Technological innovation and ceramic craftsmanship
Niccolò Casiddu
Computerised virtual elaboration; high-light of the surface mesh; representation of slicing directional lines
Introduction
The experimentation and research project stems from the real need and genuine desire to recuperate the cultural value of the ceramic craftsman tradition, reinterpreting it from a modern perspective based on the sensitivity of contemporary design.
Craftsmanship in general, and ceramic handicrafts in particular, the relative skills and expertise of which are becoming increasingly rare, are viewed with close attention and interest by today’s culture of contemporary design.
In this era of global production and trade, increasingly greater value is being attributed to designing, producing and marketing products by combining technological and expressive development with the essence of places, history, specific/exclusive know-how, and strong and recognisable identities.
For this reason, the regeneration and rediscovery of the competitiveness of Albisola’s ceramic works can also involve the opportunity/capacity of combining techniques and procedures typical of modern industrial processes with the know-–how and expertise of the craftsman laboratory. This is the operating context of the research aimed at achieving the best possible results compatible with what can be offered by technology at reasonable and affordable costs. The use of technological innovation, i.e. the application of modern and/or experimental technologies, does not necessarily imply an expensive and thus elite procedure, but a careful and well thought out decision to use the most adequate solution to solve the problem.
The hybridization of technologies, know-how and skills has always been one of the driving forces behind productive innovation, strengthened by the convergence and by the synthesis implemented by the creative act, capable of first identifying and then exploring new frontiers in the relationship between material, technology and expressiveness, venturing into a global vision in which each element, although complementary to each other, plays a fundamental and exclusive role.
Once the objective to pursue was clearly identified, research was carried by applying the direct experimental method to some case studies. It was decided to seek modern technological resources within the local context to ensure access to and interaction with such resources in the future.
This is the mindset based on which an attempt was made to find a point of synthesis among the modern technologies normally applied to projects and industrial production, and the ceramic craftsmanship of Albisola, with efforts focused to ensure that technological contribution instils new life into the artisan product, without distorting it and, on the contrary, enhancing its uniqueness while enriching it with new ideas based on what may even be very different sectors.
In this way, technology leaves behind the gelid objective of satisfying mathematical certainties and, encountering the craftsman ceramic world, recovers the value of discovery and astonishment, as Ettore Sottsass points out regarding his relationship, in particular, with the colour of ceramic: “It is fantastic to see how from these grey, opaque and even a bit dirty materials things emerge from the kiln burned by fire, but intact. As they are removed, they are completely dustless: they are pure glass, with a luminous and brilliant colour of wild beauty”1.
With this process, ceramic, the ancient material par excellence, acquires its innovative and new role as a link between design thought and material, strengthening the relationship between the industrial product and quality craftsmanship.
Experimentation
The main phases were:
- design elaboration supported by computers and IT;
- three-dimensional virtual verification of the design idea;
- elaboration of mathematical models to interface with the machine tools or rapid prototyping machinery;
- automatic creation of the physical models functional to the artisan building of gypsum moulds;
- automatic creation of gypsum moulds, after construction of semi-finished blocks with a simple geometric form.
Case studies
1. Symmetry and geometric volumes
In this case study rapid prototyping techniques2 were utilised to create a model that faithfully matched the design.
3 kg3 a gym dumbbell, is a formally simple yet also a complex object: in fact, its pure geometric forms do not allow for any margin of error during construction. It also has strong constructive symmetry and a very rigid geometric composition. It was decided to use a technique called casting to produce this hollow object, with a hole that can be closed on one of its bases, to be filled with sand or lead pellets, in order to vary its weight and thus the magnitude of the force to be applied during physical exercise.
The first sketches were followed by the geometric elaboration of the forms using a computer and special three-dimensional virtual modelling software.
A Rhinoceros4 type of program was used since it can perceive the object in its entirety, observing it from different viewpoints, checking in detail the virtual external and internal surfaces. The correct proportions and measurements can be analysed and formally checked by a computer starting from two-dimensional drawings up to the virtual 3D construction of the designed object.
The tactile verification of what is simulated on the computer is a fundamental step in the design process. In this case, the production of study maquettes was replaced by the construction of a functional model to be used afterward to produce the gypsum mould.
