I own an Ultimaker but am considering a change

Hello everyone.

I own an Ultimaker 2, I can get 40 micron layers out of it and it’s fast and quiet, but for the sort of work I do I wonder if it’s the best printer for me? I do anatomical sculpts, toys for my son etc. I am happy to do some post processing but on the UM2 I’m finding I need to prime, sand, prime, sand, then sometimes fill, sand again etc. I don’t mind a bit of this but it seems excessive. I’ve seen some Form 1 prints and the details seem greater. However the cost of the resin, especially as I’m not in the USA, seems quite high.

I wonder, for ZBrush work focussed on anatomy, and occasional CAD parts focussed on dimensional accuracy, is a Form 1 going to be better than a UM2 to the point where the extra cost is beneficial?



From my experience thus far, things like anatomical sculpts would definitely come out great on an SLA printer such as the Form1+, but for toys or engineering models where dimensional accuracy and material properties are involved, there is more to consider. My experience with the Form 1 thus far has been that it does not hold the same kind of dimensional accuracy tolerances that I can obtain with my Makergear M2 FDM printer.

I can consistently hold dimensional accuracy within .001" or .025mm on the M2 over the entire build area, but it has taken some tuning to get that level of accuracy and repeatability. With the Form1, I haven’t been able to produce models that maintain that level of accuracy and FormLabs has been unwilling to publish or commit to any accuracy specifications thus far.

The other consideration is the material properties of the resins versus what is available in FDM filaments. The standard resins , when fully cured, are commonly more brittle than what you would be used to with PLA or ABS. As with most things, its about using the right material based on the desired properties.

Having said that I’ve found that the two technologies are quite capable of producing complementary components. At present, I actually have a number of prototypes that I’ve produced where I’m using SLA printed air/vacuum/liquid manifolds that are fitted alongside ABS and nylon FDM printed parts inside ABS enclosures. I’ve also used the SLA printer for a number of quick release fittings that seal with O-rings, but I can tell you that I’ve had issues where printing the exact same object in different areas of the build platform have resulted in varied dimensional distortions and almost all of these models require post processing (sanding, drilling, etc) to normalize those distortions for proper mechanical fit between components with close tolerances. The highest precision and sharpest detail parts I have produced all come from black resin at 50 micron layer height (less laser scatter into the material surrounding the beam target point).

Unfortunately, there is no advanced calibration available within the preform software to allow users to adjust out these sorts of problems. There is a generic adjustment for scale that will allow you to adjust the scale for an entire axis, but any nonlinearity cannot be compensated. Until some advanced calibration becomes available or Form Labs starts advertising a dimensional accuracy specification, I’d be hard pressed to recommend the Form1+ for engineering models that require tight tolerances. (anything better than about .016" or 0.4mm has been my experience).

Others may have had better experiences and I’m using the older Form1. I’m on the fence about replacing that Form1 with a more capable SLA printer and have considered the Form1+, but can’t justify it until some kind of accuracy tolerances are published.


I have been using the form1+, several FDM and the Zcorp powder base and I could not agree more with David. the Form is great for accurate and look, but it is not for mechanical parts, thin parts and general parts that needs precision.
I feel form and FDM are a good combo to have, though. Since they both are needed in the design phase as both precision and look needs to be tested.
Also, as I am seeing these last two days, failures on a form are more dramatic to fix than on a FDM. Probably because I have built all my FDM and I can easily take them apart.

In form labs defense, I would like to mention that there are a lot of variables that need to be accounted for with their implementation of SLA printing. In a traditional SLA printer, the print is not subjected to the peel stresses that are created in the Form1 (and pretty much all other “prosumer” SLA printers in the same price range. This puts them at a real disadvantage for dimensional accuracy, as the forces applied to the newly cured resin layers vary across the build area and in correlation with the location and surface area that was cured in each layer. For this reason, I can certainly see why they would be hesitant to make specific claims about accuracy. Add material shrinkage to that and you have a fine bit of math to work out in order to try to compensate.

For the EE geeks that may read this, the bigger issue I’ve observed is that there is some nonlinearity in either the DAC output from the microcontroller or the galvo amplifiers, along with what seems like a slightly lower than optimal gain and/or excessive dampening (round features don’t follow a circular sweep, instead they have flats at the quadrant transitions). I’ve looked at the analog position output from the controller to the galvos while running some test prints that should generate predictable test paths. I’ve seen some anomalies, but without having access to a diagnostic mode that generates exact, repeating DAC output patterns, I can’t conclusively pinpoint the problem. I do know that for many of the parts I’m making, the laser positioning inaccuracy exceeds the influence of peel distortion. This issue is one that FSL3D acknowledges and offers a calibration routine to help reduce it. The problem with the FSL3D calibration routine is that it would be exceptionally difficult get a proper alignment visually without proper tools. A calibration printout is not satisfactory when trying to calibrate the position of an 80 micron focused laser spot on what is purported to be a resolution of 3 microns (I’d be delighted to print out things that hold a tolerance of +/-100 microns).

As of now, I’ve mostly relegated the Form1 to making components that benefit from the material properties, but don’t require much dimensional accuracy. Any parts that benefit from the material properties (air/watertight mostly) and that do require accurately located features, I print with excess material in those areas and post-process with another CNC. It is also worth mentioning that the anomalies aren’t very predictable, but they are generally repeatable, so it usually takes a few prints to get things right, but form that point I can run a number of parts without issue, so long as they don’t change position on the build platform. The flip side to this is that its the worst case scenario for PDMS life.

My initial expectations of the Form1 were too high, but that is my fault. I considered the potential of what this printer could do, but failed to factor in profitability margin and the intent of the company to limit users to a narrow band of capabilities in the name of ease of use. Form Labs isn’t a maker mentality company, offering up a plethora of options for users to tune their machines to suit end user needs. Its a corporation that is focused on making a handsome profit by producing machines that are good enough and offer enough features to get people to hand over their hard-earned cash. Before any of the fanboys jump on me for bashing their betrothed, realize this isn’t bashing at all, its just a statement of fact. FSL3D, 3D Systems, Stratasys, Afinia, etc. all operate under the same model. They are companies that exist to make a profit, and why shouldn’t they? I own a business and I operate it to profitable ends as well. Sorry if that’s a little off-topic, but I think it’s relevant when setting expectations for the future of a product you are considering.

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