The paper presents results of a study undertaken to implement the dental casting technique of small parts characterized by extremely complex drawings of surfaces and thicknesses reduced specific objects. During the study there was a similarity between this technique and casting forms obtained with models used to obtain spare fuses in the car industry. They could highlight differences between the materials and the equipment used in dental technology and art foundries

Ana DONIGA

Bogdan FLOREA

Gheorghe FLOREA

The Annals of “Dunarea de Jos” University of Galati Fascicle IX Metallurgy and Materials Science

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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 2 – 2012, ISSN 1453 – 083X 
 
 
 
 
 
THE DENTAL TECHNOLOGY IN ART FOUNDRY 
 
Gheorghe FLOREA1, Ana DONIGA1, Bogdan FLOREA2 
1“Dunarea de Jos” University of Galati 
2Politehnica University of Bucuresti 
email: gflorea@ugal.ro 
 
ABSTRACT 
 
The paper presents results of a study undertaken to implement the dental 
casting technique of small parts characterized by extremely complex drawings of 
surfaces and thicknesses reduced specific objects. During the study there was a 
similarity between this technique and casting forms obtained with models used to 
obtain spare fuses in the car industry. They could highlight differences between the 
materials and the equipment used in dental technology and art foundries. 
 
KEYWORDS: dental, foundry, design, casting technique 
 
1. Introduction 
 
Achieving a work of art or decorative, or 
cultural, is a challenge to any existing foundry and, 
especially, informer. For the production of small 
objects, whether jewelery or religious objects or 
souvenirs or ornaments, with accessibile, economical 
technology, can be a profitable productive activity. 
The dental technique, with specific castings and tools 
developed to produce them, is an alternative to large, 
massive machines that require large space for 
installation and operation, and high consumption of 
materials and energy. 
In addition, this technique provides the 
possibility to obtain thin-walled parts without surface 
defects, which usually requires no further machining. 
The possibility to obtain complex parts attracts the 
attention of artists and art foundry, giving at the same 
time, ideas to dental technicians.  
Time has moved from manually operated 
centrifugal cast machine or vacuum has changed the 
construction of the fuse model, forms and methods of 
implementing the execution model etc. 
In general the phases of dental technology are 
the same as those encountered in the casting of 
precision engineering industry, with differences in the 
chemical composition consisting of alloys and 
training materials, equipment size, etc. 
 
2. Making mold and fuse model. 
Owner results 
 
Making a model casting part that the subject of 
this study, taking into account the complexity and 
difficulty of its exectuţiei was not possible for this 
purpose using a brass icon whose design had a very 
complex: design complex and reduced height and 
thickness of the reduced model details as seen in 
Figure 1. 
 
 
Fig. 1. Metal model used in the study 
 
Unlike dental technique which fuses are easily 
realizable models for each paper in the study to obtain 
models chosen for making a mold capable of 
providing a large number of children in terms of 
reproduction and fine detail, the suitable material for 
obtaining them are caucicul silicone. By this method 
we adopted is different and quite common procedures 
foundries to manufacture precision molds which are 
currently used metallic materials, easily fusible 
metals, plastics etc. 
Again, the main conditions imposed molds are 
perfect: 
-play configuration model as the original 
metallic, precision piece depends, largely, the 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 2 – 2012, ISSN 1453 – 083X 
 
 
 
dimensional accuracy of the model, a goal achievable 
through more precise machining and finishing mold 
advanced as the active surface or, if metal molds, 
chrome plating work surfaces thereof; 
-keeping the size as well during the 
manufacturing technology fuses models, not to 
produce the dimensional deviations between tracks; 
-making it at least cost to the number of parts is 
poured. 
Taking shape piece (making mold - Fig. 2) was 
quite easy by pouring silicone rubber, in turn, form 
the two cavities separated by surfaces and 
contraformele piece of plaster made previously, the 
separation plan, configuration, model, representing it 
its flat surface. 
 
 
 
Fig. 2. Matrix used to obtain models fuses 
 
Fuses to obtain models (Fig. 3) was used dental 
wax, which melted, was injected into the mold. 
Injecting wax into the mold, the mold melt extraction 
model and its finish, before being put on stream 
operations is seen with conventional precision 
casting. 
 
 
Fig. 3. Model easily fusible 
 
"Frame" used to achieve form a metallic 
cylinder with a diameter of 100 mm, closed at one 
end with a cover that is integral with the casting 
funnel model, centrally located. The icon, different in 
shape and dimensions of castings usually in dental 
technology workshops, also meant a disposition 
otherwise shaped patterns (Fig. 4): back to back, 
evenly spaced about the stem of the funnel and the 
rods of wax it, and ventilation channels, all the wax, 
fixed to the back of each.  
Network hardware is made based on the same 
criteria as for casting accuracy, making sure that it 
has little weight as possible to achieve a minimal 
casting alloy, condition very important, especially for 
alloys high cost. 
 
