Finally got a decent hull print!

[SubICman]

A few months ago, I purchased a Flashforge Foto 8.9 4k resin printer to print hull sections with. In retrospect I should have waited and got an 8k 13.9, but that's another story.

I have been trying for the last few months to get a good print at the larger size, using both standard and water washable resins. I have used these resins on my Elegoo Mars 2 with success in the past, so i have confidence in my resin exposurecalibrations. I have had success with smaller objects, but every time I go to print big, the print fails. Typically it ends up being just the supports that print.

I have even gone as far as using different slicing softwares, between Chitubox, Lychee and FlashDLPrint. Interestingly, I Found out that my printer is not supported by Lychee.

Last night I had a print go good using FlashDLPrint sliced model until about 50%, them it started peeling from the build plate. I adjusted my base cure time and layering, and changed the print orientation and I finally got a good print, kinda. There is a little flaring at the joint I need to figure out.

Here is the first piece of a Disney Nautilus using the CGtrader files mentioned elsewhere on the forums.

[SubICman]

Here is another view without the supports.

[SubICman]

Made it to 3 good hull sections today.

[SubICman]

Update on progress on my Disney Nautilus model. Steep learning curve with the large format printer, between figuring settings for the resin and figuring how to properly support the larger pieces. For those who are wondering, i am using Elegoo Water-washable Black resin for the large hull pieces, and my cure times I have worked out is a 45s base time with 2.8 seconds a layer. The 4K large format printer I have is a Flashforge Foto 8.9 and learning how to use it versus my 2K Elegoo Mars 2 was challenging. So currently the print line-up is hull sections on the Foto with the water washable and the smaller detail parts on the Mars 2. For the details I am using Opto-Rich ABS like Black standard resin with a 40s base time and 3.5s a layer. Entering the mix for the next hull print adventure is an Elegoo Saturn S 9.1" 4K printer. I bought this one after a lot of frustration with Foto, but it turned out to be a knee-jerk reaction........oh well....what to do?

I Had a bunch of failed prints (see attached pictures) and I had actually glued 2 of the wrong hull sections together (2R to 3L), definitely have to pay attention to the pdf sheet that shows the pieces. One of my recommendations for this is to print only the side that you are working at the moment and not to try and print pairs. At the moment, I have the whole Stbd side glued together and am preparing to glue the Port side together. I have the Spar nose section printed and and I am attempting to print section 6 for the 3rd time. One done I will join the hull halves. Gorilla medium CA holds the pieces together very well, and if you try to separate them, the resin pieces typically break before the joint. As long as your print has been properly supported, cured and prepped, the pieces fit together like a glove.

The pictures only show a portion of the failures. So far the reprint tally is Section 1 x2, Section 2R x2, Section 3R x2, section 3L x3, Section 4L x3 Section 5l&R x2, Section 6 X3. A lot of the failures were due to inadequate supports or bad model position, but 1 was due to contamination in the resin tank. I have been using Chitubox to slice models for my Mars 2 for a while, and it is supported by the Foto. I have had no issues printing small items on the Mars; however I also found that the larger pieces for the Foto would fail every time with it. I started using the Foto's native slicer FlashDLPrint, and I started having intermittent successes, but the supports kept failing. I have since found that I can export .obj or .stl files from Lychee after I have orientated and supported a model, I then load that file into FlashDLPrint and apply the print settings and Voila, Success!!!!

I cannot stress more the need to calibrate your resin prints for the resin and machine you are using. Go out and find a resin print calibration matrix file (There are many, but I use the XP2 validation matrix) and play with the cure time settings until you get the best possible results. There are many videos out here by people such as Uncle Jessy, Rybonator, 3DPrintFarm and others who have videos that talk to this. Yes, they are printing role-playing minis and cosplay stuff and even dice, but the principles are the same.

Another recommendation is to get/make a wash station and a curing station that will accommodate the size of your prints..........my little UV turntable and ultrasonic cleaner had to be upgraded to handle the larger Nautilus pieces.

