This article explores 3D printer resolution, covering factors affecting it, model design considerations, their relationship, quality improvement, and differences in design at different resolutions, providing a comprehensive understanding of 3D printing.
Factors affecting 3D printer resolution
3D printing resolution is commonly referred to as layer height, which is the size of each layer applied to a 3D printed model. There are various factors that can affect the resolution of a 3D printer.
The impact of printing materials
During the FDM printing process, printing materials usually use wires with a diameter of 1.75mm or 3mm. The printing resolution depends on the diameter of the wire, and materials with a constant diameter will produce accurate printing resolution or layer height. Different materials have different effects on resolution. For example, some materials may extrude more evenly and smoothly, and can construct finer layers, while some materials may limit printing resolution due to their own characteristics such as hardness, flexibility, and fluidity. For example, materials with good flexibility but excessive fluidity may cause inaccurate interlayer fusion during the printing process, affecting the final resolution details. This requires users to choose the appropriate printing material according to the required resolution. If high resolution is pursued, then wires with stable diameter and material characteristics conducive to fine printing should be selected.
The role of nozzle diameter
Nozzle diameter is also a mechanical factor that affects printing resolution. In different printing applications, there are various types of nozzle diameters, usually ranging from 0.1mm to 1mm. Smaller nozzle diameters can make the extrusion of materials more delicate, and can construct smaller features and thinner layers, thus achieving higher resolution. However, small nozzle diameters may limit the flow rate of materials. If the speed is not properly controlled, it can easily lead to problems such as clogging and affect printing. On the contrary, large-diameter nozzles can accelerate printing, but the printed layer thickness is larger, and the details are relatively low-resolution, such as some large-size and rapid prototyping that do not require high shape and size accuracy can use large-diameter nozzles to improve printing efficiency, but will sacrifice some resolution.
The impact of a 3D printer’s own performance
The steps on the z-axis of a 3D printer can achieve printing resolution or layer height, which means that the steps that the printer can move up or down will affect the printing resolution. Compared to commercial printers, industrial-grade FDM 3D printers can easily 3D print parts with very fine layer height. For example, high-end industrial printers may achieve smaller movement units in the z-axis direction, thereby constructing a thin layer height, and their overall mechanical structure, transmission system, and control algorithms are more precise and efficient. However, ordinary commercial printers may have certain limitations in these areas and cannot achieve too small layer height, which limits the improvement of resolution. In addition, some characteristics of the light-cured 3D printing machine itself, such as resolution (such as the difference between 2k or 4k machines), also directly affect the printing resolution. The higher the precision of the screen image, the higher the resolution. Moreover, the movement of the z-axis is driven by the wire rod and guide rail. If there is a problem with this part or the quality is not high, it may affect the accuracy of the z-axis movement, ultimately affecting the layering and model accuracy.
The correlation between printing speed and temperature
Printing speed and printing temperature also affect resolution. Generally speaking, if the printing speed is too fast, the material may not be deposited in a timely and uniform manner, resulting in deviations in the shape and thickness of each layer, which in turn affects resolution. Moreover, different materials have different requirements for printing temperature. If the temperature is not controlled properly, the state of the material will be unstable. For example, in FDM printing, if the temperature is too low, the material will be difficult to extrude, which may cause discontinuity between layers or uneven layer thickness. If the temperature is too high, the material may melt excessively and drip, which will damage the accuracy and shape of the layer, all of which will cause a decrease in printing resolution. This requires setting appropriate printing speed and temperature according to the requirements of different materials and printing resolutions.
Key points of model design in 3D printing
When designing a 3D printed model, there are many important aspects to consider.
Overhang treatment
All 3D printing processes build the prototype layer by layer. Materials cannot be deposited in thin air, so the overhanging areas in the model that are supported by the underlying layers or not supported at all need to be treated with caution. Different 3D printing technologies have limitations on the angle that can produce and maintain good results without supporting materials. For example, for FDM and SLA, the angle is about 45 °. This requires limiting the overhanging parts as much as possible in model design. If the overhanging angle cannot be avoided greater than this limiting angle, support structures or model optimization adjustments should be considered to minimize or design at a smaller angle, which helps to avoid failures or quality defects in the printing process.
