WO2022205323A1

WO2022205323A1 - Method for producing solid dairy products by additive manufacturing

Info

Publication number: WO2022205323A1
Application number: PCT/CN2021/084975
Authority: WO
Inventors: Yingya WANG; Jukka Rantanen; Anette Mullertz; Christian DEHLHOLM; Weiqing Wang
Original assignee: Mille Dairy (shanghai) Co., Ltd.; Mille (shanghai) Technology Co., Ltd.; Mille International A/S; Jukka Rantanen; Anette Mullertz
Priority date: 2021-04-01
Filing date: 2021-04-01
Publication date: 2022-10-06

Abstract

A method for producing solid dairy products by additive manufacturing is disclosed in the present invention. Multiplicate nutrition dairy powder is uniformly spread into a supplying piston plate. The powder in the supplying piston plate is spread into a working piston plate to form a working powder layer. In a control system of the additive manufacturing device, a first parameter of the solid dairy products to be produced and a second parameter of the adhesive are set. The adhesive is sprayed onto the working powder layer in a predetermined pattern. The adhesive is used to bind the working powder layer. The spreading and spraying are repeated until a manufacturing task is completed. By using the additive manufacturing device, milk powder can be fabricated into a solid of multiple layers of nutritional ingredients in a desired shape which are bound via the adhesive. The adhesive can be added and modified as required to meet the specifications in relevant standards.

Description

METHOD FOR PRODUCING SOLID DAIRY PRODUCTS BY ADDITIVE MANUFACTURING

FIELD

The present invention relates to the technical field of dietetics, and particularly, to a method for producing solid dairy products by additive manufacturing and an additive manufacturing device, e.g., a 3D printer. More particularly, the present invention relates to a method for producing solid dairy products with additives conforming to national standards of food safety.

BACKGROUND

At present, the existing dairy products for adults or children are in forms of powder, liquid or semi solid. The dairy products in powder normally contain dairy base powder made by spray drying, and the final products are packed at a determined quantity in a metal can, a plastic jar, a soft plastic bag or the like. The dairy products in liquid are normally processed fresh milk containing more than 70%of water. The dairy products in solid may be of a ferment type, such as cheese and butter biscuit, or of a gel thickening type, such as condensed milk, or of a lyophilization dehydrating type, such as lyophilized ice cream, or of a powder compressed type, such as milk tablets.

The existing products of milk tablets are made by applying a mechanical pressure on milk powder, which are not easy to disintegrate, and thus are normally eaten by chewing. Meanwhile, the compressed milk tablets require extra added flow-aid agent, adhesive and lubricant, which are not suitable for infants, pregnant women, or other people who has specially requirement on product ingredients.

The inventor finds by searching that Patent CN201580059426.7 discloses a method for preparing compressed solid milk tablets including the following steps (a) to (c) . In step (a) , milk powder is compressed to obtain compressed solid milk units with a mechanical strength of 10 kPa to 300 kPa. In step (b) , the compressed solid milk units are exposed to humidifying air with a relative humidity greater than 95%and a temperature of 60 ℃ to 90 ℃ in a humidifying chamber, to be humidified. The humidifying air contains condensed water vapor. In step (c) , the humidified and compressed solid milk units are dried to obtain a compressed solid milk tablet. The tablet obtained by this method has a mechanical strength of 20 kPa to 1000 kPa, a core/shell structure, and friability less than 5%. The shell contains milk particles or consists of milk particles. The milk particles are cured and fused in planes parallel or perpendicular to the surface of the tablet.

The invention patent CN200580022195.9 discloses solid milk with proper solubility and strength, and a preparation method thereof. Only milk powder is used as a raw material. The milk powder is shaped by compression with the porosity and free fat being controlled in a certain range. Then processes of humidification and drying are performed to obtain solid milk with sufficient strength and solubility. That is, the above problem can be solved by using solid milk having a porosity of 30%to 50%, and can be solved by a method for preparing solid milk including the following steps: a compression step of compressing milk powder to obtain a solid milk powder compacted in a shape, a humidification step of humidifying the milk powder compacted product that is obtained in the compression step, and a drying step of drying the milk powder compacted and humidified product in the humidification step.

The invention patent CN200980152871.2 provides a method for preparing solid milk with sufficient hardness for practical applications and excellent compression moldability. In the method for preparing solid milk of this invention, milk powder is produced for the preparation of solid milk in step S100, and then solid milk is prepared based on it. The preparation step S100 includes a gas diffusion step S112 and a spray-drying step S114. In the gas diffusion step S112, a predetermined gas is diffused into the liquid milk used as the raw material of the milk powder. In the spray-drying step S114, the liquid milk containing the diffused predetermined gas is sprayed, and then the sprayed liquid milk is dried. By performing the above steps, the milk powder is obtained. By solidifying the milk powder, the solid milk is prepared. The mold for compression molding may determine the shape of the solid milk as a tablet. The solid milk is required to have a certain hardness (strength) to avoid breaking during transportation.

