3D Printing with Biopolymers on Textile Knitted Structures

Table of contents

1. The principle of 3D printing technology

2. Fabrics

3. Microscopic view
3.1 Cotton Single Jersey
3.2 Cotton Fleece
3.3 Cotton Pique
3.4 Double knit cotton side
3.5 Double knit polyamide side
3.6 Polyester jacquard
3.7 Polyester warp

4. CAD pattern development

5. Polylactic acid

6. Printing process
6.1 Pique
6.2 Single jersey
6.3 Fleece
6.4 Double face cotton
6.5 Double faced polyamide
6.6 Weft polyester
6.7 Jacquard polyester

7. Separation force test
7.1 Pique
7.2 Single Jersey
7.3 Fleece
7.4 Double knit cotton side
7.5 Double knit polyamide side
7.6 Weft polyester
7.7 Jacquard polyester
7.8 Jacquard polyester washed

8. Analyzing post-printing

9. Conclusion

10. Final product development

11. References

Table of figures

Table 1 Physical properties of fabrics

Table 2 Cotton single jersey

Table 3 Cotton fleece

Table 4 Cotton Pique

Table 5 Double knit cotton side

Table 6 Double knit polyamide side

Table 7 Jacquard polyester

Table 8 Warp polyester

Table 9 Pique values

Table 10 Single jersey values

Table 11 Fleece values

Table 12 Double knit cotton side values

Table 13 Double knit polyamide side values

Table 14 Weft polyester values

Table 15 Jacquard values

Table 16 Jacquard washed values

Table 17 Parameters and results

Figure 1 Fused deposition modeling sketch by CustomPartNet

Figure 2 CAD Model

Figure 3 CAM printing model

Figure 4 Printing parameters Figure 5 Print settings

Figure 6 Printer settings

Figure 7 Printing center strip on double knit CO side

Figure 8 Jacquard PES peel test

Figure 9 Pique graph

Figure 10 Single jersey graph

Figure 11 Fleece graph

Figure 12 Double knit cotton side grap

Figure 13 Double knit polyamide side graph

Figure 14 Weft polyester graph

Figure 15 Jacquard graph

Figure 16 Jacquard washed graph

Figure 17 Separation force graph

Figure 18 Printing decorative model

Figure 19 Printer printing decorative model

Figure 20 Nozzle printing decorative model

Figure 21 Final product

1. The principle of 3D printing technology

Additive manufacturing or 3D printing is the process of turning digital files into physical, three dimensional objects. This is realized using additive processes, which imply successfully laying down very thin layers of material until the object is finalized.

Since invented, it has been used for the purpose of rapid prototyping, and has evolved into a next generation manufacturing technology with the potential of allowing rapid, on site and on demand production of parts and end-products, signaling the beginning of a third industrial revolution.¹

The aim of this research is to successfully print different three dimensional structures on a variety of knitted fabrics, in order to observe the properties and the behavior of the biopolymers in these circumstances. To do so, 3 separate objects in form of thin rectangles were 3D printed on 7 different surfaces, which were later subject of a peel test that measured the adherence of the polymer to the knitted structure.

Even though 3D printing can only occur by means of additive processes, what may differ is the way layers are built to create the final object, resulting in several printing technologies. These have been classified in 2010 by the American Society for Testing and Materials (ASTM) group F42-Additive Manufacturing into 7 categories according to the Standard Terminology for Additive Manufacturing Technologies, as follows:

1. Material Extrusion
2. Material Jetting
3. Binder Jetting
4. Vat Photopolymerisation
5. Powder Bed Fusion
6. Sheet Lamination
7. Directed Energy Deposition

During the following experiments the material extrusion method was used, otherwise known as Fuse Deposition Modeling (FDM), which works with plastic filament or metal wire unwound from a coil that supplies material to an extrusion nozzle. The nozzle can regulate the flow and is able to move both vertically and horizontally, directly controlled by a computer-aided manufacturing (CAM) software package. It is also heated up to very high temperatures, so that the material can be melted and extruded in liquid form, and then harden back immediately after the extrusion. Nevertheless, for more intricate designs, an additional support is required for maintaining the shape and steadiness of the object in formation.

FDM is a commonly used technique which differentiates itself from the others by the fact that the material is added under constant pressure and continuous stream that must be kept steady and maintain its speed to enable accurate results. Also, the quality of the end product is reduced because of the nozzle radius, and accuracy and speed are low when compared to other processes. ²

illustration not visible in this excerpt

Figure 1 Fused deposition modeling sketch by CustomPartNet

2. Fabrics

The first step of this research was to procure the necessary materials on which to carry the experiments. The requirements for the fabrics were for them to be knitted structures but differ in composition or type of inter-looping, and to have different properties such as thickness, fineness or coarseness, so that the results would be comparable. After a stage of filtering, 6 fabrics were chosen, half of which made out of natural fibers, two synthetic, and one double faced.

The adherence between a textile surface and a polymer is strongly related to the structure and physical properties of the material in use, therefore the printer needs to be set accordingly, in order to enable the best results. That being said, the samples were closely analyzed to obtain information about the thickness, fineness, and microscopic appearance of the fabric, as well as fiber thickness and loop size.

The fabric thickness tester was used for measuring the thickness, whereas the fiber thickness was determined via microscope, using the option “measure distance between two points”. In the following table, a clear overlook of the composition, inter looping method and characteristics of the fabrics is given.

illustration not visible in this excerpt

3. Microscopic view

3.1 Cotton Single Jersey

illustration not visible in this excerpt

Table 2 Cotton single jersey

3.2 Cotton Fleece

illustration not visible in this excerpt

Table 3 Cotton fleece

3.3 Cotton Pique

illustration not visible in this excerpt

Table 4 Cotton Pique

3.4 Double knit cotton side

illustration not visible in this excerpt

Table 5 Double knit cotton side

3.5 Double knit polyamide side

illustration not visible in this excerpt

Table 6 Double knit polyamide side

3.6 Polyester jacquard

illustration not visible in this excerpt

Table 7 Jacquard polyester

[...]

¹ Cf. http://3dprinting.com/what-is-3d-printing/

² Cf. Christopher Barnatt at http://explainingthefuture.com/3dprinting.html 6