Given the object’s symmetry, it was determined that the best production procedure would be to divide it into two equal parts. This division made it possible to use the large base as a support surface, thus reducing the construction of supports to a minimum5. This modus operandi was also determined by the fact that the best direction to apply slicing6 facilitated the construction of 3 Kg in two parts. Afterwards, the two elements, made out of ABS7, were glued together.
Production time amounted to 36 machine hours for rapid prototyping, using 500 cm3 of ABS for the model and 20 cm3 of soluble resin for the supports. The prototyping machines can run continuously and do not require constant monitoring by a technician. Thus, production time can be optimised and operations planned based on a 24/7 schedule, instead of on the usual work hours.
The technology used to make 3 Kg involved the use of an FDM (Fused Deposition Modelling) machine with the following building phases:
1. fusion of the material through the system head;
2. path formation (road);
3. variation in deposit thickness, depending on the material used: 0.125 mm, 0.178 mm, 0.254 mm, 0.305 mm, 0.330 mm (slicing);
4. prototype building.
The prototype built using the FDM does not require any post-treatment. The process also has the advantage of being “clean” as far as environmental impact is concerned. In general, the materials used have a low fusion point and thus the effect on energy consumption is also limited. The material, in the form of a filament, is wound on a coil mounted in the rear of the machine. While being worked, the material is heated to about 270°C so that it is almost a liquid. Then, while the deposition head translates horizontally, the material is extruded and deposited on the previous layer. The system first defines the contour of the section and then its fill-in. The deposition head is equipped with two nozzles that work in an alternating pattern: one deposits the model material and the other the support material, necessary if there are projecting parts, underlying closed cavities, undercuts and holes.
Process phases: from the R.P. model to the product
2. From the file to the mould without intermediary steps
Experimentation with the 3 Kg also focused on verifying another hypothesis8: to build the gypsum mould directly without constructing a physical model of the designed object. To do this high-–speed milling9 was used to create semi-finished cast gypsum blocks using computerised numeric control machine tools10.
The mould’s technical design is created by using subtraction controls between solid figures that can be managed with the software used in 3D design engineering applications. The same three-dimensional image is used to “hollow out” or, even better, to “subtract” from a regular geometric figure, thus determining the dimensional characteristics of the mould.
The mould project file is exported in the .stl format and, once transferred into the computer linked to the machine, manages the mould building process. The file processing program is called Ideas, a software application capable of generating tool paths, after the operator has determined the most suitable mill for the project, establishing the ideal translation speed and the rpm of the spindle11, based on the settings of the cutting characteristics of the material used.
Three-dimensional virtual elaboation of the mould
Digital representation of the mould components
Then, the design activities continue by breaking the mould down into its constituent parts. Thanks to the symmetrical shape of the object it was easer to break down the virtual mould into its various parts. First, the two bases, consisting of simple parallelepipeds, were identified. The upper base contains the truncated conic hole of the riser12 to cast the barbottina13 and then empty the mould. The central part of the mould was then divided into two parts according to the axis of longitudinal symmetry. This subdivision into two shells should be suitable for casting, but because it was necessary to create perfectly defined angles and corners, each semi-mould had to be divided into three parts, based on the cutting tool path and section.
The identical central parts were hollowed out using a tool with a rounded tip, with translation movements parallel to the longitudinal axis and minimum quantities of material removed with each pass. The four peripheral parts, which are also identical, were made instead using a square-tipped tool to create sharp angles and corners. During the “hollowing out” operations, the blocks were automatically ground to reduce them to the nominal design measurements, also guaranteeing the perfect coplanarity and therefore an efficient seal between the parts produced in this manner.
Mould recomposition and assembly of the high-speed milled parts
Thus, gypsum blocks must be made with the dimensions needed to create the individual parts forming the mould. The fluid gypsum is poured into wooden forms lined with smooth laminated material to make detachment easier and create smooth surfaces. The semi-finished blocks are slightly oversized so that they can be ground during the computerised numeric control operation. Milling is carried out on dry blocks that, therefore, when removed from the forms, are allowed to dry for between a few days to several weeks.
The direct transition from the mathematics of the designed object to the construction of the mould significantly reduces the amount of time involved (the high-speed milling operations required 12 machine hours plus 1 hour to define the tool path) and produces perfect forms and dimensions. The process could be even further optimised with an assortment of prefabricated cast gypsum blocks.