 
 
Fig. 4. Layout models as a whole form-fitted 
models on the table vibrating, ready pentru 
turnarea mass packaging 
 
Generally, the material used in dental 
technology training is a mixture of refractory material 
(usually silicon dioxide), binder (calcium sulfate, 
phosphate, ethyl silicate etc..).  
And other chemicals, used to ensure certain 
properties physical. This material, marketed as 
"packing table'' not specified composition 
representing Supplier's secret.  
To obtain the mixture of training, all materials 
used in dental technique, using a container (bowl) and 
a clean spatula, scrap material enhanced hardness can 
reduce interference, change and modify the setting 
time dilation. Have the manufacturer's requirements 
fully, being about a particular product.  
Mixture was mixed in vacuum forming, thus 
ensuring uniform mixing of air and remove it, then 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 2 – 2012, ISSN 1453 – 083X 
 
 
 
was cast in the form carefully placed on a vibrating 
table. Forms manually tamping method is inadequate, 
because on the one hand wax models can be damaged 
and the other does not get a uniform compaction of 
the mixture and the complete elimination of air 
bubbles which form to fill box saturated mixture. 
After hardening and cooling shape at 35-40oC (the 
process of strengthening the reaction mixture creates 
heat), it is placed in an oven pre-heating (Fig. 5), cone 
down on such support that they can escape wax, 
which will be heated to remove the wax and bring it 
to the casting temperature. 
 
Fig. 5. The oven used to dry forms. 
Casting alloy to form precision models in forms 
fuses is warm, with temperatures above 800oC, to 
ensure their proper filling. The temperature inside the 
oven to start the heating process of the form is the 
environment. 
Turning water into steam in form, with 
increased intensity, starting at a temperature of 
110oC. During evaporation, the temperature remains 
at 110-120oC shape, and when it reached the center 
temperature of 120oC, the evaporation is finished and 
the temperature rises again. 
Cristobalitului transformation starts at a 
temperature of 220oC form increased in intensity up 
to 255oC, where transformation reached its climax, 
and ends at a temperature of 270oC. In the phase 
where cristobalitul turns itself form temperature 
should be between 255oC and 270oC. In the packed 
mass heating, quartz transformation does not begin 
until the temperature reach 570oC, and between 570 
to 580oC in a period of 30 minutes, to create optimal 
conditions for transformation of quartz. It is 
important that this temperature is reached inside the 
shape. 
Quartz sintering occurs between 820-860oC and 
is not subject to time. This process takes place 
without causing movement of expansion or 
contraction. This phase is particularly important for 
precision work. Working temperature of the packed 
mass must always reach 900oC to ensure smooth and 
accurate surface detail molded cast part. 
Casting icon was made of two alloys used 
throughout the dental technique, respectively gaudent 
(9.65% Al, 4.25% Ni, 2.07% Fe, 1.18% Mn, 
remainder Cu) and niadur (62% Ni, 24.5% Cr, 10.3% 
Mo, 1.7% Si, 1.5% Fe) and electric resistance was 
melting. (Fig. 6) 
 
 
 
Fig. 6. Electric molding furnace 
 
Fig. 7. Centrifugal casting in plant field 
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THE ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI. 
FASCICLE IX. METALLURGY AND MATERIALS SCIENCE 
N0. 2 – 2012, ISSN 1453 – 083X 
 
 
 
  
a b 
Fig. 8. Finished piece: a - from gaudent; b - from niadu 
To achieve piece molding technique was used 
centrifuge machine used for this purpose is shown in 
Figure 7.  
After cooling the alloy, form was destroyed in 
order to extract part of it, they are subject to further 
removal process known network hardware and 
finishing, obtaining finally finished icons (Fig. 8). 
 
3. Conclusions 
 
Forms of plaster, usually are part of permanent 
forms, while they are forms of temporary dental 
service, the packaging of this model requiring fuses.  
Forms obtained with fusible models allow 
casting a special dimensional accuracy even in art, 
where models are highly complex and can not be 
"copied". In modeling does not take too much 
account of contraction. 
Forms of plaster used in the study will produce 
parts with very smooth surfaces, what if parts of the 
category of art is a basic ceriţă. The high percentage 
of water in mixtures used to obtain forms, requires 
the use of their hardware only after their complete 
drying, the difference, the net favorable dental 
technique, consisting in reducing the period of 10 to 
12 times. 
By casting models forms easily fusible, the 
technique adopted, it can get pretty thin walled 
parts, and can thus significantly reduce the weight of 
the object.  
Casting method in accordance with fusible 
models in precision casting, allows recovery of burnt 
material, while in dental technology that burns thus 
lost. 
Materials used to obtain the forms in the studies 
normally use dental technique, are trade secrets of 
companies supplying and using them is by their 
recommendations. Plaster forms, even when used for 
packaging weight, are relatively inexpensive 
compared to other precision casting processes. 
 
References 
 
[1]. Florea, Gh., Chiriac, Al., Mărginean, I. - Procedee 
performante de punere în formă, Editura Europlus, (2008). 
[2]. Buzilă, S. - Tehnologia formării, Editura Didactică şi 
Pedagogică, Bucureşti, (1981). 
[3]. Chira, I., ş.a. - Procedee speciale de turnare, Editura 
Didactică şi Pedagogică, Bucureşti, (1980). 
[4]. Fedelman, S. S. - Turnarea de precizie, Editura Tehnică, 
Bucureşti, 1953 
[5]. Buzilă, S. - Procedee speciale de formare, Editura Didactică şi 
Pedagogică, Bucureşti, (1978). 
 
 
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The Dental Technology in Art Foundry

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