How to obtain high 3D printing resolution?

How to obtain high 3D printing resolution? makenica.com/how-to-obtain-high-3d-printing-resolution December 26, 2020

We have often come across the term resolution for images, which describes the detail of the image in image processing techniques. We also frequently use this term for differentiating TV screens and display quality, which is primarily based on their dimensions. Now, do we have a resolution for 3D prints?

This question has always been understated and sometimes been asked in terms of print quality, which is quite different from the term resolution. While 2D prints have resolution defined as the print quality or vibrance of the image or text printed, 3D printers also have their definition for resolution.

Several factors determine the resolution of 3D printed parts, each one exhibiting various characteristics on the finished 3D printed part. So, what exactly is 3D printer resolution if it is a combination of factors? What are the conditions that are to be followed to improve the resolution of the printed part?

What exactly is 3D printer resolution?

In 3D printers, we consider the motion of the nozzle in the 3 planar dimensions along the axes. The horizontal component consists of motion along the X and Y axes, considered as 2D motion, and the vertical resolution covering the Z-axis motion, which defines the 3D print quality.

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The XY resolution or the horizontal resolution determines how finite the nozzle can progress towards the planar axis in printing the finer parts of the 3D model. This, in turn, determines how detailed the printer can print the layers of the model provided to the system. The XY resolution criteria vary according to the printer technique deployed, which we shall discuss in detail.

The Z resolution or the vertical resolution determines the minimum thickness of the layer so that the printer can move in one print. Z resolution is heavily dependent on the printing process used, as the Z-axis motion isn’t the same for all printer types. Some of the other factors that determine Z-axis resolution include the diameter of the nozzle and the height of the layer.

Now that we know some basics on 3D printer resolutions and how they’re diversified, let us do a comparative study on how the above mentioned two resolution criteria differ based on the technique that is deployed.

SLA v FDM print resolution Fusion Deposition Modeling is a conventional 3D printing mechanism that deploys the usage of the nozzle for material distribution and motors for motion along the planes and axes. The basic principle behind FDM printers is that the material will be melted to a suitable temperature and will be allowed to continuously flow through a nozzle supported by motor action.

Here, the Z resolution of the print heavily depends on the diameter of the nozzle used to print the model. The lower the diameter of the nozzle used, the higher the precision and hence the higher the resolution, as the printer can print. The nozzle with less diameter can accurately print the sharp edges and finite parts of the print that requires high precision.

Another factor that affects the XY resolution of FDM printers is the step angle of servo motors that are deployed for the motion of the print head. The lower the step angle of the stepper motor used, the higher the precision, as the print head can duly print the accurate dimension as per the model. However, if the stepper angle reduces, the process timing will exponentially increase as greater precision print requires a great amount of time in FDM printing.

Unlike the FDM technique, the SLA 3D printing services doesn’t use molten resin and a nozzle to print a part. SLA printing technique uses a liquid resin, which is forced to undergo photopolymerization facilitated by the emission of UV laser beams of specified intensity.

One of the major factors that affect the resolution of SLA prints is the intensity of the laser beam and the optical spot size produced by the beam. The optical spot of the laser beam can be much smaller than the diameter of the nozzle, making precise prints. A high concentration of beam and low optical spot can do wonders in terms of resolution of SLA prints.

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This advantage of the SLA printing technique has resulted in finer XY print resolution than the FDM printing technique. Due to its ability to print models with much finer detailing, SLA printing is used for detailed designing and the printing of micro-sized parts. A major drawback in SLA printing is the affordability of the printer. However, several online-based one-stop 3D printing services can provide you SLA printing for affordable rates.

How to improve the resolution of my 3D printer?

Now that we have a brief idea of the 3D printer resolution, we move on to the next question of how to improve the print resolution of our printer. Well, we ain’t specialized experts to understand specifics and provide precision control, but some s be apprehended to obtain a top-notch print. Let’s explore those tips and tricks in detail.

Adjust the nozzle and the bed If you’re using an FDM printer, make sure you adjust the height of the nozzle and the printing bed, so that both remain leveled against each other. IN FDM printers, some come with a standard height that automatically calibrates itself , whereas the other requires manual setup.

You can use a feeler gauge or A4 paper for leveling purposes. Lower the nozzle and slide in a feeler gauge between the bed and the nozzle. Adjust the distance between them. Ensure that the paper slides easily between the gap. Repeat the same procedure at least 3 to 4 times to get a perfect leveling for the bed and the nozzle.

Use anti-warping resin/material Warping is one of the most commonly occurring 3D printing defects , which causes irregular dimensionality. Surface warping occurs due to the variance in cooling rate, which causes changes in dimension at variated speeds. This differential surface cooling builds internal stress within the print surface that causes the underlying layer to warp.

FDM printers are very much prone to surface warping, which significantly destroys the print resolution and quality.ABS and PLA are some of the most warping prone materials.

