Laser welding - Examples for application in ... - DENTAURUM

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Laser welding
Examples for application in prosthetics

Laser welding – Example
CoCr model cast:
Welding a small connector with filler material
Preparation:
The area to be welded is opened with a separating disc to produce a gap of 0.5 mm.
Cast filler material of carbon-free CoCr alloy remanium ® CD (REF 102-350-00) is
then fitted into the gap. This filler material must be cast beforehand in various
wax-sheet thicknesses of 0.3 – 0.7 mm.
The filler material is trimmed to size so that the dimension of the small connector
appears circularly enlarged at approx. 0.5 mm. The parts to be welded are
sand-blasted to a dull finish with Al 2 O 3 of grain size 150 µm.
The plate is tack-welded to one side of the connector with two laser weld spots.
Laser setting: 275 V/5 ms.
Using carbon-free CoCr laser wire (REF 528-200-00), weld one side of the
remanium ® CD filler to the small connetor. Aim one third of the laser beam at
the tip of the wire and two thirds at the gap to be filled.
Laser setting: 290 V/9 ms.
Laser welding wire is applied continuously to the joint area in the form of a
welding bead. The welding power must be selected in such a way that the laser
beam penetrates to the centre of the object from either side.
Fig. 1
Stand 30.05.2007
1/1

Laser welding – Example
Fig. 2
The same number of weld spots is applied alternately from above and below.
Ensure that the weld area is well covered with argon. Turn the weld area so that
it faces the argon nozzle. The weld spots should have a metallic lustre.
Now begin the actual joining process. The fille material is now welded to the second
side of the small connector alternately from above and below using CoCr laser wire.
Laser setting: 290 V/9 ms.
Fig. 3
1/2

Laser welding – Example
Finally, smoothen the surface with a soft polishing setting. This is done either
with a laser setting of 260 V and 9 ms by holding the object at a slight angle
or with a laser unit with focus expansion (approx. 2/3 expanded beam, setting
approx. 10) with a setting of 280 V and 10 ms.
The joint is then processed in the same manner and polished. The model cast
frame was made of the CoCr alloy remanium ® GM 800 (REF 102-200-00).
Fig. 4
1/3

Laser welding – Example
CoCr model cast:
Broken clasp
The fracture area is sand-blasted to a dull finish on both sides with Al 2 O 3 of
grain size 150 µm. The broken clasp is adjusted to the correct position on the
model and if necessary fixed to the plaster model with a drop of wax. The
broken part is fixed to the upper arm of the brace with a eld spot.
Laser setting: 265 V/5 ms. The fracture is then welded using carbon-free CoCr
laser wire (REF 528-200-00). Aim one third of the laser beam at the tip of the
wire and two thirds at the fracture.
Ensure that the weld area is well covered with argon. The weld spots should
have a metallic lustre.
Weld the clasp alternately from the inside and outside.
Laser wire is applied continuously to the fracture in form of a welding bead.
Fig. 1
2/1

Laser welding – Example
The surface of the weld is smoothened by the so-called smoothening process.
The procedure is described in section 6.13 of the dental procedural instructions.
The welding joint is then processed in the usual manner and polished. The model
cast frame was made of the CoCr alloy remanium ® GM 800 (REF 102-200-00).
Fig. 2
2/2

Laser welding – Example
CoCr model cast:
Extension with bent retention.
To extend a cast partial denture with a bent wire retention, the use of Co-based
wires such as Dentaurum Redur ® is recommended. When using Redur ® wire
1.75 x 0.9 mm (REF 528-158-00) a gap is first ground in the model-cast
prosthesis using a separating disc.
The Redur ® wire is then fitted into this gap in such a way that no space is left.
The areas to be welded are sand-blasted to a dull finish with Al 2 O 3 of grain size
150 µm. The CoCr wire is tack welded to the cast partial denture with one laserweld
spot.
Laser setting: 270 V/5 ms.
Fig. 1
3/1

