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The warping one is strange, warping is caused by thermal expansion/contraction and resin doesn't really change temperature during the printing process. That's o

The warping one is strange, warping is caused by thermal expansion/contraction and resin doesn't really change temperature during the printing process. That's one of the reasons you Sounds to me you either aren't printing at room temperature, don't have the resin dialed in or you got a bad batch of resin/ The other criticisms are fair, but not necessarily dealbreakers and can be mitigated. PLA is brittle as well, about the same as standard resin. Just like with FDM, there are other formulations, but the materials are different, and perhaps there are no good analogs for FDM materials. Imo resin printing is mostly useful for tabletop minis, not engineering prints. As opposed to you, I don't think resin's the future, certainly not in the hobbyist space. The fact that it involves highly toxic chemicals and fumes means you need a separate space and be really cognizant about materials safety at all times. It does have its niches, particularly in mini printing, where the high detail is useful, and you can load up the whole area with minis at no penalty to print time and have an entire army's worth of minis printed in a span of hours.

michaelt 2y ago
> The warping one is strange, warping is caused by thermal expansion/contraction and resin doesn't really change temperature during the printing process. In my experience with resin, you can get misshapen parts for a bunch of reasons: 1. Resin will change size a bit during and after curing. Not by a large amount, and of course it depends on the type of resin you use etc - but enough. And of course if your design has some thick bits and some thin bits, one might shrink more than the other. 2. Every time the machine exposes the resin, it sticks to the previous layer and to the projector screen/LCD. The machine then lifts the model, to unstick it from the projector screen. This applies force to the model, and can cause it to bend by a tiny amount - which can gradually build up over several layers. 3. Resin has to be somewhat UV transparent, for each layer to cure all the way through in a short exposure time. Because of that, UV curing later layers can pass through the part and cure resin that shouldn't be cured, on earlier layers. This is particularly the case if the shape has areas resin can pool up and won't run off. > PLA is brittle as well, about the same as standard resin. Just like with FDM, there are other formulations, but the materials are different, and perhaps there are no good analogs for FDM materials. For many printers, resin has to be brittle because of the way the printing process works. You cure a layer, it sticks to the previous layer and the projector screen/LCD, then you raise it to unstick it from the screen. If the resin is flexible, the unsticking process would cause the layer to bend, giving poor dimensional accuracy. So resin is formulated to be stiff and unyielding. FDM can print flexible materials like TPU - common 'print upside-down' designs of resin printers simply can't. Although you undoubtedly could engineer a printer that could, such as a resin equivalent of an SLS printer, which doesn't face the unsticking issue.
- varjag 2y ago
  You absolutely can print flexible materials on resin printers.
- mdorazio 2y ago
  This is factually incorrect. A quick search will show you plenty of flexible resins. Here's one: https://www.youtube.com/watch?v=eely3rxr2to https://www.youtube.com/watch?v=eely3rxr2to Resin is also much less prone to size changes than standard FDM filaments. If you've printed FDM you should know how much tolerance you have to have in your parts (ex. hole diameters) to account for shrinkage post-print, not to mention the difficulty of printing things like ABS. Resin has MANY drawbacks and in my opinion kind of sucks as a general user experience, but warping, material quality, and material options are not worse than FDM.
  - michaelt 2y ago
    > A quick search will show you plenty of flexible resins. Here's one: https://www.youtube.com/watch?v=eely3rxr2to https://www.youtube.com/watch?v=eely3rxr2to OK, you make a fair point. People will sell you such resin. But look at the video at the 4m40s mark - the dimensional accuracy is trash. The makers of these printers will all claim they have 0.01mm layers and 0.03 mm x/y resolutions and stuff like that but the dimensional accuracy of the parts coming off them is far, far, far below that no matter what the marketers claim. That cube barely has 1mm dimensional accuracy.
    - mdorazio 2y ago
      I agree on quality varying widely for resins softer than something like ABS or PETG. And tolerances are definitely never to advertised spec. It’s worth noting that Formlabs themselves sell a “silicone” resin for a hilarious $350: https://formlabs.com/store/materials/silicone-40a-resin/ https://formlabs.com/store/materials/silicone-40a-resin/ At that price point you might as well outsource it or at least print a negative and use a real silicone pour.
    - numpad0 2y ago
      It really is just open loop resolutions. You can print really sharp tweezers in SLA, that's what they mean by that.

michaelt 2y ago

> The warping one is strange, warping is caused by thermal expansion/contraction and resin doesn't really change temperature during the printing process. In my experience with resin, you can get misshapen parts for a bunch of reasons: 1. Resin will change size a bit during and after curing. Not by a large amount, and of course it depends on the type of resin you use etc - but enough. And of course if your design has some thick bits and some thin bits, one might shrink more than the other. 2. Every time the machine exposes the resin, it sticks to the previous layer and to the projector screen/LCD. The machine then lifts the model, to unstick it from the projector screen. This applies force to the model, and can cause it to bend by a tiny amount - which can gradually build up over several layers. 3. Resin has to be somewhat UV transparent, for each layer to cure all the way through in a short exposure time. Because of that, UV curing later layers can pass through the part and cure resin that shouldn't be cured, on earlier layers. This is particularly the case if the shape has areas resin can pool up and won't run off. > PLA is brittle as well, about the same as standard resin. Just like with FDM, there are other formulations, but the materials are different, and perhaps there are no good analogs for FDM materials. For many printers, resin has to be brittle because of the way the printing process works. You cure a layer, it sticks to the previous layer and the projector screen/LCD, then you raise it to unstick it from the screen. If the resin is flexible, the unsticking process would cause the layer to bend, giving poor dimensional accuracy. So resin is formulated to be stiff and unyielding. FDM can print flexible materials like TPU - common 'print upside-down' designs of resin printers simply can't. Although you undoubtedly could engineer a printer that could, such as a resin equivalent of an SLS printer, which doesn't face the unsticking issue.

varjag 2y ago
You absolutely can print flexible materials on resin printers.
mdorazio 2y ago
This is factually incorrect. A quick search will show you plenty of flexible resins. Here's one: https://www.youtube.com/watch?v=eely3rxr2to https://www.youtube.com/watch?v=eely3rxr2to Resin is also much less prone to size changes than standard FDM filaments. If you've printed FDM you should know how much tolerance you have to have in your parts (ex. hole diameters) to account for shrinkage post-print, not to mention the difficulty of printing things like ABS. Resin has MANY drawbacks and in my opinion kind of sucks as a general user experience, but warping, material quality, and material options are not worse than FDM.
- michaelt 2y ago
  > A quick search will show you plenty of flexible resins. Here's one: https://www.youtube.com/watch?v=eely3rxr2to https://www.youtube.com/watch?v=eely3rxr2to OK, you make a fair point. People will sell you such resin. But look at the video at the 4m40s mark - the dimensional accuracy is trash. The makers of these printers will all claim they have 0.01mm layers and 0.03 mm x/y resolutions and stuff like that but the dimensional accuracy of the parts coming off them is far, far, far below that no matter what the marketers claim. That cube barely has 1mm dimensional accuracy.
  - mdorazio 2y ago
    I agree on quality varying widely for resins softer than something like ABS or PETG. And tolerances are definitely never to advertised spec. It’s worth noting that Formlabs themselves sell a “silicone” resin for a hilarious $350: https://formlabs.com/store/materials/silicone-40a-resin/ https://formlabs.com/store/materials/silicone-40a-resin/ At that price point you might as well outsource it or at least print a negative and use a real silicone pour.
  - numpad0 2y ago
    It really is just open loop resolutions. You can print really sharp tweezers in SLA, that's what they mean by that.