How Make Pla Supports Easy to Remove

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Besides many test devices, Martin now has his fourth own 3D printer running and prints as a hobby for friends, family and himself. He is happy to share his experience with each new article.

Disclosure: Links marked with * are Affiliate Links. I earn from qualifying purchases if you decide to make a purchase through these links – at no additional cost for you!

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Overhangs, free-floating parts and bridges are somewhat difficult for the classic filament printer. This is because printing errors often occur here. Warping, Stringing, even collapse and subsequently an unclean print are the usual consequences.

That is why the various slicers offer many different support structures. The structures are printed with a low infill density and usually more delicate wall thicknesses so that they can be easily removed after printing. Some slicers offer the incorporation of predetermined breaking points, while others allow support structures to be built from a different material via dual extruders. This is where water-soluble filaments such as PVA* come in handy.

Before we talk about how to minimize support structures and still get a stable, smooth printed part, we talk about the tools: what do you need to cleanly remove support structures from your part?

Support structures can best be removed with fine side cutters, scalpels and tweezers. The attachment point of the support can be smoothed with sandpaper. Protective equipment such as safety goggles and respirator masks protect against flying parts and dust.

Table of Contents:

• 1 Tools and Protective Equipment
  • 1.1 Gloves, Goggles, Mask
  • 1.2 Tweezers, Side Cutters, Pliers
  • 1.3 Scalpel, Utility Knife, Nail Scissors
  • 1.4 Sandpaper and Polishing Felt
• 2 Finishing with Paints and Varnishes
• 3 Minimize Support Structures
  • 3.1 Place object on the most favorable side
  • 3.2 Settings for Support Structures
• 4 Shopping List for Removing Supports
• 5 Conclusion

Tools and Protective Equipment

The correct settings in the slicer (more on this later) help to ensure that the support structures can be removed particularly easily. However, it is not possible to do this completely without force and effort. And sometimes small plastic parts spray uncontrollably in all possible directions. Always protect yourself from injury!

Only then, when you are wearing your protective equipment and the tools are ready, do you get to work. Reworking involves a lot of dust and flying plastic parts. So make sure that no food or drinks are left out in the open. Pets and children are not allowed in the room where you are finishing your print model.

Post-processing means that you remove unwanted parts, in this case, the support structures, with tools. As a result, plastic parts will accumulate, from the smallest particles in the range of fine dust to larger ones (grains of sand, for example), to large parts that shoot across the room, depending on the tool and the amount of force used. You have to protect yourself. Choose your workspace wisely.

A sturdy tabletop as a base is good. If the table (in a workshop, for example) is allowed to get scratches and scuffs, everything is fine. Otherwise, you should provide an appropriate cover.

Ideally, you should cover all surfaces under and around the table with a dust-proof fleece. The fleece can be easily collected after work and emptied into the trash can – otherwise you should proceed thoroughly with the vacuum cleaner. And thorough in this case means that you also vacuum under furniture, in shelves and behind objects, because plastic pieces and dust spread generously.

All this is especially true for large objects. For very small parts, very little dust is produced during sanding. However, even here the clipped off supports can quickly fly into the eye!

Once the preparations in the room are complete, get ready. This protective equipment is useful:

Gloves, Goggles, Mask

You should wear gloves during post-processing if you have sensitive skin. This will prevent fine plastic splinters from getting caught in your skin and injuring you on sharp edges. You don't have to wear thick construction gloves with leather, simple disposable gloves will do. If necessary, put two or three layers on top of each other.

Since the support parts that break off can sometimes fly away at high speed during postprocessing, you should wear protective goggles*. This may sound silly at first, but when the first plastic needle shoots towards your nose, you will probably see things differently. A simple pair of safety goggles from the hardware store will suffice.

At the latest, it gets dusty when you work with sandpaper. You don't want to breathe in plastic dust (microplastics), because this stuff has no place in the lungs. Protect yourself with a mask. Simple medical masks are sufficient, even a cloth mask does a lot. FFP2 and FFP3 masks are ideal, of course.

Just like in a workshop, you should wear old clothes that are allowed to get dirty. Long-sleeved shirts made of a not-so-thin fabric and jeans make sense. These clothes protect your arms and legs from sharp-edged plastic parts. Alternatively, a work coat made of a sturdy fabric is suitable. Of course, it does not have to be the stonemason's apron made of cowhide.

Tweezers, Side Cutters, Pliers

You have two options for removing the support structures: either you loosen them carefully at the hopefully existing predetermined breaking points, or you cut. The first option is the one we are dealing with here. Various tools are suitable for this purpose.

With the tweezers* you can grab fine and very fine structures very close to the predetermined breaking point. With a little wiggling and careful bending, the support structures usually come loose quickly. It is important that you hold on to all connected parts. Otherwise, filigree structures of the printed part in particular will also loosen.

