Established in 2002, WinSun is a high-tech company that researches and develops new materials and production methods for construction, including 3D printers. WinSun today has approx. 200 employees and 98 national patents (in China). Of the 200 employees, approx. 60 people with project management and only 2 people work with R&D. WinSun has no designers / architects employed. WinSun is headquartered in Suzhou district approx. 100km northwest of Shanghai. They once had 4 production halls, but have scaled this down to 2 production halls. One is located at the head office near Shanghai and the other is in the middle of China. 

1.1 History In short, WinSun’s 14-year history (primarily according to WinSun’s website). See explanations for products under section 2:   – 2002: – 2002-2003: – 2003-2004: – 2004-2005: – 2006: – 2007: – 2008: – 2012: – 2014: – 2015: – 2016: WinSun startups WinSun develops the product GRG (Specifically fiberglass reinforced plasterboard), as the first company in China. WinSun is changing GRG’s production mode from manual art to fully automated continuous production. WinSun develops a print head and an automatic feeding system, which increases production efficiency by a factor of 10. At the same time, it created an opportunity to recycle industrial waste to GRG production. The production method for GRG production has been continuously improved up to date. WinSun develops the product SRC (Special Reinforced Concrete, Special Reinforced Concrete) using a combination of CNC automated technology, 3D printing technology and fiber reinforcement technology. WinSun develops the CMS (Crazy Magic Stone) product. WinSun is making the first 3D printed building. WinSun completes the technical system / design in order to 3D print buildings. WinSun prints as the first company in the world 10 houses in 24 hours. WinSun prints a 6 story residential property. WinSun prints office building for Dubai1 In 2015, an article was published that questioned the above story and the company’s working methods, and which, among other things, accused WinSun of cheating on knowledge. 2 1 https://ing.dk/artikel/se-dubais-3d-printede-fremtidskontor-blive-bygget-184518 2 https://3dprint.com/57764/winsun-3d-print-fake/

The vision is to expand production to the whole of China as well as internationally. Internationally, this must be done through partners. WinSun will change its production form from large and immobile Gantry printers to small flexible robot arm printers. To reduce transport costs (both economically and environmentally), the vision is to have these small mobile printers located around China, with a maximum of 300km to any construction site. 

1.3 Financing The back man behind WinSun is Mr. Ma and he succeeded in finding investors who will invest in two production halls. WinSun is expanding internationally through partnerships where they deliver the printer and get Royalty Fees for the items produced.

WinSun has developed 4 different materials / printer technologies to build different products. They produce everything from the load-bearing system (concrete walls) to the cladding of the walls (plaster) and the interior (furniture). In the following, the 4 printers are briefly mentioned, but with special focus on the concrete printer. 2.1 Other Printers In addition to a 3D concrete printer, WinSun has built 4 other printers that are used for various products. The other printers are described in the following, however, this has been made very brief as it is the concrete printer that is interested in this report. During the visit we were not aware of how the following printers were constructed, so in the following only some illustrations of objects that they have printed with the individual printers are shown. It should be noted that the following is not something we inspected during our visit to WinSun, as we were not allowed to see the production facility, but are mainly excerpts from their website. 2.1.1 GRG (Glass Reinforced Gypsum, fiberglass reinforced plaster) The GRG printer makes objects in fiberglass reinforced plaster. The material can be molded into many different artistic forms and is often used to coat the surfaces of large rooms with high acoustic and aesthetic requirements, such as theaters and concert halls. The following is an example of objects printed with the printer. Guangzhou Opera House:

2.1.2 FRP (Fiber Reinforced Plastic, fiberglass reinforced plastic) The FRP printer makes fiberglass-reinforced plastic objects. The material can be formed in many shapes and has a high strength. The printer is used to make furniture and below are some examples of objects made in the printer. Table from WinSun’s showroom (seen during the visit): Other examples of printed objects from the WinSun website.         3D Printers – State of the Art Page 7 of 34   2.1.3 CMS (Crazy Magic Stone, fiberglass reinforced artificial stone) The CMS printer makes objects in a new type of artificial stone material. The material is called Crazy Magic Stone and is made of specially treated quartz sand added to special fibers to increase the strength. The printer is used to make interior and exterior floors, walls and roofs. According to WinSun’s statements, they can produce 10,000m2 a day on their production line. A few examples from the WinSun homepage on objects created by the printer are shown below. Shanghai Mann Tea Garden Villa: Phoenix International Media Center:    3D Printers – State of the Art Page 8 of 34    2.1.4 SRC (Special Reinforced Concrete, special reinforced concrete) The SRC printer makes objects in special reinforced concrete that are mainly used for facade cladding. The facades can be made in a myriad of colors and on three different surfaces (smooth / smooth, velvet / velvet and lychee). The following is an example of objects from the printer: Beijing Strawberry Mansion:

