Small gaps in 3d print

9 Ways How to Fix Holes & Gaps in Top Layers of 3D Prints – 3D Printerly

Having gaps in the top layers of your 3D prints aren’t ideal in any circumstance, but there are solutions which you can try to solve this problem.

The best way to fix gaps in your top layers is to increase the number of top layers in your slicer settings, increase infill percentage, use a denser infill pattern, or look towards fixing under extrusion issues. Sometimes using a default slicer profile works perfectly to fix gaps in top layers.

This article will attempt to guide you through fixing this problem, so keep reading for a detailed solution.

Why Do I Have Holes & Gaps in the Top Layers of my Prints?

Gaps in prints can be a result of several errors related to the printer or the print bed. To identify the origin of the main issue you should consider overviewing some of the main parts of the 3D printer.

Below we have mentioned a few reasons which might be a reason for gaps in your 3D prints as well.

Reasons for gaps in 3D prints may include:

1. Adjusting number of top layers
2. Increase infill density
3. Under-extrusion, over-extrusion and extruder skipping
4. Fast or slow printing speed
5. Filament quality and diameter
6. Mechanical issues with a 3D printer
7. Clogged or worn out nozzle
8. Unsteady surface
9. Unexpected or immediate temperature changes

How to Fix Gaps in the Top Layers of my 3D Prints?

The video explains one side of having gaps in top layers, which is also known as pillowing.

To improve your printer’s performance and the output’s quality, there are several ways you can practice to do so.

Sometimes just using a default profile for your 3D printer works a treat, so definitely try that beforehand. You can also find custom profiles that other people have created online.

Now let’s get into the other solutions that have worked for other 3D printer users.

1. Adjusting Number of Top Layers

This is one effective method of getting rid of gaps in print layers. The solid layer’s extrusions tend to drop and drool in the air pocket because of your partially hollow infill.

The fix is simply changing a setting in your slicer software:

• Try adding more top solid layers in your slicer
• A good rule is to go by is to have at least 0.5mm of top layers in your 3D prints.
• If you have a layer height of 0.1mm, then you should try to have at least 5 top layers to satisfy this guideline
• Another example would be if you have a layer height of 0.3mm, then use 2 top layers which would be 0.6mm and satisfy the 0.5mm rule.

This is probably the easiest fix in the problem of holes or gaps in your 3D prints since it’s a simple setting change, and it’s very effective in tackling this problem.

If you can see infill through your top layer, then this should help significantly.

2. Increase Infill Density

Another common reason behind having holes and gaps in your 3D prints is using an infill percentage which is too low.

The reason this happens is that your infill kind of acts as supports for the higher parts of your 3D prints.

A low infill percentage would mean less support, or foundation for your material to adhere to, so it can lead to melted plastic drooping which causes those holes or gaps.

• The simple fix here would be to increase your infill percentage for a better foundation on your 3D prints
• If you use an infill density of around 20%, I’d try out 35-40% and see how things work out.
• A setting in Cura called “Gradual Infill Steps” allows you to enable a low infill density at the bottom of your print, while increasing it for the top of the print. Each step you use means that the infill will be halved, so 40% infill with 2 steps goes from at the top 40% to 20% to 10% at the bottom.

3. Under-Extrusion and Extruder Skipping

If you are still experiencing holes or 3D printing gaps between layers or in your top layers, then you probably have under-extrusion issues, which can be caused by a few different issues.

Extrusion issues may include under-extrusion or your extruder clicking which effects the printing badly, and signals some weakness in your extrusion system.

When the amount of filament that your 3D printer thinks is going to be extruded is actually less, this under-extrusion can easily result in missing layers, small layers, gaps within your 3D print, as well as little dots or holes between your layers.

The most common fixes for under-extrusion are:

• Increase printing temperature
• Clean nozzle to clear any jams
• Check that your nozzle isn’t worn out from several hours of 3D printing
• Use better quality filament with good tolerances
• Make sure your filament diameter in slicer matches actual diameter
• Check flow rate and increase your extrusion multiplier (2. 5% increments)
• Check if the extruder motor is working properly and is provided with enough power or not.
• Adjust and optimize layer heights for your stepper motor, also called ‘Magic Numbers‘

Check out my article on How to Fix 3D Printer Under-Extrusion – Not Extruding Enough.

