Troubleshoot #1: Blocked Bowden Nozzle


Blocked Bowden Nozzle

What is the problem?

You initiate a print model but whatever you try, nothing comes out of the nozzle. Extracting the filament and reinserting doesn’t work.

What is the cause?

A small piece of filament has been left behind in the nozzle after changing spools, often because the filament has snapped off at the end. When the new filament is loaded, the piece of old filament that is left in the nozzle doesn’t allow the new filament to be pushed through.

Tip #1: Unblock with a needle

Start by removing the filament. Then using the control panel select the “heat up nozzle” setting and increase to the melting point of the stuck filament.  For PLA set the temperature to 220 C. Once the nozzle reaches the correct temperature, use a small pin to clear the hole (being careful not to burn your fingers). If your nozzle is 0.4mm then you need a pin that is smaller; an airbrush cleaning kit works perfectly. It’s also worth getting a brass cleaning brush to remove any filament build-up on and around the nozzle.

Tip #2:

If you find that the nozzle is still blocked then you may be able to push the filament through with another bit of filament. Start by removing the filament as before and then remove the feeder tube from the print head. Heat up the hot end to 220 C for PLA and then using another piece of filament push this through from the top to try to force the stuck filament in the nozzle out. Usually if new filament hasn’t succeeded in unblocking then the extra pressure you can exert by hand might just do the job. However don’t push to hard as you’ll bend the horizontal printer rods. Once the end clears use a needle to push through the nozzle and a brush to clean any filament excess.


Troubleshoot #2: Broken Infill

What is the problem?

The internal structure (Infill) of your print is missing or broken.

What is the cause?

There are a number of reasons for the misprinting of the internal structure. The most common is incorrect settings within the slicing software, but it can also be due to a slightly blocked nozzle.

Tip #1: Checking the Fill density in software

In your slicing software check the infill density. A value of around 20% is normal; any less than this and you’re likely to have issues. For larger prints you may want to increase this to ensure that the model has enough support.

Tip #2: Infill Speed Setting

The speed at which the infill is printed can have a major effect on the quality of the structure. If the infill is looking week then decrease the infill print speed.

Tip #3: Changing the pattern

Most slicing software enables you to change the internal structure. You can have a grid pattern, or triangle, honeycomb, and more. Try selecting a different option. It might be that there is a slight blockage in the nozzle. While the blockage doesn’t effect the printing of the thicker exterior walls, because there is less flow for the internal structure the filament is getting caught.

Troubleshoot #3: Cracks in prints

What is the problem?

There are cracks on the sides, especially on taller models. This can be one of the most surprising issues in 3D Printing as it tends to manifest itself in larger prints, and usually whilst you’re not looking.

Tip #1: Extruder Temperature

Start by increasing the extruder temperature; a good start would be to increase it by 10ºC. On the side of your filament box you’ll see the working hot end temperatures, try to keep the temperature adjustment within these values.

Tip #2: Fan direction and speed

Double check your fans, make sure that they’re on and aimed at the model. If they are try reducing their speed.

Troubleshoot #4: Elephant Foot

What is the cause?

This ungainly effect can also be caused by the weight of the rest of the model pressing down the first layers when the lower layers haven’t had time to cool back into a solid – particularly when your printer has a heated bed.

Tip #1: The right balance

To stop elephant foot appearing in your 3D prints the base layers of the model need to be cooled sufficiently so that they can support the structure above, but if you apply too much cooling to the base layers you can create warping. Getting the balance right can be tricky, start by lowering the temperature of the print platform by intervals of 5 degrees, (within +/- 20 degrees of the recommended temperature). If your  Bottom / Top Thickness is set to 0.6mm then start the fan after the fan at a slightly lower height.

