The phenomenon of "warping" is one of the most common problems in 3D printing, particularly when working with thermoplastic materials that tend to shrink during the cooling phase of the material. The term "warping" means the deformation or lifting of the edges of the model from the printing plane, resulting in loss of adhesion and sometimes total compromise of the part. Understanding well what warping is, why it occurs, and how to prevent it is essential to achieving high-quality prints and avoiding wasted time and material. In the following text, we will look at all these aspects in detail, providing theoretical and practical explanations on how best to handle this problem.
The term "warping" refers to a physical deformation of the part being printed. Specifically, the outermost layers of the model (especially those in contact with the printing plane) tend to lift upward. In some cases, this lifting may manifest itself with minimal curvatures barely visible; in others, especially if preventive measures are not taken, the deformation may become so pronounced that the entire corner or side of the part becomes detached from the printing plane, causing aesthetic defects and, in the worst cases, compromising the functionality of the printed model, with the possibility of even damaging the nozzle due to possible collisions with the part.
Warping is a phenomenon that mainly depends on the temperature range and cooling rate of the extruded material. In the FDM (Fused Deposition Modeling) 3D printing process, filament is heated until it becomes fluid and then deposited layer by layer. As the material cools, it tends to shrink and contract. If this contraction does not occur evenly, internal stresses occur in the solidified part, which can cause edges to lift.
Warping can occur at different stages of printing, but it is most common especially in the first few layers, when the material is beginning to solidify and form the base of the model. The first few layers are critical: if adhesion to the plane is not optimal or if the bed temperature (or ambient cooling) is not properly controlled, significant temperature differences are created between the part closest to the plane and the upper layers. This results in uneven cooling and, consequently, warping.
However, warping can also occur in the subsequent layers, especially for objects with wide bases or high thicknesses. Under such circumstances, the thermal gradient between the newly deposited hot layers and the "older" ones can cause internal stresses in the part, contributing to uplift. Generally, the bulkier the object, the longer it will take to cool and thus the greater the risk of different temperature gradients being created along the surface of the part leading to different cooling rates.
Thermal contraction: Thermoplastic materials undergo contraction as they move from molten to solid state. When the molten filament encounters the already partially cooled layers, a temperature difference is generated that, if unmanaged, creates internal stresses. This phenomenon is most evident in filaments with a high coefficient of thermal expansion, such as ABS.
Wrong print bed temperature: If the print bed is not hot enough, the layers in contact with the surface will cool too quickly compared to the layers deposited later. At the same time, an excessively hot print bed may promote initial adhesion, but, if not properly controlled, can induce a strong temperature gradient as you go up in height.
Uneven cooling: Cooling too quickly, such as in very cold or drafty environments, accentuates the formation of tension between layers. For this reason, many professional 3D printers work in enclosed rooms or heated chambers in order to maintain uniform and consistent temperatures.
Insufficient adhesion to the plane: When the first layer does not adhere well to the print plane, any slight contraction can cause the corners or edges of the part to lift up.
Complex geometries or large surfaces: Patterns with large base surfaces, sharp edges or particularly "thin" areas are more prone to warping because stresses are not evenly distributed.
Printing speed and cooling settings: Too high a printing speed, combined with insufficient or excessive cooling settings, can alter the thermal balance necessary to prevent warping.
Materials prone to warping
All thermoplastic filaments, to varying degrees, can be subject to warping. ABS is known to be one of the most problematic materials in this respect because it has a rather high coefficient of thermal expansion. This means that the volume difference between the molten and solid states is greater and therefore the stresses involved are more important.
PLA, while being "easier" to print than ABS, is not exempt from warping, especially if printing is done in very cold environments or if there is not proper airflow. PETG is somewhere in between: it has less thermal shrinkage than ABS, but still requires good management of the print bed and cooling to avoid warping.
Special materials, such as nylon or polycarbonate, can present even greater challenges, which is why heated chambers and beds with high temperatures are often recommended to maintain dimensional stability during printing.
Prevention of warping relies on a set of best practices involving proper printer setup, selection of appropriate materials and adhesion surfaces, and control of printing parameters. Below, we review some basic strategies.
Adjust the temperature of the printing surface
Correct temperature: Consult the specifications of the filament. ABS often requires bed temperatures between 90°C and 110°C, while PLA may require temperatures between 50°C and 70°C. Keeping the bed at the right temperature reduces the thermal gradient between the first layer and subsequent layers.
