Nylon 12 Burr on edges

Ran my X/Y Calibration print with V5.1 settings after the -1.75c chamber temp drop and saw these random “streaks” on the back side of part… not sure what that is from but never seen it before.


I thought it was the roller but those lines travel "opposite of the roller path…they run front to back down the Y axis…

Trying another one at -1.5c

UPDATE!!!

I actually saw this happen on the second X/Y calibration but missed it on my camera. Very weird… the first layer it actually lasered in those streaks? Just those streaks in the exact same location. Then the second layer was the entire X/Y outline and fill… very strange. The only thing I can think is those streaks are in the file/object a layer before the actually flat bottom layer…but it is not showing up like that in PreForm so the printer has to be adding it for some reason?

Here is layer 187

Here is layer 186 where the streaks are being printed

Post processed the second X/Y Calibration print this morning and confirmed that the streaks are in the same place as I said they printed on layer 186 before the first layer of the actual model on layer 187. You can see on the attached PreForm photos that there is no streaks on layer 186… so this is somehow happening between the printer and the model as I physically watched them print (like a bar code) in those two locations before layer 187 and the part started.

Now you can see I have two identical flawed X/Y prints, so this was not mechanical.

I am going to bump this to a new thread as it is obviously some sort of bug.

Also to note… this only happened on the v5.1 speed optimization setting and not on my first v4.1 Default setting test print

On that, something I watched and only saw on the v5.1 speed optimization setting prints, was random chamber perimeter layering taken place? Like every other layer I would see a laser flash across the back wall…then a couple layers later it would laser along the left wall…and so on?

I am kind of in a time crunch and this “burring” issue needs to be figured out as soon as possible or I am going to need to go back to running Nylon 12 GF…which cost wise is not really an option anymore but at least the parts looked way better.

So, I just post processed this last Nylon 12 print of test parts and even after the temperature calibration, orientating the parts the same as they are with Nylon 12 GF prints for the past year, alternating some of those parts the opposite direction, running the Speed optimized v5.1 and doing some slight adjustments to the perimeter Downskin and Upskin settings…. I honestly think these burrs on every edge are now worse (photos attached)




Other than that the parts look and perform well but it is a no go with these sloppy looking burrs on every edge.

My next step would be to go into each CAD file and “chamfer or roll” each hard edge in the designs but this seems ridiculous when they looked perfect with Nylon 12 GF for the past year after thousands of parts.

Up for suggestions

Few turned out really bad like these with ragged burring


So I have an update…

I just printed the same batch of parts in the Legacy v2.1 setting for Nylon 12… The original… and all the parts no matter what orientation, turned out perfect with NO BURRS!!


Speed sucks obviously compared to the newer settings (Default and Speed Optimization) but hey… I have good looking parts at least after a week of trial and error.

A Formlab rep is actually still flying in next week to maybe help dial in the other settings hopefully so I will keep you all posted.

FYI… they just launched a PreForm update that I guess fixed my other issue with the “stripes/bars” being printed onto the X/Y calibration print and possibly parts. It was the new update that launched yesterday PreForm 3.41.1

3 Likes

Thanks for your patience @LEADNAV, SO glad you’ve gotten to great looking parts! Thanks for taking the time to work with our team.

Appreciate the Support visit and hopefully we can get those faster Default and/or speed optimized settings dialed in a bit more. As discussed, it is nice to have access to tweaking all these settings but now they need to be defined a bit more for the user.

In this case, it seems the legacy settings kept a nice “sanded” rounded edge to our parts. Now these newer settings seem to be an attempt to get a “crisper” more accurate edge, but it seems you blew them out the opposite direction.

So in settings, it would be nice to figure out and consolidate a few settings into a simple “corner/edge adjustment” to push edges towards a harder crisper edge or towards a rounder “sanded looking” finished edge as we have in the Legacy settings but still get that increased speed.

FDM printers do this for cornering… seems we are now having the same issue with every edge being “blown out” with a burr.