For detailed prints using FDM, the usage of high-quality material such as PLA+ or EPACF will reduce the chances of warping.

Several research works are being undertaken by popular 3D printer manufacturers to establish a warp-free material. Out of that, PolyMide CoPA launched by polymaker has shown promising results in warp-free material. PolyMide chemically controls the molecular crystallization which helps in releasing the internal stress developed well before solidification, hence ensuring constant cooling rate.

Warping can also be eradicated by choosing high-resolution 3D printers ranging from 10 to 50 microns. Printers with 20 microns produce some top quality prints with greater resolution than 50-micron prints. Check out for printer resolution before purchase if you require a finer detailed print.

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Check Nozzle temperature This criterion again specifically applies to FDM printing. The higher the nozzle temperature, the greater the chances of strings of material that oozes out during printing operation. This oozed out material will ultimately cause dimensional irregularities and surface distortion.

Before printing, it is essential to set the nozzle temperature in accordance with the filament material properties. Usually, the 3D printer control settings will have prespecified temperature levels, but when you’re using a material that is not in the database, it is always better to check the material melting point and set the heat sink temperature accordingly.

Use a smaller nozzle diameter Thigh-quality of the major points we discussed about XY resolution of FDM printing technique. The smaller the diameter of the nozzle used, the finer the material will extrude, which results in a high quality finish in designs that use sharp edges and curves.

To obtain a high-quality finish, adjust your layer height according to the diameter of the nozzle, which can be performed using the slicing software. The slicing software automatically adjusts your layer height according to the diameter options provided.

Choose your nozzle diameter in a fashion that you don’t lose layer thickness and hence lose out the mechanical stability of the print. It is advisable to choose a nozzle diameter that is on the intermediate between finer and thicker range, which can print the product matching your expectation.

Set the layer height properly Layer height is technically the height of the cured layer, also sometimes referred to as layer thickness. This has a lot to do with the Z resolution of the 3D printer and applies to all types of printing techniques. Layer height directly affects the printing time which invariably affects the print quality.

For long objects, the thinner the layer height, the longer it takes to print the model with greater perfection. Thin layers often contribute to a perfect finish across the Z direction and leading to a smoother surface.

Layer thickness is measured in microns and you can generally adjust your layer height based upon the end product you desi to obtain. However, in case of experimentation, or you don’t have any idea of the required finesse you need, you can always set the layer height between the printer layer height range, and chose a value that appeals to be optimum for the product you wish to obtain.

Use Support Materials

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There are high chances of print deformation due to the presence of gravitational forces for larger prints. The problem escalates further when you provide unique features such as an overhanging feature or single support feature along with the main print, which might result in surface abrasion.

To eradicate the possibility of this, we need to use proper supporting structures and materials that will hold these unique features with the printer base and the main print. In the case of SLA or SLS printing techniques, the support material is automatically provided by layers of powder that remains unprocessed. This holds the structure together and is easily removable.

High-quality print often comes with sharp edges and high finesse structures and can’t be printed directly in case of FDM printing. The slicer software enables the user to provide support materials for the design. The support material should be thin and less dense so that it can be pulled off easily from the main print.

The addition of support materials can help the user to print sharp and high-resolution print surfaces without surface abrasion and improper printing. Sometimes, improper design can cause material clogging, and usage of support materials can provide clear cut directions for the print head on material distribution.

Reduce the lift speed or the motor speed In the case of SLA and SLS printing, the rate at which the build plate lifts also determines the finishing quality of the material. The lift speed is also calculated as millimeter per second in rising of the build plate.

Now, the faster the lift speed of the build plate, the higher the chances of the whole print to be distorted or destroyed, due to elasticity between the vat resin and the plate.

Generally, lift speed goes hand in hand with the layer height by the slicing software, however, you can modify the lift speed based on the model you want to obtain.

It is advised to maintain the lift speed based on the range given by the slicing software. To obtain a print of high-quality finish, set the lift rate marginally lesser than the proposed lift rate, which can sometimes increase the print time.

In FDM printing, lift speed corresponds to the speed of the motor operating the Z resolution motion. Speed of motor directly depends upon step angle it moves per millimeter. To obtain a print of higher quality, it is advisable to reduce the motor speed rate in terms of mm/sec in the slicer software.

Further Insights 3D printer resolution can be checked and measured using a print resolution test plate.

The test plate is made of several individual apparatus that measures the resolution of the print based on several dimensional criteria.

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3D printer resolution ain’t a simple term as it masquerades it to be. The resolution of 3d prints varies on several factors including the printing technique, the printer manufacturing method, procedures followed, the model designed, and much more that is not easy to increase or decrease as and when we like to do.

Obtaining inch-perfect 3D printing resolution requires a lot of testing and modification procedures to be followed from the base level so that it doesn’t end up collapsed. As said, this tinkering in the printing techniques requires some expertise, something that can only be learned through experience.

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