Different from the existing methods for producing solid dairy product by compressing milk powder, molding, or vapor humidification, the present invention provides a method for producing solid dairy products by additive manufacturing, which may use infant formula powder or normal milk powder as the base powder to produce solid foods with predetermined physical properties and such as quick disintegration and multiple ingredient layers. The method can avoid the addition of non-standard additive materials such as disintegrant, and produce a complex structure solid product to improve the stability and absorption of nutrition, making the products more suitable for infants or specific consumers.

SUMMARY

In order to solve the problem in the conventional technology, which is the extra added flow-aid, adhesive and lubricant for solidifying in the dairy products are not suitable for people who has specially requirement on product ingredients, the present invention provides a novel method for producing solid dairy products by additive manufacturing technology. The solid dairy products are in a determined shape, and meet the requirements and standards to additives in solid dairy products for infants or specific consumers.

The technical scheme of embodiments in the present invention are described as following.

A method for producing solid dairy products by additive manufacturing is provided, including steps of:

S1: in the manufacturing device, spreading base powder into a supplying piston plate uniformly, and loading an adhesive into an ink cartridge;

S2: setting parameters in a control system of the manufacturing device, a first parameter of the solid dairy products to be printed and a second parameter of the adhesive, wherein the first parameter includes an outline and size, a thickness of layer, number of layer and the material of each layer; the second parameter includes a spraying rate and the volume of adhesive sprayed via ink cartridge;

S3: spreading the base powder in the supplying piston plate into a working piston plate to form a fresh powder layer;

S4: spraying the adhesive onto the fresh powder layer in a predetermined pattern, wherein the adhesive is used to bind or induce the binding of the fresh powder layer with the previous one, steps S3 and S4 are repeated until the set task is completed;

S5: taking out the solid dairy products from the supporting powder residue after the solid dairy products are manufactured and dried, and recycling the powder residue.

In some embodiments, the base powder in step S1 is milk powder including the following components in weight percentages: carbohydrate: 40-65%, protein: 5-25%, fat: 10-30%, water: 1-5%, ash: 1-10%, vitamin: 0.01%, and any other trace elements.

In some embodiments, the base powder is produced by a wet-process. The wet-process includes concentrating liquid milk added with vitamins and mineral matters; atomizing the concentrated liquid milk by a pressure atomizer; evaporating the atomized milk by a high-temperature gas to form the base powder.

In some embodiments, the base powder in step S1 includes at least two types of powder of different ingredients, step S2 further includes selecting a type of powder for each layer in the control system, and in step S3 fresh powder layers of different ingredients are formed.

In some embodiments, the base powder includes powder including a nutrient that tends to be oxidized and deactivated, and the powder layer made of this nutrient is located in a center layer of the solid dairy products.

In some embodiments, in step S3 the working piston plate is lowered by 0.3 to 0.6 millimeter per layer.

In some embodiments, in step S3 the base powder is uniformly spread into the working piston plate at a speed of 2 to 10 meters per minute.

In some embodiments, in step S3 the base powder is uniformly spread into the working piston plate at a speed of 6 meters per minute.

In some embodiments, in step S4 the adhesive is sprayed onto the working powder layer by moving at a speed of 10 to 15 meters per minute.

In some embodiments, in step S4 the adhesive is sprayed at a quantity of 2 to 5 microliters per layer on each printed product.

In some embodiments, in step S5, after the aimed task is completed, the processes of drying, removing supporting powder residue, and cleaning the products are performed, to meet requirements on appearance and strength.

In some embodiments, the adhesive is a solution or suspension made of distilled water, purified water, a solution of sugar or protein, a fat suspension or another material that is allowed to be added into infant formula powder.

The technical schemes of the present invention involve the following beneficial effects.

In the method for producing solid dairy products by additive manufacturing as provided in the present invention, a manufacturing device which is powder-bed 3D printer is used, and the dairy powder is used as base powder, and the adhesive is used as "ink" . In the control system of the powder-bed 3D printer, the first parameter of the solid dairy products to be printed and the second parameter of the adhesive are set. The solid dairy products are printed with multiple nutritional ingredients in the milk powder according to the user's design, and the finished product is obtained after post-processing. By using the additive manufacturing device, milk powder can be fabricated into a solid of multiple layers of various nutritional ingredients in a desired shape through the adhesive having the binding function. Different types of adhesive can be added as required. The printed solid dairy products have good strength and porosity, which is convenient to transport and easy to disintegrate by a liquid at room temperature for use.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the technical schemes in the embodiments of the present invention or the conventional technology more clearly, the drawings used in the description of the embodiments of the present invention or the conventional technology are briefly described hereafter. Apparently, the drawings in the following description show merely some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be acquired according to the provided drawings without any creative effort.

