What is the extrusion process of lawn mower mold?

November 26, 2021

How to make heat transfer more efficient in the lawn mower plasticizing unit?

The correct selection of heaters, the use of insulators, and technologies. It promotes temperature homogeneity allows significant savings in lawn mower mold.

lawn mower moldThe reciprocating screw lawn mower plasticizing method is used in thermoplastic injection processes. It transforms the resin from its solid state to its molten state. Moreover, then it takes it into the mold cavity.

For this, the necessary energy contribution makes through two mechanisms. First is the heating generated by the friction between the pellets, the screw, and the barrel. In addition, the most important amount of energy is provided. And second is the heating from the injection unit heating system.

What is extrusion in lawn mower mold?

In the extrusion of thermoplastics, where the lawn mower mold plasticizing mechanism is the same as that of the injection process. Similarly, the internal friction generates enough heat for the transformation of the thermoplastic. So the external heat source uses mainly in the beginning.

Why do we need lawn mower mold?

Moreover, thanks to the fact that extrusion is a continuous process, it manages to stabilize itself thermally, and rather sometimes it is necessary to remove heat from the system to control the temperature. Of course, the system is also composed of heating elements that come into operation when necessary to guarantee stability.

In injection, the discontinuity in the lawn mower mold plasticizing process leads to thermal equilibrium. It is derived from the material transport process not being achieved. So the participation of the heating elements is greater and indispensable.

Why is temperature control necessary?

In addition to bringing the material to the molten state, the lawn mower plasticizing unit responds in the injection process by the thermal uniformity of the melt and by the consistency of its temperature over time.

Moreover, achieving that, despite the thermal discontinuity, the process of injection achieves that the dynamics of heat extraction in each cycle are the same. This is a shared responsibility between the screw and the heating system of lawn mower mold.

Elements for temperature control

Generally, a common configuration for temperature control consists of three elements:

  • The temperature sensor
  • The heating element
  • The temperature control

The quality of the melt and the reliability of the product will depend on the characteristics of each one of them. It is vitally important to have the correct settings for resins and processed products.

How many zones are there in the lawn mower mold plasticizing unit?

Normally, in injection, it is customary to sector the lawn mower plasticizing unit into at least four zones. And on some occasions, it can even have ten or more. Furthermore, this will depend on the technological level of the equipment. And it also depends upon that how sensitive the process and the resin may be thermal.

There will be at least four heating zones, to respect the three zones of the lawn mower mold plasticizing screw, because the material transport condition in each of the stages is different, and the heat generation is also different.

lawn mower mold 2021

Which in the end represents a particular need in each area to compensate for the heat from the outside, allowing stability to achieve. The fourth or last zone is normally assigned to the nozzle, which due to its geometric conditions and being at the end of the unit, will have special requirements.

How to maintain the sustainability of the process?

The installed power of the lawn mower mold machines consumes the driving elements and in the heating system. In each of these systems, it is increasingly important to look for more efficient alternatives, not only because of their participation in the cost of the product but also because of the sustainability of the processes, which becomes more relevant every day.

The heating elements are available in different characteristics and technologies. There will always be more points to consider than power and size: the material, the insulation, the speed of response, will play a fundamental role in its definition.

How to maintain efficiency from the heating element?

There are different types of heating elements on the market. Among the most common are:

Mica heating bands: made from a NiCr plate rolled and insulated from the appropriate supports in mica. Easy to assemble and adjust to the surface of the barrel, they are usually installed in the nozzles of the lawn mower mold machines.

They operate well in temperatures up to 350°C, and the heating powers are around 4W/cm2. The predominant mode of heat transfer to the barrel is conduction.

Decreasing losses

Heat transfer from conventional heating elements to the lawn mower plasticizing unit occurs by conduction. However, due to the type of assembly and commonly used technologies, radiation and convection are always present in the other direction, towards the environment. This is clearly undesirable and represents inefficiency.

In the market there are insulation alternatives that prevent heat from flowing in the unwanted direction, they are known as thermal blankets or insulating blankets, with manufacturers on all continents, and that involves a wide range of materials in their construction of lawn mower mold.

The barrels can provide heat thermally

The barrel, which has always had the responsibility of containing the lawn mower plasticizing process, can also contribute to the process of making more efficient the transfer of heat from the heating elements to the resin, in addition to reducing losses.

Role of smart heat in making lawn mower mold

Smart Heat incorporates a coating with new advanced technology from Nordson, which eliminates energy losses in the lawn mower mold plasticizing unit. It is a robust coating that is applied by plasma depositing on the outer surface of the barrel. And combined with a high-efficiency thermal insulator, guaranteeing the temperature uniformity in the barrel.

Some additional benefits are:

  • it reduces defects
  • it increases the quality of production
  • it achieves reductions of between 30 and 60% in energy consumption compared to traditional belt systems
  • it reduces downtime by eliminating the need to replace or maintain traditional heating elements
  • it in addition to generating greater safety for people

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