If the support structures are not quite so finely built, the side cutter will do. These tiny pliers with a sharpened center section can be used to break structures, but can also be used for cutting if necessary.

However, you should only use the side cutter when removing support structures on the outside and in easily accessible places. You can't reach the inside of the print model so well with the somewhat coarser, bulkier tool, so tweezers are more suitable.

Hold the very massive structures on the outside of the print model with the pliers close to the predetermined breaking point and wiggle them carefully. This will loosen the support structures. But there is another possibility: You can crush the structures.

Cleverly, you set a low fill in the slicer for the support structures. This makes even solid-looking supports relatively hollow. If you now use tweezers, side cutters or pliers and briefly press down hard, the material will crumble. But you should only do this if you are wearing protective equipment! The parts that spray away can reach enormous speeds and are sharp-edged.

Scalpel, Utility Knife, Nail Scissors

Not all support structures are easy to break off. Sometimes the predetermined breaking point has not turned out as it should, sometimes none has been created – for whatever reason. Then the support material must be cut away.

The simplest tool available in every household would then be the nail scissors. This is durable enough for finer and medium structures, and the design fits into small openings.

The utility knife should be used only in exceptional cases. This has several reasons:

• Although the knife is sharp, it is also rather massive and, if it slips, causes considerable damage to the model.
• Utility knives have a blade that consists of individual segments. These segments are broken off when the knife has become blunt. However, the predetermined breaking points between the segments also break when cutting with a little more force on the component.
• The blade protrudes only a short distance from the guide of the utility knife, otherwise the knife would be too unstable. But the guide is again very clunky, so you can't reach places inside the printed part.

The utility knife is therefore suitable for rough work, but not for finer work and inside the model. You should rather use a scalpel.

The scalpel should have a replaceable blade, because the plastics used in 3D printing are sometimes quite hard. In addition, the blade should be so tight that it cannot come loose under any circumstances. You will not always use the scalpel for cutting, but also as a lever from time to time – the blade must not fly around your ears.

Good knives from the craft sector have a small, very bright lamp at the front. These somewhat higher-priced scalpels are always practical when you want to remove support structures inside the model or between filigree components. Such an investment is therefore worthwhile.

Sandpaper and Polishing Felt

No matter whether you break, crumble or cut the support structures: Where they were located remains visible on the surface. You can only achieve a smooth surface by sanding it down.

Sandpaper is very suitable for this purpose. You should avoid very coarse grit sizes. Coarse sandpaper leaves grooves in the plastic that are deeper and wider than the marks left by the removal of the support structures. Two to three different grit sizes have proven effective, so you work step by step, first with coarser, then with increasingly finer sandpaper.

Coarse work can be done with a grit between 80 and 140. For the fine work, however, you need a much finer version (400 or even finer). The coarser you start, the more sensible an intermediate step is, i.e. three different papers.

For larger areas that are not too temperature-sensitive, you can also use a small electric hand sander. Tip for those who like well-groomed nails: With an extra set of the various grinding tools, a small manicure or pedicure device is also suitable for this. Because at the end of the day, this is also just a small power tool for grinding, milling and polishing.

However, you can only achieve the absolutely velvety, soft surface by polishing with a special felt. You may also know this from stone working or from finger and toe nails: The electric tools can be fitted with a small cone of very dense felt and generate extremely smooth surfaces.

Please apply only after you have removed the dust from the print model. If the debris remains on the surface, larger crumbs of plastic may also get caught in the felt and scratch the surface. You can either blow the dust away with a small hand fan, or wipe the model with a very soft, lint-free cloth.

Finishing with Paints and Varnishes

The model comes out of the printer with a rather irregular surface. Even if you print finely and do not have to remove any support structures, you will still see the individual print layers. This may still be the case after grinding and polishing.

If you draw a thin layer of acrylic paint over your print model, the paint will smooth out small irregularities. This is because acrylic paint smoothes itself out. This also works with varnishes. You can also work on larger gaps in the surface with a fine filler.

The putty remains visible. This method is therefore only suitable if you subsequently paint or varnish the print. In most cases, this form of finishing is not necessary or is simply too time-consuming.

Alternatively, spray filler* can be used: The material from the spray can is applied in several thin layers on top of each other. Four to five passes with breaks of at least 30 minutes to dry the individual layers are necessary.

What works quite well with ABS*, on the other hand, is vapor smoothing with acetone. Acetone dissolves the material. If you steam your ABS print model only very briefly with acetone, the solvent will dissolve the outer layers and cause the layers to fuse together. The unsightly scratches in the areas where the support structures were located will also disappear. However, this is not suitable for PLA*.