Other fixes that could help out in this instance are to make sure your filament feed and extrusion path is smooth and clear. Sometimes having a low quality hotend or nozzle just doesn’t do the best job at melting the filament adequately.

When you upgrade and replace your nozzle, the changes that you can see in 3D print quality can be quite significant, which many people have attested to.

I would also implement Capricorn PTFE tubing for a smoother filament feed into your nozzle.

4. Adjust Printing Speed to be Faster or Slower

Gaps can also occur if your print speed is too high. Due to this, your printer might find it hard to extrude filament in less time.

If your 3D printer is extruding and accelerating at the same time, it can extrude thinner layers, then as it decelerates, extruder normal layers.

To fix this issue, do try the following:

• Adjust speed by increasing or decreasing the speed by 10mm/s, which can be done specifically just for top layers.
• Check print speed setting for different factors like walls or infill etc.
• Check for acceleration settings along with the jerk settings to avoid vibration, then decrease these also
• 50mm/s is considered a normal speed for your 3D printer

It allows for more cooling which lets your filament harden to form a better foundation for the next layer. You can also print a fan duct to direct cool air straight to your 3D prints.

Check out my article What is the Best Print Speed for 3D Printing? Perfect Settings.

5. Check Filament Quality and Diameter

Incorrect filament diameter can cause printing complications bringing gaps in layers. Ensure your slicer has the ideal filament diameter.

Another reliable method of ensuring this is by measuring the diameter yourself with the help of calipers that you have the correct diameter specified in the software. The most commonly found diameters are 1.75mm and 2.85mm.

The stainless-steel Kynup Digital Calipers is one of the highest rated calipers on Amazon, and for good reason. They are very accurate, up to an accuracy of 0.01mm and very user-friendly.

• To keep your filament perfect for a long time, read the guide properly.
• Get a filament from the best manufacturers to avoid headaches of the future.

6. Correct Mechanical Issues with the 3D printer

When it comes to machines, small or big issues may arise. However, the thing is to be aware of how to fix them. Your 3D printer may experience mechanical issues that can bring gaps in the printing. To fix it, try out the following things:

• Machine oiling is necessary for smoother movements and general maintenance
• Check if all parts are working properly or not
• Make sure screws are not loose
• Z-axis threaded rod should be placed accurately
• The print bed should be stable
• Check printer machine connections
• The nozzle should be tightened correctly
• Avoid using floating feet

7.

The clogged and contaminated nozzle can also significantly bring gaps in 3D Printing. So, check your nozzle and if need be, clean it for better print results.

• If the nozzle of your printer is worn out, then purchase nozzle from a trusted manufacturer
• Keep cleaning nozzle with proper instructions as mentioned in the guide.

8. Put Your 3D Printer on Steady Surface

An unstable or vibrating surface cannot bring the perfect print out. This surely can bring gaps in printing if the machine vibrates or is likely to get unstable because of its vibrating surface.

• Fix this issue by placing the printing machine at a smooth and stable place.

9. Unexpected or Immediate Temperature Changes

Temperature fluctuations can be a great reason for your print to get gaps while printing. This is the most important issue which should be fixed immediately because it decides the flow of plastic as well.

• Use a brass nozzle as it works best when it comes to thermal conductivity
• Check if the PID controller is tuned or not
• Keep checking that temperature should not fluctuate immediately

Check out this video by CHEP for some more helpful tips to fix gaps in your prints.

Conclusion

Gaps between the top layers of 3D print can be a result of various printer’s shortcomings we have mentioned above. There can be more reasons for these gaps, but we have mentioned the major one.

If you figure out the likely root cause, it’ll be easier to solve the error. The main thing is to read the guide thoroughly when you are going to use any printing machine if you want to bring perfection to your work.

