Best orientation for dimensional accuracy?

[Friedl_1977]

Hi -

I am as new as you can be to SLA printing, so my apologies in advance for the trivial question.

I recently bought a Form4 printer, unboxed it and immediately proceeded to print an Astronaut Phil model, something I used to do each time I tried out new filament printing with FDM printers. This went remarkably well with no hiccups at all.

I then proceeded to a somewhat more challenging functional part - a custom enclosure for a client’s project. The enclosure consist of several parts that all need to line up and fit together and this is where things went less great. I tried several orientations of each model and it is evident that this matters, quite a bit. It seemed that when I tilted the part to around 30-40 degrees I had the best dimensional accuracy but the flat edges weren’t very nice and required quite a bit of post processing. I then proceeded to print flat on the build plate when seemed to do the trick, until I installed the PCB and noticed that some things which had small tolerances does not line up.

Any advice on how to best orientate the model attached just to get me going will be greatly appreciated

Regards
Friedl.
RFID_Base.stl (766.6 KB)

[DKirch]

Hey @Friedl_1977!

Thanks so much for taking the time to post! Sorry to hear you’ve been running into a few issues with this particular print!

I was able to open your .STL, but I’m having a difficult time picturing your exact orientations that you’ve tried. Would you be able to either post some screenshots of the part oriented and supported as you had it, or alternatively you can send me a .form wile with the part oriented and supports added!

Thanks!

[Friedl_1977]

Hi @DKirch -

Thank you for the prompt response. I tried several orientations but there were some challenges on them all, mostly around the power button section in the middle.

Just some perspective, refer to the image attached. The base has a button made up of two parts. The first is a clear part (green in the image) that allows the LED from the PCB to be seen and then the actual button which (when pressed) makes contact with the tactile button on the PCB.

The clear section had a “guide wall” around it that fits closely around the tactile button to unsure the button lines up with the tactile switch. This had to be remove as it seems the hole on the base part was no lining up with the tactile button on the PCB. Before buying the Form4 I had some test prints done elsewhere, they worked fine.

The second challenge I faced was with mounting holes. From my previous experiences (FDM) I would alles for 0.2mm clearance (increased hole size). I thought it would be less for SLA, but obviously I am doing something wrong

Lastly was to get the Base and the ld line up on the corners. If was obvious that that the rounded corners did not print the same.

As it is quite late here, I will be able to send you some photos of the end results tomorrow. I ended up doing a lot of post processing and reprints of the button parts in order to make it functional. I had to bring about 4 different batches of both button parts and for each assembly had to to mix and match (and use a Dremel) to make it work

I am fairly sure I messed up in just about every conceivable way, so would appreciate some assistance to get going in the right direction. Wasted quite a bit of resin but as the client was in a hurry I had to print, did not have time to learn the ropes.

Here are some I tried, but ended up going with the bottom side on the build plate and the model perpendicular to the build plate.

Orientation_1.form (390.6 KB)
Orientation_2.form (656.7 KB)
Orientation_3.form (1007.1 KB)

Many thanks!!

EDIT: Also my material choice maybe was wrong, printing with standard grey V5 resin ??

[eaglechen]

Evening sir!

I started a pretty extensive thread on the Form 4 a while ago My experience with the Form 4(B) so far/ Semi-Review from a Semi-Industrial User Perspective, I hypothesize the dimensional inaccuracies you have experienced being from what I have experienced, as a result from immature print profile settings and material limitations from what I have seen. Very disappointing indeed to see the Form 4 not able to achieve 0.2 tolerances, we have found this as well extensively. If it’s fitting two printed parts together you’ll probably have to allot for 0.2mm each side or play with 0.2-0.5mm if you are going to mate with another machined part/ fastener. This is of course assuming the part does not warp during printing and afterwards…

