_A METHOD FOR PRODUCING A PRINTABLE OBJECT FIELD The present disclosure relates to producing an object that is produced using additive manufacturing. BACKGROUND There is a need to utilize modern techniques like 3D printing, in fabrication of tissue engineering scaffolds, implantable or per os delivered drug releasing dossiers, soft and hard tissue replacing reconstructions. Among many techniques tissue engineering and additive manufacturing (AM) techniques have recently been tested for manufacturing hard tissue reconstruction devices and tissue engineering scaffolds which are either biostable, biodegradable or partially biodegradable up to the indication they are used. Some criteria of a scaffold include for example biocompatibility, adequate mechanical strength, biodegradability or biostability, and sufficient porosity. Biocompatibility of a scaffold may be defined as its ability to support normal cellular activity, including molecular signalling systems, without any local and systemic toxic effects to the host tissue. Furthermore, the hard tissue replacing device or biostable scaffold should withstand loads of the physiologic function in long term. For implantable constructs and dental constructs the requirements may comprise for example non-toxicity, non- allergenicity, sufficient strength, wear resistance and surface texture (implants) and gloss (dental constructs). BRIEF DESCRIPTION The scope of protection sought for various embodiments of the invention is set out by the independent claims. The exemplary embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention. According to a first aspect there is a method for producing a printable object, the method comprising: injecting printing material using a printing element having a printing tip that is movable, into supporting material, wherein the supporting material comprises initiator that is free radical polymerization initiator compatible to enhance curing of the printing material while not causing polymerization of the supporting material, and curing the injected printing material using at least one light emitting source providing light that causes polymerization of the printing material and activation of the initiator in the supporting material, wherein the curing is performed simultaneously with the injecting of the printing material. It is to be noted that as the supporting material may comprise initiator(s), it may also be understood to be an initiator system. In an example embodiment according to the first aspect, the method may comprise a resin injection bioprinting, using 3D printer, having an injection tip moving in x-y-z directions and simultaneuously injecting and curing the material layer-by-layer for the object to biocompatible hydrogel support. In an example embodiment according to the first aspect, there is a biocompatible, translucent, non-solid supporting and oxygen inhibition of the free radical polymerization eliminating material into which the printing material is injected and polymerized in the way that printing layers will adhere to each other via polymerization reaction of the injected material. In an example embodiment according to the first aspect, there is additives of free radical polymerization initiators compatible to enhance curing of the injectable material but not causing curing of the hydrogel. In an example embodiment according to the first aspect, the radical polymerization initiator additive can be activated by the same or other wavelengths of light than the polymerizable injected material. In an example embodiment according to the first aspect, there are additives of biologically active molecules, drugs, compounds, fillers, or cells in the supporting material to be transferred to the printable object. In an example embodiment according to the first aspect, the supporting material ensures instant curing of the printable material by help of the initiator of initiator system of the printable material and by this, the printable object can have complicated shapes without having several supports to the printing base. In an example embodiment according to the first aspect, the method may be performed, at least partly, using a robocasting 3D printer that has a chamber and injection tip for the printing material which control the viscosity and dispersion of optional fillers and other additives of the printing material via temperature or ultrasound waves. In an example embodiment according to the first aspect, the method comprises using a computer program to control the printing velocity, printing layer thickness, printing material viscosity and filler dispersion, polymerization light wavelength and power in the printing process. In an example embodiment according to the first aspect, the printable object is initially fixed to the bottom of the supporting material well with the first contact of the printed material. In an example embodiment according to the first aspect, the method is performed by a system that comprises one or several curing units for activating initiators for light- initiated polymerization of the printed material allowing photopolymerization to take place during or after injecting the printing material to the supporting material for solidification of the printing material and adhering the injected material layers to each other. In an example embodiment according