Protoypes in enamelled ceramic
3. Beyond the geometry of forms
The process to build the rapid prototyping model14 was also verified for the construction of an object with sinuous and rounded shapes: the ironic revisitation in ceramic of a children’s potty.
In this case, the graphic transposition of the design idea was carried out directly on the computer. The object was produced using a virtual modelling program that completes and modifies the three-dimensional modelling by shifting the construction nodes15 of the same object, translating them in virtual space after linking them with the mouse or indicating their X, Y, Z coordinates.
Virtual elaboration of the project
Model in ABS made using the rapid prototyping method
To interface the project with the prototyping machine, the three-dimensional file is exported in the .stl format. For an object with these dimensions (270 x 380 x 260 mm) it was more convenient to break down the prototype into two parts, sectioned from a horizontal plane. This optimised the processing time and the quantity of material used, reducing the construction supports.
The supports, then partially eliminated, were needed to support the projecting parts with an inclination of more than 45°. The image shows the residual supports, made out of dark resin, preserved to keep the central concave part raised with respect to the bottom.
The surface of the ABS, the material used to build the prototype, can be finished by means of brief passes using sandpaper. Thus, it is possible to reduce the “scaling” effect, due to the sequence of deposition layers of the molten material.
The model again becomes a single piece by gluing the parts using a tough adhesive like cyanoacrylic glue. The joint line was finished with an abrasive cloth to remove any excess glue. The prototype is thus ready for the craftsman production of the gypsum mould.
The mould was made in 4 parts (the base, the two sides, the upper part) maintaining a constant thickness around the model. This improves the uniformity of the barbottina drying and, as a consequence, of the thickness of the ceramic product.
The mould is precisely recomposed by using the centering pins and the connections between the pieces.
After casting the barbottina, and waiting the time needed to ensure optimum drying, the piece is removed.
From the model to the handcrafted construction of the gypsum mould
The prototype
4. Compositional complexity
The process that leads to the craftsman fabrication of a ceramic object by casting with the support of rapid prototyping technology was also experimented starting from a vase design created by the Atelier Mendini16.
The three-dimensional virtual model was developed based on the information indicated in the two-dimensional drawing with the support of a CAD program.
Its analysis confirmed that technology could be used to product the model using automated methods. The direct transition from the mathematical elaborations to construction of the physical model maintains the geometric rigour of the spherical volumes and of the curved lines generated by their intersection.
To optimise the production process, the object was exploded into its elementary geometric elements. The main sphere, forming the body of the vase, was “hollowed out” in the areas in which the “satellite” spheres penetrate into each other.
Peoject drawing
Three-dimensional virtual elaboration
Virtual decomposition of the model to optimise the production phases
Based on how the mould is constructed, it was decided to close the mouth of the vase, slightly under the edge. In this way, the cavity created in the gypsum mould will give the edge a suitable thickness.
The control software of the prototyping machine (Stratasys FDM 3000) was used to identify the cutting lines, generated by secant planes, along which to section the single portions. This operation was necessary to optimise the construction process, obtaining the best relationship with respect to production cost. The object to be prototyped does in fact have a large number of very projecting undercut surfaces. Therefore, the construction of the monolithic prototype would require a large quantity of material for the supports, thus significantly increasing the costs.
The best solution turned out to be that of dividing the four satellite spheres into two equal parts, sectioned by the plane passing through the maximum parallel. The spherical body of the vase was sectioned by planes passing through the meridians, spaced 90° from each other, into 4 sections, divided, in turn, by the median horizontal plane.
Then, the connecting tabs were designed so that the parts would perfectly match during assembly and gluing.
The prototype, with the dimensions 575.5 x 441.6 x 318.6 mm, required about 250 machine hours to construct.
The prototype is then used as a model for the craftsman production of the gypsum mould.
The mould thickness was kept constant, and skilfully so, thus ensuring that the barbottina would solidify uniformly.
Dividing the mould makes it easier to extract the ceramic piece, which has not completely solidified after the first drying phase, thus avoiding breakage or accidental deformations.
The finished product has perfectly regular and defined spherical volumes and lines, generated by their intersection, reduced to precise geometric entities, based on the indications determined from the design documents.