2.2 Concrete printer WinSun has developed a large Gantry printer which they have located in their production halls (one hall at the headquarters near Shanghai and one hall in the middle of China). The printer has a dimension of 150m x 14m x 8m and this is WinSun’s second generation of their printer. They are currently. developing their third generation printer. We were not allowed to inspect the printer during the visit, but have seen a number of buildings they have made with it, see sections 3 and 4. The printer is primarily used to produce items which are then assembled in the space. Ie they did not create a large printer to print in large dimensions (large elements) but to optimize their production. Thus, they produce smaller concrete elements throughout the length of the printer, but the elements are no larger than they can be transported on a truck. Thus, this production is very similar to the production in Denmark with large halls where concrete elements are produced. It was stated that the printer was to be operated by only one man. He was able to control both the computer and the printer, as well as apply reinforcement as the layers were printed. The concrete printer can only print vertically. This means that the printer cannot place a layer slightly skewed on the previous layer, allowing walls to rotate or give unique shapes. This means that the printer is limited in its architectural expression, since, for example, you will not be able to make a column that rotates about its vertical axis (dispute), see example from the USA where this is done below.

Photo: Lewis Yakich’s Hotel in the Philippines. Listed by Andrey Rudenko. Example of a 3D printed column that rotates about its vertical axis.    3D Printers – State of the Art Page 10 of 34   It was stated that the printer has a capacity of 500,000m2 per year of a standard wall with a thickness of 240mm, as shown in the image below. Calculation of printer capacity: Prerequisites: Illuminated capacity of concrete printers: 500,000 sqm wall with a thickness of 240mm Production period: 300 days per year and 24 hours a day.    500,000 sqm / (300 * 24 hours) = 69 sqm / hour Width of track / track: = 40mm Layer thickness (layer height): 15mm-19mm -> Average 17mm -> 58.8 layers per m (vertical) Length of tracks on 1m wall (horizontal – laying of 1 layer of concrete):  Pages: diagonal: Total: Calculation: Total length of lanes of 1m2 wall Total concrete volume of 1m2 wall Printer speed: Volume of concrete prints = 2 * 1000mm = = = 2000mm = 1350mm = 3350mm = 3350mm * 58.8 layers = 197m * 0.04m * 0.017m = 197m / sqm * 69kvm / hour = 0.134m3 / sqm * 69kvm / hour = 197m / sqm = 0.134m3 / sqm = 13593m / hour = 3.8m / s = 9.25m3 / hour = 9250L / hour The speed of the printer seems unrealistically fast and the volume also seems unrealistically high. In comparison, the printer in Russia could print 162L / hour, ie approx. 60 times less.  3D Printers – State of the Art Page 11 of 34    3 BUILDING SYSTEM WinSun has developed a building system for the construction of raw houses based on 3D printing. The following is a review of WinSun’s construction system and some comments are made on where the considerations will have challenges with a Danish norm system, where the requirements for documentation in practice are probably somewhat more extensive. 3.1 Walls The following are the considerations made in connection with the walls.