to the first aspect, the light radiation for initiation and propagation of the polymerization is continuous or pulsatile of one or several wavelengths and it is coming from one or several directions. In an example embodiment according to the first aspect, the supporting material is non-solid material is high-viscosity liquid or gel with or without solid, semisolid, molecular, ion or cell additives which can be attached inside or surface or both of the printed object. In an example embodiment according to the first aspect, supporting material protects the printed material from oxygen whenever it is prone for oxygen inhibition of polymerization. In an example embodiment according to the first aspect, the supporting material transfers compounds of biological activity like growth factors, drugs, bioactive fillers or cells to the surface of inner parts of the printable object. According to a second aspect, there is a system comprising a robocasting device that is configured to perform the method according to the first aspect. According to a third aspect, there is a system comprising a robocasting device that means for performing the method according to the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a robocasting system and supporting material. Figure 2 illustrates the supporting material with additives which will be transferred to the printed object. Figures 3 and 4 illustrate producing a printable object that can be used as an implant. Figure 5 illustrates surface hardness of the printed object. Figure 6 illustrates surface hardness of the printed object measured from the surface and inner part of the printed object. DETAILED DESCRIPTION The following embodiments are exemplifying. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. One group of materials which has good physical properties and have been employed in AM, which may also be understood as 3D printing, and bioprinting are resin-based materials and composites. These materials can also be processed by several kinds of AM techniques. However, there are some limitations in the AM techniques to fabricate complex shaped objects and those which requires good biocompatibility. Also, there are limitations in the present AM techniques to transfer biologically active substances to the AM prepared object. Another group of material which has a role in bioprinting of tissue engineering scaffolds, drug delivery vehicles, cell encapsulation are hydrogels. A hydrogel is a cross- linked hydrophilic polymer system that does not dissolve in water. Hydrogels posses physiochemical properties that make them suitable for wide range of biomedical applications. Hydrogels are used also as biomaterial in soft tissue augmentation because their highly viscous nature resembles natural soft tissue. In addition, hydrogels can be loaded with biologically active substances and cells. However, their mechanical characteristics may be weak for hard tissue repair and replacement applications. There are several 3D printing techniques, devices and resins available which are used to fabricate tissue engineering scaffolds, implants, implantable or per os delivered drug releasing dossiers, dental and even living cell constructs. For example, a biostable thermoset monomer system that can be used in implants and dental restorations is based on mono or multifunctional acrylate or methacrylate monomers and filler composites, whereas biodegradable resin-based materials are preferred for tissue engineering scaffolds and drug releasing dossiers. Examples of drugs to be released from the printed object are anti-inflammatory drugs and antibiotics. Monomers hardens in polymerization by free radical polymerization or cationic polymerization or cationic photopolymerization which are reactions inhibited e.g. by oxygen. For having complete hardening, i.e. degree of cure called and monomer conversion (DC) of the monomers from inner part to the surface, oxygen should not be present in the curing process. Negative effect of oxygen may be hindered for example by using oxygen protective barrier before final curing of the object is performed. A high DC of the monomers may help to achieve benefits such as good mechanical properties, good biocompatibility and high surface gloss when it is desired like in dental constructs. Other methods may also be used to prevent the inhibitory effect of oxygen of light- curing. These are curing the object in a vacuum chamber or in otherwise an oxygen- free atmosphere of inert gas (nitrogen, carbon dioxide, argon, helium). When producing an object, that is a printable object, using a liquid-based AM process, with stereolithography photocuring resin may be cured layer-by-layer from a liquid bath. It may also be possible to inject the printing material in gas, for example in air, on solid surface and cure it layer-by-layer with light of desired wavelength and irradiation power. For the AM process a system such as a robocasting system, which uses a robocasting technique, may be used for the AM process. The robocasting system may be analogous to direct ink printing and other extrusion-based AM printing techniques used in an AM process including bioprinting of cells. If there is not supporting material for the injectable material, which is the printing material, the printable object may be supported using other means such as with