the adhesive boss – must be translucent in
the absorbing range of the adhesive.
3. Curing
DELO-PHOTOBOND is irradiated for several seconds (e.g., < 10 s) – until final
strength is reached.
All DELOLUX curing lamps, such as the LED lamp DELOLUX 80, are suitable.
•

4. Subject to technical change.
Reprinting, even in extract form, only permitted with express consent.
Observe protective note according to DIN 34.
Böllhoff Verbindungstechnik GmbH
Archimedesstraße 1–4 · 33649 Bielefeld · Germany
Phone +49 (0)521/4482-05 (326) · Fax +49 (0)521/4482 -658
www.boellhoff.com · fasteningtechnology@boellhoff.com
DELO Industrial Adhesives
DELO-Allee 1 · 86949 Windach · Germany
Phone +49 (0)8193/9900-0 · Fax +49 (0)8193/9900-144
www.delo.de · info@delo.de