Figure 1 is a flowchart of additive manufacturing solid dairy products according to an embodiment of the present invention;

Figure 2 is a flowchart of processing solid dairy products according to an embodiment of the present invention;

Figure 3 shows a display result of a 3D printed product magnified by 200 times by a scanning electron microscopy;

Figure 4 shows a display result of a 3D printed product magnified by 1000 times by a scanning electron microscopy;

Figure 5 shows a comparison of X-ray powder diffraction spectrum pattern between a manufactured solid dairy product and the raw material;

Figure 6 is a schematic diagram of an additive manufacturing device according to an embodiment of the present invention.

Reference signs:

1-supplying piston plate, 2-working piston plate, 3-spreading device, 4-nozzle.

DETAILED DESCRIPTION

To clarify the purpose, technical solutions (descriptions/schemes? ) and the advantages of the present invention, the technical solutions (descriptions/schemes? ) in one embodiment of the present invention are clearly and completely described hereafter with referring to the drawings in the embodiments of the present invention. This described embodiment discloses only one of all embodiments of the present invention, rather than all cases. Based on the embodiments in the present invention, all other embodiments acquired by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. Some steps, schemes, and parameters in embodiments of the present invention can be rearranged or combined if they are not conflicted. Steps illustrated in the flowchart of the present invention may be executed by one or some similar manufacturing devices with a computer system and set of computer executable instructions. Although an operating order is shown in the flowchart, the illustrated steps may be performed in a different order in some cases.

The technology of additive manufacturing, or three-dimensional (3D) printing, is a type of rapid prototyping technology. The additive manufacturing is defined as a technology of constructing an object by printing in a succession of layer by layer based on a digital model file. It can be used by a broad range of materials, and based on the mechanism of binding and its adhesive, additive manufacturing has several branches. The type used in the present invention is powder-bed 3D printing technology and powder is the main constructing material. A normal printer used in daily life can print a computer-designed 3D object. The operation principle of a 3D printer is similar to that of the normal printer, except that a different material is used for printing. The normal printer uses paper and adhesive as printing materials, and the 3D print uses physical objects, such as metal, ceramics, plastic, sand or the like which are in a form of powder, as printing materials. After the printer is connected to a computer, the printer is controlled by the computer to stack the printing material in layers, so as to produce an object according to a blueprint designed by the computer. A powder-bed 3D printer includes a nozzle, a working plate, a control system and a powder spreading device. The control system uses a software program to slice a model predetermined by a user into layers to obtain sectional shapes of multiple layers. In the producing process, the powder spreading device precisely spreads a thin layer of powder material on the working plate, and then the nozzle sprays a layer of adhesive on the powder material according to a sectional shape of this layer. The part of the thin layer of powder which is sprayed with the adhesive is solidified. The volume of adhesive determines the level of dissolution and diffusion on powder, therefore is precisely controlled according to design. Then a next layer of powder of a designed thickness is spread on the solidified layer, and the nozzle sprays the adhesive according to a sectional shape of the next layer. In this way, the layers are stacked from bottom to top until all layers of a component are printed. After the printing, the model can be obtained by only sweeping up the loose supporting powder residue. The remaining powder can be reused. As shown in Figure 1 and Figure 6, a method for producing solid dairy products by additive manufacturing is provided according to an embodiment of the present invention, which includes the following steps S1 to S5.

In step S1, base powder is uniformly spread into a supplying piston plate 1, and an adhesive is loaded into an ink cartridge. To produce solid dairy products, multiplicate nutrition dairy powder may be selected as the base powder. It is understood that, in the conventional technology, milk powder is normally produced by a spray drying process. The spray drying process is a process of spraying a liquid solution, suspension or gel to form small atomized droplets and drying the droplets into solid particles by a high temperature. The obtained milk powder is spread into the supplying piston plate 1 of the additive manufacturing device, to be used as the base powder. In an embodiment of the present invention, infant formula powder and children powder are used as the base powder, which mainly contains lactose, protein, fat, vitamin, mineral matters, biologic acid, biotin, trace elements, and special additives. The base powder may be selected as a prepared milk powder to be used in the 3D printing, so that the printed product only has a physical change from powder to solid which is portable. Alternatively, in selecting the base powder, multiple nutritional ingredients of milk powder may be separated and added respectively as required, so as to prepare different types of milk powder of different ingredients. Therefore, the printed products can have more flexible ingredient than those made by using the already prepared milk powder, thereby achieving a special strength and disintegration property. The following describes an exemplary embodiment of using milk powder as the base powder, but the present invention is not limited thereto. In practice, any powder can be used as long as the powder is suitable for additive manufacturing of solid dairy products. More specifically, the powder is containing casein and lactose at a certain quantities.

