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Lithography-based metal manufacturing of jewelry and watch cases made from 316L stainless steel and titanium alloys

a speech by Carlo Buckhardt

Abstract

In order to overcome existing restraints in the in-service behaviour of currently available additive manufacturing (AM) materials’ sets, an advanced production method for high performance technology metals was developed on the basis of a modified vat polymerisation-based (VP) printing for metal powders. The new lithography-based metal manufacturing (LMM) process is able to photoharden highly filled innovative metal-photopolymeric binder.
After debinding and sintering, the fully dense metal AM parts will provide various advantages such as superior properties with respect to cracks or internal stress when compared to laser-based powder bed fusion (L-PBF) AM parts. LMM is suitable to build very detailed, complex structures with a minimum of after-treatments without need for support structures, exhibiting superior surface quality, having less demanding requests with respect to powder particle size/morphology and allowing effective re-use of the feedstock materials.
In the paper, the LMM process will be explained in detail, its suitability for the production of jewellery and watch pieces will be demonstrated for stainless steel type materials and titanium alloys on various samples, an outlook for precious metal powders will be given

Pforzheim University

  • founded 1899
  • one of the biggest Universities for Applied Sciences in Germany (~6.000 students)
  • threefaculties: Business, Economics & Law Engineering Design
  • 29 Bachelor-and 17 Master-Courses
  • one of 7 fully certified universities in Germany

Institute for Precious and Technology Metals

Partner oftheregional precision engineering industry

  • contract research, serial inspections, damage analyses, expert opinions, production optimisations, etc.
  • fully equipped materials lab; incl. 2 SEM, FIB, EDX/XRD, Laserscan, DTA, mechanical testing, corrosionetc. (DAkkSakkredited) National and international research partner
  • recycling of rare earth metals/permanent magnets
  • additive manufacturing of metals Head: Prof. Dr.Carlo Burkhardt
  • 4 national projects, 3 international multilateral (EU) projects (>30 M€ overall budget)

LMM Additive Manufacturing

Lithography-based Metal Manufacturing

  • basedon theVat-PolymerizationPrinciple
  • verygoodsurfacecharacteristics
  • verygoodgeometricalprecision
  • nothermal distortions
  • materials: stainlesssteel, toolsteel, titanium, […]
  • suitable also for non-weldable materials
  • printing speed: max. 16 cm³/h
  • suitable for:
  • smalland very small parts(<30g)
  • smalltomoderate quantities

LMM-Process

How it works

LMM-Process

Sintering

LMM-Process

Shrinkage

LMM-Process

Precision

  • finished part tolerances up to ±0.5% of nominal dimension possible
  • stair-step effect due to layer-by-layer production

LMM-Process

Surfaces

LMM-Process

Some parts

MetShape GmbH

  • Start-up and spin-off of Pforzheim University as of 01.04.2019
  • funded by the program “Young Innovators” of the Ministry of Science, Research and the Arts Baden-Württemberg
  • specialized in additive component manufacturing using the Lithography-based Metal Manufacturing process (LMM) and related development services
  • main focus:
    • conducting feasibility studies for components and materials
    • small scale productions
    • installationof process chains for in-house production