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Alternative Castable Resin


#21

James any ideas about this resin form2 castable? I know you haven’t tested it but from pictures you might get an idea why i have monsters instead of rings.

Form2 is a laser printer so I had no reference point for base settings. So I started out with 10s then 8; 6 2. At 2 at the beginning I had a fail but after that I’ve managed to get the ring printed out. But there’s no difference in quality between 2s and 8s.

I’ve tried 0.5s and 1s but it has failed as soon as I changed the exposure to that number. I had a similar experience with FTD castable blend but the only difference would be that it comes out much nicer. Not good for jewelry because the fine details don’t work with it. Maybe it wasn’t made for z25.

As for form2 they say that it can work with 25u … I’ve tried with 50u the same results. Any ideas and tips are sure welcome.

@Sovann you mentioned ages to cure by this you meant post curing or printing curing? because I narrowed the print exposure to 2 seconds which is great.


#22

I can’t really tell what the problem is from the photos; I’m not a jeweler and I’m not really sure what the rings are supposed to look like and exactly what artifacts you are seeing.

One thing in general that if the resin is viscous, you will need more delay.

I"m not sure which other resins you have used, viscosity is rated in centipoise, CPS.

3DM ABS and Cast are around 50 cps.
FunToDo Castable is 85 cps
MakerJuice G+ is 90 cps
Formlabs Castable is 250-325 cps
Formlabs Tough is 1800 cps

Viscosity matters because after you lower the part back into the resin (especially during the earlier parts of the print where the build plate may touch or be submerged in resin), the resin will begin moving due to mechanical action. If a layer is exposed while the resin is still moving, there will be artifacts in the print.

Low viscosity resins settle very fast and do not need much delay. High viscosity resins will need more delay.


#23

Hi 3dps, sorry for the late reply. Have been quite busy lately. I just print with the B9 emerald now with the setting we discussed before without any problem. The only problem is sometime the base doesn’t stick. I just need to make sure the build plate touch the bottom of the Vat a little tight and I don’t know why 30s to 90s for the base doesn’t work for me. I always use 120s.

For the two rings, I am not sure what went wrong too. Did one of them fell off onto the Vat or it doesn’t come out at all? I think you can try to re-orient the ring and make sure it is away from the blurry side of the projected area. Same thing for the bracelet. Maybe it is because of the blurry side of the projected area that makes it fell. You can try print half of the bracelet at a time and solder them back together or put a little bit longer exposure time, like 7s or 7.5s.

For the Form2 resin, I was using the Form1 Castable though, and I had the same issue like you with the printed model. You can see from the calibration model, all the cylinders are melted together, and the ring too, all the holes are filled. I think it is from what called light bleed. For the exposure time, I don’t remember what I put. I think about 10s. I just remember one of the tech support guy from Kudo3D told me that it happened the same to him when he tested the resin from Formlabs, it took longer than normal to cure because it is designed for the laser, and the projector’s light is weaker than the laser.


#24

Hey guys thanks for the input,

@James I’m no jeweler myself just looking for the best quality that I can get. Not my best photo either but in this pic you can see 3dm cast and FTD castable resin.

With 3dm the prints are coming out fine but the burn out process is pretty bad because there’s not much or any wax in the resin. Now on the other hand with FTD I couldn’t get fine details out. Maybe it wasn’t designed for that high precision btw I was using z25.

Now I really went crazy with FTD once I was using 0.1s exposure settings and the ring came out but still the fine details like holes were missing.

Here’s form 2

Seriously deformed and only the main hole came out. I might try your idea with the delay.

Btw James any tips for tinkering with the bracelet? The settings are in the post above.

@Sovann As I mentioned at an earlier post I managed to get a ring out with 2s exposure. It’s much easier to print than b9. And faster but it’s not coming out right.

The funny thing with the bracelet is that it has came out once good then it has failed on two printers the same way … I have no clue why. Yes I’ve used 7s as base exposure. Hmm printing it out in two parts might be a bit tricky because there are some fine branches and leaves for which I have no patience to solder :P.

It’s really hard to switch between 1 resin to another :)) because you still have the old settings in the back of your head.

I’m using 45s first layer settings because for some reason this week nothing has stuck under 45. Another day at printing :stuck_out_tongue:


#25

Oh, I see, severe light bleed with fused supports.