4 reprints and ultimately having to hack the part with a dremel to get this to work is a lot of wasted time and material indeed, and in my opinion far from acceptable for a $5000 printer advertised to be a hands off industrial system. I do not actually believe you are doing anything wrong, I think your .form file 1 and 2 should have made imperfect but reasonable results, and .form file 3 should have definitely mostly printed fine. I believe the current Formlabs guidelines of just orienting flat surfaces 10-15 degrees is severely deficient, and Form 4 cannot achieve the “knifeedge” overhangs and steep/ 90 degree overhangs like other industrial DLP printers. Somethings that I found to kind of work around this from my experience:

1. 30-45 degrees is your friend, angle a flat part up BOTH X and Y axis. The printer really cannot do any steeper overhangs even like 15-20 degrees well, long/ straight sections attached from nothing to supports will really suffer as well.
2. Pretty much the auto orient is junk, at least orient the part yourself and then using auto support is reasonable. You can then edit the part to avoid nubs on critical areas.
3. It unfortunately will take time and a lot of repetition (took me 6 months to 1 year) to fully able to learn orienting and supporting. There is a lot of nuance and is very often not intuitive like FDM printing, and now I do every support and orient by hand.

Here is how I personally would go about printing this and most flat profiled things:

Orientation_Example.form (902.6 KB)

Here I purposely kept tips on edges so they can be easily sanded down. After a mineral oil dab/ polish (total black magic) on the sanded areas you will usually not be able to tell anything was there.

Some additional considerations:

1. I have pretty much currently given up on getting general purpose materials, especially grey V5, to work reliably. I experience significant warping during printing with initial 5-10mm of the part warping significantly from the rest of the model with overall poor accuracy. You can read all about this in my thread I linked to. Again, I hypothesized this being the result of not fully developed print profile and material limitation, currently still waiting for a fix from Formlabs. Tough engineering materials are way worse.
2. Precision model material is about the same material properties as Grey v5 and general purpose v5 material including grey, but is far more accurate. Not perfect, but I am currently printing everything in this due to less warping during and after printing.
3. You can read the datasheets yourself, but general purpose v5 and precision model are ultimately as strong as generic PLA plastic in terms of tensile and impact strength practically from what I have experienced. Not terrible, but not great. Printing in the Tough materials (1500/ 2000) are way more finnicky and prone to failure so I will not recommend them personally at this point in time. For what it’s worth, seems like you are making enclosures for electronics and none of these materials are ESD safe. I haven’t seen like a microcontroller getting fried from static electricity or anything inside these prints, but on paper that is a risk. Formlabs ESD resin exists, but I never used it and have no knowledge of its reliability on Form 4. You may want to try depending on how important this electronic/ your client is.

[Friedl_1977]

@eaglechen

My experience with the Form 4(B) so far/ Semi-Review from a Semi-Industrial User Perspective

Hi @eaglechen -

Thank you for your comprehensive feedback… albeit a little disheartening

I have been looking at SLA printers for a while now, Formlabs always caught my attention as I needed something that will just work. As this is not my main line of business (I am a PCB designer) I needed something I do not have to babysit, hence the decision to proceed with Form4 above other SLA printers I considered.

I recently had some clients asking for small batches of enclosures for the PCBs I design for them. Up until now, my Ultimakers have been serving me well, but they simply cannot keep up, the previous print job took 6 weeks The decision this time was to either invest in something like BambuLabs XE series or the Form4. The reason for choosing the Form4 was speed, accuracy and aesthetics. The problem I face now is that if perimeters of two mating parts do not line up, it looks terrible. The other big challenge for me its mounting holes where parts need to line up in fit into each other. With PLA this was easy to manipulate with something like heat inserts as the plastic would melt and the insert can be placed. With Thermoset plastics of course this does not work.

Look, the 20 enclosures printed and they are all there, but it took a good couple of days to get done (due to reprints) and they are not perfect at all. The buttons are finicky at best. I even made peace with the fact that I might just use this for prototyping and still have to send the parts off the be printed elsewhere, but I am now doubting whether that will be accurate to begin with.