several supporting stubs, to obtain the solid surface. Depending on the rheological properties of the printing material, a distance between adjacent stubs may be determined. The stubs may then be removed when the object is finalized. Yet, using stubs may in some examples diminish dimensional accuracy of the object to be produced. An alternative method for printing the material in gas and using several supporting stubs is to have a supporting material into which the printing material is injected. The supporting material may be liquid material. A system using this method can be used for example to deposit and cure bioink of mixture of cells, supporting matrix, nutritients to create tissue-like constructs. The bioink for example may be printed into gel poloxamer, which is a biocompatible gel supporting the printing bioink. When the poloxamer gel and other gels are used as supporting material for 3D printing with printing material that is of thermoset monomers or composites with the robocasting technique, the gel may however contaminate the surface of printing layers and the printing layers may therefore not adhere to each other via polymerization, which may cause a weak construct in the printable object. In addition, movement of a printing tip of the robocasting system in the gel may also cause movement of the gel itself which lowers the dimensional accuracy of the printable object. It may also be likely that the printing pressure of the material from the printing tip spreads into the supporting gel before it starts to polymerize. Thus, it would beneficial to have a system and/or method to produce printable objects that are well polymerized by thermoset resin robocasting injection technique which allows good layer-to-layer adhesion, eliminates of oxygen inhibition layer and provides instant curing of the injectable material and support for the injectable material for high precision printable object. A possibility to add ingredients that may be understood as additives, such as cells and compounds, to the printable object during the printing process via the supporting material may be a desired property as well. An exemplary embodiment of a robocasting device comprised in a robocasting system may be understood as a device comprising a printing head with a chamber for printing material, an injection tip which is configured to inject the printing material to a supporting material in which the polymerization of the printing material takes place, a computerized controlling unit for controlling injection parameters of pressure, temperature and viscosity, velocity of movement of the injection tip in x-y-z direction within the supporting material, light emitting units to polymerize the printed material in the supporting material and activating the initiator system in the supporting material, and a heating-cooling unit and ultrasound emitting units in the printing chamber. Such robocasting device may be utilized for printing various objects, for example objects that can be used in tissue engineering scaffolds, surgical implants for hard and soft tissue repairs and replacement, and for dental constructs. Figure 1 illustrates an exemplary embodiment of a system comprising a robocasting device such as the robocasting device described above. Thus, the system may be understood as a robocasting system. In this exemplary embodiment, there is a part of the robocasting device called a printing element, which comprises an injection tip 130 that is configured to move in the directions x, y and z 105 and the movement may be controlled by a controlling unit that is a computerized controlling unit comprising computer instructions configured to control the movement. The printing element also comprises a chamber 170 that may comprise printing material of resin or resin composites. Viscosity of the printing material may be controlled by a thermoelement 120 of the chamber 170. The thermoelement may be comprised in the printing element and may be attached to, or adjacent to, to the chamber 170. In other words, the thermoelement 120 is caused to control the viscosity of the printing material. Dispersion of fillers of the resin or resin composites may be controlled by ultrasound waves from an ultrasound unit 110. The injection tip 130, which moves in supporting material 140, may be of polished steel and may optionally be coated with material like polytetrafluoethylene (teflon) for lowering friction of the tip in the supporting material during the printing movement. The injection tip 130, in this exemplary embodiment, has also a shadow-plate 190 which hinders direct curing light transmission of the upper light emitting sources to cure the printing resin at the tip of the injection tip 130. This eliminates clogging of the injection tip by the cured printing resin. The shadow-plate 190 may be vertically adjustable to control the shadow area i.e. the distance from the injection tip where the injectable resin starts to polymerize. Thus, in general, the shadow plate 190 is placed in the injection tip 130 such that the printing material at the tip of the injection tip 130 is prevented from curing. The supporting material may be comprised in any suitable container such that the printing tip may be allowed to print the printing material into to the supporting material. The supporting material comprised in