Funny enough, I just received the Nylon 12 Tough sample part… and on it I notice the same burred edges… not sure what orientation these were printed in but that is the same barre edge we are getting on any 90 degree edge no matter what direction it is facing in the chamber.

Here you can see how bad that burr is on your own sample parts where the edges actually look like they have an intentional lip all the way around on every edge.

1 Like

When we get pitting on our parts the edges round the pitting kind of looks like that. Like a crusty edge on em.

I’m getting it all the way around the part… if it has an edge…it’s getting the burr. Not even just on flat pitted areas.

Formlabs rep was here onsite yesterday to witness it.

And as you can see on their sample part, there is zero pitting on the flats. It is just an excessive build up around all edges due to the Outline laser pass.

Legacy Setting does not do an Outline pass before the fill. It just fills the entire part layer at once.

I’ve been experiencing some slight dimpling on my 1+ with Default setting and was considering trying out Speed, so thanks for saving me the headache of dealing with this burr issue! Hopefully they’ll tune that problem out in the coming weeks because I’d really like the time-saving of Speed vs. Default.

Since I see you have a Blast on the way, I thought I should share my experience with it (and the polishing attachment):

I could not imagine our production process without the Blast (time-saving and consistent), and the polishing upgrade has yielded incredible results. If you’re not dyeing parts, it may not be as beneficial, but our black-dyed parts have looked unbelievably good with the polisher (the undyed polished sample FL sent us a few months back actually made me hesitant about purchasing the upgrade). After polishing, dyeing, and polishing again, parts look shiny, smooth, and have uniform color. Another huge benefit is the media lifetime. Glass media will break down in the Blast without much warning and it’s difficult to pinpoint an effective changeout schedule. Once this broken glass gets embedded in your parts, they become essentially undyeable (splotchy, not deep black).

If you want any polished vs. non-polished sample pictures, or have any questions, let me know!

1 Like

Then i have a few questions for you. :slight_smile:

What size media do you use?
What does your dye system look like?
What dye are you using?

Do you mind walking us thru your process? Thank you.

Just had the Formlabs rep here this week and for now we are going to run Legacy which is slow but really the same speed I am used to running Nylon 12 GF.

Default and Speed Optimization are practically the same speed overall with not much difference…

Essentially, the settings with Nylon 12 GF and the Legacy setting in Nylon 12 leaves a nice “sanded looking” or faceted edge on all your hard corners. For our parts and personal preference we like that and never really noticed it till we tried the Nylon 12 Default and especially the Speed Optimization settings. These appear to have been aimed at more accuracy in which means more refined and “true” corners and edges and speed but it looks like they went too far and blew the corners “out” a bit too much.

Even if they can adjust these to get a true crisp corner… not sure if we’d like it now for our particular parts as that slightly sanded looking soft edge we get now…we prefer over a hard corner.

But… we understand their direction and what they are trying makes more sense as we should get a print that’s true to design… and we should just add those facets on our edges in the actual design. So either way, we are good with it but they need to bring those corners back into a true corner that isn’t blown out the opposite direction.

They did provide me some powder and some settings to try yesterday after their visit here. I will give these a shot and see if I can add any feedback.

I think it would be a good setting, to have a “edge adjustment” where they consolidate a few of these in depth settings they have, into a simple “softer or harder edge adjustment… plus or minus” in the settings. That way we can simply adjust this as users to preference and/or tune of each machine.

Will keep you posted

1 Like

Our finishing and Dye process is pretty dialed in and we are happy with it. I talked about it here with the dye tank I use

Dye Tank thread

I just received the Blast yesterday and I am actually pretty pleased so far with it and its construction. So far on test runs it did pretty awesome.

Since that Dye tank thread… I added a Fry basket with handle so I can just pile parts up in that thing while every 5 minutes I give it a good shake to stir up the parts.