Yeah, it’s as @sovannor mentioned. You will need additional pigmentation for the blue Formlabs resin. But if you intend to cast with it, you need to be careful that you don’t introduce something that won’t burn out. Delay or other settings changes will not have any effect on improving this.

The difficulty with casting is that there are a lot of variables. Getting a good quality print is only the beginning of the process. Post-cure of the print, investment mix, temperature ramping schedule, and environmental gas mix all can have significant effect on the result of the casting.

For instance if you look at the B9 forums, everyone there is using the exact same printer and resin, but often get radically different results based upon their process. The current fad topic is the post-curing process. The consensus is that special post cure procedures are necessary, especially a heat-treat post-cure rather than UV-only, but the exact schedules are all witch’s brew. Same with the investment material, people have all kinds of mixes or adding boric acid, or using different brands of investment, all with varying results.

Same too with the burnout schedules. While 3DM has a recommended burnout schedule, this is based upon the chemical properties of the resin. Investment mixtures also have recommended burnout schedules, based upon chemical properties of the investment (e.g. thermal expansion and shrinkage). So if you look at the investment casting instructions for Kerr Satincast (http://www.kerrcasting.com/LiteratureRetrieve.aspx?ID=130925), you’ll see that it has a schedule with more steps to take that into account. That means some black magic and experimentation to combine the schedules for the resin and the investment to get to something that works.

Now, I’m no jeweler, but observing jewelers discuss this stuff makes me believe that it takes quite a lot of trial and error to figure out what works for any particular shop.

When you say that the 3DM burn out process was “pretty bad”, what problems did you encounter? When you say “there’s not much or any wax in the resin”, what makes you believe that this has an impact on the resulting casting?

It is possible that a different resin might work better, but since you are already getting good quality prints from 3DM Cast, you may be giving up progress that you’ve already made and returning to the first step without necessarily needing to. I’d hate to see you spend a lot of time tuning the print process if it turns out that tuning the casting process is what’s necessary.


#26

Thanks for the long explanation.

First things first I’m doing the printing and we have a dedicated jeweler who does the casting and polishing and stuff and things. He has a lot of experience and also has a degree in metallurgy. He has a projet 1200 printer and 3d prints his stuff as well so he has a lot of xp under his belt.

He said the following things there are two types of investment casting resins, the ones which are easy to print but it’s hard to burn out and there are those which are hard to print but easy to burn out. And this comes down to how much wax you have in your resin.

If you have little or no wax then you only have the resin and that photo sensitive agent in it (this is my understanding only). From his words a good castable resin has a bit of elasticity after you have cured it. Now 3dm cast is solid as a brick. But it’s easy to print with it 0.6s exposure settings for 25u layer it’s super fast. I was getting rings out around 38-45minutes in my ludicrous mode settings :). All in all 3dm is good to get prints out fast to see if the measurements are correct and you can set stones in it the right way.

Btw we have tried 2 different casters and both said that 3dm is not coming out smootlhy. Though we haven’t seen the prints.

Now with b9 it’s different the best settings to use to get the highest quality is 6s exposure and I can get a ring out around 4h. Whooooa that’s a lot of time for me to see if the ring has been designed properly and there are 100 more to test after that one :P. Yes of course I can put more rings on a the build plate.

When I’m done with b9 and cure it, it has a bit of flexibility to it which is what the jeweler was looking for. The cast should come out this week and we wait to see it.

Btw please don’t forget about the bracelet. I would love to hear about your input or tweak.


#27

Not sure what bracelet you’re referring to. I can only find pictures of rings on thread…


#28

Also, I suggest contacting 3DM on their Facebook page, especially if you have pictures of the poor quality or failed casting. They may be able to give you advice that is particular to their resin formulation.


#29

Strange you mentioned on this posts that with the bracelet we need a few tweaks to get it out:



I’ve tried photographing but it’s really hard to catch it right especially with a phone.
But the blurrier squares are more on the left and flexible side of the VAT. I’ve counted 7×6 squares which are blurred.

Here are the settings that I’ve used.

The part where it has failed it happened was around layer 800. For the b9 resin the manufacturer suggested 2.2s base exposure. Well if the stars are aligned and the wind is not blowing then I’ve managed to get a print out. I’ve started to use 4s exposure for steady prints. To get better quality I’ve used 6s because it’s a bigger object I’ve settled with 7s. xy is 41 ish and z=25.