Tip #2: A level base

More often than not the majority of print issues can be traced back to the level of the print platform. Each printer has a slightly different technique for print platform leveling. Start by using your printers manufacturers recommended procedure. Then print a calibration cube and just watch how the filament is laid down. From printing of the cube you should be able to see if the filament is being laid down evenly, if the nozzle is too close to the print platform and scraping through the molten filament or too high and causing the filament to blob.

Tip #3: Raise the nozzle

Just raising the height of the nozzle slightly can often help, but be careful too high and it won’t stick to the platform.

Tip #4: Chamfer the base

If all else fails then another option is to chamfer the base of your model. Of course, this is only possible if you have either designed the model yourself or you have access to the original file. Start with a 5mm and 45º chamfer, and experiment to get the best result.

Troubleshoot #5: Extrusion Temperature Too High

What is the cause?

Normally, having too hot a hot end or overheating is an easy fix. The hot end is too hot so you need to cool it down. There needs to be a fine balance between melting the filament so that it will flow, and enabling the filament to solidify quickly so that the next layer can be applied to a solid surface. Before you go adjusting the temperature however, first make sure that you have loaded the correct material settings for your 3D printer (as part of the filament loading process). If you have, then it could be that you need to adjust the temperature just a touch.

Tip #1: Check material settings

This might seem obvious, but just double check that you’ve given the printer the correct details about the material. The latest filament temperatures range from between 180 – 260ºC or thereabout, so it’s surprising how easy it is to get this wrong.

Tip #2: Decreasing hot end temperature

In the printer or software settings decrease the hot end temperature. Depending on the severity of the overheating, drop the temperature in 5ºC intervals.

Tip #3: Speeding up

If the filament isn’t being discolored then you could try speeding up the print speed.

Tip #4: Check fans

Check that the cooling fans are directed at the hot end. Check that they’re in the right position and if possible boost their speed to increase airflow over the cooling filament.

Troubleshoot #6: Gaps between Infill and and object’s outer wall

What is the problem?

When you look at the top or bottom of the print, you can see a slight gap between the infill and the outer perimeter walls.

What is the cause?

Gaps between the perimeter and top layers used to be a common problem, but as printer accuracy has improved and the support for different materials extends, it’s now less of an issue than it was.
However the new wave of advanced materials are far less forgiving than the likes of PLA and ABS, and we’re starting to see a slight resurgence of the problem. Gaps are caused by the filament used for the infill and outer walls not quite meeting bonding and is a relatively easy fix.
The most obvious cause of the problem is that the infill overlap is not set, or it’s set to “0”. This means that the slicing software is actually telling the printer not to allow the two parts of the print to meet.
Another issue could be the order in which you have set the infill and outer perimeters to be printed. If you’re printing the perimeter first for a high-quality print then there is generally little or no overlap which can again cause the problem.

Tip #1: Overlap’ option and increase the value

In Cura by default this is set to 15% so raise it to 30%.

In Simplify3D you’ll find the option in ‘Edit Process Settings > Infill > Outline Overlap’ again increase the value. This setting is directly linked to the extrusion width, so the % value will be a % of whatever you’re extrusion width is. When adjusting this setting always keep it below 50% or you’ll start to see the effects of the overlap in the outer perimeters of your print.

Tip #2: Printing infill before the perimeter

If you’re printing with a relatively thin outer wall the structure of the infill can show through. If this happens then you can switch the order by which the printer lays down the infill and perimeter layers. For example, in Cura check to see if you have ‘Infill prints after perimeters’ ticked.

Tip #3: Increase Hot end temperature

Some of the latest advanced materials such as XT-CF20 are a little less forgiving when it comes to spread due to the carbon fibres that make up part of their structure. When printing with these materials you may find that a slight 5-10º increase in hot end temperature makes all the difference.

Tip #4: Slowing down

Avoid the rush to get the printout, but printing at higher speeds can cause all sorts of issues if the printer isn’t perfectly calibrated. If you need to print quick you can still avoid gaps by decreasing the speed of the top layer.

