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TGA-Crucible: High-performance ceramics for thermal analytics

Starting point:

Highly purified ceramics are predominantly used as sample holders or receptacles in the thermic analysis of raw materials, e.g. crucibles or pans. Thermogravimetry (TGA) is the process of measuring the loss in mass of a sample at increasing temperatures, caused, for example, by vaporization of volatile matter. It is required to have even heat distribution around the sample and constant air circulation to allow waste gas dissipation.
  
Due to conventional manufacturing methods, currently available sample holders have a very basic form, usually cup-shaped, and thus generate concentrated waste gas and heat-accumulation at the base of the cup. Phenomena such as this, caused by sample holders, can eventually influence the measurement results.
  

Project LabCer (University of Technology Vienna, Lithoz)

  • evaluation of LCM technology concerning the production of ceramic crucibles for high-temperature analysis
  • testing of temperature stability of Lithalox HP500 Alumina
  • design of new crucible geometries for specific sample materials (glass fiber reinforced plastic)
  • significant improvement of heat distribution within sample area
  • more homogenous dissipation of gaseous components during heat treatment

 

Challenges:

  • miniaturization and highly complex geometries realizable only with great effort when using conventional manufacturing techniques
  • highly purified and stable ceramic raw materials are required
  • appropriate mechanical properties with high-temperature applications
  • high costs due to design variations in the trial phase

 

Solution:

  • design and production of complex crucible geometries using LCM-technology
  • material: Lithalox HP500, highly purified alumina

 

Advantage:

  • production of highly complex geometries easily realizable with the CeraFab 7500
  • due to tool-free simultaneous production no increase in expenses compared to conventionally obtainable “basic” crucibles
  • Lithalox HP500 as highly purified alumina is chemically inert and has mechanical properties suitable for the necessary complex geometries of the crucible.

 

Conclusion by Prof. Jürgen Stampfl, TU Wien, Inst. of Materials Science:

"Using the LCM procedure, we are able to manufacture ceramic parts of outstanding quality, which are routinely put to use as crucibles during thermic analysis. In addition to meeting the standards of quality, LCM facilitates much more economical manufacturing compared to previous production methods."

 

Osteoconductive and Bioresorbable Bone Replacement Material

Starting Point:

Due to their osteoconductive and bioresorbable properties, the ceramic raw materials tricalcium phosphate and hydroxyapatite are perfectly suited for bone replacement material and the production of scaffolds.
  
Scaffolds are implants of defined form and pore structure that are placed inside the body to treat substantial bone defects caused by accidents or tumor removal procedures. Bioresorbable implants are absorbed into the body and converted into endogenous bone tissue. Extensive knowledge of the inner structure that optimizes bone growth is needed for the development of newer scaffolds, and pore design plays an essential part in achieving the best possible osteoconductivity.

 

Challenges:

  • optimizing pore structure for optimal bone growth
  • production of various complex pore structure designs, adapted to match mechanical strains
  • searching for efficient methods for the production of patient-specific implants from batch size 1
  • flexibility in material selection

 

Solution:

  • fast production via LCM procedure
  • available materials: tricalcium phophate and hydroxyapatite

 

Benefits:

  • fast, inexpensive realization of different design variations to achieve perfect osteoconductive properties
  • fast and inexpensive production of test bodies for in vivo and in vitro tests
  • easy realization and testing of different design variations
  • particularly high feasibility of small passageways of up to 0,4 mm in diameter
  • web thickness of less than 0,3 mm practicable
  • easy customizability of implants
  • variation of the unit cell

 

Concluding Statement by Prof. Franz E. Weber, University of Zurich, Center for Dentistry

“Concerning basic research in the field of bone replacement material design, the LCM procedure is an incredibly attractive manufacturing method, even for non-engineers. Especially the combination of freely choosing material and design opens up completely new possibilities!”

