3D Printing Industry

BHDA Finishing Tips and Techniques: Support and Nub Removal

BHDA — or black high definition acrylate — is the most recent material added to our roster. Starting as a maker material, BHDA was released this fall to all shoppers because of its amazing detail, finish, durability, and color. However, this material does have one aspect that’s somewhat unusual for Shapeways: models are printed with support structures. Until today, we removed the supports from all models during post-processing in our factory. But, this went beyond what many of our makers wanted. So, starting today, to give you more flexibility around the way your models look, you now have the option to receive your BHDA models with supports still attached. Below, we’ll show you how to remove supports and, if you’ve chosen to receive your model with the supports removed, how to remove the tiny support nubs that will remain on a portion of the surface.

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The USS Arkansas 1/1800 model by C.O.B. Constructs and Miniatures with supports and after support removal

 

Why does this material have supports and nubs?

These support and nubs exist due to the production process. Before printing the model, the 3D printing engineers will check the model in order to ensure that the design meets printing guidelines and can make it through the production process. Next, support structures are added to the design file using a variety of preset supports which are selected based on your model’s geometry. If your design is particularly intricate, individual supports are added to delicate areas. These support structures hold the model to the build plate while they are printing, while offering strength to the product as it is being printed.

Once the models have had the supports added and are oriented in the build, the production team will load the models to the printer. The printers use direct light projection technology, which includes a liquid resin, and light to cure the material. Each build is created layer by layer using light voxels to cure the resin to the previous layer.

Once the build is completed and cured, the supports can be removed in the factory. If you opt to order your model with supports, this will be the first step after receiving your model. This removal process uses a metal spatula, snippers, tweezers, and mineral oil. After the supports have been removed, small nubs will remain on the part. However, it is possible to finish the surface to a smooth, clean finish with minimal effort.

 

How to hand-finish your products:

Initial Finishing Tools

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  1. Snippers: Cut off supports

  2. Craft Spatula: Scrape off supports

  3. Tweezers: Pull off supports and scraping off nubs

 

Final Finishing Tools

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  1. ≥ 600 grit sandpaper: sand off nubs

  2. Paint brush: apply finishing lotion or mineral oil

  3. Mineral oil or lotion: moisturize material to remove scratches

 

TECHNIQUES

Large Support Removal

Starting today, designers can choose to receive their models complete with supports. These designers are interested in removing the supports at home.

TIP: Check the 3D file of the model while removing these supports to avoid removing crucial parts of the model.  

If your model has many wiry parts or fragile overhangs, it is best to use snippers to remove these supports. This will help to protect the model. When you have a wall that meets many supports, tweezers or metal spatulas may be used to remove multiple supports at one time. You can angle the tweezers or the spatula flush against the wall of the model and pull downward. This will “unzip” the supports from the actual structure. Ensure you are careful with the spatula as this can cause unintentional gashes.

 

Nub Removal  

Once the large supports have been removed, small nubs will remain. These can be easily removed with tweezers, ≥ 600 grit sandpaper, and mineral oil. The tweezers are used to scrape off the larger nubs.

CAUTION: Be careful not to add excess pressure as this material can easily scratch. Cosmetic scratches can be removed, but deep scratches will need additional buffing.

≥ 600 grit sandpaper should gently rub off the remaining nubs. This should take just a few swipes back and forth to notice the nubs disappearing. This material, although strong, does polish quickly. Double check while you are polishing you are not rounding sharp edges or losing details while sanding.

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USS Arkansas 1/1800 model by C.O.B. Constructs and Miniatures

Left side before polishing / right side after sanding for 1 minute with mineral oil

 

Final Finishing Step

Once you have sanded off those final nubs and are left with a smooth surface, a few small white marks from the tools may remain. This is where the mineral oil or lotion comes in. These can be gently painted on the material to moisturize and remove the superficial scratches and scrapes.

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With all supports removed

BHDA is durable due to its strength and elongation properties, yet it is very easy to polish. This makes this material perfect for those that are looking to create miniatures. The surface is smooth and high-detail where no supports have been laid. Where the supports have been placed, these nubs can be smoothed to a soft clean surface with brief sanding. This allows for paint and other finishing treatments to be added precisely and with little post processing.

If you are looking for more information on this material, I recommend referencing the materials page — or testing one out for yourself.

A figurine with and without supports

Ill Gotten Games’ Elf Ranger shown with supports and after support removal

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