3D printing of spare parts! What does Triscan do?

The media has continuously been reporting about 3D printing applications in various sectors for a long time. At Triscan we are following this trend closely. However, we're not just standing on the side line looking in - we do more than that. In this article, you'll get an insight into our thoughts and actions concerning this topic as well as the technologies behind the much-discussed 3D printing.
 
It certainly does not require the imagination of a child to imagine the many ways 3D printing could change the spare parts industry as we know it today. Imagine being able to produce and deliver replacement parts at the push of a button when the demand arises, and never have to struggle with back orders. Imagine never having to look back on storage shelves with unsold parts. That sounds nice - right? But is that at all possible?
 
In the search of answers to these questions, we visited Danish Technological Institute, where the director of the department for Industrial Materials Technology, Claus Erichsen Kudsk enlightened us about the development of 3D printing. The Danish Technological Institute have been following the development of 3D printing from its very beginnings. Moreover, they have been a supplier of 3D prints and offered consultancy to companies concerning rapid prototyping (production of model models and prototypes related to product development projects), rapid manufacturing and additive manufacturing (utilization of 3D printing in manufacturing). 
 
In addition, two of our own colleagues have both an interest as well as experience within the field. Product Team Manager Asger Thybo Geertsen's interest in 3D printing is not just professionally based, but also privately, where Asger himself has invested in 3D printers and experimented with the technology. Marketing Manager Thomas Fuglsang Andersen has among others, during his seven-year career at the Danish Technological Institute, conveyed knowledge about 3D printing.
 
3D printing in the automotive industry
There are several examples of automobile manufacturers using 3D printing to produce parts. Audi, Rolls Royce, Porsche and Morgan are some examples - yes, we are in exclusively in the luxury class. As far as we know, Porsche uses only 3D prints to make spare parts for classic cars. It is probably no surprise that 3D prints have been used in the premier class of motorsport - Formula 1 - for many years. On the other hand, it is difficult to find examples of 3D printing of parts for popular cars, suggesting that the technology is not yet mature enough for wide range use in the automotive industry.  
 
An example
We recently tested our thesis on a plastic oil drain plug. Then we compared the material properties, accuracy, workmanship and price with a conventional injection molded drain plug. In terms of material properties, are we currently testing for durability and function over time. 
                                                              
               
3D-printed oil drain plug for VAG
 
 
 INJECTION MOULDING3D PRINTING
 

Nylon PA66
Heat stabilized

Nylon PA12
 Density 1,04-2,50 g/cm 1,01 g/cm
 Best tolerance ± 0,05 mm ± 0,3% (min ± 0,3 mm)
 Tensile strenght [MPa] 40-220 44-48
 Young modulus [GPa] 0,4-9,2 N.D.
 Elongation at break [%] 3,2-80 10,7-15
 Melting point [°C] 255  187
 HDT @ 0,45 MPa [° C] 100-263 175
 HDT @ 1,8 MPa [° C] 54-260 106
 
The above overview compares selected material properties between an injection molded oil drain plug (Nylon PA66) and a 3D printed (Nylon PA12). As you can see, the material properties show differences here. So, the specific material requirements and subsequent tests would determine if the selected material could be approved for our 3D printed oil drain plug.   
 
As can be seen in the pictures shown below, 3D printing does not achieve the same result as plastic injection molding. With 3D printed articles, it is clearly visible that they are composed of layers, which is not necessarily a problem, depending on their use.  
      
 
3D-printed oil drain plug to the left             
 
   
3D-printed oil drain plug to the left
 
In 3D printing, it is not always possible to adhere to strict tolerances. Again, this is a matter of necessity, and of course you have the option to rework a 3D printed part if necessary.  
Whether or not 3D printing can compete with injection-molded articles depends on the demand. With low demand and thus production of relatively few articles, 3D printing has a large production advantage, since the tooling and the time-consuming setup and startup of the production device are not required. For mass production, on the other hand, the roles are reversed. 
 
Our opinion
Based on our knowledge and insight into 3D printing, we do not believe that the technology is currently sufficiently developed to be used within the spare parts groups we offer. It must therefore also be uncertain whether other spare parts suppliers for the automotive aftermarket will benefit from this technology. In any case, we will continue to monitor developments closely to continuously evaluate potential opportunities. 
 
Overview of 3D printing
3D printing is by no means a new invention. The first 3D printers for commercial use were already manufactured in 1986 by 3D Systems Corporation in the USA. Today, 3D printing involves a variety of technologies for producing objects from a digital 3D drawing in stereolithography format (see illustration). 
 
 

STL-file - a 3D-model, where all surfaces are defined by triangulation
 
A common feature of all 3D print technologies is that the products produced consist of many thin layers. However, the method, material, and precision with which the objects are produced varies significantly. Initially, 3D printers were mainly used to make prototypes for product development purposes. However, as several technologies have been added, material selection has grown, and purchase prices have dropped, the possibility of using 3D printers for actual production has become an option.
 
The following overview shows the six most commonly used technologies - and which material categories they can work with. The variety of materials in the three categories plastic, rubber and metal varies greatly depending on the technology selected.
 
 Technology Abbreviation Material(s)
 Fused Deposition Modeling FDM  Plastic and rubber
 Selective Laser Sintering SLS  Plastic and metal
 Stereolithographi Apparatus SLA  Plastic and rubber
 Polyjet/Multi Jet Fusion PJ/MJF Plastic
 Direct Metal Laser Sintering DMLS Metal
 Digital Light Processing DLP Plastic and rubber