How to Fix Gaps Between Wall & Infill (Wall Separation) – 3D Printerly

You are on your way to finish your first 3D printed model, but something is not quite right with your model. The walls of your model are not fitting together with the model or worse it might be falling apart.

The best way to fix gaps between walls & infill is to identify one of the many possible causes and act accordingly. The solutions usually range from increasing extrusion temperature and width, slowing down print speed, decreasing fan speed, increasing infill percentage, or changing your infill pattern altogether.

The above-mentioned problem is known as wall separation. It is a commonly encountered problem when it comes to 3D printing. This is caused when the outer case of the 3D model does not hold together with the interior of the model often known as the infill.

This is something that can be a nightmare if you don’t know what is going on. But don’t worry we have the solutions for you, which can fix this issue in a jiffy. This problem can be resolved by tweaking some of the properties of your printer and its software.

I will go into detail about the possible causes and fixes for each one so rest assured, this problem can be fixed with a little more knowledge.

Before we move any further towards the solution, a better understanding about the different parts in a printed model and the problem itself will help the discussion below.

When it comes to 3D printing a model, one of the main advantages is that the model can be of varying degrees of hollowness. The holding structure that is inside the walls of the printed model is called infill.

Infill is a three dimensional repeating pattern that runs throughout the interior of the model. The hollowness of the finished object is determined by the density of the infill. When the density of the infill is 0%, then the model is completely hollow without any infill.

If the density 100%, it means that the object is purely solid from the inside. Apart from holding the structure, infill determines the strength of the structure too.

Before we address this issue we need to know a bit about how infill and walls are printed. 3D printing is done in layers, and each layer of the printed material is made of an outline perimeter and infill.

The outline perimeter turns out to be the wall of the printed model when it’s completed. As mention above, infill is just used to hold the object together making it rigid with the least use of material.

It will be a simple repeating pattern that speeds up the printing process. We find that the outline perimeter determines the shape and the features of the object; hence it is of a different pattern from the infill. This is the reason why wall separation or gaps between the wall and infill happen in the first place.

Being a different pattern from the infill can make the outline not stick with the infill and leave gaps in-between. This can be avoided if you carefully merge the two sections. Few things to be considered to make this happen or troubleshoot problems encountered on the way are discussed below.

There is a setting in Cura under ‘Expert Settings’ called ‘Connect Infill Lines’ and checking this box connects the ends where the infill pattern meets the inner wall. It uses a line which follows the shape of the inner wall to make your infill adhere better to the walls of your object.

Enabling this setting can also reduce the effects of infill on the quality of vertical surfaces.

It’s a good setting to try out to see if it quickly helps fix wall separation and gaps in 3D print walls.

You can also try using a Cura setting called “Fill Gaps Between Walls”, which should be set to “Everywhere” instead of “Nowhere” by default, but double check this. Simply use the Cura search box and type in “fill gaps” and the setting should show up.

Gaps can also be caused by printing of thin walls. When you use a printer with a fixed nozzle size, you might come across this problem. A nozzle is the part of the print head through which the melted print material comes through.

It moves around the print bed to place the extruded material on it to build the structure in layers. Thin walls are very hard to print, when its thickness is only a few time larger than the nozzle diameter, which is also called the extrusion width.

A solution to avoid this is by changing the extrusion width. If you are using a printer that can change the extrusion width using the software, then you can change the value with manual settings and play with the value until you find the best one.

If you are using a printer fixed nozzle size then you might want to change it manually. If you are planning to print a wall that is of uniform thickness, always use a large value for thickness compared to your nozzle’s extrusion width.

One solution is to increase the strength between the perimeter outline and the infill. Most 3D printers come with a setting for this in its software and it is called the ‘Skin Overlap’.

This setting determines the amount of overlap between the infill and the outline. The more the infill overlaps with the innermost perimeter the better the bond between the two sections.

The time for the outline to bond with the infill is an important factor that determines the bond strength. Improved bond strength will avoid wall gapping after printing.

While printing, infill is printed at a much faster pace compared to the outline. This is because the outline being the shape of the final product needs to be printed slower with precision. On the other hand, the infill being a simple repeating pattern is printed much faster.

