This article explores the relationship between 3D printer resolution and post-processing, including requirements, techniques, and synergy, guiding users to optimize post-processing based on print resolution.
3D printer resolution requirements for post-processing process
Low correction requirements for post-processing of high-precision printed parts
When the resolution of the 3D printer is high, the printed parts themselves already have good surface quality, accurate dimensions, and rich details. For such parts, the requirements for post-processing technology mainly focus on slight surface optimization. For example, in the painting process, if the high printing resolution makes the surface of the part smooth and flat, there is no need for a lot of polishing before painting to make up for surface defects. Only simple surface cleaning is needed to start the painting operation. When screen printing text or patterns on the surface of high-precision models, due to the high surface accuracy of printing, the screen printing process is easier to ensure the clarity and accuracy of the pattern or text, and will not cause problems such as uneven ink retention or pattern deformation due to uneven surface. Overall, post-processing of high-precision printed parts focuses on improving aesthetics, performing functional surface treatments (such as insulating plating on high-resolution metal models), or adding subtle decorations, while there is relatively little work on correcting the accuracy or surface quality of parts.
High correction requirements for post-processing of low-precision printed parts
Parts printed by low-resolution 3D printers may have many problems, such as rough surface (obvious layer patterns, uneven patterns, etc.), low dimensional accuracy (large errors), and missing details (difficult to reflect fine structures). These problems make the post-processing process face greater correction pressure.
(1) Increase the amount of polishing
For low-precision printed parts based on FDM, it may be necessary to use polishing to eliminate rough surfaces. Due to the layer thickness generated by layer accumulation during low-precision printing, deep polishing may be required. Starting with lower-grain sandpaper, the polishing time is correspondingly longer, which requires higher patience and operational accuracy in the polishing process to avoid excessive polishing affecting the final size of the part. At the same time, attention should also be paid to the protection of some fine structural parts with complex shapes that are easily damaged during polishing.
(2) Increase soil filling and repair operations
Low-precision printed parts may have material deficiencies or unevenness in some corners, connections, or small structures. In order to achieve better appearance and dimensional accuracy of the parts, it may be necessary to perform soil filling operations to fill in grooves or missing parts. The selection of soil filling materials, coating thickness, and drying time control all depend on the specific shape and requirements of the parts. For example, when repairing the missing parts of small decorations in low-precision printed figurines (such as accessories that do not fall off), suitable soil filling materials (such as AB soil) can be used to fill in the missing parts first, dry them, and then polish and spray paint them.
(3) Post-processing measures to improve dimensional accuracy
If the dimensional accuracy of low-precision printed parts is poor enough to affect assembly or overall function, some special post-processing measures are needed for correction. For example, for some high-precision mating parts, it may be necessary to reprocess the key surface through mechanical processing (such as milling or turning) after low-precision printing to achieve normal dimensional tolerance range. Another situation is that if the printed part is too large or too small due to low resolution, special treatment methods such as heating or humidification can be used for adjustable or elastic parts (such as plastic connecting parts) to cause the material to deform to achieve the appropriate size.
Post-processing techniques for 3D printing at different resolutions
Post-processing skills for high-resolution printouts
(1) Mild post-processing
For high-resolution prints, there is usually no need for particularly aggressive post-processing methods. If sanding is needed before painting, use high-mesh sandpaper to gently wipe to increase the adhesion of the paint surface. For example, in the processing of high-quality artwork or high-precision mechanical prototypes for fine printing, using sandpaper with a mesh of more than 800 to gently grind the surface to remove surface grease or slight unevenness can meet the painting requirements. Avoid using strong chemical reagents or excessive sanding to avoid damaging the well-formed surface.
(2) Pay attention to maintaining and modifying details
Due to the rich detailed structure of high-resolution printed parts, post-processing should pay more attention to maintaining these details and making appropriate modifications. When fine-grained coloring or adding special texture effects, more delicate tools and techniques should be used. For example, when coloring high-resolution 3D portraits with skin texture depiction, special micro-painting pens and thin-coat coloring methods should be used to ensure that the original fine structure is not destroyed while adding details. In addition, gentle methods such as using soft brushes or low-pressure rinsing should also be used when surface cleaning to avoid damage to small structures or washing materials.
Post-processing skills for medium resolution printouts
(1) Mainly to improve appearance
Medium-resolution printouts usually have a certain surface quality and level of detail, but are not yet perfect. In this case, post-processing techniques mainly focus on improving the appearance aesthetics. When polishing, use 400-800 mesh sandpaper to moderately polish the surface, which can effectively remove layer patterns and reduce surface roughness to an acceptable level. If there is a demand for color, some conventional painting methods can be chosen, such as using matte paint or high-gloss paint to color evenly. Pay attention to the uniformity of layering during the coloring process to prevent uneven color or flow marks.