[CC Clarke]

Agreed. The XP2 is an excellent exposure test for resin calibration. I'm using a Sonic Mighty 4k with Chitubox, (will be updating to a Mega 8k soon) and some hull prints have to be cut in half to fit the build plate @ 1/72 scale, but there's a night and day comparison between FDM and resin printing when it comes to fine details, and post-finishing. The learning curve is certainly steeper, but the results are worth it once support structure placement and exposure times are understood. I print and annotate many XP2 test coupons before throwing an 18-hour print at it when using a new resin.

Phrozen just released a new resin that is tougher, but with a sale price of $90 a bottle, with three or four needed for a full-sized hull, printing can get expensive!

Phrozen ONYX Impact Plus Resin Phrozen Technology｜Desktop LCD 3D Printer｜8K High Resolution (phrozen3d.com)

CC

[SubICman]

Yes, lots of test stamps....I have about 40.of them around here. So far I'm at 4 1000g bottles because of the learning curve. Only 27 a bottle but still a costly lesson.

Oh and the one setting I didn't state earlier is a .1 mm layer height for hull sections and .05 mm for detail parts.

Tim

[trout]

There is a learning curve, I have gone through a gallon of resin (at least) while working on designs. I like what you are doing!

[SubICman]

Here is the hull as it stands. I need to re-print section 1 which is the spar. The corners have curled out and the color was never right on this piece. In fact. Several pieces came out this color, and I don't know if I didn't shake the bottle enough, or if I got smokey black in a black labeled bottle.




A lot was learned in the venture so far, from proper Model support and placement, to post print wash and curing procedures. I started using the Saturn S, I like it more than the Fashforge in several respects, but the most noticeable is noise level. The Saturn S is much quieter.



I continue to plug along!

[CC Clarke]

Slow and steady wins the race. You're definately making progress! I'll be moving up to a larger Sonic Mega 8k ,(large enough to print a full-sized helmet!) for larger one-piece hull sections soon and the experience from my 4k will flatten the learning curve, since it takes two kilos of resin to fill the vat.

For half-piece hull sections, I've found using medium supports overall, and large supports for all corners (and transitions between thinner and thicker sections of the hull (like alignment features) makes a big difference with warping as the model hangs from the build plate. The standard 45 orientation angle (for my 1/72 parts) has been changed slightly and after several failures, (similar to yours) I've gone to 22.5 degrees with a 90 rotation in theta Z to fit the build plate. All of my proto hull sections are 3mm thick using standard Aqua 4k resin. Once I've hammered out a good prototype, then engineering resin is worth the additional expenditure to create the final version. Along the way, I document every section using PowerPoint slide packages with build progress photos and write-ups for details to be incorporated in the next version.

FDM printing is great for assembly jigs and internal ribs for WTCs, but for hull sections, I prefer resin for strength and superior detail. The downside to resin printing is resin cleanup and extended print times.

CCC

[SubICman]

Printed the spar section successfully yesterday. I glued it to the hull, putties the few gaps I had and shot a coat of fusion cast iron paint onto it. I am awaiting a new shipment of resin to continue the upper hull. Will be working on lower hull fittings until then.

[SubICman]

Received my shipment of Black water washable resin last night. Tonight I will be moving on to printing the lower hull rakers and keel. While I was waiting, I printed the MBT grates and the lower hatch ring. Everything but the hatch ring printed nicely in the standard abs like black resin.

The spring portion of the hatch ring failed to print due to how the 3d model was made. I am exploring on how to fix this in several modeling programs.

I also misted the lower hull with Rustoleum Universal Burnished Amber.

[CC Clarke]

If you need any help modeling or modifying a part, I might be able to help.

CC

[SubICman]

Here is the issue with the hatch ring. It is in the spring area, which is hollow. Need to make it a solid center.

[CC Clarke]

Easy. PM me if you want it want the mesh re-built.

CC

[SubICman]

1st 2 parts of the keel and the planes last night.