In additive manufacturing, the "adhesive" binder which can be in ink or mixed with solid material, is the raw material. In printing solid dairy products, the binder having a binding property which will be triggered by liquid is necessary. In order to print the solid dairy products meeting the additive standard, the adhesive may be selected as a solution or suspension made of matters allowed to be added according to regulations. Specifically, the adhesive may be a solution or suspension made of distilled water, purified water, a solution of sugar or protein, a fat suspension or other matters allowed to be added into infant formula powder. In an embodiment, the adhesive is distilled water as an example, but the present invention is not limited thereto. In practices, any adhesive can be used as long as the adhesive has the function of binding in producing solid dairy products.

In step S2, in a control system of a 3D printer, a first parameter of the solid dairy products to be printed and a second parameter of the adhesive are set. The first parameter includes an outline and size, a thickness of layer, number of layer and the material of each layer. The second parameter includes a spraying rate and the volume of adhesive sprayed via ink cartridge. By setting the first parameter and the second parameter, solid products of different ingredients can be printed according to practical needs.

In step S3, the base powder in the supplying piston plate 1 is spread into a working piston plate 2 to form a working powder layer. It is understood that the spreading may be performed by a powder spreading device of an additive manufacturing device. The base powder is transported from the supplying piston plate 1 to the working piston plate 2 and uniformly spread into the working piston plate 2.

In step S4, the adhesive is sprayed onto the working powder layer in a predetermined pattern. The adhesive is used to bind the working powder layer. Steps S3 and S4 are repeated until a printing task is completed. In step S3, a layer of milk powder is spread into the working piston plate 2 to form a working powder layer, and then in step S4 the layer is sprayed with a layer of adhesive in a predetermined pattern. Then step S3 is repeated to spread a new working powder layer uniformly on the working powder layer having the adhesive. The two working powder layers are bound by the adhesive therebetween. Then the adhesive is sprayed again. Therefore, a working powder layer and an adhesive layer are produced repeatedly, until printing of the solid dairy products are completed.

In step S5, the solid dairy products are taken out after the solid dairy products are bound and dried, and the remaining base powder is cleaned. After the printing is completed, it may require time to finish the interaction between the adhesive and the milk powder. The solid dairy products are taken out after they are totally solidified.

In the present invention, a 3D printer is used by using dairy powder as base powder, and using an adhesive as ink. The multiple nutritional ingredients in the milk powder are spread uniformly in the supplying piston plate. In the control system of the 3D printer, a first parameter of the solid dairy products to be printed and a second parameter of the adhesive are set to print the solid dairy products according to the design of the user. The final products are obtained after post processing. By using the additive manufacturing device, milk powder can be printed into mixed solids having multiple layers of nutrients in a desired shape through the adhesives having the bonding function. The adhesive can be added with components as needed. The printed solid dairy products have good strength and porosity, which is convenient to transport and easy to disintegrate by a liquid at room temperature for use

In the following embodiment, specifically the base powder in step S1 is milk powder including the following components in weight percentages: carbohydrate: 40-65%, protein: 5-25%, fat: 10-30%, water: 1-5%, ash: 1-10%, vitamin: 0.01%, and any other trace elements. The milk powder with the ingredients is suitable infant dairy products and has moderate flowability. The above milk powder is generally produced by making liquid milk into milk powder through a wet-process. The wet-process mainly comprises spraying and drying the liquid milk to evaporate its liquid component to produce the milk powder, which can minimize the loss of ingredients of the milk powder. The wet-process specifically includes concentrating liquid milk added with vitamins and mineral matters, atomizing the concentrated liquid milk by a pressure atomizer, and evaporating the atomized milk by a high-temperature gas to form the milk powder. In the wet-process, it may be required to perform the following steps of inspecting the milk source to various strict quality standards, sterilization and other relevant pre-treatments, and then the milk liquid will be proceeded in the automatic production pipeline according to Good Manufacturing Practice (GMP) standard. Adjustment in ingredients such as moderating the amount during the process may be necessary to achieve the acceptable proportions of all nutritional components.