Troubleshoot #7: Ghosting of the Internal Structure

What is the problem?

The final print looks fine but an outline of the internal support structure can be seen through the walls of the print.

What is the cause?

The issue with ghosting happens due to the infill encroaching into the path of the perimeter. This effect is most visible when your print has thin walls. The problems is caused by the infill structure overlapping with the perimeter line as it’s being laid down. Although this ghosting is an issue it’s actually an important part of the printing process, as it helps the internal structure bond effectively to the external walls. Luckily it’s very easy to overcome.

Another cause of ghosting can be that you have set an incorrect wall thickness in relation to the size of nozzle that you’re using. In normal print conditions the size of the nozzle should be directly related to the nozzle size, so if you have a 0.4mm nozzle then the wall thickness should be a multiple of this, either 0.4, 0.8, 0.12 and so forth.

Tip #1: Shell Thickness

Make sure that the value you have selected for the shell thickness is a multiple of the nozzle size.

Tip #2: Use Infill after perimeters

Most slicing software will enable you to activate Infill prints after perimeters.

In Cura open up the ‘Expert Settings’ and under the Infill section tick the box next to ‘Infill prints after perimeters’

In Simply3D Click ‘Edit Process Settings’ then select ‘Layer’ and under ‘Layer Settings’ select ‘Outside-in’ next to the ‘Outline Direction’.

Tip #3: Check print platform

Check around the model and if you see that the effect is more prevalent on one side than the other, the effect could be due to calibration. If so run through the usual calibration process.

Troubleshoot #8: Layer Misalignment

What is the problem?

Some layers in the middle of the objects have shifted.

What is the cause?

The printer belts aren’t well tightened. The top plate isn’t fastened and wobbles around independent of the bottom plate. One of the rods in the Z axis is not perfectly straight.

Tip #1: Check belts

Start by checking each of the belts are tight but not over tight. You should feel a little resistance from the two belts as you pinch them together. If you find that the top section of the belt is tighter than the bottom then this is a sure fire sign that they need a tweak and tighten.

Tip #2: Check top plate

Check the top plate and all rods and attachments at the top of the printer and make sure everything is tight and aligned.

Tip #3: Check the Z axis rods

Many printers use threaded rods rather than lead screws and although these do the job they do have a tendency to bend over time. Don’t worry about dismantling your printer to see if they’re straight, simply use the software such as ‘Printrun’ to move the print head up or down. If one of the Z axis rods is bent you’ll instantly see. Unfortunately, it’s almost impossible to accurately straighten a rod once it’s bent, but on the upside, it’s a good excuse to replace the old threaded rods for lead screws.

Troubleshoot #9: Leaning models

What is the problem?

As the print forms it starts to lean. Instead of being straight and true, vertical edges are printed at an angle, and this angle isn’t consistent throughout the print. The severity could be increasing and decreasing at different stages.

What is the cause?

Check the tension in the belts Check there’s no movement in the top plate Make sure the Z axis rods are straight

The cause of the issue is generally very simple; one of the pulleys attached to a stepper motor is slightly loose, or one of the belts is rubbing against something and stopping the full travel of the head. All you need to do to correct the issue is to make sure that none of the pulleys are slipping and the grub screws that hold the pulleys in place are all tightened.

Although this should be a quick and straightforward fix, one issue you may experience as you go to tighten the pulleys is that the small grub screws that tighten onto the shaft of the motor aren’t always that easy to access. Firstly diagnosing which pulley is causing the issue and then getting access to that pulley can be tricky and time-consuming.

Tip #1: Check X and Y axis

If your print is leaning to the left or right then you have an X axis issue. Back to front and you have a Y axis problem. Once you’ve diagnosed which it is you can then check the belts and pulleys. If you have a printer such as the PRUSA i3 then the process is pretty straight forward, as the steppers are directly connected to the main drive belt. For the Ultimaker and other printers that process can be a little more tricky.

