Process for the surface treatment of polymeric three-dimensional objects

Abstract

A process can be used for the surface treatment of three-dimensional objects which have been produced in additive manufacturing processes from at least one polymer. The process involves a) immersing the three-dimensional object in a substance mixture A, b) leaving the three-dimensional object in the substance mixture A for a time, and c) removing the three-dimensional object from the substance mixture A. The process then involves d) immersing the three-dimensional object in a substance mixture B, e) leaving the three-dimensional object in the substance mixture B for a time, and f) removing the three-dimensional object from the substance mixture B. The substance mixture A has a temperature (process temperature A) which is above the melting point of the polymer, and the substance mixture B has a temperature (process temperature B) which is below the melting point of the polymer.

Claims

1: A process for surface treatment of a three-dimensional object which has been produced in additive manufacturing processes from at least one polymer, the process comprising: a) immersing the three-dimensional object in a substance mixture A, b) leaving the three-dimensional object in the substance mixture A for a time, c) removing the three-dimensional object from the substance mixture A, d) immersing the three-dimensional object in a substance mixture B, e) leaving the three-dimensional object in the substance mixture B for a time, and f) removing the three-dimensional object from the substance mixture B, wherein the substance mixture A has a temperature (process temperature A) which is above a melting point of the at least one polymer, and wherein the substance mixture B has a temperature (process temperature B) which is below the melting point of the at least one polymer.

2: The process according to claim 1, wherein the substance mixture A contains at least 50 mass %, based on a total mass of substance mixture A, of at least one substance which is liquid at process temperature A.

3: The process according to claim 1, wherein a density of the substance mixture A differs by not more than 25% from a density of the at least one polymer of the three-dimensional object.

4: The process according to claim 2, wherein the at least one substance which is liquid at process temperature A is immiscible with further liquid components of the substance mixture A, with a difference in surface tension between polymer and liquid substance being at most 10 mN/m.

5: The process according to claim 2, wherein the at least one substance which is liquid at process temperature A corresponds to the at least one polymer of the three-dimensional object.

6: The process according to claim 1, wherein a) to f) are conducted more than once.

7: The process according to claim 1, wherein a temperature of the three-dimensional object is adjusted prior to a) to a temperature of below 0° C.

8: The process according to claim 1, wherein the substance mixture B has a temperature which is at least 20° C. below the melting point of the at least one polymer.

9: The process according to claim 1, wherein the substance mixture B is liquid at the process temperature B.

10: The process according to claim 1, wherein the substance mixture B contains substances in which the at least one polymer has a solubility of less than 10 g/l.

11: An apparatus for surface treatment of a three-dimensional object which has been produced in additive manufacturing processes from at least one polymer, the apparatus comprising: a receptacle A having a heating device, a receptacle B, and a conveyor belt from receptacle A to receptacle B.

12: The apparatus according to claim 11, having a stirring apparatus in receptacle A.

13: A shaped body from an additive manufacturing process which has been treated by the process according to claim 1, wherein after f), no heating of a surface in a temperature range of above 120° C. is effected.

14: A shaped body from an additive manufacturing process which has been treated by the process according to claim 1 and has a pH-neutral surface.

15: A shaped body according to claim 13, wherein the shaped body contains a polymer selected from the group consisting of a polyamide, a polyaryl ether ketone, a polyolefin, a polyesteramide, a polylactide, an acrylonitrile-butadiene-styrene copolymer, and a mixture thereof.

16: A shaped body according to claim 14, wherein the shaped body contains a polymer selected from the group consisting a polyamide, a polyaryl ether ketone, a polyolefin, a polyesteramide, a polylactide, an acrylonitrile-butadiene-styrene copolymer, and a mixture thereof.

Description

EXAMPLES

Example 1: SLS Component PA12 Sandblasted (not According to the Invention)

[0047] A test specimen produced by means of SLS (in accordance with DIN EN ISO 527-1 and UL94) from nylon-12 (EOSINT PA2200) is freed from powder residues by means of glass bead blasting.

Example 2: SLS Component PEA Sandblasted (not According to the Invention)

[0048] A test specimen produced by means of SLS (in accordance with DIN EN ISO 527-1 and UL94) from polyesteramide PEA (EOSINT Primepart ST) is freed from powder residues by means of glass bead blasting.

Example 3: SLS Component PA613 Sandblasted (not According to the Invention)

[0049] A test specimen produced by means of SLS (in accordance with DIN EN ISO 527-1 and UL94) from PA613 precipitated powder is freed from powder residues by means of glass bead blasting.