the container may be understood as a supporting material well 180. Walls of the well are translucent for curing light transmission. Inner diameter of the injection tip can be between 0.05 to 10.0 mm, for example 0.20 mm for dimethacrylate resin composites. Length 1002 of the injection tip from the bottom of the chamber to the tip is from 1.50 mm to 100.0 mm being 1.0 mm more than the depth 1004 of the supporting material. The depth 1004 of the supporting material at least 1.0 mm more than the height 1006 of the printed object. The printing material may be biodegradable or biostable resin or resin composite of one of several functional reactive group containing polymerizable monomer or co- monomer system with compounds allowing photopolymerization of the resin or resin composite. After polymerization the resin can be either thermoplastic, thermoset, copolymer, blend or interpenetrating polymer network. When the printing material is resin composite with particulate or discontinuous fiber fillers the fillers have less than the inner diameter of the injection tip. Printing material, that is comprised in the chamber 170, is injected through the injection tip 130 to the bottom of supporting material well 180 and subsequently light-cured by one or more light emitting sources 150 which are located in the injection tip 130 and/or on the sides or the bottom of the supporting material well 180. Light emitting sources at the sides or bottom are used to activate the initiators to form free radicals in the supporting material. Wavelength of the emitting light of the light emitting sources may vary from each other. Polymerization light may be emitted, by the light emitting sources 150, continuously or with pulses during or after the printing process. The supporting material which is not polymerized by itself may be gel or viscous liquid which supports the injectable material injected using the injection tip 130 before the printing material is polymerized by the curing light produced by the one or more light emitting sources 150. When the head of the injection tip is to be kept without curing light radiation, i.e. eliminating clogging of the head, the shadow-plate is adjusted to the correct height up to the distance of the upper light emitting source from the central axis of the injection tip 132. If the supporting material is e.g. a gel of non-ionic polyacrylamide (PAM) ( (C3H5NO)n) – water hydrogel (PAH), which supports the printing material, that has a benefit of allowing printing layers to be adhered together and eliminating or hindering formation of oxygen inhibition layer on the surface of the printed object 160. In the PAH water is bonded between cross-linked polymer PAM by hydrogel bonding. PAH is stable, non-toxic, non-allergenic, non-absorbable and non-biodegradable and therefore especially suitable for being used as supporting material for 3D printing of biomedical and dental constructs. PAH supporting material can also be composite containing PAM and additives like cellulose micro fibrils, cellulose nanocrystals, potassium salt, chitosan, alginate, polyvinyl alcohol, starch, gelatine, or inorganic fillers. Movement of the injection tip in the supporting material may cause some flow of the supporting material due the shear forces. This can cause inaccuracy to the printable object. Also, when the injection pressure of the printing material that is being injected to the supporting material is high, the printing material may become spread in the supporting material which also reduces dimensional accuracy of the printable object. Therefore, it is desired the curing of the printing material takes place instantly after the printing material has been released from the injection tip to the supporting material. For ensuring instant curing of the printing material once it becomes into contact to the supporting material the supporting material may comprise initiator that is free radical polymerization initiator for activating the reactive groups of the printing material. The initiator in the supporting material for methacrylate based injectable resin material may be for example 2,2´-Azobis(2-methylpropionamidine) dihydrochloride ([=NC(CH3)2C(=NH)NH2]2·2HCl )(AZO chloride) or other water soluble free radical polymerization initiator such as 2,2´-Azobis(2- methylbutylronitrile), 2- hydroxy-1-(4-(2-hydroxyethoxy)phenyl)-2-methyl-1-propanone, monoacylphosphine oxide, bisacylphosphine oxide, 1-hydroxy-cyclohexyl-phenylketone, 2-benzyl-2- dimethylamino-1-(4morpholinophrnyl)-1-butanone, 2-methyl-4´-(methylthio)-2- morpholinopropiophenone, 2,2-dimethoxy-2-phenylacetophenone, eosine-Y, erythrosine, riboflavin (B2) or camphorquinone. Biocompatibility of the initiators relates to the initiator compound, concentration of the initiator and exposure to the curing light. Typically curing light at UV wavelengths (350 – 390 nm) are used in 3D printing. UV light is known to be harmful for cells. When dental resin composites are cured by light, wave lengths of blue light (460-470 nm) are used with less harmful effects to the cells and tissues. Therefore, it is beneficial to used blue light instead of UV light in curing process of the injectable material for biomedical and dental constructs. For the sake of clarity, it is to be noted that in the present disclosure the PAM of the PAH is already cured