METHOD FOR CLEANING AND POST PROCESSING 3D PRINTED LIGHT CURE SILICONES

Abstract

The present invention is directed to a method for post processing a 3D printed part, to a three-dimensional part fabricated in a method according to the present invention, and further to the use of a liquid in the post processing of a three-dimensional part fabricated in a 3D printing method.

Claims

1. Method for post processing a 3D printed part, the method comprising: A) providing a 3D printed part; B) immersing said part into a first liquid medium that is incompatible with the material said part is printed from, and C) exposing said part to ultrasound.

2. The method according to claim 1, wherein the 3D printed part is fabricated in an SLA and/or a DLP method; and/or step B) and/or step C) are repeated one or more times.

3. The method according to claim 1, further comprising a step D) of immersing the 3D printed part obtained after step C) into a second liquid medium that is incompatible with the material said part is formed from, and exposing said part to radiation.

4. The method according to claim 1, wherein the first and/or the second liquid medium is selected from the group consisting of water and demineralized water.

5. The method according to claim 1, wherein step C) is carried out over a period of about 1 second to about 5 hours; and/or the exposing of step D) is carried out over a period of about 1 second to about 24 hours.

6. The method according to claim 1, wherein in step A), the 3D printed part is immersed partially or completely; and/or in step C), ultrasound is applied at frequencies of about 15 kHz to about 40 kHz; and/or in step D), the radiation is UV light or visible light.

7. The method according to claim 1, the method further comprising a step A1) of removing excess unpolymerized resin material by one or more of drip drying, manual cleaning, and application of air pressure.

8. The method according to claim 1, wherein the material the 3D printed part is printed from is a radiation-curable silicone composition.

9. The method according to claim 8, wherein the radiation-curable silicone composition comprises one or more additives selected from the group consisting of stabilizers, inhibitors, chelating agents, antioxidants, thickeners, plasticizers, fillers, dispersion stabilizers, hindered amine light stabilizers, UV absorbers, opacifiers, pigments, and dyes.

10. A three-dimensional part obtainable in a method according to claim 1.

Description

EXAMPLES

Example 1: Cleaning Comparison

[0055] Cleaning Methods

[0056] 1) Printed part: Matrix; taken out of SLA liquid and allowed to drip dried before post-cure for 20to 30 minutes.

[0057] 2) Printed part: Rook 1; taken out of SLA liquid and drip dried, cleaned by exposure to ultrasound in a water bath for 2 minutes before post-cure in water.

[0058] 3) Printed part: Rook 2; taken out of SLA liquid and drip dried, cleaned by exposure to ultrasound in a water bath for 10 minutes before post-cure in water.

[0059] 4) Printed part: Rook 3; taken out of SLA liquid and drip dried, cleaned by exposure to ultrasound in a water bath for 18 minutes before post-cure in water.

[0060] Results

[0061] 1) Drip drying allowed most of SLA silicone uncured material to come off, however, some residual material remains.

[0062] 2) Rook 1, better surface, but two small windows could not be opened, as residual silicone was present in gaps of the structure during post-cure.

[0063] 3) Rook 2, improved appearance, one of two small windows is open.

[0064] 4) Rook 3, both windows are open.

[0065] As evident from the above examples, cleaning of the printed part by exposure to ultrasound while submerged in water improves overall appearance, functionality, and level of detail veracity.

Example 2: Post-Cure Comparison

[0066]

TABLE-US-00001 TABLE 1 Post processing Sample Structure cleaning Post-cure conditions Control A ASTM sheet — UVALOC 60 sec/side (Lg UVA) (SP-2B), big at 100 mW/cm.sup.2 (UVA) dog bones Control B ASTM sheet — UVALOC 60 sec/side (Lg UVV) (SP-2B), big at 120 mW/cm.sup.2 (UVV) dog bones Control C ASTM sheet — UVALOC 60 sec/side (small) (SP-2B), big at 100 mW/cm.sup.2 (UVA) dog bones Printed AS Printed liquid wiped off, part — with BL PR-10 Sheet removed from platform with burn-layer (BL) left on Printed AS Printed liquid wiped off, — without PR-10 Sheet removedfrom platform BL and burn layer peeled off Printed/ AS Printed liquid wiped off, part EQ CL-36 LED Cure Post PR-10 Sheet removed from platform Chamber; 405 nm; 7 cured with burn-layer (BL) minutes in water with BL left on Printed/ AS Printed liquid wiped off, EQ CL-36 LED Cure Post cured PR-10 Sheet removed from platform Chamber; 405 nm; 7 without and burn layer peeled minutes in water BL off

TABLE-US-00002 TABLE 2 Tensile Tensile Strength Strength Blue Red Modulus Modulus Elongation Hardness Sample [N/mm.sup.2] [N/mm.sup.2] [%] Shore A Control A 3.94 2.27 173.87 50 Control B 3.96 2.26 178.96 49 Control C 3.98 2.05 186.26 49 Printed with BL 2.71 1.76 169.68 42 Printed without BL 1.92 1.41 163.89 38 Printed/Post cured 3.65 2.78 191.37 53 with BL Printed/Post cured 3.77 2.88 190.44 50 without BL

[0067] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. The words “comprises/comprising” and the words “having/including” when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.