Thank you for the tip on the Model Resin, I will try and see whether I have more success with that. Just bought another bunch of standard resin

For me the key things are that:

• Part should be aesthetically more pleasing than FDM
• Perimeters should line up
• Multi part prints should fit

The only issue I will run into with the model resin is than clients will not like the color. I have let go if the idea of colour printing but at least was hoping to achieve some ‘greyscale’ models (Black, White, Clear and Grey) but if the standard resins are no-good for dimensional accuracy then that leaves me with another problem.

I will print some test models today and see what happens. With regards to the orientation, my only ‘issue’ with printing the at 30-45deg is the increased material cost due to more resin being used on supports and of course the fact that I then can fit only one part on the platform, effectively increasing my production time by 500% Cost per part is a thing here, the market is very price sensitive, so more expensive materials and more materials used on the same part remains a huge challenge. On top of that, I supposed you will burn through more tanks and LPU’s for the same amount of jobs if you print one part at a time? I have seen some people in the forum calculating part pricing at $1 per ml of resin used. Here you will not sell a single part if you do not drop that to somewhere around $0.40 per ml used and then you better use those ml’s sparingly.

Kind Regards,
Friedl.

[br4n_d0n]

@Friedl_1977

The only issue I will run into with the model resin is than clients will not like the color. I have let go if the idea of colour printing but at least was hoping to achieve some ‘greyscale’ models (Black, White, Clear and Grey) but if the standard resins are no-good for dimensional accuracy then that leaves me with another problem.

You can use dyes to color the resin before printing or after a print and before fully curing in the wash stage. Formlabs has their own coloring kit, but you can also get alcohol based dyes anywhere and do your own thing.

[Friedl_1977]

HI @br4n_d0n -

But can I bye any resin? I was under the impression you have to use the color base one which is essentially the same as the standard V5 resins?

[br4n_d0n]

No, you can technically use dye with any of the resins and Formlabs themselves have shown off using the black dye on their Clear resin before. So, if you find a particular resin prints better for you then try dying it.

[Friedl_1977]

Hi -

Ok, this is good news. I a then try Precision model resin and dye it black.

Thanks!

[Friedl_1977]

@eaglechen -

Just finished reading through your other post:

@eaglechen

My experience with the Form 4(B) so far/ Semi-Review from a Semi-Industrial User Perspective

Ugh…honestly I feel like just selling the printer for whatever I can get for it

Even though I have not seen the amount of failures you have, it seems like it is inevitable. So far I have 100% success rate but of course it depends on what that means? If it means none failed to print, then yes, I have 100%. If it means did they all work and fit and line up, then NO… buy numbers will be atrocious. Now before I get stone to death by someone for having shitty models, I am with you on this. I cannot always design the way I would like. More often than not in my case there are restrictions imposed by already-in-place parts and my clients will through me off a cliff if I told them they need to accommodate my printer

I bought this with the same mindset as when buying my UM printers… Pay more for something I do not have fiddle with or spend hours post processing as I simply do not have the time. I am not expecting life-like resolution (like some of the other12k and up printers are promising) but I need flat areas to be well flat… corners to line up and holes and inserts should fit. If this is not possible, well then that is on me for not doing better research before pulling the trigger.

I am new to SLA but not new to AM as I have owned FDM printers for years and have pushed out 1000’s of parts which are still in use in real life environments. This does not make me a specialist in the field, but it does mean I am familiar with that fact that there will most likely be some kind of processing after a print, wether is is washing and curing or whether it is spending hours watching dissolvable supports dissolve. But honestly, I expected prints to be more accurate that on FDM and that for me means corners need to be square and flat sufraces need to be flat.

Regards,
Friedl.

[eaglechen]

Morning!