Tip #2: Check belts are not rubbing

Look round each of the belts and ensure that they’re not rubbing against the side of the machine or any other components. Also check to see that the alignment of the belts is correct. If one is at a slight angle then this can cause issues.

Tip #3: Tighten the stepper motor pulley grub screw

Once you diagnose which axis is causing the issue, use an Allen key to tighten the pulley grub screw that attaches to the stepper motor.

Tip #4: Check rod pulleys

More complex machines such as the Ultimaker 2 have a series of belts and pulleys. The main X, Y rods at the top of the machine feature eight pulleys. Go round each of these on the affected axis and tighten the grub screws for each. It’s unlikely that these will cause any slip but if one is loose then a belt may misalign.

Troubleshoot #10: Misaligned Layers

What is the problem?

As the print is forming, there appear to be a few issues with the quality. Look closer and you see that the layers aren’t aligned as they should. As each line is being laid down neatly side-by-side, you’ll see gaping. Look at the internal support structure and again the pattern looks out, and the outer wall rather than being straight has misalignment, causing an uneven rather than smooth face. As you rotate the model around you’ll probably find that the issue only affects the print in one direction; front to back or left to right.

What is the cause?

Over time the parts of your 3D printer — such as nuts, bolts and belts — will become loose and require a tighten. The effect of misaligned layers is similar to the cause of the more pronounced effects of shifting layers and there is no doubt that there is a crossover. If left unchecked, this problem will eventually result in shifting layers, but as the issue starts the visual effect on the prints is far less pronounced and can look very different. The cause is usually linked directly to a loose belt.

Tip #1: Check belt tension

Start by going around your printer and checking the belt tensions. Use your thumb and index finger to pinch the belts together. If the belts easily touch without putting up any resistance then they’re too loose; when you pinch you should feel a bit of slack at first and then resistance before the two belts touch.

Tip #2: Check that top and bottom belts are the same

The printer belts are normally just one continuous loop hooked around two pulleys. A common issue is that over time the belt can slip on one pulley and gradually gets tighter on the top compared with the bottom — or visa versa — and again this can cause issue.

Tip #3: Tighten the belt tensioner

On an Ultimaker the two stepper motors for the X and Y axis can be loosened slightly by untightening the allen key bolts and then pushing down on the motors and re-tightened. If it’s one of the main belts then the belt has probably slipped inside the block that secures the two ends of the belt. If this is the case the block will need to be removed and adjusted before being re-fitted.

Troubleshoot #11: Missing Layers

Whats is the problem?

There are gaps in the model because some layers have been skipped (in part or completely).

What is the cause?

The printer failed to provide the amount of plastic required for printing the skipped layers. This is called (temporary) under-extrusion.

There may have been a problem with the filament (e.g. the diameter varies), the filament spool, the feeder wheel or a clogged nozzle.

Friction has caused the bed to temporarily get stuck. The cause may be that the vertical rods are not perfectly aligned with the linear bearings.
There is a problem with one of the Z axis rods or bearings. The rod could be distorted, dirty or had been oiled excessively.

Tip #1: Mechanical Check

Start off by checking the rods and make sure that they’re all seated into either bearings or clips and haven’t popped out, shifted or moved even slightly.

Tip #2: Rod alignment Check

Make sure that all rods are still in perfect alignment and haven’t shifted. You can often tell by switching off the power (or disabling steppers) and then gently moving the print head through the X and Y axis. If there is any resistance to the movement then something is wrong and it’s usually pretty easy to tell if this is due to misalignment, a slightly bent rod or one the bearings.

Tip #3: Worn bearing

When bearings go they usually let you know about it by creating an audible din. You should also be able to feel uneven motion in the print head and when printing the machine looks like it’s vibrating slightly. If this is the case unplug the power and move the print head through the X and Y to locate the region of the broken bearing.