If the printing speed is set too high, the infill will not get enough time to set and make a strong bond with the outline. If this situation arises, it is advised to adjust the default printing speed in the printer to a lower value.

The perfect print speed to avoid wall gapping can change according to the print material used. A better way to find suitable print speed will be making small test models in different speeds.

Start from a lower speed that produces no wall gapping and increase the speed on different models until you find an optimum solution.

3D printing software acts as a powerful tool and offers the best infill patterns with good outline overlap. Even if you choose the best option doesn’t mean that you’ll get a good print.

You should also be aware of what your printer is capable of printing. One such example is your software might be set to print fine structures which your nozzle does not have the extrusion width to print.

When you print a model, you have to find the best pattern for the infill to take the least volume and make more contact with the walls. Infill patterns when used according to the shape can improve its strength.

If you find wall gapping in your model, then try using patterns that make consistent and more repetitive contact with the outline like Grid, Line and Cubic rather than shape oriented patterns like concentric.

Some infill patterns are better suited to circular or rounded designs so trial and error some of the more common ones to see which one works for you.

Under extrusion happens when the printer does not supply enough material to print. This can happen when less plastic is exiting the print head than the intended value. This results in weak builds with less structural strength to the walls together.

This can also cause gaps between the layers of the walls if the build has walls that are of multiple layers.

A few things to be noted to prevent under extrusion are the following.

You could be using a filament with the wrong diameter. The printer’s software specifies a diameter for the filament that is fed into the nozzle. Look for filaments with the specified diameter while purchasing.

If you have purchased the filament with the right diameter and still encounter the same issue, then it can be solved by increasing the value of the extrusion multiplier or flow rate.

A weak infill is created when it is not printed properly. This can cause the infill to fall apart from the walls. This can be a problem with the software itself. Key reasons can be not enough material printed or it can be caused due to uneven thickness of the print.

Fast printing can also result in infill not being printed properly. One way to prevent this is by printing with a large value of infill extrusion width. In some printers, you can achieve with the inbuilt software.

When you change values with the software, there are a couple of things to be considered. Increasing the value of infill increase the volume of material printed. To compensate for the value of infill percentage, the software will put more space in between the lines.

To avoid this problem, you should increase the value of infill percentage along with the value of Infill Line Width.

Plastic requires heat to soften and create a bond with the rest of the build. If the print temperature is too low this can cause many problems including wall separation.

We discussed that while printing, the outline and the infill are printed as separate sections. Hence, good temperature is required to keep both these sections intact. Printing at higher temperatures can solve this problem.

One more solution found is to increase the setting speed. This can be done by decreasing the fan speed which reduces the effect of rapid cooling by blowing cool air. You can achieve a warm environment for printing by covering up the printer to contain the heat produced while printing.

This problem is found when your printer prints with varying extrusion width which is unintended. This will make each lines of the print bumpy in uneven intervals. This can cause the outline of the print sticking improperly with the infill.

This in turn causes a weak bond between the walls and the infill which can create wall gaps or ultimately fall apart from the structure. This problem is caused due to various reasons as follows.

If the proper amount of material is not provided at the right time, this can be troublesome. The reason can be the filament not being fed into the printer in the right speed.

If this is the problem you need to check the spool of plastic entering the printer can rotate freely. Check whether the filament is getting tangled while printing. Also check for any blockage in the tube through which the filament is drawn.

Another reason can be the clogging of the extruder. Any foreign debris or different plastic inside the nozzle can prevent proper extrusion from happening. Cleaning the nozzle can solve this problem.

Low quality filaments can also cause this problem. Poorly made filaments contain extra additives that can destroy the consistency of the plastic. This can change the rate of melting different in different parts of the filament.

As discussed above, infill density determines the percentage of the volume occupied by the infill inside the outline. Low infill density can reduce the contact of the infill with the walls. Hence, the increased value of the infill can produce more contact.

