Problems and solutions that easily occur in the 3D printing process

Mosi Li
Mosi Li

Director Project Engineer at 3Q Machining - China top CNC Machining Custom Part Manufacturer

3D printing industry

3D printing seems simple, but in fact, various problems often appear in printing. For professional users or users who like DIY, it is relatively simple to solve the problems in the printing process. For ordinary users, it is especially important to be able to quickly find the questions and answers during the printing process. The following problems are all problems that may occur during the printing process, and we have given solutions. Of course, these answers are not unique. You can also use your own insights and experience to deal with common printer problems as a user.

No material squeezed out at the beginning of printing

If your 3D printer starts printing, the nozzle does not squeeze out the consumables, then there are four main problems:

  1. The extruder is not ready

For most extruders, when the consumables are left in the high-temperature nozzle, the consumables will slowly seep out of the nozzle, which will cause a cavity to form inside the nozzle. When you print again, the consumables will gradually fill the space in the nozzle, causing a delay of several seconds. To avoid this problem, the nozzle must be filled with material and ready to be extruded before printing. The usual solution is that the extruder will draw a circle around the printed model before printing to ensure the correct extrusion of the printed material. Of course, the user can also manually control the extruder to extrude the material.

  1. The nozzle is too close to the hot bed

If the nozzle is too close to the hot bed, the nozzle opening will be blocked and the extruder will not have enough space to extrude the material. The hot bed level can be lowered, or the distance between the Z-axis and the nozzle can be adjusted through the slicing software, through continuous adjustment, so that the nozzle has enough space to print the consumables on the hot bed.

  1. The consumables are separated from the transmission gear

Most 3D printers use gears to drive the consumables in and out, and the consumables are bitten by the gears’ teeth, so that they can accurately control the in and out of consumables. If the material has a large gap or too thin part, the teeth will not be able to bite the consumables, causing the gears to run idly and be unable to effectively extrude the consumables.

  1. The extruder is blocked

If none of the above methods can solve the problem of extrusion consumables, it is most likely caused by the blockage of the extruder. The most common blockage is that the inside of the nozzle is not cleaned up, resulting in impurities remaining inside the nozzle, or some consumables are stuck in the extruder consumable track. In this case, it is usually necessary to disassemble the extruder for dredging. You can also contact the printer manufacturer for relevant guidance or maintenance.

When printing, the model is not attached to the hot bed

During printing, if the first layer of material cannot be properly attached to the hot bed, it will directly affect the subsequent printing. At present, there are many different methods to increase the adhesion of the first layer of material, but these problems can still be sorted out and answered.

  1. Parallel problem of hot bed and extruder

Many 3D printers use several adjustable screws to control the level of the hot bed. If the level of the hot bed is not adjusted, the distance between the ext. Usually, the ruder and the hot bed are also different. Usually, one side is too close and the other side is too far. We need to adjust the level of the hot bed the manual adjustment method is: first return the extruder, roughly adjust the hot bed to be parallel to the horizontal plane, then put the A4 paper between the nozzle and the hot bed, fine-tune the level of the hot bed, gently pull the A4 paper. If there is a feeling of drag at multiple points, it means that the nozzle and hot bed level are normal.

  1. The nozzle is too far away from the hot bed

Although the hot bed has been adjusted to the proper level, you still need to ensure that the nozzle is at the normal height of the hot bed. The ultimate goal is that the nozzle is neither too close nor too far away from the hot bed. To improve the cohesion of the hot bed, the best condition is that the material coming out of the nozzle is slightly flattened.

  1. Printing too fast

When starting to print the first layer, you must ensure that the extruded consumables are correctly pasted on the hot bed. If the printing speed is too fast, the consumables will not be able to be pasted on the hot bed in time. It is recommended to reduce the printing speed by 50% when printing the first layer.

  1. Hot bed temperature control

The consumables extruded by the extruder will begin to shrink when they encounter a lower temperature. For example, when using a 100mm wide ABS consumable, if it is heated through an extruder at 230°C when it encounters a platform at 30°C, it will immediately shrink by 1.5mm. When the printer prints the second layer, it will not automatically shrink by 1.5mm.

Based on this situation, the user must control the temperature of the hot bed. When we use ABS consumables, the temperature of the hot bed is usually 100-120°C. When using PLA consumables, the hot bed temperature is usually 60-70°C. Secondly, the cooling fan will also affect the temperature control. Generally, it is recommended that the user control the fan at 0% speed when printing the first layer, and then turn on the 100% speed after printing the fifth layer.

  1. Platform attachments

Different materials have different sticking viscosities for different attachments. In this case, many companies will optimize based on commonly used materials and develop new printing platforms. If your printing platform is not designed with special materials, you can still choose to replace it with other products, such as common textured paper, you can stick it on the printing platform. At the same time, this type of textured paper can be quickly removed and replaced. Of course, you can also try other sticky products such as glue to see which one is more suitable for you.

  1. Increase the bottom area

For some users, sometimes when printing works that do not have enough surface area, you can consider adding side skirts and other modes. Through adjustments and settings, increase the surface area of the first layer, thereby increasing the viscosity.

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Insufficient or too much extrusion material

For most 3D printers, the amount of consumables extruded by the extruder does not directly display or inform the user. Due to some problems during the printing process, the extruded material will be less than or more than expected. This requires the user to carefully check the printed work to see if there are irregular distances between the textures. If there is, it is usually caused by the following reasons.

  1. Material diameter

When users buy materials, it is usually recommended to buy regular brand products. If you buy inferior products, there may be uneven material diameters. For this type of material, the diameter can usually be tested with a measuring caliper to ensure that the diameter of the material is consistent with the packaging label.

