3d printing process

[Dr PR]

You can fiddle with the exposure time to fine tune some dimensions. Long exposures cause things to be fatter. The light scatters through the resin. This allows some resin to be cured around the exposed area, adding to the intended dimension. Also, some light diffuses through thin sections, causing additional resin to cure "on top" of previous layers.

 

I have found that minimum exposure times work best for fine details. But I still can't get very small holes (0.010 inch or 0.25 mm) to come out even though this is 5x the diameter of a single pixel on my machine. Maybe this is just because I haven't been able to wash uncured resin out of the holes before I cure the pieces?

[thibaultron]

Anycubic R_E_R_F File – Detailed Look at what is being sent to the printer

 

This is a detailed look at what the Anycubic R_E_R_F file is sending to your printer, so you can determine the correct exposure for the resin you are using.

 

As a general note, I am not an expert in resin printing. In fact, I’m just starting. That is one reason I made this write up. The advice I give on setting the exposure from the results of this test, is what I have gleaned from videos and write ups I’ve found on the internet. This advice is from several well respected YouTubers and various resin printing forums. Your mileage may vary, and please, just use this as a starting point for your adventures. This is my best analysis of the print and what the tests are.

 

The file prints the same part at different exposures, with print #1 being the least exposed, (1 second) and each subsequent print exposed, at an additional 0.25 seconds. Print #8 has the longest exposure time. These times are for the Mono 4K. I don’t know if the interval is the same for the R_E_R_F files for their other models. According to Anycubic, you can change the initial 1 second time, and the rest will follow at 0.25 second intervals from the new time. My computer will not run their latest slicer software, and the next lower version will not open this latest file, so I could not test this.

 

OK, you have printed out the Anycubic R_E_R_F Exposure. Great! What the heck is the original print supposed to look like so you can judge the results?? As a note, it is best to observe the prints before washing, after washing, and after curing. Each process, especially curing can lead to warping of the part, and some of the details. After the first wash, it might be a good idea to go back and hit the areas with through or blind holes with a toothbrush, to make sure any uncured resin still in them is removed as thoroughly as possible. Handle all the parts carefully, as there are many fine details on them, that can be easily broken off. I noticed that after a day or so, the block, mentioned later. with the seven blind vertical holes in it seemed wet in that area. I think that the smallest holes did print, but still had uncured resin in them after washing, and curing. I will have to come up with some way to clean out such small holes, if any of my regular prints contain such.

 

All the parts are likely to warp during curing, hence the checking, where possible before curing. How to prevent this is left up to more experienced types than me. I think I cured them for far too long. I used a 10 minute cure, I think 2 to 5 is the recommended time.

 

This print has many different tests included so there will be a lot of areas to be checked. In the end not all areas will probably be the best on one part. You will have to pick the one that is the best overall. Start a small print at this setting, then several others varying the exposure by 0.1 or 0.2 seconds on either side of this setting to dial in the best exposure (for an Anycubic Mono 4K). For other machines you may have to use a larger or smaller interval.

 

Here is a picture of my first “successful” print of this test. The failure of the upper right is due to part of my failed actual first print that was stuck to the FEP, I should have checked the FEP before I continued. I think that the sheets of flash, also were caused by this.

 

On all the tests with a series of objects with decreasing size, it is likely that some of the smaller objects or holes may not print. The best you can do is select the exposure that produces the most ones. This is where hitting the holes with a toothbrush and cleaner, may clear out a hole that printed, but still has uncured resin stuck in it. For small details on your regular prints, you may want to do this too.

 

I managed, after playing with several programs, to convert a copy of the R_E_R_F.pwmo file to a Sketchup .SKP format, then imported it into CHITUBOX. These are screen shots taken as I zoomed in to get a closer look at what is being sent to the printer. I have not been able to break up the 8 print group so that I could look at just one part, so the pictures will also show adjacent parts. This is the best I could do.

 

This is the entire 8 part group. The thin border shown in this, and other shots, is the CHITUBOX working surface.

 

This picture shows one of the center angled plate areas seen from the top. This area has flat vertical plates printed at the corner joining the two angled plates. Each plate is thicker than the one next to it.  The pillars also change diameter as they go from one side to the other, I think matching diameter to the plate thickness in that row. In addition as the pillars progress from the center corner out they get progressively shorter, until ending at the second to last row. The last row consists of through holes the same diameter as the adjacent pillar.