(There is a solution) Gaps/holes in 3D printing walls

I am new to 3D printing, I recently bought an Ender 5 Pro. I'm trying to print with 1.75mm PLA but the results are very poor unfortunately. When I got there after leveling the table, I got a decent result from the display dog ​​and started printing small things where the quality was acceptable. I then tried to switch to larger items, but the print failed halfway through due to insufficient adhesion.

There were other quality issues with this print and you can already see that there are holes in the walls:

I did another round of table alignment and Z alignment to make sure the adhesion was good and the test print came out pretty good in all corners and center. Single-layer rectangles are not perfect, the lines split in some places, but mostly they are small. But now I have a different problem: all the prints are very dirty, less clear, they are not as strong as before, and there are also large holes in the walls. The same base of the statue (how I had to stop after getting dirty before) looks like this now:

Another attempt failed after a few hours (e.g. printing stopped and printed nothing in the air), but there are also problems with holes/gaps even more noticeable:

Finally, as a test, I printed an object with the same G-code as before, and the result is very different. The object on the left is the new one. It is weak, you can feel by pressing that the walls are not solid, they bend. The "eye" rectangle is also not clear:

There is a difference though, I changed the extruder nozzle between, the new one was also in the Ender package, it is also 0.4mm, as the original should have been, I changed to try with the new one.

Due to the last test with the same gcode and a different result, I think the problem may be in the hardware setting as well, not just in the software. Does anyone know what I'm doing wrong?

EDIT 1 : after calibrating the ejection amount and lowering the print temperature from 200 C to 190 C, now I get the following result. Used values:

• Table temperature: 65 C initial, 60 C for others
• Printing temperature: 200 C initial, 190 later
• Print speed: 80 mm/s
• Wall speed: 40 mm/s
• Retraction: 10 mm
• Retraction speed: 80 mm
• Wall thickness: 0.8 mm
• Layer height: 0.2 mm
• Starting layer: 0.2 mm
• Line width: 0.4 mm

EDIT 2 : Based on the comments, some changes have been made and here are the results. Cube XYZ,

• print speed reduced to 60 mm
• layer height 0.12 mm
• Seam alignment Z is the sharpest corner
• Fill density 30%
• Retraction distance 8 mm
• Retraction speed 40 mm

It looks good, although the layers are visible, some ghosts right on X and Y. Dimensions not correct though: X=20.07mm, Y=20.03mm, Z=19.84 mm

Are X/Y allowed? What to do with Z, increase steps/mm ?

Finally, here's the 3D benchy too, although it looks mostly ok, there are some bumps in the walls and small strings in the exposed areas. This has been printed previously and with different settings though:

• Layer Width 0.2mm
• Print speed 80 mm
• Retraction 10 mm
• Retraction speed 80 mm
• Z Seam alignment set randomly

EDIT 3 I tried now to print a polypearl which has thin curved lines. The first attempt failed after 2 hours, a pen appeared on the nozzle, which ruined the print. It was a print from 190 p. I gave it another try and printed with 200 C and surprisingly it completed the job. See below photos, here are my settings for it (changes for Cura 4.6.0 default Super Quality):

• Layer Height: 0.08mm
• Initial layer height: 0.12 mm 92$ (default 500)
• Print jerk: 8 mm/s (default 10)
• Retraction distance: 8 mm
• Retraction speed: 40 mm/s

The model adheres well to the glass plate even without glue or hairspray, maybe a little too well. I see some problems, although I'm not sure how normal they are:

• the outer area of ​​the first layer is not very pleasant
• there are some oozing, strange lines on the surface and between the columns
• The top end of the turret is somewhat dirty and has a horizontal line attached to it (of course, it can be easily removed).
• the bottom is very smooth, I can see the texture of the glass (the top of the Creality glass is textured) and the texture of the very first failed print when I didn't take into account the extra height of the glass after leveling and the print head hit it hard and the nozzle was completely damaged. Rookie mistake.

These images are here: https://photos.app.goo.gl/ZfuMFFedL171eLeM7

Are these problems normal/acceptable?

