How to choose the right micro-feeder

Micro-feeding is a growing vertical in the plastics industry and is expected to surpass revenues of $1.5 billion USD by 2025 according to a recent study published by Grandview Research. In the last few years new products have emerged on the market with far greater precision and accuracy than before, hence the industry is witness to more companies who have introduced micro-feeders into their product portfolio. Aimed at producing smaller dosage units, whether by using injection or extrusion methods, this document will try to highlight a few important factors need to be taken into consideration when trying to determine the right micro-feeder fit.


Volumetric or Gravimetric. What is the right type of feeder for me?

Without a doubt the right choice to make is a gravimetric feeder. A gravimetric feeder is the only feeder that guarantees accurate dosage by weight and not be volume, as volume feeding is dependent on granule geometric shape. In volumetric feeders, especially those who feed granule after granule, whether with a piston or with an engine, there is no control over weight, only on the number of granules.

Changes in granular weight by different manufactures, in different batches produced by the same manufacture or even in the same batch, are commonplace. This can create a large variant in dosing, especially when trying to introduce micro dosage. It can also bring to product rejection and to waste due to the fear that products will not meet exact product specifications.

Range of Throughput

The more the better. This answer holds true for low throughput as well as large arrays of throughput that are beyond the determined range for micro-feeders. There are some micro-feeders that can allow a narrow throughput range, meaning a limited throughput that can not be adjusted upwards or downwards, other than by interchanging certain parts. Other micro-feeders can reduce their throughput to desired levels, but they are limited as to their upper range, and cannot process more than a range of several hundred g/h. It is important to choose a micro-feeder that can feed in low throughput as well as high throughput. It is not advisable to purchase a micro-feeder that is suited for a specific application today but will be deemed useless for future applications.

Loading – Should it be done Manually or Automatically

It is true that when talking about low throughput there is infrequent reload of material, but still manually loading of material for a factory with multiple production lines can be exhausting and lead to lack of material in the feeders. Therefore, it is important to choose a micro-feeder with automatic loading capabilities. Loading using a Venturi pump is a simple and effective process when using a micro-feeder.


Material Type

There are many types of materials that can be used by a micro-feeder. Even granules can be found in many types — large & small, round and pea like, high uniformity or low, these are factors that the micro-feeder must contend with. This also holds true to concentrated micro-granules that are popular in masterbatch uses. Many micro-feeders are limited in the type of materials they can process versus others that have a wider range of usage of various types of materials.

SGD-Micro is a gravimetric feeder able to determine exact throughput and control it. It has a wide throughput range starting with a few grams per hour all the way to 6,000 g/h. It comes with a Venturi loader which enables automatic loading every time materials run out. This way it is possible to use a wider range of materials in different shapes and sizes even those that are micro-granular.