 

 

This picture shows both surfaces of the angled plates. The second angled plate consists of square through holes, that appear to be the same width as the vertical plates and get longer as they progress to the outside. Check that both angled plates are flat in both directions.

 

 

This shows the other side of this plate.

The long vertical block on the right has a series of varying diameter horizontal through holes printed in it. This block also has a series of vertical blind holes printed in its top. I’ll show these later. The end of the next block has a depressed circle with two crosses printed in it, One cross is raised (the X) the other depressed (the +) relative to the bottom surface of the circle.

 

This shows the same area from a higher angle. Note that the print number is displayed here. Check the lettering here to see if any letters are missing, incomplete, or blurred.

 

In the two pictures above is shown an additional two tests. On the left is a hexagonal tower with a hemispherical depression offset to touch one face. Note that in the file the wall on that side has a flat top, at the joint, many, if not all, of the final prints will have a notch or gap here. The smaller the gap the better.  I was using a Wash and Cure station to clean the parts. The washing action may have washed away this thin area. If your print has such a feature, perhaps careful hand washing would preserve it.

 

 

The next two pictures are of the last block at the end of the part, the one that has the crosses on one end.

 

On the outside edge of this block are the numbers 1 through 9 and a 0. Check that these are all present, and crisp, not blurry. Also check that the bridge section is straight and the opening is square.

 

 

The next picture shows the top and the end opposite the crosses of this same block.  Verify that the checker board pattern on the end is complete and crisp. The top has a series of long depressed boxes. Check these, and compare the actual number printed to those that were supposed to print out. This is another area that hand cleaning may have helped. In some prints, it looked like the smallest boxes may have printed, but not been completely cleaned out before curing.

 

The above picture also shows the seven blind vertical holes in the top of the adjacent block, that I mentioned earlier.

 

At the other end of the print, next to the previously mentioned hex pillar are two additional shapes. One is a cube with the number 5 inscribed in the top, and the other is a sphere. Checking them is self-explanatory.

In the above picture you can also see the rod and pillar and tapered columns that are under the one angled plate. I did not see these and broke most of them off, while handling the cured prints, before I noticed them. These should all be present, and straight. The next pictures are more close ups of these.

 

In the picture below, note the  pillar under the angled plate closest to the corner of the two plates. It should be attached via the thin cylinder to the underside of the plate. Also note the previously mentioned through holes along the top of the plate.

If anyone sees something I missed, or mistakes I made, please speak up! I hope this helps you to improve your prints!

 

Here is a link to another short write up on this subject, I found:

https://www.reddit.com/r/AnycubicPhoton/comments/fnym88/improving_adhesion_understanding_photon_s_rerf/

[Kevin-the-lubber]

Hi Ron, you mentioned you've found some good forums for resin printing - would you mind sharing the links please. I've found it quite difficult to find anything outside of facebook, which I simply won't use, and have a recurrent problem that I'm struggling to fathom. I doubt it's unique and some of the old hands will most likely point me in the right direction. In case you're interested, it's this;

This is supposed to look like this;

As you can see, the bottom gets ripped off the (heavy duty) supports and warps into a curve. This is not a particularly large piece and, although in this instance I've printed flat, the same kind of thing happens on anything large where I need a straight edge. It can't be a question of just adding more support, if there was any more it'd be ridiculous. Something similar happens if I print it straight onto the plate, you can see striation where the layers are being pulled apart. I think it may be something like the FEP isn't sufficiently tensioned, or that the settings need adjusting, but I'm always a bit fearful of playing with these too much in case I tear the FEP etc. On the larger printers this gets expensive!

 

nb - I do wish that test was available for elegoo printers, but unfortunately it's not. There are plenty of generic test pieces out there but none that, like this, change the printer settings during the print so you can just do one test.

[thibaultron]

Most of the forum information I found was with Google searches on specific questions. The Anycubic Facebook one is the only one I follow. For the others, if I found a reasonable answer, I copied and pasted it to Word, for future reference. I didn't save the links. Sorry.

[thibaultron]

As far as your print problem, I would try printing it in a vertical position. This will reduced the pull force on the FEP, as it will have less surface area being pulled on. Others may be able to give further advice. There are a few FEP installation videos on YouTube, that you could do a search for. On my Mono 4K it is simple, as they built it so that the FEP comes premounted on a frame that screws into the bottom of the tray.