Model in ABS made using the rapid protoyping method
Portion of the gypsum mould for the casting
The product extracted from the mould
The prototype
Conclusions
The experimentation explored the relationship between craftsmanship and technological innovation, verifying the real possible constructive dialogue between two apparently and originally very distant worlds. The synthesis obtained was very encouraging. The application of computer technologies to develop designs and to carry out numeric control operations during some production process phases generated much interest in all those involved. The designers verified the possibility of using tools suitable to generate a complete description of their ideas and to control the total compatibility between the design and the product built. The craftsmen, in their different areas of competence, found a reliable support for producing artefacts that highlight the uniqueness of the know-how of the profession and the intimate knowledge of the material, together with a delicate and fascinating metamorphosis from shapeless mass to finished product. In the relationship with the craftsmanship, the world of modern technologies has found new stimuli to face and solve specific problems as well as new and interesting operating prospects.
The explorations, verifications and results obtained confirmed the validity of the assumptions that gave rise to this experimental research, while also identifying new interesting development prospects.
Applying techniques such as rapid prototyping to fabricate models to use to produce moulds or high-speed computerised numeric control milling to build the moulds directly starting from prefabricated gypsum blocks demonstrated the production reliability, economic competitiveness and preventive control potential of the processing times and the formal quality of the product, highlighting its full integration into the process of “being a craftsman”.
It was also verified that how technologies are applied must (and can) be modified in relation to the characteristics of the design and the consequent construction needs, and can be fully integrated into the actions of doing so typical of craftsman in general and of the ceramist in particular.
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1. Stefano Casciani, Architettura dalla terra: la ceramica secondo Ettore Sottsass Jr., in “Domus speciale”, inserted with “Domus”, no. 887, Dec. 2005.
2. Rapid prototyping – RP: set of systems capable of reproducing even formally complex objects using additive techniques that begin from the mathematical characteristics of the objects.
3. Project: 3Kg; designer: Alessandro Biamonti; experimentation: rapid prototyping model building; digital processing: Alessandro Biamonti; prototype construction: Techimold Servizi S.r.l.; mould building, casting, firing: Jorge Hernandez; enamelling: La Nuova Fenice di Barbara Arto.
4. Rhinoceros: three-dimensional modelling program used extensively in architectural engineering and design.
5. Supports: these are necessary if the object has projecting forms with diagonal lines with an angle of more than 45°. Made with fibreglass, they can be eliminated after building.
6. Slicing: scaling the surface of a rapid prototype, following stratification of the building material by horizontal planes with a predetermined thickness.
7. ABS: acrylonitrile butadiene styrene, thermoplastic copolymer.
8. Project: 3Kg; designer: Alessandro Biamonti/Chiara Bevegni; experimentation: gypsum mould building by means of high-speed milling; digital processing: Alessandro Biamonti; construction of semi-finished gypsum objects: Ylli Plaka; prototype construction: Techimold Servizi S.r.l.; casting, firing: Ylli Plaka; enamel, lustre, 2nd/3rd fire: La Nuova Fenice di Barbara Arto.
9. High-–speed milling: mechanical process that utilises the tool’s high rotation speed and rapid movement to remove chips.
10. Computerised numeric control: machines equipped with automated systems that manage the cutting speed, the definition and the path of the tools to optimise the production process.
11. Spindle: mechanical part that transmits the rotary motion.
12. Riser: piece projecting from the upper part of a fusion casting after drawing.
13. Barbottina: binder made by mixing water and clay.
14. Project: Cagarino/Puzzola; designer: Guido Venturini; experimentation: rapid prototyping model building; digital processing: Guido Venturini; prototype construction: Techimold Servizi S.r.l.; mould building, casting, firing: Ylli Plaka; enamel, lustre, 2nd/3rd fire: La Nuova Fenice di Barbara Arto.
15. Node: it is possible to assign a different weight to each node, i.e. a different capacity to drag lines of construction or surfaces with it, in the spatial translations.
16. Project: Tre sfere; designer: Alessandro Mendini; experimentation: rapid prototyping model building; digital processing: Chiara Bevegni; prototype construction: Techimold Servizi S.r.l.; mould building, casting, firing: Ylli Plaka; enamel, lustre, 2nd/3rd fire: La Nuova Fenice di Barbara Arto.
Research commissioned in 2006 by Attese Edizioni to the Department of Science for Architecture, Faculty of Architecture at the University of Genoa within the context of the 3rd Biennial of Ceramics in Contemporary Art.
