...and now for something different


#1

Seeing how Formlabs is about to release their $3500 Form 3, I thought I’d look around and see where the state of SLA is at, and what’s new out there.

I was looking at the New Peopoly Moai 200, which looks pretty impressive, with a much larger build envelope (200x200x250), for less than the Form 3.

And at the other end of the spectrum a Mini Masked SLA (LCD) printer from Monoprice for only $200.

https://www.monoprice.com/product?p_id=35435

I’m really tempted to get that little thing just to play with it. If it doesn’t work, it still only costs a little more than what Formlabc charges for 1 litter of resin


#2

The big difference there is going to be the engineering and build quality, they’re also using the tilt method for layer separation like the Form1 did which puts a lot of stress on the print.


#3

Well, I just came from the local Casino about $300 up, so I though what better use than to buy the little MonoPrice printer.

I should be getting it by Friday, so in the meantime, I though I’d play with the software. They offer 3 options: Slic3r, ChiTuBox and Creation Workshop MonoPrice DLP.

So far I only played with the Slic3r software since I’m already familiar with it from my FDM printer, and frankly it’s pretty darn good. Not as fast as Preform, and it does tend to crash a lot with defective files, but it does create some decent supports.

Can’t wait to send this to the little printer and see what it can do


#4

Yeah, for $200 it’s not much of a loss to try it out.


#5

did you make the figures or buy them?


#6

Monoprice also gives you 30 days money back, so you’re really not out anything if you really don’t like it from the onset.

BTW. I already got the printer this afternoon, and I’m printing the 2 busts above, but I must have used the wrong profile, because the estimated time is 8 hours, so it won’t be done for a while.

I’ll post photos of the results tomorrow.


#7

No, I got them and a few others on Thingiverse. They’re part of a chess set, but I removed the pedestals:


#8

Update & results:

This morning when I got to work, the print was waiting for me. So, the results:

For a first test, uncalibrated, just fill the tray and press print, it was successful. It took 8:10 hours to print, which is a loooong time for a 1200 layer print, but that’s because of the out-of-box settings which I think were wrong.

The resin that was included with the printer was clear, and the print came out a bit on the yellowish side, so I think that the exposure time was to high. Also, this type of resin is much more susceptible to UV than the stuff we use on the Formlabs printers. After cleaning the print I put it in a window to cure further and left it for about 30 minutes. when I got back to it, it was overcured, a pretty deep amber color, and removing the print from the supports by hand, was nearly impossible. I had to use a wire cutter to cut every one of them off. Very strong stuff.

BUT, there’s a big problem: There are a whole bunch of lines in the print as if it had either shifted or over cured a some layers. It’s not apparent at the lower layers, but it’s immediately apparent at the higher ones. Don’t yet know what it is, but I’ll see if I can figure it out.


#9

maybe cleaning mirrors solve problem ?

i assume this laser replacement wont cost 900euro +tax :sweat_smile:
nice finding sir! +1


#10

There are no mirrors or lasers, this is an MSLA printer, it uses an LCD with a UV light array shining through it.


#11

Yep, You have proven that you get what you pay for. You may get better results by playing around with the numerous variables, but it will take you time (potentially a lot of time) So how much is your time worth?

Questions you need to ask yourself include questions about the screen quality, the power of the light source, the actual wavelength of the light source, the uniformity of the light power across the build area (is the power at the extremities of the build platform the same as at the centre?) - Its not unusual to see UV power differences across the build area of up to 40% in the budget printers). Also with that LCD screen just how much of the UV energy is passed through the screen? This just touches upon the light source / LCD issues, there are many more.

In addition to the potential light source / LCD issues in a low cost budget “toy” do you expect highly accurate ball screws (for the Z axis accuracy) and accurate linear slides for the build platform (for the X/Y axis accuracy and positions) all of this is needed to give a dimensionally accurate model as it builds

I would not expect anything on a low end low cost printer other than being able to print something - which you have done…


#12

Unlike you, I enjoy “toying” around with electro-mechanical things, and I didn’t buy this printer as something that I would need to use in a production environment where time is money.

It’s a learning toy, but one I’m going to have fun with. The fact that I was able to get a print, straight up after simply plugging it it, and pressing print, shows how far along this industry has come. Even now, there are people that buy a Form 2, plug it in, send a print to it, AND GET NOTHING !! So, I think I’m doing pretty good.

How much time I will put into it to get it to print right, who cares, I look at it as FUN!

If you just want something that works “perfectly” on the first print, then go ahead and buy your $3500 printer, this one is obviously NOT for you.

But I’m sure there are quite a few folks here that love to tinker, and are quite intrigued by this little doodad. :smiley:


#13

Did you get out bed on the wrong side today Dudemeister??

Your post is very presumptive and quite wrong. For example you have concluded that I don’t enjoy “toying” around with electro-mechanical things. You are so far wrong in that respect its incredible. I have spent the majority of my working life “toying” around with electro-mechanical things. In fact the last couple of years has involved the development and configuration of a number of 3D printers and their associated materials for a wide selection of applications, that is not from an end users view point but a development engineers stance.

There are lots of forums out there where I can look at various printers and the trials and tribulations of people playing, unsurprisingly I look on this forum to find and learn more specifically regarding Formlabs printers rather than looking to read about someones trials and tribulations with a low end budget printer.