Tip #4: Check for oil

Lubricating the joints is easy to forget, but keeping everything well oiled is essential to the smooth running of the machine. Sewing machine oil is ideal and can be purchased for almost any haberdashery at a relatively inexpensively price. Before you go applying liberally just check that the rods are clean and free of dirt and printing debris, a quick wipe of the rods before applying fresh coat of oil is always a good idea. When all rods look clean just dab on a little, but not too much. Then use print such as Printrun to move the head through the X and Y axis to make sure that the rods are evenly covered and moving smoothly. If you add a little too much oil don’t worry just wipe some off with a lint free cloth.

Tip #5: Under-Extrusion

The final issue could be under-extrusion and finding the solution for this can cumbersome.

Troubleshoot #12: Model Overhangs

Whats is the problem?

You load your print into your slicing software and everything looks good. Hit print and you nd that some parts of the model print absolutely ne, whilst other parts end up as a stringy mess. This might seem obvious and the issue of overhangs is often seen as a 3D printing rookie mistake. But it’s surprising just how often even experienced 3D printers are hit with an overhang issue.

What is the cause?

The process of FFF requires that each layer is built upon another. It therefore should be obvious that if your model has a section of the print that has nothing below, then the filament will be extruded into thin air and will just end up as a stringy mess rather than an integral part of the print.

Really the slicer software should highlight that this will happen. But most slicer software will just let us go ahead and print without highlighting that the model requires some type of support structure.

Tip #1: Add supports

The quickest and simplest solution is to add supports. Most slicing software will enable you to do this quickly.

In Simplify3D click Edit Process Settings > Support > Generate support material; you can the adjust the amount, pattern and settings.

In Cura just click the Support type from the Basic settings.

Tip #2: Create in model supports

Supports generated by software can be intrusive so creating your own in your modeling application is a good alternative. It takes a bit more skill but can enable some fantastic results.

Tip #3: Create a support platform

When printing a figure, arms and other extrusions are the most common areas that cause problems. Using supports from the print bed can also cause issues as they often have to span quite large vertical distances; for structures that are supposed to be easily removed and fragile, this distance is prime for causing problems. Creating a solid block or wall under arms etc and then creating a smaller support between the arm and block can be a great solution.

Tip #4: Angle the walls

If you have a shelf style overhang then an easy solution is to slope the wall at 45º so that the wall actually supports itself and removes the need for any other type of support.

Tip #5: Break the part apart

Another way to look at the model is to break it apart and rather than print in one section make two. With some models this enables you to flip what would be an overhang and make instead make it a base. The only issue with this is that you then have to find a way of sticking the two parts back together.

Troubleshoot #13: More First Layer Problems

What is the problem?

The first layer does not stick properly, and some parts come loose. There are unwanted lines at the bottom.

What is the cause?

These 3D printing problems are typical signs that the print bed hasn’t been leveled properly. If the nozzle is too far away from the bed, the bottom surface often shows unwanted lines, and/or the first layer does not stick. If the nozzle is too close, blobs may be the result.

Also important: the print bed has to be as clean as possible. Fingerprints on the plate can prevent the first layer from sticking to the plate.

Tip #1: Level the print bed

Every printer has a different process for print platform leveling, some like the latest Lulzbots utilize an extremely reliable auto leveling system, others such as the Ultimaker have a handy step-by-step approach that guides you through the adjustment process.

Tip #2: Adjust the nozzle height

If the nozzle is too high then the filament won’t stick to the platform, to low and the nozzle will actually start to scrape the print off.

Tip #3: Clean the print platform

Every so often it’s a good idea to give the glass print platform a good clean, especially if you apply glue. The grease from your fingerprints and the excessive build up of glue deposits can all contribute to the nonstickiness of the print platform.

Tip #4: Add glue

Applying a thin layer of glue to the print platform will help add a little more adhesion if you do this make sure you give the bed a clean at regular intervals as the over application of glue can have the reverse of the desired effect.

