Editing Pottery (section)

=== Shaping ===
Before being shaped, clay must be prepared. This may include [[List of pottery terms#K|kneading]] to ensure an even moisture content throughout the body. Air trapped within the clay body needs to be removed, or de-aired, and can be accomplished either by a machine called a vacuum [[List of pottery terms#pug|pug]] or manually by [[List of pottery terms#W|wedging]]. Wedging can also help produce an even moisture content. Once a clay body has been kneaded and de-aired or wedged, it is shaped by a variety of techniques, which include:

* Hand-building: This is the earliest forming method. Wares can be constructed by hand from [[Coiling (pottery)|coils of clay]], combining flat slabs of clay, or [[Pinch pot|pinching]] solid balls of clay or some combination of these. Parts of hand-built vessels are often joined with the aid of [[Slip (ceramics)|slip]]. Some [[studio potters]] find hand-building more conducive for one-of-a-kind works of [[art]].[[File:At_the_potter's_workshop.webm|thumb|A potter using a potter's wheel describes his materials (in Romanian and English)]]
* The [[potter's wheel]]:  In a process called "throwing" (coming from the [[Old English]] word ''thrawan'' which means to twist or turn<ref>{{Cite web |date=June 12, 2019 |title=Why On Earth Do They Call It Throwing? {{pipe}} Contractor Quotes |url=https://contractorquotes.us/earth-call-throwing/ |url-status=dead |archive-url=https://web.archive.org/web/20070203065817/http://www.ceramicstoday.com/articles/why_throwing.htm |archive-date=February 3, 2007}}</ref>) a ball of clay is placed in the centre of a turntable, called the wheel-head, which the potter rotates with a stick, with foot power or with a variable-speed [[electric motor]]. During the process of throwing, the wheel rotates while the solid ball of soft clay is pressed, squeezed and pulled gently upwards and outwards into a hollow shape. Skill and experience are required to throw pots of an acceptable standard and, while the ware may have high artistic merit, the reproducibility of the method is poor.<ref name="ReferenceA2">"Whitewares: Production, Testing And Quality Control." W.Ryan & C.Radford. ''Pergamon Press.'' 1987</ref> Because of its inherent limitations, throwing can only be used to create wares with [[radial symmetry]] on a [[vertical axis]].
* Press moulding: a simple technique of shaping by manually pressing a lump of clay body into a porous mould.<ref>Two Centuries of Hellenistic Pottery Homer A. Thompson. Vol. 3, No. 4, The American Excavations in the Athenian Agora: Fifth Report (1934), pp. 311-476. The American School of Classical Studies at Athens</ref><ref>New Zealand Potter. Vol. 30 No. 1 1988, pp. 7</ref><ref>Forming Techniques - for the Self-Reliant Potter.  Henrik Norsker, James Danisch. Vieweg+1991.Teubner Verlag Wiesbaden</ref>
* Granulate pressing: a highly automated technique of shaping by pressing clay body in a semi-dry and granulated form in a [[Moulding (process)|mould]]. The body is pressed into the mould by a porous die through which water is pumped at high pressure. The fine, free flowing [[Granular material|granulated]] body is prepared by [[spray drying]] a high-solids content slip. Granulate pressing, also known as ''dust pressing'', is widely used in the manufacture of [[ceramic tile]]s and, increasingly, of plates.<ref>Using Polymers as a Binder for Improvement of Mechanical Strength of Tableware in Isostatics Press Technology. A. Arasteh Nodeh. Iranian Chemical Engineering Journal – Vol.9 - No. 48 (2010)</ref><ref>Control And Automation In The Ceramic Industry Evolution. José Gustavo Mallol Gasch. Ceramic Forum International. December 2007 84 (12):E55-E57</ref><ref>Reference Document On Best Available Techniques In The Ceramic Manufacturing Industry. European Commission August 2007</ref>[[File:Sèvres_-_Grand_atelier_-_calibrage_140.jpg|thumb|Jiggering a plate]]
* [[List of pottery terms#J|Jiggering and jolleying]]: These operations are carried out on the potter's wheel and allow the time taken to bring wares to a standardized form to be reduced. ''Jiggering'' is the operation of bringing a shaped tool into contact with the plastic clay of a piece under construction, the piece itself being set on a rotating plaster mould on the wheel. The jigger tool shapes one face while the mould shapes the other. Jiggering is used only in the production of flat wares, such as plates, but a similar operation, ''jolleying'', is used in the production of hollow-wares such as cups. Jiggering and jolleying have been used in the production of pottery since at least the 18th century. In large-scale factory production, jiggering and jolleying are usually automated, which allows the operations to be carried out by semi-skilled labour.