Also here’s a bracelet that almost made it :slight_smile:

This is the most perfect the rest that I’ve printed came out just like in the first prints.


#30

Has anyone on here tried the B9 Yellow resin? I just got in a bottle and am currently waiting for a new vat to arrive from Kudo before trying it out. I was wondering if anyone has used it yet, what’s experiences with it been like, and what some of the baseline exposure times are for the resin.


#31

The UV filter in the projector is not removed in Titan printer. The purpose of that filter is to extend the lifetime of the projector DMD chip and to meet the health regulation. Printers that use the wavelengths around 405nm are not UV printers indeed. 405nm is visible purple light. As a result, it will be very slow to use B9 resins. Can try something around 10 seconds per layer for 50umXYZ for B9 resins. Some might even have to use 16 seconds, depending on the projector brand and condition. Formlabs use a laser gyro to draw the pattern. Laser spot size is about 150um. With all the power concentrated within this tiny spot, the resin has to be much less sensitive to light. Formlabs’s resin will thus be even slower than b9’s. Besides, laser gyro based printers can not reach the resolution of a DLP printer. There is no need to formulate a resin that has a better resolution than their printer can handle. For printers using a LED lamp, the intensity is usually the lowest and the resins are formulated to be very reactive. This type of resin is not compatible to Titan either.


#32

Since I’m looking to print small, high resolution models for jewelry applications I’ll likely be printing at 37um. I’ll try for settings between 4-8 seconds and run some calibration tests to see what works best.

Since printing speed will eventually become a factor for a practical application of this printer in our manufacturing process what can I do to increase the performance of the printer?
Aside from running the device with the “Eco” mode switch to increase the power intensity of the light

  1. Can we ourselves remove the UV filter from the projectors (obviously at the cost of projector life)
  2. Are there other projectors available on the market that would project in a more appropriate wavelength of light for curing the B9 resins that could be substituted in place of say my Acer projector?

From my understanding these resins have a wax component not found in most other types of resins out there. While on the one hand it cures a lot slower, from the reviews on it I have read the B9 Yellow offers the best burnout for investment casting. Residue left behind by the resin results failed casts or ones that require extensive labor and repair work so it is important I am able to dial in a good brand of castable resin with this printer


#33

Since your Acer projector is out of warranty, you can try to remove the filter and see what happen. B9 resin is sensitive to UV light just like our resins. It is formulated to be slow for some reason. Maybe to make it less compatible with other printers. There is no commercial UV projector in the market. Texas instrument does sell UV DLP module but it cost $7000.

It is better to try 3DSR castable resin before taking the risk of damaging your projector. There might be more modifications other than just removing the UV filter.


#34

B9R-4-Yellow
50xyz
10sec base exposure


#35

I don’t think they (B9C) formulate the resin to be slow for a particular reason other than the high solids content and UV blockers required for the thin layer thicknesses (25 micron) and to prevent overcuring in subsequent layers.

The B9 printer removes the UV filter from the their Vivitek projectors and replaces it with an IR filter to reduce the cure time. While UV is detrimental to the life of the DMD chip, the biggest concern is the IR damage done to other glass components in the light path, like right in front of the color wheel.

I have not heard of any person who ran an Acer sans filter, where the projector didn’t fail way sooner than expected.


#36

So are you happy with the way that print turned out? It looks good!

Just make sure you cure the daylights out of it before you cast it. :slight_smile:


#37

@ rkundla
Where can we find the information about the IR filter? As far as we know, IR generates heat. Unless the UV filter removes both the UV and IR, there is no reason to add an IR filter.


#38

Finally got around to casting! Here is the finished product printed on a Titan 2 using B9-Yellow resin, cast in solid 18K gold.


#39

This model was a little bit challenging to print at 50mu as it extended outside of the focal area of the projector but with a fairly conservative printing parameter the entire model did print incredibly well. Had either some burnout residue or breakdown in my investment that caused the model to cast with some porosity on the surface. Despite requiring a little bit more cleanup then the other models I have cast the piece still turned out very clean in the end. Overall I’m happy with the performance of the B9R-4-Yellow resin on the Titan2, we have been successful in casting multiple times now without having to deviate too far from our normal workflow procedure and time schedule of our traditional lost wax casting process.