Tip #5: Textured sheet for cold print beds

On cold print platforms, a common solution is to apply a stick-on film or sheet that increases the adhesive properties of the print platform.

Troubleshoot #14: Non-Manifold Edges

What is the problem?

Parts of your print are missing or the final print is weak and falls apart despite the exterior quality of the print looking fine. Sections of the print look completely different from the print preview or the final print has geometry errors that make no sense.

What is the cause?

In the 3D world you can simply intersect the two, they still exist as individual objects, but the software we use also enables them to intersect in the virtual world.

In order to get the two to print correctly the objects need to be merged so that any inner walls are removed and an object with a single undivided inner cavity is left.

Another common cause is if you have an object such as a cube and delete one of the surfaces.

You essentially have an object with a hole, it might look like a shape with five sides, but it only exists in the virtual 3D space, this is geometry with no physical form.

Tip #1: Use latest slicer software

Most of the latest slicer engines all support the automatic fixing of non-manifold edges but it’s still good practice to ensure that your models are correctly formed and print ready.

Tip #2: Fix in Horrible in Cura

In Cura open Expert Settings and make sure that under ‘Fix Horrible’ you have Combine everything (Type-A) ticked.

Tip #3: Fix ‘Non-manifold’ in Silmplify3D

In edit ‘Process settings’ click the ‘Advanced’ tab and select ‘Heal’ next to ‘Non-manifold segments.

Tip #4: Use the layer view

In your slicer software use the layer view to check through the model so you can see where the issues appear. A quick slide through the layers will often highlight an easy to fix problem.

Tip #5: Use software to fix issues

One of the easiest ways to fix models with non-manifold edges is to use software; Blender and Meshmixer both have features built in that will quickly enable you to highlight problems with your models and fix them prior to slicing.

Tip #6: Merge objects

Really it’s better to fix your 3D models prior to importing them into your slicing software. To do this, make sure that when you have two objects that do intersect or overlap you choose the appropriate Boolean function to either intersect, merge or subtract.

Troubleshoot #15: Over-Extrusion

What is the problem?

Over-extrusion means that the printer supplies more material than needed. This results in excess material on the outside of the model printed.

What is the cause?

Typically, the Extrusion multiplier or Flow setting in your slicing software is too high (see the section above)

Tip #1: Extrusion multiplier

Open your slicer software and check that you have the correct Extrusion multiplier selected.

Tip #2: Flow setting

If that all looks correct then decrease the Flow setting in your printer’s software.

Troubleshoot #16: Pillowing

What is the problem?

The top surface of the print shows unsightly bumps or even holes.

What is the cause?

The two most common causes are improper cooling of the top layer and that the top surface isn’t thick enough.

Tip #1: Filament size

More common with 1.75 mm filament. Pillowing is an issue that can affect all 3D printers, however, it’s far more common on those using 1.75 mm filament over 2.85mm.

Tip #2: Check the fan position

Cooling is normally the issue start by checking your fans. As the print starts your printers fans will be set to low or off, after the first few layers have printed they should kick into action. Check that the fans around the hotend start to spin, then as the print finishes check the fans are all good and working. If all seems OK just double check that the direction of the fans is correct and that they’re pushing cool air towards your print and not elsewhere.

Tip #3: Set fan speed in G-Code

Another cooling issue happens when each successive top layer of molten plastic is applied. As it covers the inner support structure it needs to be cooled quickly to avoid falling into the holes between the supports. The speed of the fans can be adjusted in the G-Code, a common G-Code for Fan On is M106 and is M107 Fan Off. You then just need to the Fan speed to maximum for those top layers. An example would for a 1cm x 1cm cube printer at 0.1mm layer height. The G-Code in this case output through CURA for the Prusa i3, we can look through the code and see that there are 97 layers. Knowing that we have a ‘Bottom / Top Thickness setting’ of 0.6mm we can look back to ;LAYER:91 then in the line after add M106 S255. M106 sets the fan going and S255 sets it to full blast.