[henrythestaffy]

Kevin, I would look at why the fep sheet is winning the tug of war with the build plate by firstly checking the size of the connection from the supports to the model. It appears they are not strong enough to handle the pulling forces. The strength of the support is only as good as the point it connects to the model in most cases. Maybe alter it to make the connection a little deeper and wider. Second, as suggested above, tilt your model in a way that creates a lesser amount of connection to the fep. Say around 30 to 40 degrees. Printing a large surface parallel to the build plate is not a very good habit to get into. When a model is tilted you can get away with using finer supports. If these steps dont help then i would look at replacing the fep sheet as it seems to have too strong a hold on the model as it prints. Good luck.

 

Paul

[Dr PR]

There are a couple of issues there that I have been experimenting with.

 

1. Any large surface parallel to the print plate/FEP will come out lumpy, no matter how many supports you have. The force needed to pull the print surface away from the FEP will cause the print to pull away from the outside edges where the support density is lowest. This allows the printed surface to bend, especially for the first few very thin slices after the supports have printed.

 

Another problem is the forces generated when the print rises from the resin vat (to allow more resin to flow over the FEP) and then descends back into the resin vat. The pressure generated when the resin is squeezed out from between the print object and the FEP film can cause the thin printed surface to bulge up between the supports.

 

So the newly printed surface is in the middle of a tug of war between the separation forces when the print lifts and the pressure forces when the print descends again. The result is a warped surface for the first few slices and then the rest build up on this surface.

 

You can reduce both of these forces by setting (Chitubox/Settings/Print tab) a slower Lift Speed and Retract Speed. This may significantly increase the overall print time, bit may be what is necessary to get a good print.

 

2. Print times also affect how these thin layers and small diameter objects come out. The resin is pretty much transparent to UV light. This means that as very thin objects are printed horizontally some light penetrated the current slice and exposes resin on top of it. Sole light is also scattered in the resin causing extra resin to be cured along the edges of the part. Thin narrow  parts may flex as described above, displacing the parts between supports slightly. New layers are printed in the correct position, causing the part to be fatter in the middle between supports. Reducing the exposure time reduces the amount of this excess resin exposure.

 

3. A solution to these problems is to place the part at an angle to the print surface/FEP film. In theory a 45 degree angle should give the best surfaces, but this may not work with long parts that would extend out of the print area. But in practice a 15 degree angle from vertical works pretty well.

 

4. Another solution is to position the part so it has the smallest possible surface area in contact with the FEP at each slice. Hollowing the part may be necessary to accomplish this, The Chitubox Hollow function does this very nicely, and adds internal supports necessary to support the print. Be sure to use the "Dig Hole" function to make a drain port so resin can drain out of the interior of hollow parts.

 

Adding the drain port on the surface nearest the print platform will also reduce suction from resin in the the hollowed part while the part is lifting from the FEP.

 

5. Finally, what is the room temperature where your printer is located? The curing of resin is a chemical process. It is triggered by the UV light, but the rate at which it cures is very temperature dependent. If it is too cold the resin will not cure quickly and things may come out too thin. Also, the resin flows more slowly when cold, and this can increase the pressures as the part lifts from the FEP and descends again. On the other hand, if the resin is too warm it will cure extra fast, and this can exaggerate the over curing from UV light penetrating the excision layers and scattering in the resin. Check what the manufacturer recommends for the printing temperature.

[Kevin-the-lubber]

Thanks Ron, Paul. I should have found some other examples but this was all I had to hand; this outcome happens to some degree or other on all kinds of larger pieces regardless whether it’s tilted and even with a dense array of heavy supports. A little while ago I was printing what in effect is a simple box with no lid or bottom, about 8cm x 5cm, with a 2mm wall thickness. Whether angled or flat, it would warp during the print. Yet I can load up the plate with loads of individual smaller objects and have no problems. Equally, I’ve printed some large-ish delicate things using only thin supports and been fine. It’s perplexing. For the object in the photo I did indeed print it edge on in the end, this is fine when that’s an option but sometimes the orientation options are limited.

[Kevin-the-lubber]

4 hours ago, Dr PR said:

There are a couple of issues there that I have been experimenting with

Dr PR, thanks, that's given me some ideas. I hadn't even thought about the squeezing aspect. But most of all you're confirming that there's nothing wrong with the machine, this is user error, which is good, because I can fix me but not the machine 🙂. I think my problems fall into the category of '99% of the time you'll get exactly what you sent to the printer. 1% of the time you're going to have to work at it'.