I also now have two five gallon buckets…one with holes drilled in it to drain. I will fill the solid bucket with water halfway to dump the parts after dying directly into it. I then dump that bucket into the draining bucket while hosing everything off…then back to the solid bucket with fresh water…back a fourth a few times to rinse the extra dye off.

Then I keep them sitting in fresh water, bring it to my drying table with a fan on it, and pull them out of the water and lay them out to dry.

I do all this to minimize the time the freshly dyed parts are touching the air before being completely rinsed off. It is also a lot faster doing the bulk of them in a water bucket then spraying each off by hand.

You will get no “blotches” and a uniform dye across each part doing it like this and it only takes a few minutes to rinse a whole chamber.

I used to pull them out of the dye tank onto a baking sheet, then run over to start rinsing each off…but then you have parts sitting there waiting to be rinsed while excess dye is drying. I would get a lot of dark excess spots etc… good news is, the dye is so deep that if this happens, after they are dry you can just blast them off again with glass media and they look perfect.

Hmm, strange that jmasterson didn´t get tagged in my reply as it was him i was referring to when i had the questions. But i also appreciate your answer about your process. :smiley:
Thx @LEADNAV

Care to join in on your process aswell @jmasterson ?

1 Like

I held off on the polisher but interested to add it and try in the future. Just setup and started testing the Blast yesterday. I actually have to pick up the bigger grit today to load in it that they suggested as I been running a 60-120 and/or 100-170 mesh size until now in my media cabinet. Ran some through the Blast and the parts looked great but they said it may fall through into the waste basket more.

Question on the polisher… do you ONLY run the polisher and plastic beads or do you first blast with glass bead… then swap media?

1 Like

Media Size: Before using the polisher, we used the G6 Glass Beads from Blast-it-All. Now with the polisher we are locked in to use the FL provided media. It is expensive, but from my understanding it should have a nearly infinite lifetime compared to the glass. We only use polishing media because it cleans almost as effectively as glass, and of course has the polishing benefit. Something to consider if you have internal tight corners, small holes, or tight gaps is the media size. The polishing media is significantly larger than our glass media (600-900um vs. 200-300um), and we had to slightly alter some designs to keep these plastic beads from getting trapped in gaps. We also had to limit sharp edges (internally and externally) to clean more thoroughly and provide a better finished look. FL preset polishing runs are for something like 30 and 45 minutes, but 15 minutes has been enough time for us.

Dye System: We are using a basket fryer (similar to this) at the moment but hope to upgrade to the option @LEADNAV is using (I noticed in FL recent video that they are using this exact model). In the french fry cooker we’ve set up a cheap circulating pump (like this) to keep everything mixed. We run around 175F for 35 minutes (probably overkill on the time but worth the wait). The tank is hooked up right on a stainless surface next to a deep sink. A shallow bin is kept full of water in the sink. After the time is up, we pull the basket out and slosh it around the bin while running water over top. Parts are then laid out on grates under a fan, and once dried they are polished again. This is when the polishing effect really pops.

Dye: Using any Rit Black dye should work well, especially the DyeMore since it’s suited for Nylon. However, we’ve opted for Rit ProLine powder as it’s much more cost effective and used industrially. Aiming for 1.5-2% dye concentration by weight has yielded good results for us. We also add about 2% white vinegar. The dye bath is used for about 1.5 weeks before remaking the mixture. Exposure to air will oxidize the dye bath and heat accelerates the process. What we’ve noticed is that the red/yellow components of the dye oxidize much quicker than the blue component, and this will leave you with poorly balanced color and blue parts (we learned this the hard way).

Quick question @LEADNAV, does the dye tank you’re using implement a pump to agitate water or is the circulation a result of the fluid heating?

Kinda getting off topic here on this thread about Burred edges, so may want to start a new one on finishing, but appreciate the info.

I have a mix of parts where some I’d like to possibly try polishing but some have deep internals and spring mechanics where I imagine this may be an issue with the plastic beads. From the looks of it though, it doesn’t seem to hard to dump and swap media as I read it doesn’t need a full clean out to do so…is it easy to swap in your opinion?