Tip #4: Increase top layer thickness

The easiest solution is to increase the top layer thickness. Most applications will enable you to do this in the advanced section, under the ‘Bottom / Top Thickness setting’. You’re aiming for at least 6 layers of material normally and up to 8 for smaller nozzles and filament. If your layer height is therefore set to 0.1mm then set the ‘Bottom / Top Thickness setting’ to 0.6mm. If the effect of pillowing still exists then increase to 0.8mm.

Troubleshooting #17: Poor Surface Quality for Supported Models

What is the problem?

You’ve printed a complex model with supports created with your chosen software. But when it comes to removing the structure, small remnants of material are left on the surface. When you try to sand or remove the remaining material, it ruins the overall effect of the model.

What is the cause?

Supports are an essential part of 3D modelling and a subject that can divide opinion. Many models can actually avoid the need for supports completely with a little adjustment of the model to angle verticals, or design integral support structures into the model. You may also be surprised by the full capabilities of your printer, with most being able to bridge 50 mm gaps and print angles of 50º without any support at all.

Software solutions such as Cura and Simplify3D are capable of producing outstanding support structures, and for the most part these automatically generated supports will far exceed the quality of any home grown solution. But although auto-generated supports do the job, they can be dificult to remove. Applying your own support structures is a neater solution, but you’ll need to delve into the settings of your software to tailor the supports to your models.

Using Cura, click on the “Custom” options tab and then scroll down to “Supports”. By default you’ll have two options; “Enable Support” and “Support Placement”. Hover your mouse over the grey bar until you see the “Gear” and click, you’ll now see the Cura preferences; select “Support Pattern” and “Support Density” to start. There’s plenty of other options here that you can start to play with as you become familiar with the adjustments.

Tip #1: Dual Extrusion

An expensive solution, but if the majority of your prints use complex support structures then a dual extrusion printer such as the Ultimaker 3 or the Cel RoboxDual is really the only way to go.

Tip #2: Check support placement

Cura and most software will enable you choose whether your support structure is just touching the build plate or everywhere. For most models select “Touching the Build Plate” to avoid cleaning areas of the model that really shouldn’t require supports.

Tip #3: Check the capability of the printer

Quite often people use supports without realising that their printer will quite happily bridge a gap or print at relatively steep angles. Most printers are capable of bridging gaps of 50 mm and printing angles of 50º without error. Create a test print and see what your printer is really capable of.

Tip #4: Adjust the support pattern

Depending on the model type, a change in the support pattern might be all it takes; try switching from “Grid” to “Zig Zag”.

Tip #5: Reduce Support Density

In your slicer software switch the view to “Layers” and take a look through the support structure. Default software will usually apply a dense support structure. If you reduce this density the support will become weaker, but as long as your printer is finely tuned this shouldn’t be an issue. In Cura a support density of 5 can be used successfully and vastly reduces the effect of the structure on the model’s surface.

Troubleshooting #18: Stringing 

What is the problem?

There are unsightly strings of plastic between parts of the model.

What is the cause?

When the print head moves over an open area (otherwise known as travel move), some filament has dripped from the nozzle.

Tip #1: Enable Retraction

Retraction is an important factor when it comes to quality of finish and can be enabled through most slicing software. Its function is pretty simple and works by retracting the filament back into the nozzle before the head moves. The idea is that it avoids molten filament from trailing behind the head creating thin strings in its wake.

Tip #2: One click retraction activation

Most applications such as Cura offer a one click activation option, this uses a set of default parameters and for the most part is perfectly adequate. However, if you want a few more options there’s often a more settings buttons. Here you can adjust the minimum travel of the head before retraction is activated.

Tip #3: Minimum Travel (mm)

Reducing the minimum travel is usually the quickest fix for stringing if the standard retraction isn’t doing the job. Drop the value in 0.5mm until stringing is stopped. Activating retraction will increase your print speeds.

