Common Problems

Printing with engineering materials has these common problems:

  1. The material is prone to moisture, resulting in poor print quality (with the elephant foot effect)
  2. It can easily cause clogs when printing
  3. Can have poor bonding between layers when printing

Solutions and Suggestions

Dry the filament

  • Check if the package of the filament is intact. If not, please dry it before printing.
  • Dry the filament before printing as long as you are not sure if the filament is damp.
  • Drying condition for Bambu PA-CF and other engineering materials: 80℃, at least 8 hours. If you use the printer’s heat bed for drying, it needs at least 10 hours at 90 ℃ (you need to turn the filament roll over halfway, please refer to Procedure and 3mf file for drying filament with the X1C printer | Bambu Lab Wiki ). A comparison of the print quality before and after drying:
  • After drying the filament, please store itin an airtight container/bag with effective desiccant. This will help keep the filament dry for about 2 weeks.If storing it with AMS, ensure the desiccant is effective, and always remember to keep the AMS buckled. If the desiccant is found to be ineffective (turning from power-like to lumpy or pasty), please replace the desiccant and dry the filament before the next printing.

The state of AMS desiccant:

Packaging of desiccant

Use Larger Nozzles

When printing carbon fiber-reinforced engineering materials like PA-CF and PAHT-CF, do not use a 0.2 mm nozzle, otherwise, the probability of clogging will be very high. When the diameter is increased from 0.4 mm to 0.6 mm and then to 0.8 mm, the printing fineness decreases in turn, but the clogging probability also decreases in order, so the 0.6 mm nozzle is recommended as the first choice, and the 0.4 mm nozzle is the second choice (the recommended layer height is between 0.15 and 0.3 mm, and the maximum printing speed should be about 100 mm/s). Before using these materials, it is recommended to set the nozzle temperature to 280 °C, and then use an Allen key and a needle to clean the inside of the nozzle to reduce the risk of clogging during the printing process. 
Do the same if the nozzle gets clogged during printing, and make sure the inside of the nozzle is clean before the next printing. If the nozzle is clogged, please refer to Nozzle clogs | Bambu Lab Wiki to clean it.

Group models

When the time of printing each layer is too long, these materials’ Z direction bonding will get weak and the small models will be no longer strong(the previous layer has been over-cooled). So, when you need to print many small models, you should assemble them into different groups and print by object(default setting is by layer), and maybe on different plates, rather than put them on the same plate and print by layer.

Hold down Ctrl, select several models with the left mouse button and then right-click to select “Assemble” to assemble several models into one group
It is recommended to select “By object” in the “Print sequence”.
Printing by layer is not recommended

4. To strengthen your models printed with PA-CF or other CF or GF reinforced engineering filaments, you’d better get them annealed at about 80 °C for 8 hours after printing. And the best annealing temperature of Bambu PA-CF, PET-CF, and PAHT-CF is 120 to 130 ℃ (5 – 8 hours). After that, the comprehensive mechanical properties can be improved by about 10% to 20%: the annealing effect depends on the annealing temperature and time, the size and structure of the model itself, the filling density, the wall loops and other printing settings; please note that some models may shrink and warp after annealing.

5. When printing a model with support, it is necessary to remove the support structure within 2 hours to prevent it from being difficult to remove after being damp and softened, especially for Nylon (PA) such as PA-CF and PA6-CF that tend to absorb water. If it is difficult to remove the support because the prints have been placed for too long, please dry them, let them cool down, and then remove the support in time.

6. PA, PA-CF, PAHT-CF, PA-GF and other PA (Nylon) materials have relatively strong water absorption capacity, and after being used in humid air or water for a period of time, their strength and stiffness may decrease to varying degrees due to absobing water—become soft, especially for thin, slender and long prints; so, if the using scenario of the prints requires very high strength and stiffness, please avoid them. At the same time, these materials usually become tougher and more resistant to impacts, drops, and collisions when they get damp; so, if the using scenario of the prints requires only moderate and not very high strength and stiffness, you can make the prints get dampened and softened before use.In addition, fully impregnating the surface of these materials‘ products with paint, wax and other water-proof coatings can inhibit them from absobing water and getting soft.

7. Note that when drying filaments and annealing printed models, it is recommended to use devices that can provide uniform temperatures, such as Blast drying oven, and do not use microwave ovens or household ovens. Avoid too strong force or uneven heating (away from the oven’s heating area), so as to avoid damage to the filament, spool, or model due to local overload and or overheating.

Suggested settings

1. Generally, the higher the infill density is, the greater the strength and material consumption will be. To keep a balance between strength and material consumption, the Strength Presetting(6 Wall loops and 25% infill density) is highly suggested when printing big models that are expected to withstand high loads. Of course, if you can accept more material consumption, you can manually set a higher infill density for greater strength.

2. If the model size is large and the infill rate is set high, e.g. 60% (default is 15%), and warping occurs at the bottom of the model, you can adjust the infill rate appropriately. In addition, the infill pattern with more straight lines is more likely to cause shrinkage, you can change the infill pattern to spiral to reduce the risk of shrinkage. For some structural parts with high strength requirements, you can set 5 loops of walls and 25% infill rate, and try to avoid using more than 50% infill rate to reduce the tendency of shrinkage; for most non-structural parts with low strength requirements, you can directly choose the default 2 loops of walls and 15% infill rate. To get more details, you may refer to: https://wiki.bambulab.com/en/knowledge-sharing/common-print-quality-problem

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