How To Get Rid Of Lines In 3D Printing, Flow Rate and Homing in 3D printing.


3D printing has many settings and parameters that make it a task of narrowing down on fixing a specific problem.

To get rid of groves in 3D printing, you need to optimize your 3D printing slicer settings and temperature, as well as replace the essential mechanical parts on your printer. You need to ensure you use a stable 3D print surface and your 3D printing bed is correctly leveled.

The sides of a 3D printed part contain hundreds of individual layers. If your 3D printing process runs smoothly with no issues, then you are assured of a single smooth surface in the end.

However, if something goes wrong, even with one layer in your printed model, you will notice some lines in the end product surface.

3D Printing Is Here To Stay

Let’s expand more on why you keep getting lines in your 3D print, the effect of flow rate on 3D print, and so much more. Also, check out how using Vat polymerization helps in producing high quality prints by checking our post What Is Vat Polymerization In 3D Printing? SLA & DLP : Pros and Cons

Why am I getting lines in my 3D print?

Here is a list of some common causes of these 3D print lines: (Source)

Also, check the impact of microns setting. Check our post How Many Microns Are There In 3D Printing? Do They Matter?

Problems causing lines in the 3D printing process and how to fix them

Let us now have a look at the solutions to the above problems causing lines in the 3D printing process: (Source)

High temperatures

Too high temperatures make the plastic material melt, thus allowing the plastic material to extrude freely, with less control.

To fix this problem:

  1. Start your 3D printing at a lower temperature as you build up gradually
  2. Take a few test prints until you find an optimal temperature, you can embark on your actual print.
  3. In case you are getting under extrusion, increase your temperature slightly.

Abrupt temperature changes

The fluctuation in temperature makes your 3D print filament cold or hot, disrupting the printing process. This can cause the print layers to extrude differently, creating lines on the sides of your 3D print.

To fix this problem:

  1. Ensure your PID controller is properly tuned to keep the right temperature tuned all the time.
  2. Use the brass nozzle to achieve better thermal conductivity and avoid abrupt fluctuations.
  3. Maintain temperature variations at ±2 degrees Celsius.

Mechanical problems

Here are some of the mechanical problems that are likely to cause lines effect in your 3D printing:

  • Bent Lead Screws 

This is one of the key causes of Z-banding since the lead screw can bend causing some strange lines patterns on the print surface. If your 3D printer lead screw is bent at certain layer heights, a movement will affect your 3D print quality negatively and this can lead to the lines on your 3D print.

  • Rod maintenance required

If the 3D printer rod is wearing out after continuous use, it will affect the functioning of the Z-axis. This will in turn affect the printing pattern, leading to the lines effect. Lubricate the rod to enable it to move smoothly.

  • Wheel and belt adjustment

The wheel and the belt of your 3D printer should be adjusted and fixed properly unless you will notice strange lines appearing on the surface and sides of your print.

  • Linear bearings

Slow in linear bearings is another mechanical problem that may lead to Z-wobble giving imperfections such as lines on the side of your 3D print.

  • Over extrusion

Excessive filament coming through the printer nozzle may make the nozzle touch the thick layers leading to a line effect on the 3D print.

To fix this:

  1. Lower the filament flow rate through the nozzle
  2. Reduce the extruder temperatures to avoid excessive melting of filament.
  • Damaged extruded nozzle

This may be caused by printing using abrasive filaments or general wear and tear. Since the nozzle is too close to the printing bed, the damaged extruded nozzle may scrap the tip-off, causing the lines effect on the 3D print.

To fix this problem:

  1. Replace the printer nozzle with a high-quality new one
  2. Test the printing temperatures
  3. Get a hardened steel nozzle.
  • Printing too fast

When the nozzle extruder is moving too fast, it may start depositing too much filament materials on the sides of your 3D print, causing line patterns at the curved sides.