(2) Moderately strengthen the accuracy of structure and size
Although the dimensional accuracy of medium-resolution printouts is better than that of low-resolution ones, certain processing is still needed in some situations where high structural and dimensional requirements are required. If there is a problem with dimensional tolerance, simple machining methods such as milling and drilling can be used, but the processing range should be strictly controlled to ensure the stability of the overall structure. At the same time, if the shape of the printout is slightly irregular or some parts of the structure are not strong enough (such as the cantilever being too long), external reinforcement components can be added (such as adding small support structures and fixing them with glue or welding) or local reinforcement treatment can be carried out (such as surface coating reinforcement materials).
Post-processing skills for low-resolution printouts
(1) A large number of surface repairs
The surface of low-resolution printed parts is often rough and uneven, with obvious layering and irregular shapes. First, a large amount of surface polishing should be carried out, starting from sandpaper with low mesh size (such as 150 mesh) and gradually increasing to higher mesh size (such as 400 mesh) to remove most of the obvious layering, protrusions, and unevenness. During the polishing process, attention should be paid to maintaining the approximate shape of the part to avoid excessive polishing causing damage to the original shape of the part. If there are large defects on the surface (such as potholes or voids), soil (such as common AB soil or other fast-drying filling materials) should be used for repair and polishing.
(2) Emphasis on dimensional accuracy
Low-resolution printed parts often have large dimensional errors. If it involves coordination with other high-precision components or has strict requirements for dimensional accuracy due to its own functions, it is important to focus on dimensional accuracy. For example, for parts that are too large in size, mechanical processing can be used to remove excess material (such as turning some columnar structures); for parts that are too small in size, plastic inserts may be adjusted by appropriate stretching after heating. Also, careful inspection and processing should be carried out for parts with assembly problems (such as for parts with internal perforated structures, if the aperture is too small, re-expand the hole or use tapping treatment, etc.). In addition, if the low-resolution print is based on the prototype and requires rapid secondary molding, some simple and quick post-processing methods can be used to ensure basic dimensional accuracy, such as covering the appearance with rubber paint to hide the surface unevenness and enhance the hand feel, and obtain the initial molding sample of the product as soon as possible for subsequent modifications and improvements.
Synergy between 3D printer resolution and post-processing
The resolution lays the foundation for the post-treatment process
(1) Precision level preparation
The resolution of a 3D printer directly determines the original accuracy of the printed parts. High resolution enables the initial shape, size, and surface details of the parts to reach a high level of accuracy. This creates a good starting point for post-processing technology, which can be better modified and improved on this basis. For example, high-resolution printed parts do not require a lot of deep polishing and compensation work during surface treatment (when the accuracy requirement is not extremely high), because their surface is relatively flat and smooth. Post-processing is more about further polishing and refining the surface texture to improve the surface finish.
(2) The influence of surface condition on the difficulty of post-processing
The resolution of the printer also affects the surface state of the printed part, which has a significant impact on the difficulty of the post-processing process. High-resolution printed parts have delicate surface texture, thin layer texture, and high dimensional accuracy. This means that in post-processing steps, such as cleaning parts, there is no need to use strong cleaning methods to achieve better cleaning results, because the surface is not easy to retain too much printing material. During texture processing and coloring, pigments are more likely to adhere to smooth surfaces and can prevent problems such as unevenness, color accumulation, or texture distortion. On the contrary, low-resolution printouts have many problems such as rough surfaces and large accuracy errors that cause screen printing errors due to surface conditions, and poor results when producing high-precision spray paint effects (such as simulating metal texture multi-layer gradual change color spray paint).
Supplementary improvement of resolution by post-processing
(1) Improve appearance quality
Even if the resolution of the printer is limited, post-processing technology can still supplement and improve the appearance of the printed part. For example, through sandblasting or fine polishing and polishing, the surface of low-resolution printed parts can become smoother, visually compensating for the roughness caused by low resolution to a certain extent; through high-quality painting, electroplating or coloring processes, the single color of low-resolution printed parts can be changed into a colorful and textured appearance, distracting attention from insufficient resolution, and improving the quality of the entire printed part through color and excellent appearance processing.
(2) Improve functional performance
For some functional 3D printed parts, post-processing technology can supplement the shortcomings caused by low resolution in improving their functional performance. For example, annealing the structural components printed with low resolution can improve their mechanical properties, including strength, hardness, etc., so that although the resolution is low, it can still meet the actual functional requirements. Similarly, for pipeline components printed with low resolution and rough surface affecting sealing performance, special sealing coating treatment post-processing technology can be used to meet the sealing requirements, thereby compensating for the defects caused by insufficient resolution in function.