 

I read an article a while back about ideal angles and I don't think it was 45 degrees. It was all about the arrangement of the pixels. Generally, I just try to reduce the amount of surface tension, balanced against the wasted cost of supports.

 

[thibaultron]

I remember a video about that, but can't find it. I've watched 50 or so videos. Does anybody have a link to it?

[Dr PR]

The "ideal" angle of 45 degrees is for prints with the vertical step (slice) thickness equal to the horizontal pixel size. This will generate the smallest "jaggies" but also the most of them. Steeper vertical angles produce jaggies that are the pixel size but a lot fewer of them. At angles less than 45 degrees the jaggies size is dependent upon slice thickness and the number is dependent upon the pixels in the slice.

 

I posted some drawings and photos in post #173 in this thread that illustrate these effects and discussed how to minimize them.

[mikegr]

I tested my Anycubic Mono 4K today. In short its a budget version of the standard mono with more plastic and no fan but a 4K resolution.

I only printed the sample file following the set up instructions. There was no smell at all with box on top. I have put the printer close to balcony  , while aluminum window protecting it from the sun

[Kevin-the-lubber]

12 hours ago, Dr PR said:

The "ideal" angle of 45 degrees is for prints with the vertical step (slice) thickness equal to the horizontal pixel size.

That makes sense, doesn't it. I did wonder how the the writer drew those conclusions but decided he knew a lot more about it than me.

 

Re' enclosures: I've decided it's about time I got a stable temperature sorted out, after thinking on your earlier advice. My larger resin printer is on a worktop in the (usually quite cold) garage and I've been noticing more fails compared to the small one, which is in my warm office. So I've just bought a large kitchen base unit i.e. a big mdf box with doors, and a small thermostatically controlled greenhouse tube heater. That should do the job.

[thibaultron]

A couple of links on the proper angle for a flat surface print. It depends on the resolution of your printer, and what you want the best surface of your model to be.

 

This one is a link to the page with the diagrams and write up mentioned in the above video.

 

https://themechninja.com/07/3d-printing-flat-surfaces-on-a-sla-3d-printer/

 

This video will reduce some of the fine detail, but has a neat test file.

 

 

And this video will help to get correctly scaled parts.

 

[Dr PR]

That formula is very useful - I hadn't tried to calculate it myself.

 

arctan(layer height/pixel width)

 

Use the same units (inch, millimeter, whatever) for both layer height and pixel width.

 

The videos assume that most people print at a 0.05 mm slice thickness, and that is common. But you can improve surface smoothness by using thinner slices. My Photon Mono will print 0.01 mm slices and this makes much smoother horizontal surfaces. But As I noted in my earlier post, layer/slice thickness has no effect for angles greater than 45 degrees - for these surfaces pixel size is the limit.

 

Chitubox allows several antialiasing settings (Anti-aliasing Level, Grey Level and Image Blur Pixel). These settings cause the "jaggies: to be filled in partially, significantly reducing the effect. With the proper print angle and adequate antialiasing settings you can get surfaces that are so smooth that you need a magnifier to see any roughness, and then it may only be visible as a slight light pattern on the surface.

[Egilman]

On 5/5/2022 at 6:48 PM, thibaultron said:

Some lessons learned from this:

1.       From now on, I’m only going to do one step at a time. Waiting to finish filtering the resin, and sealing the bottle, could have been done before I worried about the stuff on the FEP sheet.

2.       I need to start really working on cleaning out the shop, so I can move the workbenches, and put down the vinyl floor, bad hip or no.

3.       I need a larger supply of towels and gloves.

4.       I need to clean out the shop, even if it hurts to get rid of some of the useful stuff.

5.      If I have a selection of almost identical parts, number them after curing so I don’t mix them up while comparing them!

6.       I need to further research the final curing times needed for my resin. I understand that over-curing them, can cause multiple problems, while under-curing is a Bad thing!

7.       Don’t repeat this stupid mistake!

8.       Did I mention, not knocking over the bottle again? Yes, sorry!

9.       Get a proper organics filter mask, not the blue paper ones they supply. While there was almost no odor from the spilled resin, why take chances.

10.   I need to get a smaller sieve type container to put small parts in while washing, the Wash and Cure supplied basket has holes that small parts would fall through.

11.       Seal the seam between the sides and top of the printer base, with Capton(SP) tape. Some resin dripped into this seam, when I was pouring it into the resin tray.