Even heat distribution: It is important that the printing bed has an even heating system. If some areas of the bed are cooler than others, it will create weak points from which lifting may begin.
Improve adhesion to the bed
Cleaning the Platen: Before starting printing, clean the printing surface thoroughly to remove dust, oils and residues from previous prints. The use of isopropyl alcohol or specific cleaners improves adhesion.
Special surfaces: It is important to select the correct printing plate according to the material you want to print. A coated printing plate can be found for each material to improve adhesion of specific materials.
Use of glues or lacquer: Applying a thin layer of glue stick, hairspray (specifically for high temperatures) or adhesives specially made for 3D printing to the platen can increase adhesion, especially for notoriously problematic materials such as ABS.
Manage airflow and ambient temperature.
Enclosed environment: If possible, use a printer with an enclosure or build one around the printer to keep the internal temperature constant. This reduces sudden drops in temperature and exposure to drafts.
Cooling fan: Adjust the speed of the fan. For PLA, a more active fan can help solidify the layers, but be careful not to create excessive thermal shock. For ABS, often reduce the fan to a minimum to avoid too rapid cooling.
Specific print settings
Brim, Raft or Skirt: Printing a "skirt," a "brim" (an additional edge that increases the contact area with the plane) or a "raft" (a base of multiple layers underneath the model) can increase the stability of the part and promote edge adhesion.
First layer height: A first layer that is well flattened on the plane (but not excessively so) improves adhesion. Many slicers offer specific settings to adjust the height of the first layer and the printing speed to ensure optimal contact.
Print speed: Printing at too high a speed can cause vibrations and imperfections that undermine the adhesion of the first layer. A slower speed in the first few layers helps anchor the part better.
Use of a "heat chamber" or heated chamber.
For very sensitive materials such as ABS or polycarbonate, one of the most effective solutions is to print in a heated chamber, which is an enclosed environment where the temperature is constant and appropriately high (often 40-50°C or more). This reduces the thermal gradient between layers and minimizes the risk of uneven contractions.
Choice of filament
If warping persists despite the measures taken, it may be beneficial to change filament types. Some manufacturers offer modified versions of ABS or PLA enriched with fibers or additives that reduce thermal expansion, improving stability. There are also "blend" filaments specifically designed to minimize warpage during printing.
Check filament moisture: A filament that has absorbed too much moisture (especially nylon and PETG) can cause extrusion and adhesion problems, which in turn promote warping. Always store filament in airtight bags with desiccants, dry filament before use as specified by the manufacturer, and use desiccators during printing.
Check the flatness of the substrate: A printing substrate that is not perfectly flat makes it difficult to achieve even adhesion. If some areas are higher or lower, the deposited layer may be too thin (causing under-extrusion and poor adhesion) or too thick (with excess material and possible lumps). It is important to level the platen regularly and, if the printer allows, use self-leveling (ABL) systems.
Optimize part design: When possible, take action on the geometry of the object to reduce the risk of warping. Avoid excessively thin edges or extensive base surfaces; if not possible, consider introducing holes or reinforcing structures. Sometimes rounding edges or dividing the model into several parts for assembly can reduce internal stresses.
Experiment with retraction and cooling speed: Small changes in retraction (retraction) and fan speed settings can optimize filament deposition, avoiding lumps and excessive cooling.
Monitor the first few layers: It is good practice, especially for important or long-lasting prints, to carefully check the adhesion of the first few layers. If you notice signs of lifting, you may need to stop printing and adjust parameters to prevent an unrecoverable defect.
Use advanced slicing software: Some programs offer specific settings to prevent warping, including adjustable platen temperature settings for different layers, variable print speeds, brim and raft customization, and more.
Warping is a phenomenon that affects both beginners and professionals in 3D printing. It can sometimes seem like an inescapable doom, but in reality it is the result of very specific physical factors: from the thermoplastic nature of filaments to environmental printing conditions, through adhesion and slicer settings. Fortunately, once the causes are understood, effective countermeasures can be taken.
Experience and experimentation play a key role: each printer, filament, and working environment may require different adjustments. With time and careful observation of prints, it becomes easier to recognize signs of potential warping and take preventive action.
However, if you want to avoid these problems altogether and achieve high-quality results without having to go through time-consuming testing and calibration, relying on a online 3D printing service like Weerg is a smart solution. With professional machinery, advanced materials and strict quality control, Weerg makes it possible to receiveperfectprintswithout the risk of deformation or defects.