HelicalDrilling
Optic
The D+G Helical Drilling Optic allows thefabricationofmicroholes

precision.

Increasingly

smallwithhighestholes

withextraordinarily restrictive tolerances, which areexpected particularly in the field of fuelinjection technology, can be obtained. The
desired diameters of the holes typically reachdown to 50 μm at a material thickness up to 1mm, resulting in aspect ratios of up to 20.
Special hole geometries with defined taperingsuch as a negative conicity are frequently

demanded for specific flow formation. The
drilling process itself has high reproducibility, as
well as high reliability and the drilling system iseasy to handle.

Key features:• high precision and stability in 24/7
production• short installation time
• no influence on laser parameters (beamquality, pulse duration, polarization)

key component for the production ofhigh precision holes:

Optical concept

Technical principle

Three specially designed wedges for systematic

A helical drilling process carried out by the D+G

deflection of the laser beam are the main

Helical Drilling Optic meets the desiredelements of the D+G Helical Drilling Optic.

requirements both from a quality and a

During the drilling process, all three wedges

geometry aspect. This optic uses a rotatingrotate around the optical axis of the incident

system of optical wedges to lead the focus oflaser beam. A variation of the distance between

the laser on the exact course predetermined bywedges 1 and 2, which are mounted in opposite

the drilling strategy.

orientation with respect to one another,

Conventional trepanning cuts the desired hole

generates a lateral offset of the beam on theout of the workpiece in a single roundtrip.

focussing lens. This offset leads to a definedContrary to this, with the helical drilling

inclination angle at the workpiece’s surface,process, the laser beam ablates the holeproviding large flexibility in selecting a taper

geometry, proceeding on a helical path into theangle. A rotation of wedge 3 relative to wedge 2

depth of the workpiece.

permits the setting of an angle of incidence ofthe laser beam on the focussing optic. This inturn causes a path diameter on the workpiece.
The optical concept of the D+G Helical Drilling
Optic is characterized by high accuracy andsimple adjustment, compared to competing
approaches. On the top of this, it offers thepotential

toincrease

process

efficiency

remarkably by drilling with an inclination angle,
thereby exploiting the whole beam cross section
for widening the hole.

Thus, trepanning is refined by splitting up thedrilling procedure into many single steps. This
technology

produces

highestprecision

morphologies. The D+G Helical Drilling Optic

permits a path diameter from 0 to 400 μm as
well as an adjustment of the beam inclination
angle between 0 and 5° relative to surface
normal of the workpiece. Due to this, laser
drilling with well defined geometries can beachieved.

Control unit
The control unit of the D+G Helical Drilling
Optic is based on the principle of allocating
intelligent, autonomous drive units. The
modularly designed system is rather easy toextend. Process parameters such as path
diameter, path speed and inclination angle, as
well as additional peripheric parameters, canbe independently adjusted during the process.
In

fully

automatedsequencesholding

operation,

helicalprocess

drilling

andperipheric parameters as a function of time,
can be recorded and recalled.
The interface to an external, superior control
system is configurable and can either be
implemented by conventional control signals
or by industrial bus. A peripheric interface isavailabletocontrol

additional

systemtechnology, such as a beam attenuator.
Periphery parameters can be included inprocess sequences and regulated throughdigital output. The control unit of the D+G
Helical Drilling Optic can be supplied as an

Holes of various diameters and undercuts canbe produced in the workpiece without
interrupting the manufacturing process. The
amount of time required for shifting thedrilling parameters is so short that parametervariations can even be performed within nonstop drilling. Hole geometries with bevellededges, fillets of the aperture or Laval-like
outlines can be reached by means of specificdrilling strategies. The combination of process
strategy (path diameter and inclination angle)
and pulse energy (possibly pulselength) opens up completely new possibilities for efficient processes,
whilst maintaining highest
quality. For example, a holecan be prefabricated very
quickly with high pulse
energy. Afterwards, theresulting recast can beablated with less pulse
energy or pulse
duration.

independent, enclosed unit in industry usable
housing, as well as an integrated solution forcustomized systems.

Applications
Hole geometries withadvanced complexity canbe achieved in addition tocylindrical or conical holes with sharp edged
entrances and exits. As independently
controllable

drive

units

enabletheadjustment of the drilling diameter (on thefly)

andthebeaminclination

angle,numerous process strategies are possible.

Accessories and Services
Wedge-Set: Different configurations (i.e.
design wave length) are delivered preadjusted. They can be changed by ourcustomers within a few minutes. Focussing
optic: We offer a range of certified focussing
optics for various wave len¬gths and focallengths. Adjustable mounts are available. Gasflow nozzles and solutions for processing
assurance are available on request. Processing
development: Based on our exp¬erience inlaser drilling, we assist the pro¬cessing
development. Within our laboratory we candemonstrate and fabricate different processes.

Technical Specifications
Optomechanical Unit
Size
WeightBeam height above table

Wavelength
Orientation for mounting
Maximum rotation frequency
Max. time to change rotation frequency
Beam inclination angle 0 to 5° for f = 100 mm
Max. time to change inclination angle
Drilling diameter 0 to 400 μm for f = 100 mm
above 400 μm
Max. time to change drilling diameter
Achievable drilling tolerance

500 x 440 x 280 mm
40 kg
138,5 mmany (selectable between 0,18 μm - 2 μm)
any
3000 min-1
3 s (1000 min-1/s)
continuously adjustable
1,5 scontinuously adjustableon request
1s±1 μm (reproducibility of path diameter)

Control Unit
Electrical power requirements

3-phase AC / 400 V / 50-60 Hz / 3,5 kVA / 25 A(max. pre-fusing)Control unit housing

Industrial grade cabinet with integrated
console (width / height / depth in mm: 600 /760 / 350) Integration in existing machining
stations and customized housing on request
Interface with opto-mechanical unit

System interconnection of customized length(max. 10 m)

User interface

Console with touch screen (LCD monochrome)
Visible area 123 x 68 mm
Dimension for mounting 210 x 158 mm

Interface to peripheric equipment

Digital output 24 V (max. 20 mA)
Analog output 0 V to +10 V (max. 2 mA)

Interface to external control

Digital input 24 V (8 mA)
Digital output 24 V (max. 20 mA)
Profibus-DP optional

contact ● Dausinger + Giesen GmbH
Rotebühlstrasse 87
70178 Stuttgart
Germany

phone ● +49 (0)711 907060-550
fax ● +49 (0)711 907060-99
email ● info@dausinger-giesen.deinternet ● www.dausinger-giesen.de