3.1.1 Vertical carrying capacity The walls are typically made in a total thickness of 240mm, with each side being approx. 40mm thick and the sides are then joined by diagonals (also 40mm thick). The diagonals are introduced to support the wall to achieve a much larger column capacity (load-bearing capacity). The diagonals typically have an angle of approx. 45 degrees relative to the sides and therefore they will stiffen one wall page per second. ca. 320mm. The thin wall sides of 40mm will thus avoid folding and can be designed to take up a large printing capacity. This however, provided the diagonals and sides have sufficient interaction (including the tensile capacity of the concrete). Manually horizontal reinforcing irons are inserted between some of the layers at a vertical distance as determined by the design / structural engineer. However, one may be concerned about whether the reinforcement is active in all cases, since the reinforcement is not always in the concrete, but only along the sides, see the picture below (not directly in contact with the concrete). The fluctuating quality of performance will also present some challenges in relation to Danish norms.        3D Printers – State of the Art Page 12 of 34         The walls will, with the above design / stiffening with diagonals) have a capacity which (in isolation) can carry smaller buildings (expected: 3-4 floors, depending on the compressive strength of the concrete), but it will not be sufficient to execute tall buildings (many floors). The wall must be considered unarmed and it is most likely to cause major problems to get the design approved for Danish norms, see among other comments below on horizontal castings. For tall buildings, zones are introduced between the walls, which are cast after the wall is installed and where traditional pillar reinforcement is introduced. In this way, tall buildings will carry their own weight point-wise via reinforced columns which are inserted into the wall at a distance according to the design. It is therefore not computationally the 3D printed wall that carries the load in tall buildings (in practice they will carry much of the load), but the subsequent in-situ molded columns. It was not disclosed and it was also not possible to see inside the wall of the building with 5 floors whether or not pillar reinforcement was introduced into the walls. WinSun stated that they are currently is working on a 3D printed building at a height of 100m (about 25-30 floors) and this should use the above method with in-situ molded reinforced columns inside the walls.

3.1.2 Casting threshold (coherence between elements) The walls are delivered in wall elements which have an extent that corresponds to what is space for one truck. The individual wall elements are reinforced together by shackles protruding from the end of the wall.  3D Printers – State of the Art Page 13 of 34   ment. The collections are cast afterwards, see the pictures below. The walls are often carried out at a height of 1-2 meters and then stacked on top of each other. No overflow is carried out and the horizontal castings are made so that the concrete elements are crushed on each other. According to Danish norms, this practice will not be feasible, as no normal force will be transferred between the walls (or very little). There is no knowledge of the interface between the two elements. To give some vertical cohesion, zones are introduced where a threaded rod / coupling can provide vertical cohesion between two wall elements. The coupling is introduced at the factory by casting between two diagonals and one side (a triangle) and inserting a coupling. This coupling can then be used to provide a tensile anchorage between two wall elements. Nothing was clarified about how the forces spread into the wall. They also use the clutch to lift the element.

3.1.3 Doors and window openings When WinSun produces door sills and window openings, they place a wooden board in the doorway on which the printer can print, see the image below. The plate can be removed after casting if there is sufficient reinforcement to absorb the draft. However, it will require some deformation of the bar to activate the reinforcement and therefore some cracks are expected. The method of casting over door beams is the same as for the other walls, but with extra horizontal reinforcement in the wall. There are several examples, see the pictures below, that there are clear cracks in the overlap. This may be due both to the fact that the reinforcement does not lie in the concrete layer, but within the layer and thereby is not active or as mentioned above, that some deformation needs to take place for the reinforcement to become active when the wooden board is removed.        3D Printers – State of the Art Page 15 of 34                               3.1.4 Stability (absorption of horizontal forces / disc forces) No method of incorporating horizontal forces / slicing forces into the walls was specified. Since no significant net reinforcement has been introduced in the wall, it must be assumed that the design depends on the tensile strength of the concrete. This in itself will present challenges in relation to Danish norms. In addition,  3D Printers – State of the Art Page 16 of 34    over horizontal zones, where there is no tensile strength in the concrete, as the wall elements are not underlain. Here, the design must include the vertical coupling to the transfer of the feature, as well as the weight of the building. However, it is not immediately shown how the relationship between the wall elements is and how the forces run in the wall. It must therefore be expected to be difficult to get the design approved for Danish standards. However, WinSun has examples of the introduction of windscreens into the building by performing this windscreen in an insulated wall, see further in section 3.1.6, however, there are still no real ways in which disc forces can be absorbed into the building system.

