Method for treating the surface of moulded parts
A method is for treating a surface of a molded part produced according to a 3D printing method using a plastics material. A solvent is selected from the group consisting of halogen-free and non-polar hydrocarbons and derivatives thereof and/or a solvent selected from the group consisting of bio-based solvents and is applied to the surface of the molded part. A device is for treating a surface according to the method described.
1. Method for treating a surface ( 11 ) of a molded part ( 10 ) produced according to a 3D printing method using a plastics material, wherein a solvent selected from the group consisting of bio-based solvents is applied to the surface ( 11 ) of the molded part ( 10 ), wherein the bio-based solvent is 1,8-Cineole.
2. Method according to claim 1 , wherein the solvent is applied in vaporous form to the surface ( 11 ) of the molded part ( 10 ).
3. Method according to claim 1 , wherein the bio-based solvent is applied to the surface ( 11 ) of the molded part ( 10 ) in a low-oxygen atmosphere.
4. Method according to claim 1 , wherein at least one additive is added to the bio-based solvent before it is applied to the surface ( 11 ) of the molded part ( 10 ).
5. Method according to claim 4 , wherein the additive is selected from the group consisting of:
antioxidants,
heat stabilizers,
polymerization inhibitors and
combinations or mixtures thereof.
6. Method according to claim 4 , wherein the additive is selected from the group consisting of:
sterically hindered phenolic compounds,
sterically hindered amines (HALS),
phosphites,
phosphonites and
combinations or mixtures thereof.
7. Method according to claim 4 , wherein the at least one additive is added to the bio-based solvent at a concentration of between 5 ppm and 4000 ppm based on the bio-based solvent.
8. Method according to claim 4 , wherein the at least one additive has a boiling point and a decomposition temperature that is above the boiling point of the bio-based solvent.
9. Method according to claim 1 , wherein the plastics material is selected
from the group consisting of thermoplastics and light-curing plastics materials.
10. Method according to claim 1 , wherein
(a) the molded part ( 10 ) is introduced into an interior ( 21 ) of a pressure-tight container ( 20 ),
(b) a negative pressure is generated in the interior ( 21 ) of the container after introducing the molded part ( 10 ) into the container ( 20 ),
(c) the solvent is heated up to a specified solvent temperature and
(d) the heated solvent is introduced from a solvent container ( 40 ) into the interior ( 21 ) under negative pressure after introducing the molded part ( 10 ) into the interior ( 21 ) of the container ( 20 ),
wherein
the temperature of the molded part ( 10 ) is lower than the solvent temperature and
the solvent is evaporated into the interior ( 21 ) or is introduced as a steam into the interior ( 21 ) upon being introduced, said solvent steam condensing on the surface of the molded part ( 10 ).
11. Method according to claim 10 , wherein the interior ( 21 ) of the pressure-tight container ( 20 ) is brought to a specified first internal temperature before step (a) or after step (a).
12. Method according to claim 3 , wherein by introducing the solvent into the interior ( 21 ) (step (d)), the temperature of the interior is brought to a specified second internal temperature, wherein the solvent is introduced into the interior:
until the specified second internal temperature is reached as long as the solvent is introduced into the interior or
over a specified period of time, wherein the specified second internal temperature is reached after the specified period of time.
13. Method according to claim 12 , wherein the temperature of the interior is brought to a third internal temperature after introducing the molded part ( 10 ) into the interior ( 21 ) (step (a)) and before introducing the solvent into the interior ( 21 ) (step (d)), wherein the third internal temperature is lower than the specified second internal temperature, whereby the molded part is brought to a part temperature which is lower than the specified second internal temperature.
14. Method according to claim 10 , wherein a negative pressure is generated in the interior of the solvent container ( 40 ) before introducing the solvent from the solvent container ( 40 ) into the interior ( 21 ) of the pressure-tight container ( 20 ), wherein the pressure in the interior ( 21 ) of the pressure-tight container ( 20 ) is lower than the pressure in the interior of the solvent container ( 40 ).
15. Method according to claim 14 , wherein the pressure difference between the interior ( 21 ) of the pressure-tight container ( 20 ) and the interior of the solvent container ( 40 ) is selected so that a turbulence in the solvent introduced into the interior ( 21 ) of the pressure-tight container ( 20 ) is caused due to the pressure difference.
16. Method according to claim 10 , wherein
(e) after the introduction of the solvent into the interior, the molded part is dried.
17. Method according to claim 16 , wherein steps (d) and (e) are repeated a number of times.
18. Method according to claim 17 , wherein a negative pressure is generated to dry the molded part in the interior ( 21 ), wherein the generation of the negative pressure is interrupted at least once in that a transport gas is supplied into the interior ( 21 ), wherein the transport gas is supplied to the interior ( 21 ) when the pressure in the interior ( 21 ) is less than 50 mbar, the pressure in the interior ( 21 ) being increased to a value of between 50 mbar and 100 mbar by supplying the transport gas.
19. Method according to claim 16 , wherein steps (d) and (e) are repeated multiple times, wherein during one repetition
in step (d), the temperature of the interior is brought to a second internal temperature which is higher than the second internal temperature in the previous execution of step (d) or
in step (d), the temperature of the interior is brought to a second internal temperature which is lower than the second internal temperature in the previous execution of step (d) or
in step (d), the temperature of the interior is brought to a second internal temperature which is to a large extent equal to the second internal temperature in the previous execution of step (d).
20. Method according to claim 19 , wherein during a repetition and prior to carrying out step (d) the temperature of the interior is brought to a temperature which is lower or higher than the second internal temperature in the previous execution of step (d).
21. Method according to claim 19 , wherein the temperature of the solvent is reduced after each repetition.
22. Method according to claim 16 , wherein
after step (d), a holding time (H) is provided during which the molded part is located in the interior ( 21 ) of the pressure-tight container ( 20 ) in an environment that occurs immediately after the introduction of the solvent or the solvent steam into the interior of the pressure-tight container and/or
after step (e), a holding time (H) is provided during which the molded part is located in the interior ( 21 ) of the pressure-tight container ( 20 ) in an environment that occurs immediately after the drying or immediately after the suctioning off of the solvent or the solvent steam from the interior of the pressure-tight container.
23. Method according to claim 10 , wherein, after step (d), the solvent evaporated in the interior space ( 21 ) and/or the solvent condensed on the inner wall of the interior space ( 21 ) are suctioned off, wherein the suctioned-off solvent is processed, and the processed solvent is returned to the solvent container ( 40 ).
24. Method according to claim 10 , wherein the negative pressure in the interior, the solvent temperature, and a temperature within the interior of the container are coordinated so that the solvent evaporates in the interior upon being introduced into the interior or enters the interior as solvent steam.
25. Method according to claim 10 , wherein a turbulence in the solvent steam introduced into the interior ( 21 ) is caused in the interior.
26. Method according to claim 10 , wherein the molded part is heated before step (a).
27. Method according to claim 10 , wherein a plurality of liters of solvent are heated to the specified solvent temperature.
28. Method according to claim 10 , wherein the solvent is heated to the specified solvent temperature, which is above 50° C.