Hexagon demonstrates Alphie Mixer solution for MIM feedstock uniformity

Hexagon Product Development Pvt Ltd, headquartered in Gujarat, India, has highlighted how its Alphie Mixer range addresses the uniformity challenges sometimes faced during in-house preparation of Metal Injection Molding feedstock.

In a recent post, the company explained that inconsistency in feedstock can lead to poor mold filling, dimensional instability, surface defects, and part failure during sintering.

To demonstrate this, the company shared the experience of one of its customers in the MIM industry. The customer had decided to develop its own in-house feedstock using a proprietary binder formula. The goal was to optimise product performance while maintaining process control.

However, the customer found a challenge in homogeneously blending materials of vastly different densities and flow characteristics. The <20 µm metal powders offered low flowability while the binders and waxes were sticky and featured much higher bulk densities. When dealing with these attributes, conventional (i.e. z-blade, paddle and drum) mixers tend to cause layered separation, hot spots and, ultimately, non-uniform batches, Hexagon stated. These faults lead to unpredictable results in molding and sintering.

To overcome these problems, the customer implemented the Alphie 50, a 3D inversion-type tumbling mixer specifically designed for homogenous powder blending across a wide range of densities and particle sizes. The customer noted that in addition to mixing performance, this mixer was chosen for design convenience, ease of use and batch repeatability.

Using the Alphie 50 mixer at 30 rpm for fifteen minutes, with a 30% fill volume, the customer was able to achieve the appropriate dispersion of binder and wax into the metal powder without clumping or hotspots and without overheating the thermoplastic. This reportedly led to improved feedstock consistency, thus enabling better mold filling and fewer sintering defects.

The success of the Alphie mixer was attributed to several key features. These included its 3D tumbling motion. Unlike traditional blade or ribbon mixers that shear the material, Alphie operates with gyroscopic inversion motion, creating a tumbling effect that allows powders to interpenetrate naturally. This can be useful for fine and dense particles, reducing segregation and dead zones.

Additionally, Alphie’s interchangeable stainless steel mixing drums allow customers to pre-fill drums while a batch is running, eliminating downtime and maintaining full batch isolation and traceability.

Conventional mixers often require careful layered filling of heavy and light powders to reduce segregation. Alphie’s movement ensures complete integration without manual layering. With Alphie’s closed container design, the risk of fine metal dust contaminating the workspace was also eliminated, ensuring both operator safety and cleanroom compliance.

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