To fix this:

  1. Reduce your 3D printing speed in 5 to 10 mm/s intervals
  2. Check on your advanced printing speed settings to change certain parameters.
  • Unstable print surface

This could be either your printing bed or the surface where you have placed the 3D printer. Any extra vibration from the 3D will affect the result of the print.

To fix this:

  1. Level your print bed to ensure it is accurate
  2. Place your 3D printer on a stable printing surface.
  • Bad filament diameter quality

 Poor quality printing filaments may disrupt the 3D printer feeding pressure through the nozzle extruder. This is likely to cause lines on the side of your 3D print.

To fix this:

  1. Use a 3D filament guide that can pass through the extruder
  2. Purchase filament from a reputable seller or manufacturer
  3. Ensure your filament diameter is within tolerance by measuring it.

How does the flow rate affect your 3D prints?

3D printer flow rate refers to the slicer setting that regulates the amount of filament to extrude. The 3D printer flow rate is usually set to 100% or 1.0 depending on the slicer. If you set your 3D printer flow rate to 100% or 1.1, you will be increasing the 3D printer flow rate by 10%. (Source)

One would ask why 3D printing flow rate is such an important aspect? To achieve accurate and attractive 3D prints, you need to first consider the correct flow rate in 3D printing. Incorrect flow rates may lead to both under and over-extrusion, which may lead to the production of poor-quality prints.

Why would you need to change the flow rate of your 3D printer?

Changing the flow rate of your 3D printer will help improve the outlook of your 3D prints. This change of flow rate is important for each filament material as these different filament materials have different extrusion properties and densities. (Source).

Printing with too high flow rate

Printing with too high flow rate can lead to over-extrusion, where the 3D printer force out too much filament material. This is basically characterized by blobs, drooping, stringing, and oozing.

To fix the over-extrusion problem, carry out the following:

  1. Reduce the printing temperature
  2. Reduce your flow rate
  3. Ensure your correct filament diameter input is correct.

Printing with too low flow rate

Printing with too low flow rate can lead to under-extrusion, where your 3D models have layers with holes and dots or have thin layers.

Check out our article on Why a 3D print becomes brittle and how to fix It!

To fix the under-extrusion problem, carry out the following:

  1. Increase the printing temperature
  2. Increase your flow rate
  3. Check out for the correct filament diameter input.

How do you smooth PLA without sanding?

Spray in horizontal movements across your print, starting and stopping beyond the model

To smooth PLA without sanding, all you require is a can of spray paint capable of bonding well with plastic and a bottle of FDPS (Fast Drying Polyurethane-Clear Satin). This process will enable you to print faster with a relatively larger layer thickness. It will also cover up any possibility for lessened quality.

Use a spray paint color of your choice with this process, but you don’t require sanding or any other post-processing techniques (source). Here is a simple step-by-step and non-labor-intensive process to perform this: (Source)

  1. Check for any dirt or dust on your printed model, ensuring that there is no unwanted material that may get trapped in your 3D smoothed-out model.
  2. Coat your 3D print with a layer of spray paint of your choice, quickly followed by a Polyurethane layer. A good polish can help your 3D print shine.
  3. Now place your coated 3D print carefully under a fan to enable it to dry quickly and prevent dripping. You will start noticing that the combination of Polyurethane and spray paint will mix into layers, alongside any unexpected flaws or holes. This process works best with patience and thin layers.

What does homing mean in 3D printing?

Homing in 3D printing refers to the method by which a 3D printer determines the 3-dimensional location of its nozzle extruder The homing process occurs before each 3D print and it involves the X, Y, and Z-axis motors nudging until it reaches the axial limit.

With the homing recorded data, you can determine where the extruder will begin the print on the XY plane and how high your 3D printer will position the build plate during the beginning of a print. (Source)

Conclusion

The layer lines experienced in 3D printed parts are mostly considered a big problem. However, this should not be a problem as such. There are several ways of hiding or eliminating layer lines on your 3D-printed parts.

At 3D Print Schooling, you will get well-researched content that enlightens you on how to go about lines that might occur in your 3D print and all information you may need to know about 3D printing.

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