The formulated liquid milk is directly powdered by a spray drying process. The existing spray drying process is carried out in a drying tower. An atomizer is provided at the top of the drying tower. A fan capable of generating hot air is arranged inside the drying tower. An outflow port is provided at the bottom of the drying tower. The spray drying process specifically includes dispersing the liquid milk into mist droplets, which is generally performed by atomization using a pressure atomizer, a centrifugal atomizer, or an airflow atomizer. The present embodiment uses a pressure atomizer as an example, but the present invention is not limited to the pressure atomizer. Specifically, the pressure atomizer includes a high-pressure pump and a spray gun. The liquid milk enters the high-pressure pump. After being pressurized, the liquid milk is concentrated and transported to the spray gun at the tower top for spray drying. The pressurized liquid milk is shot to the top of the spray drying tower to be sprayed out as droplets, which are dispersed into the air. After being heated by the hot air in the tower, the water in the droplets can be quickly evaporated, so that the liquid milk is made into milk powder. In order to improve the evaporation efficiency, the temperature of the fan may be maintained at 170-195 ℃ and the temperature of the exhaust air may be maintained at 85-95 ℃.

In the following embodiment, the base powder in step S1 includes at least two types of powder of different ingredients. Step S2 further includes selecting a type of powder for each layer in the control system, and in step S3 working powder layers of different ingredients are formed. Different from directly using the milk powder as the base powder, in this embodiment, the components of the milk powder are separated and used as different base powder of different components. Before the additive manufacturing, the first parameter is adjusted according to different formula requirements on product components. That is, the nutritional ingredients of milk powder (lactose, fat, protein, etc. ) are printed as separate layers through additive manufacturing to build solid products, so as to have a special strength or disintegration property. Specifically, the composition, an outline and size, a thickness of layer, number of layer and the material of each layer may be preset. Finally, in the printing process, the solid dairy product is formed in a layered manner. This technology is to construct the powdery solid layer by layer, enabling fine processing of each layer. For special dairy powder containing multiple nutritional ingredients, this technology can be used to process different nutritional ingredients in different layers to achieve different requirements for stability, strength, disintegration, dissolution, and absorption.

By the printing method of constructing powdery solid layer by layer, base powder can be formulated differently. Specifically, a type of base powder includes a nutritional component that is easily oxidized and inactivated, and the working powder layer formed by the based powder is located at the center layer of the solid dairy products to improve the stability during production, storage, and transportation. The nutrition component that is easily oxidized and inactivated nutrients is wrapped in the center of the solid powder to reduce the chance of contact with the external environment, so that it is isolated with most of the oxygen, thereby having a high chemical stability.

Furthermore, in the following embodiment, during the operation of the additive manufacturing device, the base powder is taken out from the supplying piston plate 1 and uniformly spread into the working piston plate 2 to form a working powder layer. In this process, the supplying piston plate 1 is supplemented with the base powder after the base powder is removed. After the base powder is spread into the working piston plate 2, in order to maintain the height of the top working powder layer to facilitate subsequent spreading, the bottom of the work working piston plate 2 needs to be lowered by a certain height to leave space for the next layer spreading. Further, in step S3 the working piston plate 2 is lowered by a height of 0.3-0.6 millimeter per layer, to maintain printing accuracy.

In the following embodiment, in the step S3 of spreading the powder, the powder may be spread by a powdering roller or a scraper of the additive manufacturing device. It can be understood that the present invention is not limited to the above two spreading solutions. Any tool can be used as long as it can spread the base powder in the supplying piston plate 1 into the working piston plate 2. By controlling the speed of spreading the powder, the spreading uniformity of base powder can be improved. Further, in step S3 the base powder is uniformly spread into the working piston plate 2 at a speed of 2 to 10 meters per minute, which has shown a good control on the accuracy and uniformity of the spreading. In some embodiments, in step S3 the base powder is uniformly spread into the working piston plate 2 at a speed of 6 meters per minute.

In the following embodiment, after the working piston plate 2 is covered with a layer of base powder, that is, after forming a working powder layer, the nozzle 4 is controlled to spray according to a specific pattern. In this process, the nozzle 4 is required to move horizontally and vertically, to spray in the designed pattern. In order to ensure the accuracy of the adhesive spraying, it is required to ensure that the nozzle 4 sprays at a certain spraying speed and spraying quantity. Further, in step S4 the adhesive is sprayed onto the working powder layer by moving at a speed of 10 to 15 meters per minute. In some embodiments, in step S4 the adhesive is sprayed onto the working powder layer by moving at a speed of 12 meters per minute.