Thanks Ron for this, I've been going through some of these same issues with my Mono X trying to print a J-47 replacement for my F-86F...  (except for the clean-up part) The explanation of what is happening with the RERF file, I've printed one, but couldn't find a thing online on what it represents... Now I know.... Thank You....

 

Yeah it's time to change the IPA...  Pricy, very Pricy... 25.00 a gallon and I need 2.5 gallons... I think I've got  6 successful prints and about a dozen failures on this batch... the Wash N Cure makes doing cleaning easy, but I think Water Washable is in my future.... (still have 3/4ths a liter of basic grey to go)...

 

And I don't know why I forgot about this thread and forum area... I should have started posting here five weeks ago and I probably wouldn't have run into all my  recent frustrations with print failures.......

 

Yech, live and learn...

 

Again thanks

 

EG

[thibaultron]

90% IPA Walmart, in 1 quart bottles. I bought 3 gals worth for about $49 with sales tax.

[Kevin-the-lubber]

I buy in bulk off ebay, 5 UK gallons at a time.

 

Tail-chasing at the moment with both printers and both resins I use (elegoo ABS like & syratech fast). Stuff not sticking to the plate or separating mid-print. Weird, I don't generally change settings and I've done dozens and dozens of good prints with the same.

[Egilman]

5 hours ago, thibaultron said:

90% IPA Walmart, in 1 quart bottles. I bought 3 gals worth for about $49 with sales tax.

Yep I checked at Walmart today, they were out of 91% IPA in the Qt. bottles... 3.49/bottle was the price here, 14.00 a gallon +tax and you should have seen the Fred Meyers price for it, 1.99 a Pt.  in the medical aisle.... Didn't have enough in stock to fill my needs... 

 

So I went ahead and bought the industrial grade 99% IPA from the local hardware store at 24.99/gal.,  and I will be looking for a good washable resin in the near future.... The admiral told me to buy the good stuff, the equipment is too costly to use the cheap stuff.... {chuckle} She then told me that I can have the old 24 cup coffee maker to filter the stuff through... (she is cooperative in this way most of the time)

4 hours ago, Kevin-the-lubber said:

I buy in bulk off ebay, 5 UK gallons at a time.

 

Tail-chasing at the moment with both printers and both resins I use (elegoo ABS like & syratech fast). Stuff not sticking to the plate or separating mid-print. Weird, I don't generally change settings and I've done dozens and dozens of good prints with the same.

So was I for the last week or so, wondering why my prints are failing, and doing some research into why and not finding answers... I'll probably open up a thread on my project here, (designing and printing a 1/32 scale J-47GE-27 Engine to go along with my Kinetic F-86F build) Currently I've had enough success to know that I need to redesign it to better fit the scale... But I think it would look great at 1/16th or 1/8th scale... And maybe some of the wealth of experience here will help...

 

That's been the project for the last five weeks or so... But a lot of this....

Has kept me seriously frustrated for a while....

 

Anyway, reading this article with it's plethora of great resources and info as rejuvenated my mense for this... It's great to see friends who have resolved the same issues I've been having... (and willing to share...

 

Thank you, Thank you all...

 

EG

[Egilman]

Hey Brothers, I went ahead and cleaned everything well, and ran the RERF Exposure Test pattern... (using anycubic basic grey resin)

 

As explained by Ron, it prints 8 test patterns at different exposure steps...... the first #1 is at .8 sec the last, #8 is at 3.6 sec. so they step up at .4 seconds a plate.....

The entire plate as printed.... Clearly #1, (upper left corner) has an issue with layer adhesion and #8 has an issue with detail definition (overexposure)

 

The first four plates....

Clearly #1 at .8 sec. (upper left) is not going to cut it, the sphere did not stay attached and the final layer did not adhere to the layer below....

#2 at 1.2 sec (upper right) everything adhered but some features did not print well.. Namely the needle on the angled plate seem to have wandered all over the place like they were being stretched...

#3 at 1.6 sec. (lower left) is much more defined and although the needles on the angle still show some deformity and we lost a few very small holes the definition appears a lot more solid with properly formed squares and the sphere appears smooth and good square hole pattern showing on the lower angle plate...

#4 at 2 sec. (Mono X default) shows everything printed solid there is some stretching on the needles but the holes in the lower angle are much clearer we lost another small hole and a couple of the rectangular boxes are beginning to disappear....

