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Rotomolding process — Take food box production as an example

This is the production process of a food box production enterprise, you can refer to learn the relevant knowledge of rotomolding.行政楼2

Rotomolding is a relatively new and advanced production method of plastic processing, which is characterized by:

1, suitable for processing large hollow products, such as water tank, oil tank, large recreational equipment, isolation wall, etc.

2,The processing cost is low, especially the mold cost is only 1/3 of the injection mold. Its disadvantage is high demand for raw materials, and the finished product processing accuracy is poor compared with injection molding.

Its production process is as follows:

一、 Preparation of raw materials

(一) Raw material requirements for rotomolding production

1.melting index is generally not more than 5.0g/10min.

2.powder particles 30~60 mesh (round particles can not have a large number of tail and prisms, flake particles).


(二) Requirements on raw materials for rolling plastics production

A single rope-grade LLDPE is difficult to ensure the specific requirements of products (such as war storage boxes produced by our company), so composite materials (also known as plastic modification) are generally used, such as 7042 and UR644 materials with good fluidity but insufficient strength. So in order to ensure the quality of specific products, 7042, 6090, 500S or UR644, A760. Specific product raw material formula is obtained after tens of millions of scientific tests, confidential, is patented, anyone can not change the formula without testing.

A single specific product should also be added according to the performance of the product, some master, antioxidants, such as the production of color to join the roll plastic grade master. The product is used outdoors for a long time, adding antioxidants, the production of fire retardant materials, anti-aging agents, promoters and so on.

(三) the specific technological process

1. According to the arrangement of the leader, all kinds of raw materials and accelerators listed in the product formula are put into the mixer by specially-assigned personnel, and the mixer is mixed at the beginning of the mixer. The mixing time is >10 minutes (the mixer is divided into ordinary mixer and high-speed mixer, and it is recommended to use high-speed mixer if the fund permits. The key point of this process is the precise ratio of all kinds of raw materials, which must be used with qualified standard instruments.

2, extrusion granulation machine operator with hand disk motor pulley, the machine can easily run, the material after mixing batch into the granulation machine, motor button and so on. After the motor ammeter rises, close the heating button and adjust the temperature of the heating area. My company purchased the granulating machine is divided into four heating areas, from the hopper forward in turn: each area, generally 150℃. The second zone is 180℃. After exhaust the third zone 180℃. The nose is 190 ℃.

After the extruded material strip is cooled by the water tank, it is inserted into the granulator and the power switch of the granulator is closed. The pelleting machine will automatically pull into the material strip for pelleting. Making machine operator should observe the workings of the extruder, if discover to there is expected to squeeze out extruder vent, should be immediately cut off the electrical source and stay after the machine stops working completely off the nose extrusion die, change into the new mesh (old mesh without damage after fire, still can continue to use), reopened extrusion granulator, plastic raw materials the company as a new material, In principle, it can be changed once a day. After extrusion, the material should be properly air dried according to the actual situation of the material before granulation.

The purpose of this procedure is to modify raw materials. Note: The heating temperature of raw materials should be adjusted according to various raw materials.

Extruder granulator has double screw and single screw points, cold cut and hot points, the company is using cold cut granulator.

3. Grinding powder is a necessary process before rolling production because the material used in rolling production is powder material, and the raw material purchased by the market is granule material. After the granulator operator checks that there is no foreign matter in the machine, the granular material after granulation is put into the hopper, the grinding machine is started, and the feeding speed is adjusted for grinding. After grinding, the raw materials shall be dried as appropriate, and the drying temperature shall not exceed 30℃.
This process focuses on the quality of grinding powder, particle size of 30~60 mesh, round particles, no edges, corners, flake, trailing particles.

Post time: Oct-28-2022