and no further reactions of the PAH supporting material are intended to take place. The intention of the initiator, such as AZO chloride, is to enhance and support free radical polymerization of the printing material when it becomes into contact with the supporting material PAH. Concentration of PAM in water for the PAH can be between 0.1 – 20.0 wt % being for example 3.0 wt %. For increasing the rate of the curing of the injectable methacrylate resin the supporting material PAH may also comprise activator compound which is compatible with the initiator (AZO chloride) of the supporting material. An example of the activator is 2-(Dimethylamino)ethyl acrylate ( ^{H2C=CHCO2CH2CH2N(CH3)2} ). Concentration of the initiator AZO chloride in the supporting material PAH can be between 0.2 – 8.0 being for example 4.0 wt %. Supporting material can also be glycerol gel or highly viscous monomer of bisphenol-A-glycidyl dimethacrylate (bisGMA), urethanedimethacrylate (UDMA), bisphenol-A-ethylmethacrylate (bisEMA) or any other monomer or co-monomer system which is not polymerized by the light from the light emitting sources 150 of the robocasting device. It is also possible to add additives such as biologically active compounds, drugs and cells to the supporting material for being transferred to the printed object. Examples of biologically active materials are nano- or micrometre scale bioceramic or bioactive glass particles, bone morphogenic growth factors, peptide and RGDs. Also pH controlling compounds may be used as additives, in the supporting material, to optimize the pH to be most suitable for cells and tissue regeneration. An example of pH controlling compound is sol-gel bioactive glass which increases pH by fast dissolution and release of ions for ion exchange reaction. When the printable object, after the printing is completed, is aimed to release the biologically active substances or cells to the tissue engineering environment or in tissues in situ, the printable object is made of biodegradable polymers such as poly(lactic acid), poly(caproloactone) or poly(glycolides). Polymer of the printable object used in applications of this kind are porous which ensures high permeability to nutrients, oxygen and metabolic products. The supporting material is also preferred to be biodegradable hydrogels. Biodegradable hydrogels are natural-based hydrogels like polysaccharides (e.g. chitosan) and proteins (e.g. collagen), or synthetic such as poly(lactic acid) (PLA), poly(glycolic acid) (PGA) and polypropylene fumarate (PPF). The printed object 160 in this exemplary embodiment is a tissue-engineering scaffold or bone anchoring implant like dental implant, soft tissue replacing implant, stent or dental restoration (filling, crown, fixed partial denture, removable denture, orthodontic device, occlusal splint, surgical guide, dental model). The printed object 160 can also be any other object, such as a technical object, which is printed to the supporting material. Figure 2 illustrates an exemplary embodiment of a printable object 215 which has been fabricated to the bone defect of long bone 260, which has been damaged. The damaged long bone 260 may have been scanned using computer tomography (CT). Based on the CT scan of the defect, a digital model of the printed object may be produced, using computer software, and the digital model may be used as an input to the printing device that then prints the object based on the received input. In this exemplary embodiment, the printing device is a robocasting printing device such as described in FIG.1 comprising a printing element 200 that comprises a printing tip that can be controlled to move in directions 205. The printable object is printed onto a container comprising supporting material 210, which in this exemplary embodiment is biodegradable supporting material. In this exemplary embodiment the printable object, after receiving the input comprising printing instructions obtained based on the CT scan, is then be printed in biodegradable chitosan scaffold which comprises mesenchymal stem cells (MSC) 270. Supporting material functions also as cell culturing medium with the ingredients required for cells in this exemplary embodiment. The printing material 280 is in this exemplary embodiment visible blue light polymerizable resin of poly(lactic acid) (PLA) with polymerizable methacrylic groups. MSCs will be trapped to the spaces between the layers 290 of the printing material during printing of the printable object 215. After curing, the scaffold with cells will be cultivated further or directly implanted on the defect site 220 thus promoting bone growth. Additional fixation plates may be used to stabilize the healing bone. Figure 3 illustrates an exemplary embodiment of printing a printable object into supporting material. The printable object may be any object for which the method of printing an object onto supporting material and then immediately curing it is suitable. Purely for example purposes, in this exemplary embodiment the printable object 315 is an anatomically formed one-piece implant based on a cone-beam computer tomogram image and an stl-file formed based on the computer tomogram image. In this exemplary embodiment, the robocasting system according to the exemplary embodiment of Fig.1 is utilized and thus there is the printing