 

The lower four...

#5 2.4 sec. (upper left corner) We've lost the tiny holes and rectangles but the needles are at their best definition we are seeing hints of overexposure...

#6 2.8 sec  (upper right corner) Definitive signs of overexposure especially on the rectangles where we have lost quite a few of the smaller ones and the middle ones are showing partial fill ins...

#7 3.2 sec. (lower left corner) serious over exposure, we are down to two holes and one is barely visible, the hexagon in the lower left corner is showing signs of light bleed causing ragged edges and the smaller rectangles are either filled in or are filling in.. The edges are beginning to take a less crisp appearance as well....

#8 3.6 sec. (lower right corner) the needles are at their most solid shape we have almost lost all the small holes and almost down to half the rectangles the square holes on the bottom angle are filming over as the overexposure activates some of the resin in the middle...

 

The default is set at #4 2 sec., but in my opinion #3 1.6 sec., is just as good with less stretching of the needles on the lower angle... #5 shows the best overall definition but we lose the very small holes and rectangles.... The rest aren't worth it in my opinion...

 

In my chasing around the web I've read great many people using 1.8 sec and having great results looks like a splitting of the difference between #3 & #4... I now see why they are advocating that setting... 

 

This is how this test is run and considered, it should be run on all resins as it is dependent on the resin being used, different resins have different reactions and curing rates and different levels of exposure... 

 

Lychee slicer has the ability to index different resins and their settings so when your setting up a file to be printed you can select the resin and the correct settings for that resin will be installed in the file to tell the printer how to process the file most optimally...

 

Anycubic Basic Grey, I'll be using 1.8 seconds exposure on the next print which will be that angle test that ron so graciously posted....

 

Also another thing, LCD Power Level, Anycubic recommends 80% for the Mono X... I checked mine and as shipped it's at 100% power..... There may be occasions where you will want to use 100% power but for most according to many sources should not....

 

Next up, the angle test....

 

EG

[Egilman]

Ok I ran the Arc-Tan test piece... the Anycubic Mono X has .050 x .050um pixels and I'm using a .050 layer height so the calculation is simple, 45 deg. is the optimal print angle...

 

This will change of course if I use a different layer height, but I probably won't at least not in the near future....

 

Anyway I'm now printing up a 1" test cube for checking scaling... So we will see how close it is to accurate...

 

Now, I feel like I'm getting somewhere...

[Egilman]

Alright.... Three successful prints in a row, the last one my own creation...

 

1" print scale test cube... (And yes a 45deg print angle give a great smooth finish)

She measures 1" on a side and the cut-throughs are at 1/4 and 1/2 for the round holes 3/4 for the hexagon and .800 for the square....

 

Overall..

Hex ID size...

It prints spot on.... less than .01% variation....

 

That's well within the tolerances I had to cut to in the toolroom in my younger days....

 

Most acceptable....

 

The Mono X is a great tool... now lets make it actually do something...

 

EG

 

[thibaultron]

Here is a video I found on setting the exposure times for the base levels.

 

 

[Egilman]

Hi, anyone have any suggestions or advise on supports? Automatic or manual?  the videos are almost unwatchable and are all over the map and mostly based upon the paid pro version of Lychee... (or based upon versions from last year and five major update changes ago)

 

Nothing out there about the free version.... There's a LOT of whining about the internet on the automatic settings as being wholly inadequate for the job... And although the nerds are trying the videos are basically unwatchable.... I'm sure they give out decent info but I would rather not take a nap before they get to it or hear about the next great idea they have for modeling the greatest thing since fire... 

 

Any ideas or suggestions?

 

Edited May 28, 2022 by Egilman

[Kevin-the-lubber]

Manual every time for me. It can be a bit of a drag, doing them by hand, but for our kind of stuff - tends to be small and precise - you’ll more often get the result you want at the first try. 
 

One tip: if the item is very delicate, raise it off the bed by 10 or 12 mill rather than the ‘normal’ 5 or 6. Let me go back one step and explain: I remove supports by snipping them off at the raft end first, them gently twist them off the object. The reason for increasing object to bed distance is so that the supports are longer and there is more opportunity for the support to bend when being snipped, as opposed to the object. If they object is super thin and the supports are very short, there is a tendency for the object itself to get broken by the snipping.

