Patent Application
20180290400
This invention relates to a 3D printing device and a method for 3D printing.
It is becoming increasingly common to employ the technologies of 3D printing and Fused Deposition Modeling (FDM) to form prototypes or customized products. However, one notable problem is how to detach the support structures from the desired article after completion of 3D printing or FDM. The large bonding stress between the desired article and the support structures would cause damage to the desired article when the support structures are detached from the desired article.
Normally, 3D printing and FDM use the same material, such as Acrylonitrile Butadiene Styrene (ABS) or Polylactic acid (PLA), to form the support structures from the desired article. However, the high bonding stress between the desired article and the support structures made of the same material can easily cause damage to the desired article when it is being detached from the support structures.
One known solution is using water-soluble plastics such as polyvinyl alcohol (PVA), alkali-soluble plastics, acid-soluble plastics or gasoline-soluble plastics as the material to form the support structures. However, it takes a long time to solute the support structures made of these materials and the solutions also cause environmental issues.
This invention is to provide a 3D printing device. The 3D printing device comprises a first printing head and a second printing head. The first printing head is used to print a desired article with a first material. The second printing head is used to print support structures for supporting the desired article during printing with a second material. The first material has a first surface cooling time which is the time that the surface temperature of the first material drops from 170° C. to 70° C., the second material has a second surface cooling time which is the time that the surface temperature of the second material drops from 170° C. to 70° C., and the second surface cooling time is less than the first surface cooling time by at least 15 seconds.
This invention is to provide a method for 3D printing. The method comprises the following steps: printing a desired article with a first material; printing support structures for supporting the desired article during printing with a second material; and detaching the desired article from the support structures. The first material has a first surface cooling time that the surface temperature of the first material drops from 170° C. to 70° C., the second material has a second surface cooling time that the surface temperature of the second material drops from 170° C. to 70° C., and the second surface cooling time is less than the first surface cooling time by at least 15 seconds.
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By the fast surface cooling property of the second material, the surface of the support structures 92 printed with the second material can rapidly cool down and solidify earlier than the desired article 91 printed with the first material. Therefore, the bonding strength between the desired article 91 and the support structures 92 is significantly reduced since the printed support structures 92 will be cooled down and solidified in the surface area very soon; the solidified surface layer of the printed support structure 92 is formed before the solidification of the desired article 91, so it prevents or reduces the blending or joining of the first material and the second material. By means of the using of the second material with the abovementioned properties, the support structures 92 printed with the second material can be easily detached from the desired article 91 without damage to the desired article 91. In addition, the support structures 92 printed with the second material would not transfer too much heat into the desired article 91 and have negative effect on the solidification of the desired article 91. By this way, detaching the desired article 91 from the support structures 92 is time-effective, cost-effective and environment-friendly.
When the first material is Acrylonitrile Butadiene Styrene (ABS) with glass transition temperature around 105° C. and surface solidification temperature around 97° C. or Polylactic acid (PLA) with glass transition temperature around 60° C. and surface solidification temperature around 76° C., which are commonly used by 3D printing or Fused Deposition Modeling (FDM), the second material preferably may have a heat deflection temperature (HDT) of 125° C. under a testing load of 1.8 MPa, the glass transition temperature may be around 210° C. and the surface solidification temperature may be around 155° C. in one preferable embodiment. Because of the higher heat deflection temperature (HDT), glass transition temperature and surface solidification temperature of the second material, the 3D printing device 3 prints with the second material under a working temperature of 200° C., and thus the second printing head 32 of the 3D printing device 3 preferably is an independently heatable printing head.
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In one preferable embodiment, the second material is SORPLAS™ produced by Sony Corporation™. SORPLAS™ has excellent surface cooling ability and is a recyclable fireproofing material.
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Based on the above, the method comprises the following steps: printing a desired article 91 with a first material; printing support structures 92 for supporting the desired article 91 during printing with a second material; and detaching the desired article 91 from the support structures 92. The first material has a first surface cooling time that the surface temperature of the first material drops from 170° C. to 70° C., the second material has a second surface cooling time that the surface temperature of the second material drops from 170° C. to 70° C., and the second surface cooling time is less than the first surface cooling time by at least 15 seconds. The second surface cooling time from 170° C. to 70° C. of the second material preferably is less than the first surface cooling time by at least 25 seconds, and further preferably is less than the first surface cooling time by at least 30 seconds.
When the first material is Acrylonitrile Butadiene Styrene (ABS) with glass transition temperature around 105° C. and surface solidification temperature around 97° C. or Polylactic acid (PLA) with glass transition temperature around 60° C. and surface solidification temperature around 76° C., which are commonly used by 3D printing or Fused Deposition Modeling (FDM), the second material preferably may have a heat deflection temperature (HDT) of 125° C. under a testing load of 1.8 MPa, the glass transition temperature may be around 210° C. and the surface solidification temperature may be around 155° C. in one preferable embodiment. Because of the higher heat deflection temperature (HDT), glass transition temperature and surface solidification temperature of the second material, the step of printing support structures 92 with the second material is performed under a working temperature of 200° C. and the step of printing support structures 92 with the second material is performed by the second printing head 32, which is an independently heatable printing head.
The method for 3D printing preferably comprises heating a printing platform 33, on which the second material and the first material are ejected or sprayed, to between 100° C. and 150° C.
In one preferable embodiment, the second material is SORPLAS™ produced by Sony Corporation™. SORPLAS™ has excellent surface cooling ability and is a recyclable fireproofing material.