Wall thickness setting
When designing 3D printed parts, wall thickness is an important consideration. If the wall thickness of the model is too thin, some small parts of the model may not be printed smoothly or the printed product may be too fragile and easily damaged. On the contrary, if the wall thickness is too thick, occasional cracking or damage may occur due to excessive internal structural pressure. This requires a reasonable wall thickness setting in the design, which is also related to the expected printing materials and printing technology. For example, the internal pressure that some special materials can withstand and the structural strength that can be maintained will affect the reasonable range of wall thickness. Moreover, different 3D printing processes can achieve or support different wall thickness requirements. Generally, when designing, it is necessary to refer to the characteristics of the selected printing process and material, and design a wall thickness greater than 0.8mm for the model as much as possible to ensure the feasibility of printing and the quality of the finished product.
Warpage prevention
Due to the physical changes that occur in the materials used for 3D printing (such as melting, sintering, or scanning and solidifying with a laser), the heating and cooling of the materials can cause parts to deform during printing, especially large and flat surfaces that are particularly prone to warping. Warping can be avoided by using correct machine calibration to increase surface adhesion between the parts and the printing bed, avoiding the use of large planes, and adding rounded corners to the 3D model. For example, in the design of some flat parts, using a certain curved surface or structure to disperse stress and replace large planes can effectively reduce the occurrence of warping problems, ensuring the accuracy and quality of printed products.
Detail level adaptation
When creating a 3D model with complex details, it is necessary to remember the accuracy that each 3D printing process can print. Different 3D printing processes and materials will affect printing speed and cost. Determining the minimum printing accuracy is a crucial decision for the model. When designing, consider whether the final printing process and materials can meet the detailed requirements of the model. For example, some printing technologies may only achieve a minimum detail size of 0.2mm. If the designed model has details smaller than this size requirement, these details will be lost or the printing will fail.
Model geometry requirements
The model also needs to meet the standards of 3D printing in terms of geometric requirements. Firstly, the model must maintain a tight state (watertightness). If there are loopholes in the model, the printer cannot recognize the boundary and cannot print. Some software can be used to detect this problem, such as 3dsMax’s STL detection function. Secondly, the model must be a manifold, that is, one edge on the mesh cannot represent more than two faces at the same time, otherwise there will be printing problems, and non-manifold areas need to be adjusted through software tools. Furthermore, all surface normals of the model should point in the correct direction, so that the printer can distinguish the internal and external structures of the mesh and model. Otherwise, it is impossible to determine whether it is the internal or external of the model, and printing errors may occur. In addition, aspects such as the maximum size of the model (because the printer has a size limit, if it is too large, it may need to be split and printed or cannot be printed), the minimum thickness (involving the minimum wall thickness that the printer can print, if it is too thin, it will fail to print), and the correct clearance setting are all aspects that need to be considered in terms of geometric requirements. Finally, excess geometric shapes (such as some reference points, lines or surfaces during modeling, hidden geometric shapes) need to be deleted, and duplicate surfaces also need to be cleaned up.
Relationship between resolution and model design in 3D printing
Constraints of resolution on model design
Printing resolution sets the limit for the implementation of details in model design. If the resolution is low (such as a large layer height), it may not accurately present the refined appearance required for the design when printing models with small details. For example, if you want to print a model with many small textures or fine structures, these details may be lost or distorted at low resolution. For example, when making small statues, if low resolution printing is used, the facial features of the characters, such as fine expressions and hair strands, cannot be well constructed. At this time, it is required to avoid designing overly fine and small details in model design, so as not to be reflected or greatly discounted in printing. If it is a high-resolution (small layer height) printing situation, you can moderately increase the details of the model design, but also pay attention not to exceed the limitations of the printer resolution that can be fully and accurately expressed, otherwise it may cause problems in the printing process, such as files that are too large (due to saving too fine details) that the 3D printer cannot handle, or printing that takes too long or even fails due to too complex details. In addition, the resolution-related parameters of different 3D printing technologies (such as pixel accuracy in light curing) will limit the size relationship in the model design (such as the length-width pixel ratio relationship related to the molding area). If this relationship is not considered in the design, it may cause distortion and distortion of the model during printing.
