Feature article: PIM International, Vol.1 No. 2 June 2007, pages 34-37, 1724 words

Author: Peter Vervoort, ELINO Industrie Ofenbau, Germany

ELINO Industrie Ofenbau, Carl Hanf GmbH + Co.KG, Zum Mühlengraben 16-18, D-52355 Düren, Germany

Introduction

Elino Industrie Ofenbau, of Düren, Germany, recently completed the installation of a new continuous MIM debinding and sintering system for ITB Precisietechniek, The Netherlands. This report reviews the technological developments to be found in this innovative furnace.

Debinding and sintering steps in the MIM process have traditionally been carried out in batch type furnace systems. First attempts with continuous processing, using modified PM sintering furnaces demonstrated that continuous processing is possible and can provide a substantial reductions in production cost. Recently MIM parts producers have encountered growing interest from the automotive industry. In order to meet the demand for larger parts and reproducible process conditions, a new type of continuous debinding and sintering furnace has been developed. This MIM furnace system features three process units, each adapted to specific process step requirements. In this article the new furnace system is described together with actual results on commercial MIM parts.

Outline of thermal processing steps for MIM

A MIM feedstock for steel powder usually consists of 60 vol.% metal powder and 40 vol.% of binder, which equals about 8 wt.% of binder content. For comparison, powder mixtures used in the conventional PM process usually only contain 1 wt.% of anorganics (lubricants)

Removing the large amount of binder (at least 8 times as much) from the injection moulded part is clearly more complex. The removal of all binder during the heat-up phase of the sintering process, as is common in conventional PM [1], would cause ...

Further sections of this article include:

- Catalytic debinding and equipment
- Thermal residual debinding and sintering
- Integrated furnace system
- Conclusion

Figures and Tables:

Fig. 1 A selection of MIM parts produced in the new continuous debinding and sintering furnace (Courtesy ITB Precisietechniek, The Netherlands)

Fig. 2 Schematic representation of the catalytic debinding system

Fig. 3 View of a load tray in the sintering zone at an operating temperature of approx. 1360°C

Fig. 4 Integrated MIM continuous furnace (courtesy ITB Precisietechniek, The Netherlands)

Fig. 5 Comparison of cycle time between batch and continuous MIM processing