* [[List of pottery terms|Roller-head machine]]: This machine is for shaping wares on a rotating mould, as in jiggering and jolleying, but with a rotary shaping tool replacing the fixed profile. The rotary shaping tool is a shallow cone having the same diameter as the ware being formed and shaped to the desired form of the back of the article being made. Wares may in this way be shaped, using relatively unskilled labour, in one operation at a rate of about twelve pieces per minute, though this varies with the size of the articles being produced. Developed in the UK just after [[World War II]] by the company ''Service Engineers'', roller-heads were quickly adopted by manufacturers around the world; it remains the dominant method for producing both flatware and holloware, such as plates and mugs.<ref>An Introduction To The Technology Of Pottery. Paul Rado. Pergamon Press. 1969</ref>
* Pressure casting: Is a development of traditional slipcasting. Specially developed [[Polymeric material|polymeric materials]] allow a mould to be subject to application external pressures of up to 4.0 MPa – so much higher than slip casting in plaster moulds where the capillary forces correspond to a pressure of around 0.1–0.2 MPa. The high pressure leads to much faster casting rates and, hence, faster production cycles. Furthermore, the application of high pressure air through the polymeric moulds upon demoulding the cast means a new casting cycle can be started immediately in the same mould, unlike plaster moulds which require lengthy drying times. The polymeric materials have much greater durability than plaster and, therefore, it is possible to achieve shaped products with better dimensional tolerances and much longer mould life. Pressure casting was developed in the 1970s for the production of sanitaryware although, more recently, it has been applied to tableware.<ref>'Sanitaryware Technology'. Domenico Fortuna. Gruppo Editoriale Faenza Editrice S.p.A. 2000.</ref><ref>{{cite web |title=DGM-E.pdf |url=http://www.dorst.de/dorst_seite/Infolines_PDF/Infoline%20DGM/DGM-E.pdf |access-date=2010-09-04}}{{dead link|date=August 2017|bot=InternetArchiveBot|fix-attempted=yes}}</ref><ref>{{cite web |date=2000-11-21 |title=Ceramicindustry.com |url=http://www.ceramicindustry.com/Articles/Feature_Article/4025c9fbcb9c7010VgnVCM100000f932a8c0____ |url-status=dead |archive-url=https://web.archive.org/web/20110708132727/http://www.ceramicindustry.com/Articles/Feature_Article/4025c9fbcb9c7010VgnVCM100000f932a8c0____ |archive-date=2011-07-08 |access-date=2010-09-04 |website=Ceramic industries.com}}</ref><ref>''Dictionary Of Ceramics''. Arthur Dodd & David Murfin. 3rd edition. The Institute Of Minerals. 1994.</ref>
* [[RAM press]]ing: This is used to shape ware by pressing a bat of prepared clay body into a required shape between two porous moulding plates. After pressing, compressed air is blown through the porous mould plates to release the shaped wares.<ref>Operations Optimization Of RAM Press Machine By Frame Assembly Techniques. Pairoj Bootpeng, Yuttapong Naksopon, Nuttawut Pebkhuntod, Pattana
Charuenying, And Pakawadee Sirilar. Suranaree J. Sci. Technol. 21(2):105-109</ref>[[File:Slip_Casting_di_kilang_Claytan.png|thumb|Filling a plaster mould with slip]][[File:Sèvres_-_petit_coulage_-_démoulage_19.jpg|thumb|De-moulding a large vase after it has been slip cast]]
* [[Slip casting]]: This is suited to the making of shapes that cannot be formed by other methods. A liquid [[Slip (ceramics)|slip]], made by mixing [[clay]] body with water, is poured into a highly absorbent plaster mould. Water from the slip is absorbed into the mould leaving a layer of clay body covering its internal surfaces and taking its internal shape. Excess slip is poured out of the mould, which is then split open and the moulded object removed. Slip casting is widely used in the production of sanitaryware and is also used for making other complex shaped ware such as teapots and figurines.
* [[Injection moulding]]: This is a shape-forming process adapted for the tableware industry from the method long established for the forming of [[thermoplastic]] and some metal components.<ref>"Novel Approach To Injection Moulding." M.Y.Anwar, P.F. Messer, H.A. Davies, B. Ellis. Ceramic Technology International 1996. ''Sterling Publications Ltd.'', London, 1995. pp. 95–96, 98.</ref> It has been called ''Porcelain Injection Moulding'', or ''PIM''.<ref name="autogenerated103">"Injection Moulding Of Porcelain Pieces." A. Odriozola, M.Gutierrez, U.Haupt, A.Centeno. ''Bol. Soc. Esp. Ceram.'' Vidrio 35, No. 2, 1996. pp. 103–07</ref> Suited to the mass production of complex-shaped articles, one significant advantage of the technique is that it allows the production of a [[cup]], including the handle, in a single process, and thereby eliminates the handle-fixing operation and produces a stronger bond between cup and handle.<ref>"Injection Moulding Of Cups With Handles." U.Haupt. ''International Ceramics.'' No. 2, 1998, pp. 48–51.</ref> The feed to the mould die is a mix of approximately 50 to 60 per cent unfired body in powder form, together with 40 to 50 per cent organic additives composed of [[Binder (material)|binders]], [[lubricant]]s and [[Plasticizer|plasticisers]].<ref name="autogenerated103" /> The technique is not as widely used as other shaping methods.<ref>"Injection Moulding Technology In Tableware Production." ''Ceramic World Review.'' 13, No. 54, 2003. pp. 94, 96–97.</ref>
* [[3D printing]]: There are two methods. One involves the layered deposition of soft clay body similar to fused deposition modelling (FDM), and the other uses powder binding techniques where clay body in dry powder form is fused together layer upon layer with a liquid.<ref>Research on The Application of Ceramic 3D Printing Technology. Bin Zhao. March 2021 Journal of Physics Conference Series 1827(1):012057</ref><ref>From Control To Uncertainty In 3d Printing With Clay. Benay Gürsoy. Computing For A Better Tomorrow. Education And Research In Computer Aided Architectural Design In Europe. Pp. 21-30. 2018</ref>
* [[Injection moulding]] of ceramic tableware has been developed, though it has yet to be fully commercialised.<ref>'The Application Of Injection Moulding Technology In Modern Tableware Production. 'P. Quirmbach, S. Schwartz, F. Magerl. Ceramic Forum International 81(3):E24-E31, 2004</ref>