Laser welding – Example
Using carbon-free CoCr laser wire (REF 528-200-00), weld the two parts
together. Aim one third of the laser beam at the tip of the wire and two thirds
at the gap. Ensure that the weld area is well covered with argon.
The weld spots should have a metallic lustre. The joint is welded completely on
the top side and then in the same way on the opposite side.
Welding material is fed constantly to the joint in the form of a welding bead.
Fig. 2
3/2

Laser welding – Example
The surface of the weld can be smoothened by the so-called smoothening
process. The procedure is described in section 6.13 of the dental procedural
instructions.
The welding joint is then processed in the usual manner and polished.
The frame for the lingual bar was made of the CoCr alloy remanium ® GM 800
(REF 102-200-00).
Fig. 3
3/3

Laser welding – Example
Combination weld for model of cast partial denture (CoCr)
to secondary telescopes (Au-Pt).
Preparation:
A prefabricated retention in the form of a conical peg (REF 111-901-00) is
waxed to the secondary telescope.
Fig. 1
Fig. 2
4/1

Laser welding – Example
The cast partial denture is waxed up over this retenion and left open in the
occlusal and tissue areas. To ensure the best possible fit, the joining gap must
be kept as narrow as possible. The more accurately the work is done, the better
the fit after welding. The parts to be welded are sand-blasted to a dull finish
with Al 2 O 3 of grain size 150 µm.
Welding is carried out on the master model. The first two fixing points are
located on the occlusal side in such a way that the weld on the opposite side
is in the centre of the retention peg.
Laser setting: 270 V/4 ms.
Ensure that the weld area is well covered with argon. The weld spots should
have a metallic lustre. The workpiece is then removed from the model and two
fixing points are applied from the tissue side. The workpiece is then checked for
an accurate fit on the master model.
Fig. 3
4/2

Laser welding – Example
Now weld the joint at high power alternately from the occlusal and tissue side.
Laser setting: 280 V/5 ms.
The number of weld points opposing one another must be identical. If any
warping should be noticed during welding, it must be compensated by
applying counter points. It may therefore be necessary to apply a higher
number of points to one side of the weld in order to compensate for warping.
Fig. 4
In this manner, one joining element is fully welded before beginning to weld the
next secondary crown with the cast frame. This allows the exactness of the fit to
be continuously monitored.
The joint is closed interdentally using a low welding power (270 V/4 ms).
The secondary crowns were made from the alloy Orplid H by Hafner and the
cast partial denture of the CoCr alloy remanium ® GM 700 (REF 102-100-00).
4/3

Laser welding – Example
Laser welding of galvano crowns. Connection with waxed
up and cast pontics.
Preparation:
When waxing up the pontic, it is recommended to form a ring brace or an E brace
of the same thickness in the occlusal third around the galvano caps.
The cast part is sand blasted with Al 2 O 3 of grain size 80–100 µm at a pressure of
3–4 bars. The galvano caps are given a dull appearance using a black marker pen.
Important!
Ensure that the frame fits onto the crowns without any tension and that the
width of the gap between the galvano caps and the cast is as narrow as possible.
Fig. 1
If the preparatory work is accurate enough, it is not necessary to use filling
material. If a wire is used, its diameter should be no greater than 0.4 mm.
Diameter 0.35 mm (dull) is ideal. Material of the same type must be used.
Basic laser setting: 270 V/7 ms, focus at 0 setting. When using a laser with
adjustable focus, a wider weld can be achieved at a setting of 290 V/6 ms.
Focus lever at setting 8–10 (for DL 2002 SFS) or 6 (for Desktop or Com4Laser).
5/1

