Elegoo Mars 3 FEP Replacement Helper

cults3d

This is a small helper for replacing the FEP of the Elegoo Mars 3 VAT. The VAT of the Mars 3 is slightly larger and oddly shaped so I designed a good fitting helper. The FEP sheet of the Mars 3 (and other Elegoo printers) must be installed slightly floppy and gets tensioned afterwards by screws under the VAT. This FEP replacement helper will provide the optimal curvature for the FEP so it gets perfectly tensioned in the end. I fully tested the helper, see the pictured guide on how to change the FEP sheet. Currently, there are now three ways to print it: (1) The one-piece version can only be printed with an FDM printer or on a larger format SLA printer like the Elegoo Saturn. The one-piece version is 192x140x13 mm^3. (2) The two-piece version can be printed on dialed-in Mars 3. Please see attached image for orientation for best results for the puzzle noses. Of course, the two-piece version can also be printed on FDM printer, albeit the gap of the puzzle pieces might be challenging small for some cheaper FDM printers. (3) The four-piece version can easily be printed on Mars 3. The pieces are smaller and can be printed quicker but placing the many supports for the puzzle noses might be too annoying (at least for me). Remarks for SLA version: I recommend dialed-in resin settings for Mars 3 for best results and perhaps a resin mixture of ABS-like and Siraya Tech Tenacious 3:1 to provide enough flex to the puzzle noses. The gap between the puzzle pieces is 0.2mm, so there is currently some room for printing imperfections. You can always print only the top part with the puzzle noses if you want to see if your printer settings match the 0.2mm tolerance, see image attached. (If someone needs a larger gap because the puzzle pieces are too tight, then write me a message. Previous purchasers confirmed that 0.2mm gap fits perfectly for them) Small guide on how to replace the FEP: I added the whole process as a small image gallery. The essential tools are: hex bit/key in size 2, 2.5 and 3 new FEP/nFEP/PFA sheet for Mars 3. The term "nFEP" or "FEP+" is just a marketing term for PFA. You can also buy a roll of PFA for much cheaper than the usual FEP/PFA sheets. Scalpel or sharp knife cloth and IPA for cleaning this replacement helper :-) further recommended: very fine grit (~3000) sanding paper for de-burring the metal edges of the VAT and a torque wrench from 0.2 to 1.2 Nm for even tightening of the new FEP. Step-by-Step guide: Dissasemble the whole VAT. Store the screws somewhere safe. Clean the VAT. 1.1 The rim of my VAT had rough edges which ultimately pierced my FEP at the very edge. I carefully sanded down the rough edges with very fine sandpaper. Have a look if this is applicable to your VAT). take the VAT replacement helper and place it in front of you. (img1) Place the frame with the 10 large countersinks in the helper. Countersinks must face downwards. (img2) Place FEP sheet approximately central on the helper and frame. (img3) Place the frame with the 12 smaller countersinks gently on top. (img4) Press the frame down and keep pressing down. Hand-tighten the smaller screws (M2, 1.2 Nm) while pressing down. (img5) 6.1 This needs some flexibility and dexterity in your fingers. The FEP sheet will be slightly wobbly after tightening the screws. Don't worry, this is normal (you can't change the Gaussian curvature of a sheet :-) ). Take a scalpel or sharp knife and cut of the excess FEP around the frame. (img6) Turn over the frame and place it gently in the VAT. Carefully screw in the larger screws with M2.5 bit/key a few turns. DO NOT tighten them fully yet. (img7) (This step will take the most time.) Step by step tighten the screws with slowly increasing torque. A torque wrench is helpful here. Ideally, the FEP should be tensioned uniformly. When tightening one screw you should tighten next one screw on the opposite side, e.g., one screw left and then one right. You may have to tighten the screws multiple times as the FEP is slowly getting stretched. Take your time here. You can check the current tension of the FEP sheet by gently blowing on it. The vibration frequency will slowly increase with tension. An evenly stretched FEP will result in a better separation of the printed parts from the FEP sheet. (img8) 10.1 If you have a torque wrench, start by tightening all screws to 0.2 or 0.3 Nm. Afterwards, increase the torque to 0.5 or 0.6 and so on. The FEP will be fully stretched at a torque of approx. 1.2 Nm. Screw in the black VAT alignment screws (M3). (img9) Congratulations, you successfully changed your VAT :-)