Further, in step S4 the adhesive is sprayed at a quantity of 2 to 5 microliters per printed product per layer. In some embodiments, to have a better spraying effect, the adhesive is sprayed at a quantity of 0.01 microliter per square millimeter per layer.

Further, in order to improve the manufacturing efficiency, a batch of products to be printed can be arrayed in software in advance, by setting the size, the quantity and the space between each product. In practices, the array can be achieved by moving a single nozzle according to the setting. Alternatively, the array may be achieved by synchronously moving multiple nozzles, which remarkably improves the printing efficiency.

As shown in Figure 2, in the following embodiment, in step S5 after the printing is completed, the processes of drying, removing supporting powder residue, and cleaning the products are further performed to meet requirements on appearance and strength. Specifically, since the part outside the printing area is also spread with the base powder during the printing process to support the printed part, after the additive manufacturing is completed, the printed solid dairy products need to be left to stabilize for 5 to 30 minutes, in an environment of controlled temperature and humidity. Then, the products are released, that is, the products are removed from supporting powder residue. Then the surfaces of the products are cleaned by, for example, blowing, brushing or other treatments.

The printed products are required to have sufficient strength to avoid damage during transportation. However, a too high strength will affect the disintegration rate of the products. Therefore, it is required to balance between the quality of strength and its disintegration rate. By the above processing method, taking a printed product of a solid dairy with a diameter of 20 millimeters and a height of 6 millimeters as an example, it is tested through experiments that the printed solid dairy product can be disintegrated in 30 seconds by gently shaking in 50 milliliters of water at 25 ℃, and dissolved in the water to form dairy colloid. It can be concluded that the 3D printed solid dairy products can be disintegrated at a high rate.

In order to better show the characteristics of the solid dairy products obtained through the above technical solutions (descriptions/schemes? ) , Figures 3 and 4 visually show the appearance of 3D printed product under a scanning electron microscope.

Figure 3 shows the appearance of a 3D printed product magnified by 200 times by a scanning electron microscopy. Figure 4 shows of the appearance of a 3D printed product magnified by 1000 times by a scanning electron microscopy. It can be seen that manufacturing process results in a slight dissolved/melted appearance on the surface of the milk powder sample, but it does not destroy the original spherical structure of the powder particles. This phenomenon is due to the sprayed ink which partly dissolves the material and causes the formation of liquid bridges among powder particles, and finally solid bridges binding particles as a whole solid is formed. Additionally, the dissolved materials agglomerate with the extra added lactose crystal in ingredient, increasing the mechanical strength of printed products.

In addition, Figure 5 shows a comparison between the X-ray powder diffraction spectrum of the obtained 3D printed product and the raw material. Figure 5 shows that the additive manufacturing process changes the milk powder material significantly from the amorphous form of the original milk powder to the crystalline state, which proves that the ink induces a dissolving and drying process, and the amorphous lactose in the milk powder is therefore recrystallized and rearranged to form an integrated solid structure. Therefore, the 3D printed solid dairy products have a good strength.

From the above results, it can be seen that the solid dairy products produced by the abovementioned method have a good mechanical strength and a quality of fast disintegration for re-dissolving before use.

In a specific embodiment, it is designed to manufacture a solid dairy product in a piston plate shape with a diameter of 20 millimeters, a height of 6 millimeters, and a weight of 1.2 to1.4 grams, including totally 15 powder spreading layers each has a thickness of 0.4 millimeter.

The milk powder is spread uniformly in the supplying piston plate. A powdering roller spreads the milk powder in the supplying piston plate uniformly into the working piston plate at a speed of 5.63 meters per minute to form a working powder layer, so that the milk powder is spread uniformly into the working piston plate at a speed of 2 to 10 meters per minute. After the adhesive is prepared, a needle with a preset aperture is used for printing. During the spraying process, the adhesive is sprayed onto the working powder layer at a speed of 10 to 15 meters per minute and a quantity of 3.5 microliters per printed product per layer. After the spraying of the adhesive for one layer is completed, the working piston plate is lowered by 0.3 to 0.6 millimeter per layer, to prepare for the next powder spreading. The spraying of the adhesive and the spreading of powder are repeated until the 3D product is finally printed. Then by performing the processes of drying, removing supporting powder residue, and cleaning the products, the crushing hardness of the processed solid dairy product is equal to or greater than 30 Newtons, meeting the requirements on mechanical strength for production-handling, transportation, and storage before use.