Model design adapts to different resolution requirements
When printing at different resolutions, the model design needs to be adjusted accordingly. For low-resolution printing (such as in rapid prototyping), the design details of the model can be simplified, focusing on the overall structure and approximate shape. For example, some complex curves can be approximated with simple polylines to reduce small features or decorations. This can not only meet the needs of fast printing, but also avoid the low quality of the model caused by excessive pursuit of details in low-resolution printing. For high-resolution functional or display model printing (such as small statues or high-end product appearance models), it is necessary to emphasize the quality and fineness of the model. More detailed elements can be added in the design, such as adding fine textures, more complex shapes, and fine edges. In terms of overall structure and wall thickness, changes should also be made based on the accuracy and strength requirements corresponding to different resolutions. For example, if the material allows for high-resolution printing, the wall thickness can be appropriately reduced to make the model more delicate and lightweight, but low-resolution printing needs to maintain a relatively thick wall thickness to ensure basic strength.
Notes on Improving the Quality of 3D Printing Models
Printer and material related
Printer accuracy detection
When purchasing a 3D printer, it is necessary to first understand the printing accuracy of the machine. The manufacturing and assembly accuracy of the 3D printer, as well as the vibration during operation, will affect the 3D printing accuracy, which depends on whether the walking parts in the mechanical part are accurate and reasonable. Before printing, the printer should be fully tested and calibrated to ensure smooth and stable movement of each axis, and to avoid deviations and defects in the printed model caused by mechanical problems of the printer itself. At the same time, pay attention to the resolution-related indicators of the printer, such as understanding its unique resolution parameters and the maximum accuracy that can be achieved according to different 3D printing technologies, so that you can have a clear expectation of the printing results and better adapt to the performance of the printer when designing the model. If the printer resolution is limited, avoid designing overly detailed and complex models.
Reasonable selection of printing materials
3D printers use different types of materials or the same material with different qualities, resulting in significant differences in the glossiness, strength, accuracy, and other aspects of the final model. The performance of each type of printing consumable is different, some are fragile and some are strong, some are soft and some are hard, some are smooth and some are rough, some have high density and some have low density. The most suitable material should be selected based on the actual printing needs (such as whether it is a functional model, display model, requirements for strength, smoothness, etc.), the design characteristics of the model (such as structural shape, thickness, etc.), and the performance of the printer. If you have high requirements for resolution and model fineness, choose materials that are more conducive to fine performance in terms of material characteristics and are compatible with the printer. For example, in FDM printing, some brands and specifications of materials perform better in terms of diameter stability, which helps to improve printing resolution. Also, pay attention to the quality of the material. Poor quality materials may contain impurities that affect the uniformity of the material, thereby affecting the quality and accuracy of printing during extrusion or curing.
Printing Parameters Related to Tips
Control layer thickness (layer height)
The layer thickness here refers to the layer thickness/layer height when slicing. If the layer height is too large, obvious step patterns will be produced on the solid surface after molding and dimensional errors will be caused. The smaller the layer thickness, the higher the surface smoothness of the model after molding. However, a smaller layer height also means an increase in printing time, so it is important to balance and choose the appropriate layer height according to the required resolution and actual printing needs. For example, for some display art models, a smaller layer height can be used to obtain higher surface quality, while for rapid testing prototype models, the layer height can be appropriately increased to reduce printing time. At the same time, it should be noted that the optimal layer thickness adaptation range between different printers and materials is also different. In actual operation, the appropriate layer thickness setting can be determined through multiple tests.
Optimize nozzle temperature and diameter
The nozzle temperature determines the bonding performance, stacking performance, wire flow, and extrusion line width of the material. Therefore, the nozzle temperature should not be too low or too high. It should be selected within a certain range according to the characteristics of the selected metal wire to ensure that the extruded metal wire is in a molten flow state. If the temperature is too low, it may cause uneven material extrusion, droplet production, and other problems that affect printing quality; if the temperature is too high, the material may melt excessively, resulting in uneven surface of the model. The diameter of the nozzle also affects the accuracy of the finished product. For large-diameter nozzles, the layer thickness is thicker. Although 3D printing is faster, the finished product will be rougher. For small-diameter nozzles, although the 3D printing process time is increased, the finished product is more delicate. Choose the appropriate nozzle diameter according to the requirements for resolution and speed, and ensure that the nozzle temperature remains stable and within the appropriate range during the printing process.