Yes the Kitchen equipment I originally started to use has internal pumps for circulation and yes from what I hear everyone at Formlabs started to use that same model. Funny because I actually found some other printer company that now sells that exact unit but white labeled with their brand on it and marked up huge as a “professional SLS dye tank”.

I too found that I need to dump and remix every two weeks and I actually prefer the Rit DyeMore “Graphite” in the bottles. To me the Graphite has a more professional color and look whereas the black just looked “dyed”… just personal preference.

The recent big improvement I made was the stainless fry basket with handle. I can now fill that thing with parts and I run 185 degrees for 35 minutes while being able to pull the lid and use the handle to slosh the parts around in that basket without fear of loosing a part to the bottom of the tank.

Yes, this handle makes it so the lid is not sealed so you do loose a lot of water due to evaporation, but It works out because by time the water level is too low it is time to remix the tank anyway.

Then I just fill it up, add one whole bottle of Rit Dye, a splash of dish soap and a splash of vinegar and good to go. (sorry for the mess I been busy…but everything wipes down pretty easily)

I don’t have a deep sink in my little shop so here are my two simple “Flush” buckets I use to rinse.

I thought about building a 5 gallon bucket rotary rinse… to auto flush rinse n tumble the parts kind of like the Blast tumbler… but I’m sure that will be Formlabs next machine in the ecosystem… A “wash machine n dryer”…

1 Like

I have only made the change over from glass to plastic once, so I can’t say for sure how much trouble this would be. It was a fairly straightforward process as far as dumping and swapping media. I think a couple things to consider would be:

  1. The polisher requires a specific nozzle, which may not output the same volume of media. The fluid injection point somewhat obstructs the flow which could speed up glass media breakdown.

  2. The polisher uses a different media screen to separate between waste and media hopper, so this would probably need to be swapped out each time too.

  3. The FL recommended air compressor (Eastwood QST 30/60 - 4 HP) has been great but not perfect. It’s quiet and easy to maintain but I would suggest opting for something with a bit more power. FL did add adaptive airflow settings so instead of a Blast cycle aborting at low PSI, it will pause and allow the compressor to catch up. Since we’re only running for 15min instead of the preset 30/45minutes, it only requires one short pause which is no problem.

If you ever want to test the polishing upgrade on a part that you’d expect to be most problematic, I could print one and run it through my process.

Glad to see we’re both on a similar track on the dyeing process, and thanks for the answer on tank agitation. I hope we see something related to dyeing or washing announced during the User Summit in a couple weeks.

I will say that something I did not account for…Nylon 12 parts “float” in the dye tank…and Nylon 12 GF parts do not.

Just realized that… not a big issue in that I am not worried about them floating away… but I have to stir more frequently now as I am worried about the few parts bobbing on the surface may get uneven dye blotching.

Just an interesting fact that I will have to account for now.

I happened to have a scrap print that works great as a floating mesh cover with protruding posts. The posts point into the dye tank and help keep everything submerged. Some very small parts do float through, but it’s been a pretty good solution overall.

If you have to stir your dye bath throughout the process this idea would definitely need some tweaking for better accessibility.

1 Like

I have been able to minimize burring slightly off the Formlabs setting recommendations by adjusting

Perimeter Upskin Laser Powers changed from stock 28500 to 13200mW

Perimeter Downskin Laser Powers changed from 13735 to 8500mW

I still have a slight edge forming but it has greatly improved.

It was suggested

“I should start by lowering the mW by a couple 1000mW at a time. You probably wont see much of a difference until downskin is lowered to around ~10000mW and upskin is lowered to around ~15000mW but you will need to tinker with it.”

That was the case as I saw zero improvement till I got below those numbers. I think a little lower on the Upskin side may get rid of that remaining edge on the one side.

I am adjusting this all from the Default setting… I may try to run these adjustments on the speed optimization setting to see what happens.