I would not discount your AM and printing experience. Your real world experience is significant and you have solid understanding of client and field expectations. By and large you have a world of difference to who Formlabs typically sells this printer to and market this as a click to print experience. Couple additional thoughts:

First of all, you make a good point and I think this is a critical Formlabs understand this. I have had multiple Formlabs representatives quote me the “95%+ success” and “highest amount of successful print in a single day” of Form 4. I do not believe that this is a fabrication at all, but I do encourage Formlabs to be more holistic and realistic about this due to these following factors:

• I have seen at some university print farms I visited where technicians just click the “successful” button indiscriminantly if a print completes without inspection. This seems pretty common out there in the field.
• I have even personally click the green button of success after a print finishes, just to pull the print out of the printer and realize it has warped on closer inspection.
• Of course, a huge number of Form 4s probably work in like a factory settings printing little parts such as archess or small parts like connector designed for printing directly on platform. Obviously, these will succeed but in my opinion this is a low bar for printer capability because these are niche and $250 SLAs can do this easily.

Ultimately, I think the bar should be a deliverable, real part in hand after post processing as an “industrial” system. I don’t think the Formlabs success system captures this accurately. If that is the success, my success rate is probably 25-50% at most. Whether a print designed to show off the strong point of the printer and ignore what is challenging to make in the real world “finishes” is a low bar that most $150 printers on Amazon can do with even rudimentary tuning.

Unfortunately, it seems that the Form 4 sucks the most at is making straight and accurate things, and it is worse at making these things straight and accurate in Tough resins (which unfortunately are usually blocky engineering things that need to be straight and accurate). Ironically, I think Formlabs is right that the 4K display is good enough and can do a very good surface finish with good antialiasing often superior to compared to the “12K” printer snake oil the $250 printer companies likes to sell, but the Form 4 is being completely held back by it’s material and print profile settings. Given how Form 3 development went, I think it’s likely this is a 1-2 year fix. I also am unfortunately beginning to think this is a material science issue as well and the system will never quite get this perfect, but an improvement is certainly desperately needed. For now, I’m printing lots of teeth colored things and nothing else…

You example model I believe follows every Formlabs design guideline, and should be extremely easy to make consistently. I even want to bet Form 3 can possibly do this fine. I think this is perhaps a facet of marketing with Formlabs, they show straight and accurate things straight on platform with no support material on Form 4, and in reality no one designs that way, and most people buy a 3D printer for the geometry freedom. Besides, it’s obviously disheartening watching a $500 FDM printer nail a PLA flat part within 0.2mm and have this printer not.

One last thing: you are right indeed, it makes zero difference how fast the printer is if post processing takes forever. In this case, washing the part, drying (sometimes 6-24 hours), taking off supports, curing, and sanding is substainstially slower and is often 2-4x the effort of printing itself. An industrial FDM printer 2X slower usually means 30-60 min of support dissolving and parts are immediately ready to use, and tends to be faster than the Form 4 process a lot of the times. This is all completely also ignoring curing and post-processing being an extremely experimental process, an entire sub-discussion I alluded to in my thread as well…

edit: dyeing a part is pretty experimental outside colorkit resin. No idea how dye will interact with precision model. I would buy the color kit dye, mix into black color, and use 1/3 to 1/4 at most of a whole portion into the cartridge, any more the part may not like it. You will have to play with this quite a bit.

[Friedl_1977]

Hi @eaglechen

@eaglechen

I would not discount your AM and printing experience. Your real world experience is significant and you have solid understanding of client and field expectations.

Well, it is purely based on FDM aside from the 4L of resin I burned through the last couple of days. All I want from this printer is to print functional parts that line up and fit when mating them. A smooth surface finish is a bonus.

I am having trouble understanding the “printing precision models”, if you need to sand it down with various grit values sandpaper afterwards, does this not negate the whole idea of “precision” ? Or worse, take a Dremel to it

Well… If I were to hit the Thumbs-up button only after trying to mate all the parts of the enclosures and if it was to represent whether it meets my standard for a product I feel good about selling to a client, I am sad to say I would probably have not done it once. IF this was the criteria, the MatterHackers Astronaut Phil would have been my only Thumbs-up

Maybe I just had too hight expectations for this printer or of course, maybe just need to figure how to print with it. This is made worse when your clients sends you photos of the same enclosure printed on their $600 FDM printer, just under 3 hours and perfectly fit together.