 

 

The Contact Holder of a Tribological Sensor

   

Starting Point:

Complex contact holders are needed to manufacture novel tribological sensors. Because of the particular operating conditions (high temperatures, electrical isolation), it is necessary to apply high-performance ceramic.

 

Challenges:

  • to position the tribological sensors as close as possible to the contact point, a very compact construction is necessary
  • realization of a range of miniaturized functional elements within a component
  • due to minimal size the necessary design complexity is hardly feasible with conventional technology

 

Solution:

  • production via LCM-technology
  • employed material alumina

 

Benefits:

  • by using LCM technology functional prototypes can be produced quickly and cost efficiently
  • easy realization and testing of highly diverse design models
  • time efficient manufacturing through omission of tools
  • especially successful realization of passageways 0.4mm in diameter

 

Conclusion Oliver Kriese, Senior Manager CIM Company Robert Bosch GmbH:

“Especially in the early phases of product development, when the design has not yet been fully finalized, the LCM-technolgy is a very attractive realization method for prototypes. In particular, the combination of functional material and high design complexity opens up a whole new range of possibilities!”

  

A new type of static mixer with variable channel design

Starting point:

In order to mix two or more components together, static mixers are used for many areas of chemical processes and techniques. Concerning microsystems the focus is on minimizing the diffusion path and the total volume of the component.

Ceramics offer excellent properties in high temperature resistance as well as chemical resistance.

 

Challenges:

  • production of structures with highly complex internal geometry using high-performance ceramics
  • implementation of supply systems for the distribution of different materials

 

Solution:

  • To reduce the diffusion paths for the mixed materials after exiting the structure, different designs have been developed. These designs are based on honeycombs in which the various materials flow through adjacent channels and are thus finely dispersed.
  • By introducing cut-outs between the channels and flow guiding elements inside the channels mixing can already be accomplished within the structure. Alternatively, the channel diameters can also be varied.
  • Production of the structures with the LCM-Technology of Lithoz and the corresponding alumina suspensions

 

Benefits:

  • Realization of high-performance ceramic components with a complexity that could not be produced until now
  • The change of the channel diameter also achieves a change in speed, and this results in a relative change of pressure.
  • (reduction of cross section à increase in speed à decrease of pressure
  • In combination with the adjacent channel, which has its maximum diameter in the area of the connection, the mixing between these channels takes place due to the pressure difference.

 

Conclusion: Dipl.-Ing. Uwe Scheithauer

„The LCM-Technology of Lithoz makes it possible to produce high-performance ceramic components with geometries that were not feasible before.”

 

Production of Sensor mounting with LCM-Technology

Current Situation

Sensor mounting parts are used in the field of measurement and testing technology frequently under extreme conditions. Beside high thermal and chemical resistance the mounting parts have to be electrically insulating.

  

Because of these specific requirements ceramics are the material of choice due to their excellent material properties for the production of sensor mounting parts.

  

Next to the specific material requirements this case study shows the necessity of various design alterations (e.g. length) regarding the position of the sensor mounting part. The above mentioned design shows an example of a part being produced with PIM, which can only after the production of suitable tools work cost efficiently with very high quantities.

  

Production of sensor mounting parts via powder injection moulding

  • Cost efficient production of lot sizes of 100.000+
  • Production time for sensor mounting parts: 4pcs/minute
  • Production of a multi-component tooling due to the production part complexity
  • Tooling costs: € 25.000
  • Production time for tooling: 2 months

  

Challenges:

  • Very high costs for small scale series up to a few hundred pieces
  • Design alterations and consequently tooling changes lead to high additional tooling costs
  • Long tooling production cycles hinder a fast market introduction of new products

   

Solution:

  • Production of sensor mountings using the LCM-technology by Lithoz
  • Material: Aluminium oxide
  • Production time: 16 pieces / 10 hours

   

Benefits:

  • Cost-effective production method for small scale series up to 800 pieces
  • No tooling costs because the parts are produced directly from CAD-data
  • Design variations can be realized very easily and fast directly from the computer facilitating a fast market launch of new products
  • The sensor mountings which are produced with the LCM-technology have the same shape and the same mechanical and chemical properties as conventionally produced parts!