Scientific removal of supporting structures (if any)
During the 3D printing process, if there is a support structure, it may leave marks or damage the model during the removal process after printing. Try to reduce the use of support structures during the model design stage by optimizing the layout and design angle of the model (such as avoiding large overhang angles). If support structures must be used, choose appropriate support structure parameters (such as support density, shape, etc.), and consider facilitating subsequent removal and minimizing the impact on the surface quality of the model in the design of the support structure. Scientific methods should also be used when removing support structures, such as using special tools and appropriate forces, to avoid unnecessary damage to the model.
Model design related
Avoid overly detailed design (relative to printer resolution)
When designing the model, the resolution of the printer should be fully considered. If the printer has a low resolution but designs a large number of subtle features, ultra-thin wall thickness, or ultra-high precision shapes, these parts will be difficult to achieve during the printing process. Therefore, in order to keep the detailed design of the model within the range that the printer can accurately print, printing quality can be ensured by simplifying the details of the model, appropriately increasing the wall thickness of key parts, or increasing the feature size. For example, for some rapid production and low-resolution prototype models, larger rounded corner designs can be used at some complex corners of the parts to replace the original sharp corners to adapt to the accuracy of the printer, and also to facilitate the accumulation and fusion of materials during printing.
Optimize the geometry and layout of the model
Optimize the model from the geometric shape, minimize the narrow and long shape parts (because the material bonding stability of the narrow and long parts is poor during printing, which is prone to problems), add some reinforced structures or change the shape to a form that is easier to print and ensures strength, such as changing the sheet shape to a columnar shape. In terms of layout, key details can be placed in areas that are not easily deformed or have high printing accuracy. If there are multiple parts in the model, the stability and accuracy of each part during printing can be guaranteed through reasonable layout, such as avoiding large mutual interference between parts (such as excessive interweaving between support structures and other parts).
Differences in 3D printing model design at different resolutions
Model design under low resolution printing
Structural simplification becomes mainstream
Under low-resolution printing, it is difficult to achieve complex detail presentation due to resolution limitations (such as large layer thickness). Therefore, in structural design, it is necessary to tend to simplify and minimize unimportant small structures or decorative components. For example, when printing a rapid prototype of a building model, if most of the focus is on testing the overall building layout and main structural proportions, the model’s panes may not need to be refined one by one, and can be represented or omitted by simple blocks. Some details such as railing decorations do not need to be finely modeled. For the complex curve part of the model, it can also be appropriately simplified, such as using polylines instead of curves, which can meet the needs of fast printing without causing serious distortion or printing failure due to low resolution.
Enhance overall shape and structural stability
In order to make up for the shortcomings in detail presentation and avoid structural defects that may be caused by low resolution, it is necessary to focus on strengthening the integrity of the overall shape and the stability of the structure. Some auxiliary support structures can be added during the design (here, the support structure does not refer to the additional support materials added in 3D printing, but is part of the structural design of the model) to enhance the overall strength. For example, thickening the thin-walled structure or increasing the area of some key connecting parts can ensure that the model has sufficient structural strength to resist possible deformation or damage after printing. For example, if a large-sized low-resolution bridge model is printed, if the pier is slightly thickened or the connection structure between the bridge deck and the pier is thickened, it can ensure that the model can maintain basic shape stability after printing.
High resolution print down model design
Highlight refined detail design
In high-resolution printing (such as small layer height, high pixel accuracy, etc.), more refined details can be designed. The texture of the model can be more detailed, such as adding realistic skin texture to the character model, rich patterns on clothing, and other descriptions. The edges can also be designed to be sharper and finer, such as designing the contour edges of the model into very thin curves or straight thin lines (if the printer resolution can support it), and adding more complexity to the geometric shape, such as manufacturing some small and exquisite interlaced structures or nested structures, which can be clearly and accurately presented under high-resolution printing, so that the model can achieve higher Quality Standards in appearance and function (if it is such a fine structure with functional requirements).
Optimize part clearance and connection accuracy
Due to high resolution, smaller size construction can be achieved to a certain extent. Therefore, when multiple parts are composed or joints need to be connected, the clearance accuracy and connection accuracy between parts can be improved. For example, when designing a model that requires movable joints, the clearance at the joint can be designed more reasonably and precisely (if the actual demand is so), which can make joint movement smoother and more realistic. When designing parts for an assembled model, the matching accuracy between parts can be improved (such as designing more fitting connection structures such as buckles and mortise and tenon joints), making the model more closely and accurately combined after printing.