 

There are probably other ways of solving that problem, and I’m all ears if so. I hardly ever turn to YouTube as so much of the time the videos are painful to watch, dragging things out forever when 5 seconds would do.

[Kevin-the-lubber]

Ps. Nothing wrong with free lychee apart from the ads. The only thing I don’t like about it is that you can’t bevel the raft, whereas you can in free chitubox. I only use lychee now when I want to mirror supports functions, which saves a lot of time, otherwise I just find Chitubox easier and much more tolerant on non-manifold objects.

[Egilman]

55 minutes ago, Kevin-the-lubber said:

Ps. Nothing wrong with free lychee apart from the ads. The only thing I don’t like about it is that you can’t bevel the raft, whereas you can in free chitubox. I only use lychee now when I want to mirror supports functions, which saves a lot of time, otherwise I just find Chitubox easier and much more tolerant on non-manifold objects.

I think when this print finishes, I may take Chitubox for a spin and see for myself.... Lychee really took a downturn for me when they put the hole feature into the paid subscription part... (not that I would use it that much) but all the adjustments they claim one should make for great support are in the paid version... And their championing of it centers around the ease of editing supports...

 

I need something that is simple, full featured and well supported... and with Lychee you only get that in the paid version.... A big downer for me....

[thibaultron]

Check that Chitubox supports your brand and model of printer.

[Dr PR]

I have been using the free Chitubox and I am satisfied within how it works. Their tech support is pretty amazing, often responding within a few minutes to my email questions!

 

1. You can create custom settings for different resins and save them for future reference.

 

2. You can add settings for any printer - if you know them. For my Anycubic Mono I just started their Photon Workshop slicer program (not nearly as good as Chitubox) and copied the settings from it.

 

3. Chitubox sometimes doesn't add enough default supports and the print fails, leaving the part stuck to the FEP film. I have been manually placing supports with mostly good results. Most of the failures I am seeing are always due to not enough supports near edges and corners. If it isn't supported a surface will flex during printing and come out warped. Another related problem is supports that are too narrow at the contact point with the print part - the support doesn't connect to the printed part and is worthless.

 

4. Chitubox offers many options for designing individual supports, including the base shape and size, support shape and width, support end diameter, shape and depth of penetration into the surface. The only thing that doesn't seem to work correctly is cross links between supports. For me these are a nuisance, but turning them off in the settings doesn't prevent the program from adding them anyway. These can make it very difficult to remove supports from fine details.

 

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On another topic, I have using denatured alcohol (95% ethanol and 5% methanol). This was recommended by Anycubic for cleaning their Basic Grey resin. It is sold in gallon cans for about $18 the last time I looked - look for it in the paint stripper and wood finish products. It has always been cheaper that 95% isopropanol (isopropyl alcohol), primarily because it is available in gallon quantities.

 

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And now a question: I read in someone's post that they used hot water or a heat gun to soften warped pieces and then bend them back into shape. Has anyone tried this? Do you heat the part before curing or after?

 

The single greatest frustration I have found with 3D printing is that thin details like hand rails are often distorted by the forces of separating the print from the FEP and then pressures from resin flow as the part returns to print the next layer. These parts are always bent between the supports, and often come out "fat" in between supports. So far this problem has made 3D printing useless for many of the things I have tried to make. If I can reshape the warped railings and pipes after printing there are a lot more things I could use 3D printing for.

[Kevin-the-lubber]

Phil, the hot water trick was used by Daniel (Dafi) over on his Victory log. I guess if you have a former to shape the object to, it’s probably quite easy to re-shape after softening with a little heat. Whether it’ll hold the shape I don’t know. I agree about cross supports, but I’m sure you have some control options for these in Chitubox? I’d guess that in the paid version you can place them by hand, but I can live without that. Interesting to hear about the customer support, it had never occurred to me to ask them when I have problems like my square edge pet peeve.

 

Egilman, what’s the cream-coloured resin in #259? The result looks better than the grey resin? I use way more supports than you, I’ve just gravitated towards more over less over time, as I was getting frustrated by the fails. To get over my recent hump of fails I had to increase the exposure times quite a lot, the point being that I’m having to use different settings for the same object, printer, resin etc from those which were successful last year. I guess (printing seems to always involve a lot of guesswork!) this is down to temperature, humidity etc.

 

I also built a heated booth for the printers as even in summer the temp in my garage can be quite cool. Basically I just bought a flat pack kitchen cabinet + doors and added a small tubular greenhouse heater.