  

Conclusion of Dr. Johannes Patzer:

"The presented case study shows that the LCM-technology of Lithoz is a useful and cost-effective supplement for powder injection moulding. The LCM-Technology offers a tool-free manufacturing process with which small scale series and shape variations can be realized very quickly and inexpensively. The manufactured components are in their properties identical to conventionally manufactured components."

Jewel Bracelet made of High-Performance-Ceramics

The situation so far:

Established Viennese souvenirs quite often lack in finesse, temporary design demands and esprit. But Vienna has more to offer than Mozart, Sissy and Klimt. The city requires souvenirs which reflect the diversity as well as the innovative and trendsetting mindset of Vienna.

 

Viennese-Souvenir Project

With her project, Désirée Heusl developed a charm bracelet with small and very detailed pendants reflecting the uniqueness of Vienna. May it be the city´s landmarks, your favourite coffee-house, a legendary club or a traditional dish - for each of the unique Viennese characteristics a ceramic pendant can be collected. Finally you can assemble the individual charms on your bracelet and take with you the impressions and experiences of your trip to Vienna.

  

 

Challenges

  • Material reflects the innovative character of Vienna and features exceptional wearing comfort
  • Development of unbreakable and very detailed 3-dimensional geometries
  • Fast and cost efficient production of different pendants
  • Development of a stringent material concept

 

Solution

  • Production of pendants and chain links with the LCM-Technology of Lithoz
  • Material: High-purity alumina

  

Benefits:

  • Fast and cost efficient realisation of various geometries
  • Due to exceptional material properties of high-performance-ceramics the produced parts feature highest toughness with very fine details
  • Development of a stringent material concept through integration of 3D-printed chain link segments
  • Extraordinary wearing comfort due to exceptional material properties of high-performance-ceramics (hypoallergenic)
  • Material and process symbolise the innovative power of Vienna

  

Conclusion by Désirée Heusl

“As an Industrial Design Student it is in general very interesting for me to experiment with different materials and manufacturing processes. Particularly the new innovative digital manufacturing technologies offer exciting possibilities. For my project the cooperation with Lithoz was a unique possibility to combine these new technologies with traditional jewellery.”  

 

Pneumatic intracardiac-catheder-pump with high-performance ceramics

  

The situation so far:

Currently available heart pumps use an electrical power unit (stimulus) which leads to heat development causing possible damage of blood corpuscles.

 

  

Projekt Assistocor (TU Vienna, MedUni Vienna):

  • Manufacturing of a mechanical heart pump with a helium gas power unit
  • Hermetic decoupling of power unit and pump part
  • Significant increase of pump capacity of the heart
  • Temporary, (post-operative) pump assistance of the heart after surgery
  • Combination with intra-aortal balloon pump for optimized blood supply of coronary vessels possible

  

Challenges:

  • Small and highly complex geometric shapes only possible with huge effort
  • Biocompatible materials with matching mechanical properties necessary
  • High initial costs due to design variations during prototype production/phase

 

Solution:

  • Production of complex components of the heart pump with LCM-technology by Lithoz
  • Material: Aluminium oxide

 

Benefits:

  • Small and highly complex geometric shapes can be easily manufactured with the CeraFab 7500
  • Cost efficient prototyping through tool-free manufacturing in parallel production (more than 10 design variations)
  • Aluminium oxide features good biocompatibility and suitable mechanical properties for complex and small parts

  

Summary of Ao. Professor Dr. Margit Gföhler:

"The 3D-Priniting technology for aluminium oxide developed by Lithoz enabled us to implement a cost-effective prototyping process for such a highly complex medical product. Aluminium oxide is a perfect fit for miniature parts due to its biocompatibility and mechanical properties."