8 factors affecting 3D printing accuracy

With the rapid development of modern science, more and more people have access to a 3D printer, and experience the charm of 3D printing. At present, fused deposition molding (FDM) is the mainstream technology of desktop 3D printer. The working principle FDM is that the filamentous thermoplastic material is heated and melted by Nozzle and extruded，and then formed layer by layer as a completed products. It mainly uses polymers such as ABS and PLA as printing materials.

Some people are concerned about the accuracy of products printed by 3D printers. How accurate is the product printed by the 3D printer? What factors affect the printing accuracy of 3D printers? Today, we will take fused deposition molding (FDM) as an example to explore six factors that affect the accuracy of 3D printing products. I sincerely hope this article will be helpful to 3D printing users.

1. Shrinkage of the printing consumables.

The printing consumables/printing material (like PLS and ABS）change its form from solid to liquid and then to solid during the 3D printing process. When the material is solidified and formed, the material will shrink a little bit.

The deformation caused by shrinkage will affect the accuracy of the finished products printed by the 3D printer.

If the printing consumables that you want to use has been decided and confirmed, what can we do to increase the printing accuracy? Usually, we can compensate for the material shrinkage by setting the value of the “shrinkage compensation factor” in the three directions of X, Y, and Z in the slicing software.

2. 3D printer frame structure

The manufacturing and assembly accuracy of the 3D printer itself and the vibration in the working process will affect its printing accuracy.

The frame structure of the printer and the stiffness of the materials have a great impact on its printing accuracy. The frame of our 3D printer adopts industrial grade aluminum profile, the whole machine is strong and stable. With sturdy construction, the machine has very limited vibration in the printing process. At the same time, Z-axis is with double screw design, good synchronization and more stable movement, thus it can guarantee more accurate printing effect. The more stable of the printing platform, the more accurate of the printing product a 3D printer can offer.

3. Nozzle diameter of the 3D printer

The diameter of the 3D printer nozzle determines the width of the extruded material, and affects the fineness of the finished product. Using a smaller diameter of the printer nozzle, you are more likely to get a finer product than with a larger diameter of the printer nozzle.

3D printing prints/constructs objects layer by layer, so the setting parameter of its layer thickness will also affect the fineness degree of the finished product: if you choose a nozzle with a large diameter, the layer thickness will also be thicker. In this way, the printed product will be rougher (although it will print faster); On the contrary, if you choose a small diameter nozzle, the layer thickness will be thinner, so the printed product will be finer.

4. Nozzle temperature

The nozzle temperature has great impact on the bonding properties, stacking properties, material flow rate and extruded material width. Therefore, the temperature of the nozzle can neither be too low nor too high. If it is too low, the viscosity of the material is high and the material extrusion speed is slower; if it is too high, the material will tend to be liquid, the viscosity coefficient will decrease, and the fluidity will be enhanced, and the extrusion speed will be too fast to print a high accurate object. Therefore, the temperature of the Nozzle should be set properly according to the properties of printing consumables, so as to ensure that the extruded material is in a state of melt flow.

5. Molding room temperature

Molding room temperature will affect the thermal stress of the printed product. Although high temperature helps to reduce the thermal stress, the product may get wrinkled easily. If the temperature is too low and the material extruded from the nozzle cools too fast, it is easy to increase the thermal stress and cause the warping of the product. In order to print products successfully when using ABS material, it is better to keep the temperature of the forming room at 50-60 degrees Celsius; while when printing with PLA material, it is necessary to have good ventilation and heat dissipation, and there is no need to maintain a constant temperature.

6. 3D print layer thickness.

The thickness of the layer is the height of the layer when slicing. Because each layer has a certain thickness, it will produce layer pattern on its surface. The higher the layer thickness is, the more obvious of its layer pattern, and lead to more roughness on the product surface.

For the FDM (Melt deposition molding), it is impossible to eliminate the layer pattern completely. But we can set a smaller layer thickness to achieve a smaller layer pattern, and increase fineness of the printed products.

7. Compensation value.

This refers to the value difference between the actual machining contour line and the design/draw contour line of the product. If you want to print the product with high precision, we suggest that you should set the compensation value when 3D modeling, and it is especially important to set the compensation value for the inner hole. What compensation value should i set?

The setting of the compensation value is related to the diameter of the extruded material and the performance of the 3D printer. Users of 3D printers need to make a few trails and find the most appropriate compensation value in the process of using the printer.

8. Extrusion speed and printing speed

When the printing speed is reasonable, the larger the extrusion speed, the larger the cross-section width of the extruded material; when the extrusion speed increases to a certain value, the extruded material may adhere to the nozzle and rub against the outer surface of the product.

When the printing speed is faster than the extrusion speed, there will be insufficient extrusion, and cause holes/bubbles inside the product, and it is difficult to form properly.

On the contrary, when the printing speed is slower than the extrusion speed, the fused material may get accumulated on the nozzle, surface of the printed product is uneven, and there are bumps on the surface, which affects the printing quality.

If we want to get 3D printing products with high printing accuracy, we should set the appropriate printing speed and extrusion speed. To have a comprehensive understanding of 3D printing technology and equipment, to analyse various factors that affect 3D printing accuracy, and to make optimization, we improve 3D printing accuracy and produce exquisite printed products .