Tip #4: Just cut them off

This isn’t the most elegant of solutions but simply taking a scalpel to the strings is quite often the quickest and easiest solution, and has the benefit that it doesn’t increase print times.

Troubleshooting #20: Under-Extrusion

What is the problem?

Under-extrusion is when the printer cannot supply the material needed (or as fast as needed). Underextrusion results in thin layers, in layers with unwanted gaps, or in missing layers entirely.

What is the cause?

There are several possible causes. First, the diameter of the filament used does not match the diameter set in the slicing software. Secondly, the amount of material that is extruded is too low because of faulty slicer software settings. Alternatively, the flow of the material through the extruder is restricted by dirt in the nozzle.

Tip #1: Check the filament diameter

Start with the simplest issue, have you set the correct filament diameter in the slicing software. If you’re unsure about the diameter the value along with the recommended temperature is usually printed on the box.

Tip #2:  Measure the filament

If you’re still not getting the results you want and filament flow is the issue, then use a set of calipers to double check the filament diameter. You should be able to tweak the filament diameter settings accurately in the slicer software settings.

Tip #3: Check the head

After printing, most printers will lift the printhead away from the print base. Quickly check that the nozzle is clear from a build up of filament and dirt.

Tip #4: Set the extrusion multiplier

If there is no mismatch between actual filament diameter and the software setting, then check the extrusion multiplier (or flow rate or flow compensation) setting may be too low. Each slicer application will handle this slightly differently but the principle is to increase the setting in steps of 5% and then restart the print process.

In Simplify3D open the Edit Process Settings dialog and go to the Extruder tab – the Extrusion multiplier setting of 1.0 corresponds to 100%.

In Cura open the Material tab and increase the Flow setting (you may need to enable the Flow setting through the Preferences dialog).

Troubleshooting #21: Warping

What is the problem?

At the base of the model, the print bends upwards until it’s no longer level with the print platform. This can also result in horizontal cracks in upper parts.

What is the cause?

Warping is common as it’s caused by a natural characteristic of the plastic. As the ABS or PLA filament cools it starts to contract very slightly; the problem of warping arises if the plastic is cooled too quickly.

Tip #1: Use a heated print platform

The easiest solution is to use a heated print platform and to set the temperature to a point just below the plastics melting point. This is called the “glass transition temperature”. If you get that temperature right then the first layer will stay flat on the print platform. The print platform temperature is often set by the slicer software. You’ll normally find the recommended temperature for your filament printed on the side of the packaging or on the spool.

Tip #2: Apply glue

If you still find your print lifting at the edges then apply a tiny amount of stick glue evenly on the bed to increase adhesion.

Tip #3: Try a different platform type

Change your print bed to one that offers better adhesion. Manufacturers such as Lulzbot use a PEI (Polyetherimide) print surface that offers excellent adhesion without glue. XYZPrinting supply a textured tape in the box with some of their printers, basically a large sheet of masking tape, and again adding this works excellently, although only with nonheated print platforms. Zortrax 3D printers have a perforated print bed, models weld themselves to this surface eliminating the issue completely.

Tip #4: Level the Print platform

Print platform calibration can be another cause, run through the calibration process to check that the bed is level and nozzle height is correct.

Tip #5: Increase contact

Increasing the contact between the model and bed is an easy fix and most print software has the option to add rafts or platforms.

Tip #6:  Adjust advanced temperature settings

If all else fails then you’ll need to take a look at your advanced print settings both on your printer and in your print software. Try increasing the print bed temperature by increments of 5 degrees. In the slicer software take a look at the fan cooling, this is usually set so the cooling fans switch to full power at a height of around 0.5mm, try extending this to 0.75 to give the base layers a little more time to cool naturally.

Even if your printer has a heated print platform, it’s always recommended that you use glue and regularly calibrate the bed level.