  1. Increase the squeeze multiple

If the diameter of the material remains the same as in the label, but there is still a problem of insufficient extrusion material, then the extrusion speed needs to be adjusted. This is a very practical setting for users. Users can directly modify the amount of extrusion to squeezing more material. ABS material is usually squeezed 109%, while PLA is 105%.

  1. Reduce the extrusion speed

If the material is normal and the amount of extrusion is too much, then reduce the amount of extrusion accordingly to keep the printing at a normal level.

Insufficient sealing of the top layer

To save printing consumables, most 3D printers use different filling methods for the internal space. The commonly used ratio is 20%-30%. That is to say, there are only 20%-30% consumables inside the enclosed product. In this case, the work can still maintain a certain strength. However, in the printing of some works, users will find that the capping of some works is not perfect, and even holes or gaps appear. If you encounter this problem, here are a few simple settings that can be adjusted and repaired.

  1. The number of top layers

When the number of top layers is insufficient, it is easy to cause the material to fall, etc., so the number of layers can be increased accordingly.

  1. The filling rate is too low

Too much lowering of the filler will make the internal space too large, which will cause the top cover to not be effectively supported. It is recommended to increase the internal filling ratio.

  1. Insufficient extruder material

Due to insufficient extrusion material, the nozzle cannot meet the expected requirements, which can be adjusted by adjusting the extrusion volume.

Wire drawing or leakage

Wire drawing is the residual thread-like object left when the extruder crosses the open space. The common measure to solve this problem is to control the “retract” function in the slicing software. If the retraction is turned on during the slicing, the consumables will be pulled back a certain distance in the opposite direction before the print head moves to the next point. When moving to the next point, the consumables are squeezed out again. Although it can be avoided in theory, in practice there are still the following problems:

  1. Insufficient withdrawal distance

The most important setting in withdrawal is the withdrawal distance. This setting determines how much plastic is withdrawn from the nozzle during withdrawal. Normally, the more plastic withdrawn from the nozzle, the less obvious the drawing is.

  1. The withdrawal speed is too slow

Another important setting in retraction is the retraction speed. This setting determines how fast the consumables are withdrawn. If the withdrawal speed is too slow, the melted consumables will flow out of the nozzle. If the withdrawal is too fast, the unmelted part and the melted part of the consumables may separate or may occur squeezing, biting, etc.

  1. The temperature is too high

If the temperature of the extruder is too high, the consumables in the nozzle will become very sticky and will easily flow out of the nozzle, but if the temperature is too low, the consumables will be more difficult to extrude. If the withdrawal distance and the withdrawal speed are quite appropriate, but the wire drawing still occurs, you can try to lower the extruder’s temperature by 5-10 degrees Celsius.

  1. The moving distance in the air is too long

The hanging distance will also have a great influence on the drawing. Short-distance movement and the melted consumables do not have enough time to flow out of the nozzle, but the long-distance movement is prone to drawing phenomenon. Some slicing software has related settings to avoid long-distance movement.

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The object is overheated

When the melted consumables are extruded from the nozzle, the temperature is usually between 190-240 degrees. At this temperature, the plastic is very easy to deform. Only when the extrusion temperature and heat dissipation are relatively balanced, the consumables can flow from the nozzle smoothly. After it comes out, it is quickly cooled and formed. The following are several reasons for this problem and suggested solutions.

  1. Insufficient heat dissipation

If your printer has a fan for cooling consumables, turn on the heat dissipation function when slicing;

  1. The printing temperature is too high

The too high temperature will also cause the accessories and consumables to melt, so the printing temperature should be lowered by 5-10 degrees;

  1. The printing speed is too fast

If the above two solutions do not solve the problem, it means that your printing speed is too fast. Automatic heat dissipation can be set during slicing, which can ensure that each layer has sufficient time to cool and shape;

  1. Other questions

If the above solutions cannot solve the problem, you can try to print multiple parts at once, which can increase the cooling time of the consumables.

The offset problem

Most printers use a stepper motor to drive the movement of the machine, which means that the printer does not have the function of detecting where the print head is. However, once the stepper motor is interfered by external force or has a large resistance, it may cause the print head to be misaligned. The printer has no detection and correction measures, which will cause the printed product to be misaligned or shifted.

  1. The moving speed of the print head is too fast

The printing speed or idling speed exceeds the speed that the stepper motor can handle, and the problem of misalignment will occur. You can lower the idling speed, and also lower the acceleration if necessary.

  1. Mechanical problems

If the above method does not solve your problem, then you need to check the mechanical and electronic aspects. Most machines use belt drive. The belt may stretch and become loose over time, which will cause the belt to slip off the pulley. The solution is also relatively simple. The belt drive mechanism generally has a mechanism for adjusting the degree of belt tension, we can adjust the belt tighter to solve the problem. But it needs to be noted that if the adjustment is too tight, it will form a huge resistance between the shaft and the bearing, which may cause it to be unable to rotate. Therefore, the degree of tightness needs to be moderate. Another mechanical problem is the machine screw (top screw). This small screw is used to fix the pulley on the stepper motor’s shaft, allowing the pulley to rotate with the motor shaft. But if the screw is loose, it will cause the phenomenon that the shaft rotates but the wheel does not rotate. This situation can also cause offset problems.

  1. Electronic issues

If the offset is caused by the electronic aspect, it is possible that the power supply current of the stepper motor is insufficient, which causes the stepper motor to not have enough power to overcome the resistance. It may also be that the stepper motor driver chip is overheated, which causes the stepper motor to stop rotating before the chip cools down.

  1. Pull by external force

In addition, it is necessary to check the phenomenon of misalignment caused by external force pulling. For example, the improper placement of consumables or the power cord of the extruder may cause it to be pulled or entangled with other objects, resulting in misalignment.

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