I can say this… If I need to let parts dry for 24 hours before curing them, I will not use this printer ever and will most likely sell it to the first person to make me a decent offer. I sincerely hope this is not needed. The bottom line is I need to print enclosures, if I cannot do it with this, then I need to find something else. I have downloaded some test models, will start printing them to see if I can figure out how to use this machine and hopefully make it work for me.

[eaglechen]

“precision model” as in precision model resin. That is the only thing the Form 4 can print with a semblance of accuracy right now in my general testing and only material I am using, not perfect, but possible (0.2-0.3mm average accuracy and some failures). Every other material I’ve tested fail this by 10X.

I will accept having to do some work in support nub removal. However, grinding and sculpting the part to make it work defeats the point of a 3D printer, especially one marketed to the caliber Formlabs does.

Your expectation for the printer is very reasonable. There is really not too much to supporting and orienting a part despite initial learning curce. Electronic enclosures is a classic marketed use case for Form 4 and I believe the printer not doing this well speaks to its current definiciencies. keep in mind, Formlabs advertises every material as validated, accurate, and reliable (far from current truth). This can change with software updates, but currently I personally would have reservations having to rely on this printer for customer jobs. I have currently paused the majority of my customer facing printing.

Extremely unfortunate that those FDM parts you showed above looks much more accurate and striaght than anything I have gotten off the Form 4, ever. I could have bought a fleet of those printers for the price of my 4B, and then bought a couple more for the resin I have wasted and effectively thrown in the trash…

edit: again, don’t mind giving a printer company a premium, but stuff needs to mostly work.

[Friedl_1977]

Hi -

This is precisely my point.

I initially planned to buy another Ultimaker S5, but I am sad to say ever since the S3 I get the impression they were relying heavily on their reputation and some newer players like Bambulabs are leaving them in the dust.

So I changed by approach, decided to stick with the UMs I have, add a Bambulabs X1E (for speed and quality) and then add a Uniformation GKTwo to my arsenal. All of this would have cost about 40–50% of what I have spent so far. In the end I decided to go with Formlabs Form4 and my reasoning was that almost every video I have seen on any other SLA printer out there, showcase miniatures. I could not find one showcasing functional parts, accept Formlabs. That and the fact that I do not have time to tinker with Resin settings and exposure tests. I need to click and prints… and they need to be usable.

So, I withdrew from my savings and decided to invest into adding another possible revenue stream to my business. Sadly now it seems like I did not make the right choice? I will most likely not give up quite yet, but I need to carefully consider how much more money I would invest (in more resin, vats and mixers) and how many more hours I will want to put on the machine before trying to offload it.

I cannot afford to have this just sitting here printing things to use around the office, It needs to work or I need to cut my losses and sell it.

Regards,
Friedl.

[DKirch]

Hey @Friedl_1977,

Thank you for the additional information! I want to assure you that we see absolutely fantastic print results across the board for the Form 4, and I’m confident that we can figure out what might be happening so you can get back to printing with full confidence.

I reached out to our services team and they recommended getting in touch so they can dig into your file and printer more specifically. I’d recommend sending them exactly what you sent me in this thread to get them caught up, and they’ll take it from there!

I realize these sorts of issues can be disheartening, and we sincerely apologize for the frustration as you figure this out, but I assure you we’ll get you going at full speed soon.

[Friedl_1977]

Hi @DKirch -

Thank you for the feedback and pointing me to the services team. I will reach out to them for sure as I would like nothing more than to make this work for me and hopefully passing on what I have learned to other SLA-newbies such as myself.

I am also happy to provide insight into expectations and challenges from small production users such as myself. As it its quite late here, I will most likely reach out to them tomorrow. I have done some thread print tests will also post my results.

Regards
Friedl.

[Friedl_1977]

Hi @DKirch -

I will reach out to support now, just wanted to post these finding here as it might (or not) help some other people.

I decided to first run a thread test as this is something that I use (A LOT) and working with inserts on SLA parts have been proving difficult at best. Items I design for clients are often meant to be serviceable so opening and closing enclosure lids or battery compartments benefit well from having threaded inserts.

