Overview of post-processing methods for FDM 3D printing models
Hello! With you, the Top 3D Shop and today we have an unusual overview, it is not about technology, but about post-processing of 3D printing models.
technology. FDM , since this is the most common and accessible technology, and the processing of such models is required most.
A few points that should be borne in mind before printing the product.
The first moment is the thickness of the layer. The thinner the layer, the higher the surface quality and the less post-processing required. Naturally, you will have to pay for high quality printing time.
If you need a glossy surface, there is no point in wasting time on printing with a minimum layer thickness - the model still needs to be polished and polished, or applied to the primer and paint.
Consider the future post-processing costs and when establishing the thickness of the wall.
Usually it is about 2 mm, and on details for subsequent grinding or chemical polishing it makes sense to increase the wall thickness to 3-4 mm, because these processes remove the material. With insufficient wall thickness, during post-processing it is easy to wipe or dissolve the surface to holes.
On FDM printers, we almost always print with support. Ideally, if the printer can print with two materials, make the support soluble.
Large parts of these supports are removed mechanically, the rest is dissolved, then the model is simply washed and one can proceed to the following operations.
If the printer prints with one material and the supports are printed from the model, pay special attention to them when creating the file for printing.
With the right settings and a simple form of support products are removed easily.
If the connection points of the supports occupy a significant area on the model, after their removal there will remain characteristic traces that require further processing.
Do not spare the time to configure the supports, you will save it during post-processing and the print will look neater. If the model is large, it is often worth cutting it into pieces in order to reduce the number of supports. Seams after gluing to process easier, than traces from set of supports on all area of a print.
Modern slicers support advanced support settings. When setting up, pay attention to their number and the contact spot between the support and the model, both of these values should be, if possible, as low as possible.
It is also important to have the location of the supports: do not leave the place of their contact with the model in hard-to-reach places, if this can be avoided. Remember that the model for printing can be rotated or divided into parts.
Let's talk a little about the wonders of modern chemistry. For post-processing, various solvents are used, depending on the model material and supports.
Use of dichloromethane and acetone also helps in gluing the parts, and in chemical polishing .
For bonding parts of large or complex models, you can use both household adhesives, creating on the surface of its own adhesive film, and solvents.
The second is preferable if the most durable connection is required.
The most common solvents used for processing and gluing plastics are dichloromethane and acetone.
Work with any glue, solvents and paintwork in well-ventilated areas, protective gloves and goggles. The inhalation of these substances and getting them on the skin or mucous benefits to your health will not bring.
Acetone is often used for the treatment of ABS plastic, because it softens and dissolves it more slowly than dichloromethane, which makes the treatment with it more accurate. It is used both for gluing and for surface treatment, with the application of a brush or a piece in " acetone bath ".
Dichloromethane is preferable for gluing, it acts faster. When bonding with a solvent, it is sufficient to cover the surfaces to be glued and press against each other with effort.
The resulting seam is removed during further processing, after sanding and priming it will not be visible.
To create soluble supports, when printing models from ABS , is often used. HIPS . This plastic is soluble limonene , which does not react with ABS, which makes this combination ideal.
Almost perfect. There are two disadvantages: the cost of limonene and its sharp smell of citrus, which someone might not like.
Grinding and polishing
The easiest way to process: take the sandpaper and erase the top layer of the model. With a certain skill, you can achieve a very flat surface.
Overdoing, you can wipe a hole in the product if the wall thickness is too small. This method of treatment is more suitable for ABS than, for example, for PLA, as the PLA begins to soften already at 60 ° C. Accordingly, if you also PLA, do it slowly and carefully, so that the plastic does not roll under the sandpaper.
The process is rather dirty, it is better to do it in protective goggles and a mask, as there is a plastic suspension in the air, which is unpleasant and harmful to breathe.
To handle difficult places, you can use a drill with various nozzles.
Mechanical polishing, in general, is not very different from polishing, It is produced by the smallest nazhdachkoy and cloth with polishing paste.
If mechanical treatment is carried out after the chemical treatment, it must be waited before the solvent completely evaporates and the surface hardens.
Chemical polishing is performed by leveling the surface by dissolving the top layer. The solvent is applied by brush, aerosol or by placing the part in a closed boxing filled with solvent vapor.
Pre-paint primer is applied in those cases where the surface of the model is even, and the ground serves to fill the microscopic cavities and improve the adhesion of the paint to the surface of the object. Ground for this we use aerosol , it is inexpensive and convenient to handle. For larger volumes, it is better to use an airbrush.
Correcting primer more rough, it is designed to correct flaws in the model, errors in printing, smooth out irregularities or badly ground seams.
For it, you can use the usual latex filler and, again, the primer. The process is simple enough: we cover everything that we do not like, wait for drying, we carry out polishing and polishing.
If the result does not suit, we repeat.
We only go to this stage when the desired texture of the surface is fully achieved, there are no unplanned seams and flaws, which after painting will become even more noticeable.
Before painting, as well as before the pre-paint primer, make sure there is no dust and other foreign inclusions on the surface. Do not forget about the means of protection.
Carrying out these simple procedures will give printers a high quality surface that will delight you and your customers.
Materials and reagents for post-processing, buy in the Top 3D Shop - we will select the necessary set for any technical process, we will promptly execute it and deliver it.
You can find out more about 3D printing on our master classes : each printer buyer receives the right to a free visit to the master class, for the rest it will cost 2000 rubles.
On September 2? the master class is free for all, within the framework of the exhibition-conference " Top 3D Expo. Digital Education 2018 ", The visit itself is also free, but it requires preliminary registration Online. The number of seats is limited, please make an appointment.
Until next time!
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