As shown in Figure 6, the present invention also provides a scheme of the additive manufacturing used in the abovementioned method for producing solid dairy products, which includes: a supplying piston plate 1, a working piston plate 2, a spreading device 3, an ink cartridge coupling with a control system and a nozzle 4. The supplying piston plate 1 is configured to contain fresh dairy powder as the starting material. The spreading device 3 is configured to uniformly spread the dairy powder in the supplying piston plate 1 into the working piston plate 2 to form a working powder layer. The nozzle is connected with an ink cartridge, and the ink cartridge is configured to contain the adhesive. The control system receives setting parameters by user from the computer, and controls the nozzle 4 to spray the adhesive in a preset pattern on the working powder layer. The adhesive is used for binding the working powder layer.

Specifically, before printing, the milk powder is uniformly spread into the supplying piston plate 1 to be used as base powder to be processed. The base powder may be selected as already formulated milk powder, which may be poured into the supplying piston plate directly. The base powder may also be formulated during the additive manufacturing process to form milk powder with different nutritional components. Specifically, the components of the milk powder may be separated and loaded into different supplying piston plates, to be formulated as needed in subsequent processing. The adhesive is loaded into the ink cartridge to be used as "ink" for printing, to bind the upper and lower powder layers.

A User may use design software to build a model and import the model into the control system of the 3D printer, to be sliced into a series of 2D patterns. That is, the imported 3D model is sliced according to the parameters such as a layer number and thickness inputted by the user. The sectional parameters of each slice determine the spraying area of the adhesive in the subsequent printing process. Specifically, in the control system of the 3D printer, a first parameter of the solid dairy products to be printed and a second parameter of the adhesive are set. The first parameter includes an outline and size, a thickness of layer, number of layer and the material of each layer. The second parameter includes a spraying rate and the volume of adhesive sprayed via ink cartridge. By setting the first parameter, various milk powders with different ingredients can be prepared, so that the printed products are more flexible in the nutritional ingredients than the products printed using the already formulated milk powder, and thereby can have a special strength or disintegration profile.

The spreading device 3 transfers the milk powder in the supplying piston plate 1 to the working piston plate 2. During the printing, the spreading device 3 moves on a horizontal surface above the supplying piston plate 1 and the working piston plate 2. In order to ensure the continuity of the powder spreading, the bottom of the supplying piston plate 1 and the bottom of the working piston plate 2 can move up and down. After the spreading device 3 takes some milk powder from the supplying piston plate 1, the supplying piston plate 1 lifts the internal milk powder, so that the spreading device 3 takes the powder in the next spreading process. Correspondingly, the working piston plate 2 lowers, after the spreading process, the internal milk powder, so that the nozzle 4 can complete the spraying of the adhesive by only a plane movement, thereby improving the spraying accuracy.

Specifically, to achieve the powder lifting and lowering actions in the supplying piston plate 1 and the working piston plate 2, a driving device such as an air piston plate, a motor, and a gear coupling with a screw, can be installed at the bottom of plate, but the present invention is not limited thereto. Further, the spreading device may be a scraper or a powdering roller, but the present invention is not limited thereto.

In the following embodiment, the nozzle 4 and the spreading device 3 are controlled independently by the system as required to guarantee the precision of manufacturing. Further, the nozzle 4 is flexibly installed on the bar of spreading device 3, and the nozzle 4 moves alongside with the bar which is perpendicular to the moving direction of the spreading device 3. Specifically, the additive manufacturing device is provided with a lateral guide rail, so that the spreading device 3 can slide laterally on the lateral guide rail from the supplying piston plate 1 to the working piston plate 2. The spreading device 3 is provided with a longitudinal guide rail on the bar, so that the nozzle 4 can slide longitudinally on the longitudinal guide rail. With the horizontal guide rail and the vertical guide rail, the nozzle 4 can spray the adhesive at different positions on a plane. This embodiment is simple in structure and precise in control, which is suitable for the method for producing solid dairy products by additive manufacturing of the present invention.

Further, in the following embodiment, there are more than one paralleled nozzle at nozzle 4. Specifically, multiple nozzles connected with different ink cartridges containing different adhesive materials can be used for printing several materials at the same time, which can make the manufacturing process more functional and effective. Also, in order to improve the printing efficiency, multiple nozzles can be configured to move synchronously to increase printing area at a time.

The methods disclosed in the several method embodiments in the present invention can be arbitrarily combined to obtain a new method embodiment unless there is conflict.

The features disclosed in the several product embodiments in the present invention can be arbitrarily combined to obtain a new product embodiment unless there is conflict.

The features disclosed in the several method or product embodiments in the present invention can be arbitrarily combined to obtain a new method or product embodiment unless there is conflict.

The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutes that can be readily conceived by a person skilled in the art without departing from the scope of technique in the present invention should fall within the protection scope of the present invention. Therefore, the protection scope of the present invention is defined by the claims.