I used the model that I found somewhere on the Formlabs site, I will attached the STL. I printed two versions of both M2 and M3 models, one Perpendicular and directly onto the build platform and the the second at a 30 deg angle. See images below:

Let me explain my results:

The first two images are the M2 tests. The model has several holes on different planes with various “face offsets”.

1. I used the ARROWMAX electric screwdriver to ensure I do apply the same amount t of torque to all the tests (as far as possible). It has around 0.25N.m torque and has no trouble driving screws into threaded inserts.
2. The print on the left was printed directly on the build platform
3. The print on the right was printed at a 30 degree tilt
4. I printed vir Clear V5 resin. Initially cured with no heat and 5mins as this seems to be default after updating the Cure. However prints was still tacky. I cured for 5mins more no difference. I then cured for 5min at 65C which used to be the profile before I updated and this “remove” the tackiness. Maybe due to the fact that is is winter here now, so room temperature was around 8C - 10C.

As you can clearly see the print that was printed at a 30 deg angle printed a little better even though the only chance I had of getting the screws all the way, was at the the maximum offset of 0.06. With the model printed in the platform, there screws went in around 50% before locking up.

Next I did the M3 tests, refer to the images below.

So no surprises there, the results was the same as with the M2 ones except for the fact that neither of the prints at any orientation allowed for me to insert the screws all the way. I added three M2.5 screws to there bottom holes (0.00 face offset) which fit almost perfectly with one exception where the screw never locked up when fully inserted.

My estimate is that threads with a 0.1mm face offset should work. I will design a model similar to this but with 0.08mm, 0.1mm and 0.12mm (where possible) offsets and reprint.

TEST MODELS:

• 2mm_thread_test_v2.step (4.4 MB)
• 3mm_thread_test_v2.step (5.1 MB)

Regards, Friedl.

[DKirch]

Thank you so much for posting these results! This is really great info for anyone else who finds themselves working around these tolerances.

[Friedl_1977]

Hi @DKirch -

I will post more as soon as I have had tome to model top something and print. For now I am sanding and repairing the enclosures and they need to go out to the client ASAP.

Hope to hear from support soon.

Regards, Friedl.

[Friedl_1977]

Hi -

I did more Thread tests. Based on the previous model, I designed my own one to make sure the threads are the same as on the cap screws I am using (M3x0.35)

In the next image it shows the different face offsets I used on the model, increasing from 0 to 0.08mm on each face of the thread.

The second image shows three different orientations I printed on:

1. Flat on the platform - horizontally
2. Flat on the platform Perpendicular to the build platform
3. The tiled along X and Y axis (±40deg)

Print settings:

• Resin: Grey V5
• Layer height: 0.1
• Wash: 10 minutes on high
• Drying time: 30min
• Cure: 10 mins at 35C

After curing the prints were still a bit tacky so I sprayed and wiped them with clean IPA. Below are my results using the same Arrowmax 0.25N.m screwdriver.

Each one of the models on printed in the orientation represented in the Photo. As you can see the image on the left had the poorest accuracy. Driver could only drive the screws a little bit into the model at the 0.08mm offset.

The model printed flat (horizontal) on the build platform had the best results at 0.06mm and 0.08mm (on the top face). On the 45deg face the screws were not able to be driven in at all nor on the vertical face (not the absence of any screws there)

The last model on the right was printed tilted along 3 axis. I was able to drive the screw easily on the top face (both 0.06mm and 0.08mm) and had reasonable success with the 45deg face. The Vertical face remained a problem.

I am not sure whether this results helps. It seems for holes printed perpendicular to the build platform much larger offsets will be required. I was unable the achieve this in Fusion on a M3x0.35 pitch thread. As you can see from the absence of the 45 degree face at the 0.08mm offset section. I supposed M3x0.5 might fair better, but I have 1000’s of these so was hoping to use them.

Here is STEP file of the model if anyone wants to print with something other van Standard V5 @eaglechen
Threads.form (1.7 MB)