Example 4: FDM Component Untreated (not According to the Invention)

[0050] A test specimen produced by means of FDM (in accordance with DIN EN ISO 527-1 and UL94) from acrylonitrile-butadiene-styrene ABS is freed from the support geometries and washed.

Example 5: FDM Component Untreated (not According to the Invention)

[0051] A test specimen produced by means of FDM (in accordance with DIN EN ISO 527-1 and UL94) from polylactide PLA is freed from the support geometries and washed.

Example 6: SLS Component PA12 Surface-Treated at 200° C. (According to the Invention)

[0052] A test specimen produced and processed further as in example 1 is additionally immersed in an oil bath (MARLOTHERM N) at 205° C. for 20 s. Then, the test specimen is removed and immersed in a water bath (25° C.) for 10 s.

Example 7: SLS Component Surface-Treated at 170° C. (According to the Invention)

[0053] A test specimen produced and processed further as in example 2 is additionally immersed in a glycerol bath at 170° C. for 20 s. Then, the test specimen is removed and immersed in a water bath (25° C.) for 10 s.

Example 8: SLS Component Surface-Treated at 230° C. (According to the Invention)

[0054] A test specimen produced and processed further as in example 3 is additionally immersed in an oil bath (MARLOTHERM N) at 240° C. for 20 s. Then, the test specimen is removed and immersed in a water bath (25° C.) for 10 s.

Example 9: FDM Component Surface-Treated at 120° C. (According to the Invention)

[0055] A test specimen produced and processed further as in example 4 is additionally immersed in a bath of propane-1,2-diol at 150° C. for 20 s. Then, the test specimen is removed and immersed in a water bath (25° C.) for 10 s.

Example 10: FDM Component Surface-Treated at 160° C. (According to the Invention)

[0056] A test specimen produced and processed further as in example 5 is additionally immersed in an ethylene glycol oil bath at 180° C. for 20 s. Then, the test specimen is removed and immersed in a water bath (25° C.) for 10 s.

Example 11: SLS Component PA12 Surface-Treated at 200° C. (According to the Invention)

[0057] A test specimen produced and processed further as in example 1 is adjusted to a temperature of −30° C. in a cooling chamber for 4 h. Then, the test specimen is additionally immersed in a substance mixture at 200° C. for 20 s. The substance mixture consists of 80 percent by mass of a heat transfer oil (MARLOTHERM N) and 20% of a nylon-12 (VESTAMID L1723 blk sw). The substance mixture is constantly mixed using a stirrer. Then, the test specimen is removed and immersed in a water bath (25° C.) for 10 s.

Example 12: SLS Component PA12 Surface-Treated at 190° C. (According to the Invention)

[0058] A test specimen/UL test specimen produced and processed further as in example 1 is adjusted to a temperature of −60° C. in a cooling chamber for 16 h. Then, the tensile test specimen/UL test specimen is additionally immersed in a substance mixture at 190° C. for 40 s. The substance mixture consists of 80 percent by mass of a heat transfer oi (MARLOTHERM N) and 20% of a nylon-12 (VESTAMID X7166 nc). The substance mixture is constantly mixed using a stirrer. Then, the test specimen is removed and immersed in a water bath (25° C.) for 10 s.

TABLE-US-00001 Tabelle 1: Results of the test specimen tests Modulus of Tensile Elongation elasticity strength at break Roughness Example [MPa] [MPa] [%] Sa [μm] Comment 1 1750 49 18 42 Component white, UL94 3.2 mm HB 2 183 9 216 63 3 2242 58 26 44 4 2136 56 3 382 5 3127 51 5 128 6* 1714 48 57 22 7* 184 10 384 28 8* 2231 59 64 24 9* 2120 55 5 298 10* 3133 52 5 92 11* 1713 48 42 16 Component black 12* 1694 47 33 15 UL94 3.2 mm V2 *according to the invention

[0059] The test specimens were tested according to DIN EN ISO 527-1 and UL94. The arithmetic mean height (Sa) was used as a measure of the roughness. The Sa was determined on the underside of the test specimen using a Keyence VHX6000 microscope. The results of the illustrative tests can be found in table 1. It can be seen that the roughness of the three-dimensional objects was markedly reduced by the process according to the invention. The elongation at break of the three-dimensional objects in the examples according to the invention was markedly increased, while the other mechanical characteristics were maintained at the same level. In addition, in example 11 a black surface was achieved. In example 12 a flame-retardant effect was achieved.

[0060] A reduced surface roughness of the three-dimensional objects could thus be achieved with the process according to the invention. Furthermore, additional effects such as colour or flame-retardancy could also be achieved by the process according to the invention.