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3D Printing

The HRZ offers a 3D printing service that allows both employees and students of the University of Bonn to have models made here in house with our own 3D printer - whether models for courses or prototypes.

We offer a 3D printing service that gives employees, institutes and students of the University of Bonn the opportunity to have objects produced promptly and inexpensively. Whether for research purposes, for teaching events or as prototypes, we can provide you with prints in various qualities and material designs.


The prints are printed either with an FDM printer from Ultimaker or with an SLA/LFS printer from Formlabs. Depending on the printer and print job, the price, maximum print volume, possible material selection and quality of the print differ.


The maximum print volume for PLA printing is 21.5 x 21.5 x 30.0 cm (W/D/H).
The maximum print volume for SLA printing is 14.5 × 14.5 × 18.5cm (W/D/H).


If you would like to use our 3D printers or you would like to establish a longer-term cooperation between your institute and the 3D printing service of the HRZ, please contact us: You can call, write an e-mail or come by in person during our opening hours. We will then be happy to discuss the further procedure with you.

 

Phone: 0228 73-2751

Mail: [Email protection active, please enable JavaScript.]

 

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The Modelling Tool

At the HRZ we work with the freeware program TinkerCAD (https://www.tinkercad.com). On the website it is possible to import a stl, obj or svg file and then develop it into a finished model and make subsequent improvements, be it a logo, a change in proportions or size. Likewise one can simply create one or more projects freely with form templates and release them for others to view and collaborate. Tinkercad is a cloud based solution. Someone who does not want to entrust their data to a cloud should use tools like Blender (free of charge) or Autocad or Fusion 360 (both can be found https://www.autodesk.de). On websites such as https://www.thingiverse.com/, existing templates can be used free of charge. As far as size is concerned, for more complex and larger projects it is possible to complete the model in individual parts that can be joined together later.

3D Printing Preparation

To prepare the print we use the free Ultimaker Cura software. Here we pay special attention to the printing accuracy, depending on the model and whether a support material (polyvinyl alcohol, PVA for short) is required. This is printed together with the actual model, but is water soluble and can be removed without leaving any residue.

The actual printing material is polyactide (PLA). It is a low odour, is produced on the basis of lactic acid/maize starch and is easy to process.

At the moment we are using the colours

PLA Black

PLA Transparent

PLA Silver grey

PLA Pearl White

for printing.

Printing Method

As far as the printing process is concerned, there is more than one possibility with 3D printing. We use the fused deposition modelling (FDM) process. In this process, the print head presses hot plastic onto the printing plate in webs. The model is divided into inner and outer shell, which provide the main factor for the stability of the model, and infill, which stabilizes the print inside with a kind of grid structure. The support in turn supports overhangs outside the print object.

Important before printing!

Tensile load in layer direction

The bond between the individual layer/layers is not as strong as the individual track, so it is advisable to play against the layer under load.

Accuracy of fit

An FDM print shrinks minimally and because the first layer is pressed on the printing board, inaccuracies can occur.

Traction

The first layer of a print is "thicker" and automatically does not cool as quickly, so the adhesion surface should be considered.

After Printing

Once the printing process is complete, the support material must first be dissolved in a water bath. In the next step the surface of the model can be cleaned with very fine sandpaper under running water and all edges can be smoothed. In the last step you can dye or varnish the finished result.

Prices

The costs for 3D printing are as follows:

6€ per print flat rate.

0,15€ per gram PLA filament

0,45€ per gram PVA filament (water soluble support material)

Payment is made by means of a direct debit authorisation via the institutes. Students pay in cash.

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