▲ 4

Let's see what errors I'm seeing (accumulated from what I've commented):

The legs seem to be very weak. This can be either a clogged nozzle, printing too fast, or too low a temperature, or too low a pressure (for example, an incorrectly calibrated extruder). Try cleaning or a fresh nozzle, another parameter game can wait after you fix the next big problem.

To fix under extrusion if it persists after fixing the chime, experiment with the following settings:

• Check the mechanical system. Make sure the extruder
  • has no defects. I saw a lot of underextrusions when my extruder arm broke. The gear turned, but no longer pressed on the thread.
  • presses the filament with the idler bearing well against the hob gear.
  • is properly calibrated for physical parameters. Use the extrusion multiplier to account for different materials.
• Temperature. If the extrusion is not going well, increase it by a factor of 5. The °C steps can help.

The dented cube shows this best: massive ringing occurs. This is the effect that occurs when the printer changes direction rapidly - the printhead cannot speed up and slow down indefinitely as it has momentum, and as a result oscillates around the new path a bit, like a sine ring. This creates a "ghost" of previous toolpath changes on the flat face, which is why I asked for the cube to be printed.

There are 2 software fixes to fix ghosting and ringing:

• Reduce the print speed.
  • this comes at the cost of longer print times
• Improve your maximum acceleration and jerk
  • Slightly lowering the maximum acceleration (from 500 mm/s2 to 1000 mm/s2) can significantly improve print quality with little to no effect on overall print time and keep print speeds high.
  • Jerk is a derivative of acceleration; figuring out the two values ​​that might be best for setting up a printer can be a lot of experimentation.

There is also a hardware way to reduce it in many designs by shaving weight off moving parts or strengthening the design:

• Get a lighter printhead
  • removal of unnecessary add-ons
  • replacement for lighter print head design
  • transition to Bowden design
  • in CoreXY: use lighter rails
• Toughen the structure
  • Adjust the carriage mount so that it compresses better
  • replacement of bearings and bushings with bearings with tighter tolerances
  • ties can significantly strengthen the structure of the portal and cube

This could come from any of several sources. In descending order of similarity:

• the first layer is not a multiple of the actual layers (eg 0.12 instead of 0.2 mm), resulting in a partial layer at the top of the cut. in the example given, this would result in a fixed negative error of of about 0.08 mm.
• Incorrectly calibrated first layer. Depending on your alignment skills this can result in a fixed error of up to 0.1mm for a bad calibration up to 0.025mm for a really good calibration. This error can be either positive or negative.
• Z-axis inconsistencies due to misaligned lead screw, sticky lead screw, or insufficient Z-step motor voltage. Both tend to create a systematic error - as when printing a given percent loss of height. Such inconsistencies can be eliminated by solving the problem mentioned: first check the orthogonality, then carefully lubricate the screw with light machine oil (not WD40!), finally, increase the motor voltage a little. Only if your results are severely out of order, you should check if your steps/mm are set correctly. But I don't see the need for it.

24 Apr 20 , @ Trish

Problems, defects, 3D printing errors and solutions

Often during the operation of a 3D printer, problems may arise due to which defects appear on the finished model. Or instead of a neat product, plastic noodles suddenly appear on the table.

In fact, the causes of defects can be conditionally divided into 2 types - these are physical and software.

Physical ones are those that arise due to problems with the mechanics or any other causes that can be eliminated physically. These include problems with printer mechanisms (belt tension, backlash), clogged or deformed nozzle, incorrect table geometry, etc.

Software - these are defects that occur due to incorrect slicer settings or, less often, errors in the printer firmware. For example, incorrectly selected print speed, retract settings, incorrectly selected temperature for plastic, etc.

Very rarely, the problem may lie in the wrong or “flying” printer firmware (although usually the printer simply will not start then), overheating of some boards during printing, etc. These are rather special cases, so we will not consider them.

Model peels off or does not stick to platen

This is the most common 3D printing problem. Every 3D printer has had a case when the first layer treacherously rolls, clinging to the extruder, or the most offensive - when it tears off a partially printed model from the table. The first layer must stick tightly otherwise nothing will be printed.

Gap between table and nozzle 9 too large0026