3.1.5 Installations (electricity) Installations can be drawn immediately into the wall, but there are several examples of them being milled into the wall afterwards, see the pictures below. However, this should not be necessary if the design (installations) was better planned before printing. 3.1.6 Insulated wall element WinSun has made some considerations about designing an insulated wall element, but has not used it yet. In principle, a double wall is made where one part is executed with ribs / diagonals and the other without. The two parts of the wall are assembled at the ends, providing significant cold bridges. Winsun has not shown examples of how to insulate between the parts, a task that is considered to have performance challenges. One of the walls is not stiffened by diagonals, so there is room for insulation. The wall will, due to its                  3D Printers – State of the Art Page 17 of 34   small thickness, will be challenged if it is exposed to vertical load as it is not stiffened by a diagonal.In practice, it will probably absorb some vertical load, even though all the load can be absorbed in the rear wall, and therefore will occur large cracks unless a connection is introduced between the wall and the back wall to retain the wall. For example, it could be with binders or reinforcement. It has not been stated whether WinSun uses any of the parts. In the form, WinSun suggested introducing a coupling that is inclined and can act as a crosswind. The connection is thus inside the insulation. The coupling interacts with the wall by casting concrete at the ends (ie top and bottom of the wall). However, this casting will in practice provide a cold bridge that will not be acceptable under Danish conditions. However, the above is an indication (however weak) of how slice forces are absorbed into the wall.

3.1.7 “Insulation” (waste) There was a somewhat different relationship to waste than in Denmark. It was very natural for WinSun that in the spaces between the diagonals, you put in all the construction waste you had, so you were free to dispose of it, see the image below. The waste was described as having a certain U-value, which is why it was considered as insulation.                                  3D Printers – State of the Art Page 18 of 34    3.1.8 Art / decoration / freedom of design One of the advantages of the 3D printing method is the flexibility of the casting / printing, as it is “free” to make variants / deviations. This was expressed, among other things, by the fact that several places had been made for plants to be inserted in the wall. This was done by failing to cast one side of the wall into an area and the notch could then be used as balcony boxes.          3D Printers – State of the Art Page 19 of 34    3.1.9 Finishing the walls WinSun had developed a method to automatically coat the walls. They claimed that the machine / printer was fully automatic in this regard as well. So there were two possible surfaces if one did not want the raw “printer look”. Wall polishing with automatic machine: Clothing with plaster:

It is also noted that in most of the houses there was a damp smell of “wet cellar”. However, this can probably be done with the installation of ventilation systems. 3.2 Tires WinSun uses two types of tires. 3.2.1 Traditional in-situ molded tires At WinSun’s “normal” 3D printed houses, WinSun makes the tires in the traditional way, ie as in-situ molded tires. However, they use the 3D printer to make formwork along the edge of the tire so that tire formwork is not necessary. This saves time especially when the tire is not right as there will be a lot of mold work in such a situation. The tire is lowered downwards like other in-situ molded tires via an underlying scaffolding system.   3D Printers – State of the Art Page 21 of 34      3D Printers – State of the Art Page 22 of 34    3.2.2 Wall structure “laid down” WinSun has, among other things for the office building in Dubai, performed the tire construction by casting a “ring”, which they have subsequently laid down. The ring has been reinforced between the concrete layers so that they have a high tensile / bending capacity. The rings are made at a height of approx. 1.5m and cast together afterwards (at the construction site). The casting will probably be difficult to get 100% close, so the solution will be challenged in the Danish climate.                      3D Printers – State of the Art Page 23 of 34  Casting two “rings” / elements -> Molding threshold    3.2.3 Traditional Trapezoidal Plate Alternatively, WinSun performs their tire system in the same way as you know from the UK, where you make the underside of the formwork with trapezoidal panels (cast with concrete on top, composite effect) and these trapezoidal plates are then supported by steel beams and steel columns. 3.3 Pillars Columns are made immediately as formwork for an in-situ molded column, which means that after the installation (and before casting) the reinforcement is introduced into the column. By introducing diagonals, the column can presumably be designed in the same way as the walls for smaller loads without the introduction of column reinforcement. Note, however, that in such a situation there will be the same challenges with regard to molding for the columns as there are for the walls.

WinSun has 2 production halls that they want to produce from and want to expand production further, see section 1.2. During the visit, they further stated that in the near future they have plans to build a house over 100m, which they regard as a breakthrough in showing the possibilities with their building system.

Published by Jarett Gross

Construction Tech Correspondent Spreading Awareness of Cutting Edge Firms Building the Future of the Industry

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