**6. References**


After single or multiple uses the wicking agent accumulates a certain amount of organic phase – binder degradation products. This phase decreases the porosity of the wicking agent and thus its capillary-extraction ability. However, it can be regenerated by heating it to around 600°C, where all the organics burn. In practice, a wicking granulate with different amounts of residual organic phase can be used for debinding different parts. Small parts are debinded in the embedment, which is rich in organics, whereas the large parts are debinded using freshly regenerated granulate with a maximum capillary-extraction ability. As a

Removing the organic binder from the powder-injection-molded parts with the use of highly a porous granular embedment has been shown to be an effective method. It offers many benefits, such as shorter debinding time due to capillary extraction. Also, it guarantees a gentle physical support for the parts and therefore reduces certain flaws, such as distortion and cracking. Wick-debinding also has an important drawback, such as the practical problems of cleaning the debinded bodies. These drawbacks are the reason, that wick debinding is avoided if possible. In the case of high pressure injection molding it is possible to avoid using the wick embedment because of the use of high melting point

However in the case of low-pressure-injection molding, where the debinding process is even more delicate the use of wick-debinding has a firm place. Furthemore, future improvements in wick-debinding and the developments of novel procedures can make this highly effective way of removing the binder from injection-molded parts easier to apply and more

Bao Y.; Evans J. R. G. (1991). Kinetics of Capillary Extraction of organic Vehicle from

Bauer W.; Knitter R. (2002). Development of a rapid prototyping process chain for the

Bouzid M.; Mercury L., Lassin A.; Matray J. M.; Azaroaual M. (2011). In-pore tensile stress

*Interface Science.* Vol. 355, No. 2, (March 2011), pp. 494 - 502, ISSN 0021-9797 Cetinel F. A.; Bauer W.; Muller M.; Knitter R.; Hausselt J. (2010). Influence of dispersant,

Curry J. D. (1977). US patent number 4011291: Apparatus and method of manufacture of

Dakskobler A.; Kosmač T. (2009). Rheological properties of re-melted paraffin-wax

Vol. 8, No. 2, (March 1991), pp. 81 - 93, ISSN 0955-2219

(August 2002), pp. 3127 - 3140, ISSN 00222461

2010), pp. 1391 - 1400, ISSN 0955-2219

(July 2009), pp. 1831-1836, ISSN 0955-2219

Ceramic Bodies. Part I: Flow in Porous Media. *Journal of European Ceramic. Society*,

production of ceramic microcomponents. *Journal of Materials Science,* Vol. 37, No. 15

by drying-induced capillary bridges inside porous material, *Journal of Colloidal and* 

storage time and temperature on the rheological properties of zirconia-paraffin feedstock for LPIM, *Journal of European Ceramic. Society,* Vol. 30, No. 6, (Januar

articles containing controlled amounts of binder, filed September 1975, published

suspensions used for LPIM, *Journal of European Ceramic. Society*, Vol. 29, No. 10,

result, the embedment can thus be consequently used for ever smaller parts.

polymeric binders in addition to the low melting point wax.

**5. Conclusion** 

popularize in the industry.

March 1977

**6. References** 


**5** 

*Japan* 

Kazuaki Nishiyabu *Kinki University,* 

**Micro Metal Powder Injection Molding** 

Powder injection molding (PIM), which encompasses metal powder injection molding (MIM) and ceramic powder injection molding (CIM) is a net-shape process for the manufacturing of high volume and high precision components for use in a variety of industries. The micro-miniaturization of dimension and structures in MIM is facing with various technical problems, such as incomplete filling to narrow cavity, failure in demolding of fragile green compacts, and deformation in debinding and sintering process. Therefore micro MIM (μ-MIM) process is a more sophisticated process for tiny metal components and micro structured parts. This chapter introduces a general flow of MIM process, the material properties of the feedstock and focuses on the unique phenomena in the micro injection molding and the filling behaviour. A flow simulation of micro gear and micro dumbbell tensile specimen will be carried out and the flow pattern by short shot test and internal pressure measured will be compared to the simulation results. The production method of micro sacrificial plastic mold insert MIM (μ-SPiMIM) process has been proposed to solve drastically the specific problems involving the miniaturization of MIM parts. The sacrificial plastic mold (SP-mold) is prepared by injection-molding polymethylmethacrylate (PMMA) polymer into Ni-electroform. Micro-sized stainless steel 316L powder feedstock is injectionmolded into the SP-mold which consists of micro multi-pillar structures. The effects of metal particle size and processing conditions on the quality of molded and sintered parts are evaluated. For the higher quality of μ-SPiMIM process, the feedstock composed of nanosized Cu powder and oxymethylene-based binder is adequately prepared and molded into PMMA films with fine line-scan structures which are prepared by nano-imprint lithography (NIL) technique. From the evaluation results on the effects of particle size of metal powder and processing conditions toward the high precision of sintered parts, it is concluded that the μ-SPiMIM process has a great potential to produce precisely the complex metallic parts

Metal powder injection molding (MIM) is a manufacturing method that combines traditional powder metallurgy (P/M) with plastic injection molding as shown in Fig.1. Over the past decade it has established itself as a competitive manufacturing process for small precision components that would be costly to produce by alternative methods. It can be used to produce comparatively small parts with complex shapes from almost all types of materials such as metals, ceramics, inter-metallic compounds, and composites (German, 1984). Recently MIM

**1. Introduction** 

with fine micro-structures.

**1.1 What is metal powder injection molding (MIM)?** 