#14

First let me say that I did have a very good night sleep, thank you very much. :smiley:

“but it will take you time (potentially a lot of time) So how much is your time worth?”

While my assumption about whether or not you enjoy toying around with these things may have been wrong, it was only because of statements like the one above.

I look on this forum to find and learn more specifically regarding Formlabs printers rather than looking to read about someones trials and tribulations with a low end budget printer.

Like all other forums, this one does contain threads that are not always about FormLabs, so if you don’t like reading about them, then don’t.


#15

i dont think it is anything to do with getting a wrong side up the bed. he just simply viewing this as a individual user who not necessarily want to spend thousands, and like to experience with stuff, this is a open minded approach.

in the other hand, sounds like to me you are really protective with formslab stuff perhaps even works for them, so you approach here isn’t natural and cant provide a independent opinion regarding this subject, so why push it?


#16

Again, wrong… I am not protective of Formlabs “stuff” a read through my postings will show you that. I certainly do not work for them. What I do see though is quite a nice product that is sometimes spoilt by poor commercial practice and silly policies.


#17

I think the upper layers showing more line is likely the result of the leverage of the taller print as it gets peeled shifting the print more- that is- the printer’s repeat-ability of accuracy goes down with Z height.

Also- with a DLP printer, the smaller the Cross section, the fewer number of pixels being used to draw the profile- so I would expect smaller objects with finer detailing, like the head, to look a little rougher than larger masses like the chest.

As far as speed- I don’t think you are gonna get it a lot faster. The form 2 exposes smaller cross sections faster than larger ones because of the area it has to cover- but DLP printers- especially low cost ones- do not have a very bright light source… and as a result, they require the same amount of time for every layer no matter how small the cross section being exposed.

I have yet to see an affordable DLP that is faster than the Form 2- which is frustrating because the Carbon printer manages to print so fast- so you know its possible with a intense enough light source.

however- as far as printing rougher looking parts that do not require super fine finish… this might be an attractive option. How’s the build volume compare to the Form 2?


#18

From the photos, it’s definitely overcured, But it also looks like the layer separation technique is going to be an issue putting a lot of stress on the model. That might be the cause of the lines as well or it could be something to do with the z-axis screw.

As far as experimenting goes, one of the main reasons I like the Formlabs stuff is not having to experiment, I’m fine with them figuring out the resin formulation/print settings.


#19

Sculptingman is correct in what he is saying - the exposure time per layer on a DLP printer is the same irrespective of the amount of detail in the layer. That is simply down to the need to supply into the resin a fixed quantity of UV energy to effect the cure. (the amount needed is fixed according to the resin formulation)

If a layer is overexposed reduce the time per layer.

If it looks like the separation between layers is with too great a force reduce the “lift speed” which is the speed of separation of the print from the FEP

Generally speaking a DLP printer will print a larger surface area object faster than a printer using a laser spot to effect a cure for a layer. Lets look at a laser spot size of 140um and the time needed to cure a single circle of 140um diameter. The laser is going to win on speed stakes every time for this against a DLP printer due to the much higher UV power available in its 140um spot from the laser. If the resin requires (for arguments sake) 10 Joules of UVenergy to cure 100um2 of resin. Then a 250mw/cm2 power laser will deliver that spot of energy much quicker than a 1mw/cm2 dlp printer.

However if that 140um spot has to transit (paint) a large surface area (lets say this time a circle of 140mm diameter) to effect the cure then there will come a time when the simultaneous exposure of the entire area at 1mw/cm2 in one exposure time frame (the DLP printer) is actually faster than the area being “painted” to effect the cure by a moving 140um laser spot

Zachary_Brackin mentioned that the print looks over cured, it might be, but a factor to consider is that the light sources in the cheap DLP printers often show large discrepancies in available UV power across the build area (measured differences can be up to 40% deviation of power. That means that in areas of a print layer some of the resin will be more cured than others, this sets up large stresses in the printed part. Those stresses are often seen as distortion or layers separating

More expensive DLP printers will feature better (more uniform) light sources and sophisticated software to provide something often described as “Hot spot compensation”


#20

Yes, the print is way overcured, but not because of the printer, as I mentioned in the original post, I had put it in a window facing the sun, and left it there for 1/2 hour, which is what did the trick. I was used to standard UV resins for the Form, which do not cure that fast. This stuff cures incredibly fast, so next time I’ll be more careful.

I really haven’t had a chance to play with it this weekend, I left the printer at work, so I’ll probably tinker with it Monday. But one thing I did notice is that it had two built in profiles, the “medium” one was what I had used to print originally, and that exposed the bottom layers for 40 seconds, and the subsequent layers for 8 seconds. The “fast” profile does 35 and 6 seconds respectively. I sent a “fast” test print to it on Friday before I left work, so I’ll see what it looks like tomorrow.

The peel technique on this printer is to simply lift the platform. No tilting, no sliding, just pull up. The system uses a low peel force FEP film, and I watched it while working and there doesn’t seem to be any significant force required to lift the platform, but then again I didn’t watch the whole process, so maybe the lines I’m seeing are due to some layers being more stubborn than others during lift.

I’ll see if the lower curing times of the fast profile do any better.