The present invention provides methods for producing a solid dairy product by additive manufacturing. This has the advantage in the printed solid dairy products of good strength and porosity, which is convenient to transport and easy to disintegrate by a liquid at room temperature for use

Definitions:

As used herein “solid dairy product” means any solid food made by heating, drying, or freezing or fermentation with milk as the main raw material. Suitable dairy products include milk, yogurt, cream, butter, cheese and casein. Preferred is milk.

The term “base powder” as used herein refers to any raw material in powder form that derived from milk. This product has suitable physical properties such as flowability and stability which can be proceeded by the used additive manufacturing device to obtain aimed product. The term is intended to include milk powder. As used herein “milk powder” refers to a manufactured dairy product made by evaporating milk to dryness.

The term “adhesive” as used herein refers to. any pure water, solvent, solution or suspension made of distilled water, purified water, a solution of sugar or protein, a fat lipid suspension or another matter allowed to be added into infant formula powder.

Claims

A method for producing a solid dairy product by additive manufacturing, comprising steps of:

S1: spreading base powder uniformly into a supplying piston plate of an additive manufacturing device, and loading an adhesive into the cartridge of said device;

S2; setting, in a control system of the additive manufacturing device, a first parameter of the solid dairy product to be produced and a second parameter of the adhesive, wherein the first parameter comprises an outline and size, a thickness of layer, number of layer and the material of each layer; the second parameter comprises a spraying rate and the volume of adhesive sprayed via ink cartridge;

S3: spreading the base powder in the supplying piston plate into a working piston plate to form a working powder layer;

S4: spraying the adhesive onto the working powder layer in a predetermined pattern, wherein the adhesive is used to induce the solidification of the working powder layer, steps S3 and S4 are repeated until a manufacturing task is completed;

S5: taking out the solid dairy products after the solid dairy products are solidified and dried, and cleaning the remaining base powder.
The method for producing solid dairy products by additive manufacturing according to claim 1, wherein the base powder in step S1 is milk powder comprising the following components in weight percentages: carbohydrate: 40-65%, protein: 5-25%, fat: 10-30%, water: 1-5%, ash: 1-10%, vitamin: 0.01%, and any other trace elements.
The method for producing solid dairy products by additive manufacturing according to claim 2, wherein the milk powder is produced by a wet-process, the wet-process comprises:

concentrating liquid milk added with vitamins and mineral matters;

atomizing the concentrated liquid milk by a pressure atomizer;

evaporating the atomized milk by a high-temperature gas to form the milk powder.
The method for producing solid dairy products by additive manufacturing according to any one of claims 1-3, wherein

the base powder in step S1 comprises at least two types of powder of different ingredients, step S2 further comprises selecting a type of powder for each layer in the control system, and in step S3 working powder layers of different ingredients are formed.
The method for producing solid dairy products by additive manufacturing according to claim 4, wherein the base powder comprises a nutritional ingredient, such as fat and special protein, that could be oxidized and deactivated during storage, the working powder layer made of this powder is located in a center layer of the solid dairy products by a delicate layer design, to improve the stability during production, storage and transportation.
The method for producing solid dairy products by additive manufacturing according to any one of claims 1-5, wherein in step S3 the working piston plate is lowered by 0.3 to 0.6 millimeter per layer.
The method for producing solid dairy products by additive manufacturing according to any one of claims 1-6, wherein in step S3 the base powder is uniformly spread into the working piston plate at a speed of 2 to 10 meters per minute.
The method for producing solid dairy products by additive manufacturing according to claim 7, wherein in step S3 the base powder is uniformly spread into the working piston plate at a speed of 6 meters per minute.
The method for producing solid dairy products by additive manufacturing according to any one of claims 1-6, wherein in step S4 the adhesive is sprayed onto the working powder layer by moving at a speed of 10 to 15 meters per minute.
The method for producing solid dairy products by additive manufacturing according to any one of claims 1-9, wherein in step S4 the adhesive is sprayed at a quantity of 2 to 5 microliters per obtained product per layer.
The method for producing solid dairy products by additive manufacturing according to claim 1, wherein in step S5, after the manufacturing task is completed, the processes of drying, removing supporting powder residue, and cleaning the products are performed, to meet requirements on appearance, mechanical strength and disintegration rate.
The method for producing solid dairy products by additive manufacturing according to any one of claims 1 to 11, wherein the adhesive is a pure water, solvent, solution or suspension of a solution of sugar or protein, a lipid suspension or another matter allowed to be added into infant formula powder.
A solid dairy product produced by a method as defined in any one of claims 1-12.