Laser welding – Example
Procedure:
1.) Position the frame free of stress on the crowns.
2.) Fixing is done on the master model.
Setting 270 V/4 ms.
Then remove and apply 4 counter points at the same setting.
3.) Application of weld:
Setting: 270 V/7 ms.
With more delicate structures, welding can be done safely by shifting the
crosshair by 2/3 to the ring brace frame.
The weld seam is applied with a 2/3 overlap on the upper and lower side of
the ring brace all the way around.
A frequency of 2 Hz should not be exceeded with tacking laser.
Fig. 2
Important!
To avoid deformation of the cervicel edge, a minimum clearance of 2 mm should
be created for the weld seam. (Do not wax up too closely to the preparation limit).
Finish the weld seam on one crown before welding the next.
5/2

Laser welding – Example
The galvano crowns were manufactured using the Hafner system.
The pontic was cast of Orplid Keramik 2 (87,5% Au, 11% Pt), free of Pd, Cu and Ag.
Color: yellow.
Fig. 3
5/3

Laser welding – Example
Fig. 1
Laser welding of ridge structures with implant based components
Preparation:
The structural components are screwed onto the implants. In this case, these are
the cone shaped titanium elements with the compensating sleeve of the Tiolox ®
implant system.
The pre-fabricated structure elements are available from Dentaurum as
rematitan ® bar and rematitan ® attachments in both micro and macro versions,
complete with rematitan ® bar sleeve and retenion. The master model is prepared
for the mounting of the Paralas parallel aligning and fixing device for the
laser welding technique (REF 090-520-00).
With the help of the insert of the parallelometer, the model sleeve is embedded
in plaster in a previously cut hole according to the previously determined path
of insertion. With the correct parallelometer insert, the bar is placed between
the compensating sleeves and cut to size with the conical titanium cutter
maxi plus (REF 123-613-00).
Fig. 2
6/1

Laser welding – Example
Fig. 3
The rematitan ® bar must be fitted with great accuracy and without any gap,
ensuring perfect contact.
Fix the screws for the moving parts of the Paralas in position.
Begin the joint between bar and structure with a tack weld. First apply a central
vestibular weld spot to one end of the ridge.
Laser setting: Voltage: 250 V
Pulse duration: 3 ms
Focus position: 0 gesetzt.
Fig. 4
Ensure that the weld area is well flooded with argon. The weld spots must have
a metallic lustre.
6/2

Laser welding – Example
Then apply a counter spot from the lingual side using the same power setting.
The actual welding process is carried out from the vestibular and lingual side
with increased power settings etc.
Laser setting: Voltage: 270 V
Pulse duration: 4 ms
Focus position: 0
Important: each single spot must be balanced by a single spot on the opposing
side made with the same setting parameters.
Vestibular
Oral
1,2: Tack weld
3,4,5 etc. Joining weld
Fig. 4
In this way, the rematitan ® bar is welded to the balancing sleeve all the way
around, until a continuous bead of weld spots overlapping by 2/3 is achieved.
At first, each bar is connected to only one implant post. Only afterwards is
the other end of each bar welded. This ensures that the accuracy of the fit
can be constantly monitored and the danger of warping in the structure
as a whole, minimized.
6/3

Laser welding – Example
Fig. 5
After the welding process, the bar structure is finished and polished using the
rematitan ® finishing set (REF 135-500-00).
Fig. 6
The rematitan ® retentions are welded to the shortened rematitan ® sleeve with
weld spots applied at the side.
Laser setting: Voltage: 270 V
Pulse duration: 1.5 ms
Focus position: 0
6/4

Laser welding – Example
The pre-fabricated titanium structure components allow accurate and
economical working with one type of material only.
Fig. 7
Complete rematitan ® ridge structure with rematitan ® rider in position.
rematitan ® ridge components:
REF
210-010-00 rematitan ® bar hinge macro complete 1 pack
210-011-00 rematitan ® bar attachment macro complete 1 pack
210-012-00 rematitan ® bar sleeve macro 1 piece
210-020-00 rematitan ® bar hinge micro complete 1 pack
210-021-00 rematitan ® bar attachment micro complete 1 pack
210-022-00 rematitan ® bar sleeve micro 1 piece
6/5

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