One of my favorite features of Heroforge is the ability to order a digital copy of my custom minis. Both the delivery time and the cost savings are big wins for me. The STL is usually available within an hour of purchase and it gives me a new project for my 3D printer. The following is my own independent guide. I do not have any professional connection to Heroforge at the time of this post.
As the title describes, I’m using the Anycubic Photon DLP printer for printing miniatures. The resin I’m using is the manufacturer’s resin.
All the software used here is free. I’m using Blender to edit the digital model from Heroforge. The slicing application is supplied with the printer and its available on the manufacturer’s website for free. The slicing software is designed for the Photon, so unless your Photon is in the mail, I don’t expect downloading it for yourself without the printer will be of any use.
Preparing the STL File with Blender
This step could be considered optional however in my personal experience, I have fewer print failures when I do this.
As is typical of most commercial miniatures, the underside of the base on a Heroforge model is recessed by about 2mm or so. Without a solid flat base, the model fails to stick to the build plate more often than not. If the model does stick, unhardened resin will get trapped in the cavity and either be wasted when I remove the mini from the build plate, or it will harden anyway. So I remove the recess from the base in Blender to improve the chance of a good print. It would be nice if Heroforge didn’t make this a feature of their models. At the scale of these minis, the amount of extra material used in resin for a solid base (or in any material for other 3D printers) would be very small so I can’t see using a little extra material as a big deal. I think this is probably a design choice to have the same features as other commercially made minis, or it could be a cost savings for Heroforge that adds up since they print in much higher volumes. In any case, no big deal, the recess is easily removed in short order.
In blender I start by selecting all the vertices on the underside of the model (except for the vertices that make up the perimeter of the base). Then I use the Delete -> Dissolve Vertices function to remove the recess and keep the model solid.
Correcting Defects in the Model with Blender
So far, all of the STL files I have purchased from Heroforge have had some stray vertices not connected to the model, or non-manifold spots (holes in the model). In this particular model, there was only one hole to be found under the model’s left arm. Another Delete -> Dissolve Vertices fixes that. I’m not sure how critical these are to correct since I didn’t clean up my first model in Blender and it still sliced and printed just fine (though it took a few tries to get it stuck to the build plate with the recessed base). Since I’m already in Blender, these holes are easily fixed with a couple of clicks.
At this point I’m done with Blender and I export the model as an STL file. My time using blender is usually no more than 15 minutes.
Next I load my STL file into the Anycubic software to add supports and slice the model. Most intricate models from Heroforge will require supports to get to the final product.
Using the supports function, I apply the auto support function to start. This adds way more structure than needed, but I find that this can add useful supports that the program won’t let me add manually. Next I remove all of the platform supports. Platform supports tend to leave the base of the model irregular and I don’t like the result so I remove those. I also remove many of the supports that I don’t feel are required and add a few that I think are. The more supports you have, the more clean up you need to do later. The main goal of supports is to ensure a successful print job and they are essential for printing, but too many supports and clean up can ruin the detail in your model. Getting a sense of what is needed is simply a matter of practice.
I’m printing at a resolution of 0.03mm per layer which is higher resolution than the factory settings. The results look awesome, but the print times are not as awesome. Since I don’t have a lot of print jobs in the queue, I can choose quality over quantity. Slicing is just a click of a button, and takes about a 20 – 30 seconds to complete.
I always check the preview. I learned that the hard way. It’s easy to raise the model off of the virtual platform in the software and you might not notice. If that happens, your first layer or so will be blank and the print will probably fail. Zero the height of the model and re-slice in that case.
On an extrusion printer, it’s pretty easy to tell when a print job fails. The object will detach from the build surface and you’ll usually end up with a big mess. On a DLP printer like the Photon, you won’t be able to tell by looking at it until the print bed rises higher than the edge of the resin vat. And that can take a couple hours. When I start a print job, I’ll listen to the first few layers. If the print job is sticking to the build plate correctly, I’ll hear the film make a snapping noise as the plate rises and pulls the hardened resin away from the film. If the job doesn’t stick to the build plate, I won’t hear much sound at all when the plate rises.
At my resolution and timing settings, a 28mm scale model takes about 3 – 5 hours to complete depending on the height, so making sure that it starts right saves me a lot of time. This model took 4 hours and 38 minutes. After the printing is complete, I remove the model from the build plate using a sharp knife to ease it away. The Photon came with a plastic spatula. It doesn’t work. I use a smooth non-flexible knife instead and I just be extra careful when I remove the model so I don’t damage the build plate.
First, the detached model gets an IPA (95% alcohol or better) bath to neutralize and wash away the unhardened resin. I’ll then follow up with a quick bath of warm water and soap.
My main concern at this point is getting the supports removed from the model while the resin is still uncured and somewhat pliable. Once the resin has been fully cured, the model has hardened and becomes brittle. Its more likely to break if you wait to remove the supports.
I’ll make careful use of a straight and curved edge Exacto knife to remove the support material and smooth out the rough edges. The base will have some deformations from the support material so I’ll use 400 grit sandpaper to clean those up.
Washing and trimming can take 45 – 60 minutes.
To harden the model all you need is a UV lamp or some sunshine. Usually I’ll just put my prints on a window ledge for 3 – 4 hours. In the summer, 2 hours is usually enough.
If you want to stop the curing process, the model needs a coating of something. Also, the resin is toxic, at least the liquid resin is, so putting a layer of something between you and the resin is probably a good idea in case there is still some residue. Acrylic paint will stick directly to the resin model but it will scratch off fairly easily. Primer is your friend here whether you intend to paint the mini or not.
I do a light priming on the model. I call it a light priming because the coat won’t be thick enough to fully cover over the resin color, and it also won’t be entirely uniform. This works best for me. I’ve done a full coat of primer on minis before and I discovered a few things. First is that it’s hard to get an even, full coat of primer without destroying fine detail in the Model. Second, being overly light on the primer works just as well as a heavier coat when painting. Third, you can see the detail better if you are light on primer if you don’t intend to paint. One likely downside is that the light coat of primer won’t completely stop the curing process.
Once primed, the mini might show a few spots that still need cleaning up with the Exacto knife. I’ll clean those up if I think they really need to be.
Priming and drying time is around 20 minutes.
From the digital copy to a paintable figure it can take around 8 hours. Most of the time is taken up by the printing and curing process so I can devote my time to other pursuits during those stretches. The end result is really good on the Anycubic Photon and I think it’s worth the investment. Once all the prep is done on the digital files, I don’t have to redo any of that work which is nice if I want multiple copies of something.