The presence of dust in plastic granules used as raw material in injection moulding can become a significant problem, especially in the production of objects, elements and components that must be perfect in their appearance.

In this article, we are presenting a case study we faced recently.

The client’s request: dust removal from plastic granules

The customer who asked for our intervention operates in the plastic processing sector and, specifically, in injection moulding. It is a well established company, with a machine park that includes around 50 presses

In addition to the development and production of moulds, the company also supports customers in the production and assembly of high-quality plastic components in the following sectors:

  • domotics,
  • medical,
  • automotive,
  • water treatment.

Regarding the topic of this case study, the company had to cope with a dust problem in plastic granules. The incident occurred during the production of an aesthetic component on behalf of a multinational company operating in the household appliances sector.

Following a problem in the production line, the plastic granule supplier often sent batches of material containing a high amount of dust to our moulding company. The dustiness of the raw granule led to a sharp increase in the percentage of rejected parts, due to inclusions and streaks affecting its aesthetic quality and precluding its use.

As mentioned at the beginning, the presence of dust in plastic granules used as raw material for injection moulding can negatively affect the aesthetic performance of the finished product in several different ways.

  1. Surface defects such as scratches, spots, or stains. These occur because the powder does not blend uniformly with the plastic material during the moulding process, creating imperfections on the product surface.
  2. Non-uniform colouring. Powder can affect the correct distribution of pigments or dyes in the plastic material. This can lead to colour variations or stains.
  3. Finishing problems. Dust in plastic granules can prevent a proper finish. For example, it can make it difficult to achieve a glossy surface or a specific texture, as the dust particles interfere with the surface structure during melting and solidification.
  4. Burn marks. During the moulding process, the powder may overheat, leaving dark or burnt traces, particularly evident on light-coloured or transparent objects.
  5. Inclusions and bubbles. The powder can trap air or other contaminants, creating inclusions or bubbles in the plastic material that are also visible on the surface.
  6. Increased roughness. Dust particles can increase the surface roughness of the finished product, affecting its appearance, touch and in some cases its functional properties.

To avoid situations such as those described, it is important that plastic granules are free of dust and other contaminants. However, as we will see in the next section, the machinery installed did not allow the company we are talking about to solve the dust problem.

The Vismec solution: a tailor-made dust removal plant

In fact, the feeders used by the moulding company and supplied by one of our competitors could not remove the dust from the granules. These feeders were installed all along the material handling cycle: some single-phase with a fabric filter and one three-phase with a ground cartridge filter.

The company tried to solve the problem manually by combining a sieve with a domestic hoover to remove dust from the virgin material before drying. Although this solution improved the situation, it failed in bringing the waste percentage below the required minimum values and resulted in significant loss of time for the operators.  

Consequently, Vismec proposed to the customer a specially designed solution consisting of:

With the supplied machinery, the customer created a material handling chain that includes:




The organisation of such a supply chain has ensured an effective dust removal from the material and a drop in the incidence of waste to normal levels.

As you can see in this case study, Vismec technical and sales team works to offer clients the most effective response to the challenges they face. If your company is also looking for a partner to solve a problem or critical situation in your sector, contact us: we will study the best solution together with you.