element 200 that comprises a printing tip that can be controlled to move in directions 205. The scanned anatomy of the root to be extracted is transformed to the 3D printable object, that in this exemplary embodiment is an implant, 315. The surface of the printed object 315 has topography of printing layers 310 which enhance attachment of the implant to the bone by increasing the surface area for osseointegration. After 3D printing the implant 315 and final curing with the additional light emitting sources 250, the finalized object 320, which is the finalized printable object 315 that is extracted from the printing well, is sterilized with autoclave, hot air, critical point carbon dioxide or hydrogen peroxide plasma, implanted to an extraction socket and the object 330 is attached to it. Thus, in this exemplary embodiment, the robocasting system may be utilized to obtain the printable object 315 based on a source model 360 based on which the stl-file, that is used for obtaining the printing instructions. It is to be noted in general that curing may be performed at multiple occasions using for example an initial curing and final curing. It is also to be noted that there may also be more curing stages and that only a subset or all the light emitting sources may be used at each curing occasion. Thus, at different curing occasions a different combination of light emitting sources may be used. In some exemplary embodiments, when a printable object is printed using a robocasting system and printing material is printed into supporting material comprising initiator, initial stabilization of the printable object to the bottom of the printing well may be made by a lower curing light emitting source, which may comprise one or more light emitting sources placed below the supporting material well. During printing, the printing material may initially be polymerized with upper curing light emitting sources, which may be light emitting sources placed above the supporting material well. Irradiation power may be for example low irradiation power such as 100 mW / cm ² . Final curing of the printing material and thereby of the printable object may be made with all curing light emitting sources and in some example embodiments, all curing light emitting source may also comprise light emitting sources placed on a side of the printing well. Figure 4 illustrates another exemplary embodiment in which a robocasting system according to the exemplary embodiment illustrated in Fig.1 is utilized and thus there is a printing element 400 that is caused to move in the directions 405. In this exemplary embodiment, the robocasting system is utilized to obtain a printed object 440, which is an anatomically formed implant based on the cone-beam computer tomogram image and the formed stl-file. The printing material is injected to supporting material that comprises in this exemplary embodiment additives that are in this exemplary embodiment bioactive particles 410 that may be of bioactive glass, tricalcium phosphate, hydroxyl apatite, carbonated apatite, calcium carbonate or their combinations of particle size from 0.1 to 500 micrometers to the supporting material with volume fraction of 2 to 80 % . The image obtained is used as an input for printing the printable object 420, which, as mentioned, in this exemplary embodiment is an implant and the surface of the printable object 420 has topography of printing layers 425 which enhances attachment of the implant to the target environment such as bone by increasing the surface area for osseointegration and by help of bioactive particles which will be interlocked to the printing material during polymerization 430. After 3D printing and final curing with the additional light emitting sources 450, the object 440, which is the finalized printable object extracted from the supporting material well, is sterilized with autoclave, hot air, critical point carbon dioxide or hydrogen peroxide plasma, implanted to the extraction socket and attached to the target object 440. Figure 5 illustrates a graph regarding example results regarding good polymerization of printing layers to each other when the printing was made in polyacrylamide-water gel. Homogeneity of the printed material was measured as surface microhardness (vickers surface hardness number, VHN) of ground and polished surface of the printed object which has been printed horizontally or vertically in the supporting material. Low standard deviations demonstrate that the surface is well polymerized throughout the surface including printing layer interfaces. In the figure 5 the x-axis 510 indicates measuring areas that may be randomly selected measuring areas, and the y-axis 520 indicates VHN. Figure 6 illustrates another graph of example results. In this graph the y-axis 620 indicates VHN and x-axis 610 indicates measuring area. Surface hardness of printed dimethacrylate based resin composite and lack of oxygen inhibition layer on the surface of a printable object when printing material was polymerized in contact to the supporting material and is indicated in bar 1. A comparison was made to surface hardness of ground and polished inner part of the object indicated as bar 2. Even though the invention has been described above with reference to examples according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.