Acetone vapors are very harmful to health. You should therefore always work in a well-ventilated room. Ideally, you should build your own vaporization station from a transparent plastic box. Instructions can be found on the Internet. Acetone is not an option if children or pets could come into contact with it! The chemical is simply harmful to health and should be handled with the necessary caution.

Important: Before you apply ink of any kind to your print model or work with a spatula or spray filler, your print model must be free of dust and grease. You must therefore first clean it thoroughly. It doesn't matter whether you then work with paint from a spray can, an airbrush system or acrylic paint and brush.

You can achieve the highest level of surface refinement with effect varnish: stone-look, wood-look and the like naturally cover up minor damage caused when removing support structures.

Minimize Support Structures

Support structures are necessary because your 3D printer cannot print into the air. Everything has to rest somewhere, otherwise the print is extremely error-prone. Nevertheless, you should minimize support structures.

Because even removing the structures can lead to the destruction of your printed part. In other words, the model will not only be more beautiful and better if you cut it. In the following section, you will learn how to minimize the use of supporting elements. The tips are general, so you can use them in any slicer and for any 3D printer.

Place object on the most favorable side

You can rotate and flip your part in the slicer until the side with the largest bearing surface is down. Or you can turn and turn until you can run the print process with as few supporting structures as possible. This is best explained with an example:

We start from a house that is roughly cube-shaped. On top sits a mono-pitch roof (sloping flat roof). On the highest side of the house there is a free-floating balcony, which is accessible from the upper floor. There are only lower and upper floors. The balcony is accessible through a door, next to it the wall is broken by windows.

On each side of the house are windows, doors are under the balcony and on the opposite side. The print model is hollow, each floor consists of one large room. Nevertheless, the false ceiling is shown. As I said – a very simple construction.

If the house is printed upright, support structures will have to be created between the roof and the false ceiling and between the false ceiling and the floor. Further support structures will be necessary under the balcony.

If, on the contrary, the house is placed on the side, it looks different: If the house is located on one side without a balcony, the railing-free balcony can simply be built upwards as a wall. After all, the side of the balcony, which consists only of a slab, rests on the building slab. Only inside the house support structures must be built from one outer wall to the other.

If the house is on the side opposite the balcony, it looks different again. Also in this case, the balcony can be printed freely. Inside the house will be necessary support structures. But the roof, which slopes upwards, must also be supported during printing, depending on the slope. So this position is also not optimal.

With one exception: the patterns on the roof surface created when removing the support structures can be used artistically and understood as filigree drawings of roof tiles or shingles!

This was an extremely simple example to show you how you can play with the position of your model. By the way, if you give the house in the example a base plate, you increase the stability of the model – and save another support structure, almost printing the building lying on its side.

By the way, for some parts, this can mean that you put them on the diagonal and support them almost everywhere from below, but you don't need any structures on the inside. Outside support structures are usually easier to remove.

Settings for Support Structures

The default settings in the slicer are usually not optimal. Check the settings and change them until you are satisfied with the result. You should pay attention to these settings:

• Wall thicknesses: The wall thicknesses of your print model should be more solid than the walls of the support structures.
• If possible, set predetermined breaking points.
• Infill: The less dense the infill the support structures are, the easier you can remove them. Conversely, infills of the desired components should be more massive so that they do not accidentally break away when the support structures are removed.
• Support only on the build plate: With some models (also depending on the slicer) you can set that support structures are only created between build plate and model, but not within the model.
• Overhang threshold: The value is interesting if you have support structures created automatically and do not insert them manually one by one. Then the value indicates from which overhang (angle, 90 degrees is vertical) the slicer automatically inserts support structures. By changing the value you can minimize supports: The lower the value, the less support.
• Patterns: The simpler the patterns of the infill, the easier they are to remove. For example, Prusa slicer: straight patterns are standard and easy to remove. Rectangular grids are more stable and support better, but are also more difficult to remove. The honeycomb is really robust and difficult to remove.

Shopping List for Removing Supports

• Respiratory protection*
• Disposable gloves*
• Safety goggles*
• Nail scissors*
• Tweezers*
• Scalpels*
• Utility knife*
• Side cutter*
• Pliers*
• Sandpaper*

Conclusion

Removing the support structures is the first step in post-processing the print model. Since this often results in irregular surfaces and minor damage to the print model, the removal of support structures seamlessly transitions into surface smoothing.

However, with a few tools, which are available in most households anyway, the individual steps should be fairly easy to master.

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Disclosure: This website is the property of Martin Lütkemeyer and is operated by Martin Lütkemeyer. Martin Lütkemeyer is a member of the Amazon Services LLC and other Affiliate Programs. These are affiliate advertising programs designed to enable websites to earn advertising revenue through advertising and linking to Amazon.com and others. Links marked with * are affiliate links.

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Source: https://the3dprinterbee.com/how-to-remove-3d-print-support-structures-smooth-easy/

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