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How to choose a second-hand injection molding machine

January 13, 2023

How to choose a second-hand injection molding machine

The important factors that usually affect the selection of injection molding machine include mold, product, plastic, molding requirements, lwm yam. Yog li ntawd, the following information must be collected or obtained before making a selection: 1. Mold size (width, height, thickness) , weight, special design, lwm yam.; 2. The type and quantity of plastic used (single raw material or multiple plastics); 3. The appearance size (length, width, height, thickness) and weight of the injection molded product; 4. Molding requirements, such as Quality conditions, production speed, lwm yam. After obtaining the above information, you can follow the steps below to choose a suitable plastic injection molding machine:

1. Choose the right type:

Since there are many types of second-hand injection molding machines, it is necessary to correctly judge which type of injection molding machine or which series the product should be produced at the beginning, such as general thermoplastic or bakelite raw materials Or PET raw materials, lwm yam., are single-color, double-color, multi-color, interlayer or mixed color, lwm yam.

Tsis tas li ntawd, some products require high stability (closed loop), high precision, ultra-high injection rate, high injection pressure or rapid production (multi-loop), lwm yam., and the appropriate series must also be selected for production.

2. Can fit the txhaj:

Determine whether thebig column inner distance”, “mold thickness”, “minimum mold size” Thiab “mold plate sizeof the machine are appropriate according to the mold size, so as to confirm whether the mold can be placed.

Daim Ntawv Ceeb Toom: â‘ The width and height of the mold must be smaller than or at least one side is smaller than the inner distance of the large column; â‘¡The width and height of the mold should preferably be within the size range of the mold plate; â‘¢The thickness of the mold should be between the mold thickness of the injection molding machine; â‘£The width and height of the mold must meet the minimum mold size recommended by the injection molding machine, and it is not acceptable if it is too small.

3. Take out injection molding products:

Determine whether themold opening stroke” Thiab “mold ejection strokeare sufficient for the finished product to be taken out by the mold and the finished product.

â‘ The mold opening stroke must be at least twice the height of the finished product in the direction of opening and closing the mold, and must include the length of the vertical sprue;

â‘¡The ejection stroke must be sufficient to eject the finished product.

4. Can lock the plastic solution:

The tonnage ofclamping forceis determined by the product and plastic.

When the raw material is injected into the mold cavity at high pressure, it will generate a force to support the mold. Yog li ntawd, the clamping unit of the injection molding machine must provide enoughclamping forceto keep the mold from being stretched. The calculation of the clamping force requirement is as follows:

① Obtain the projected area of ​​the finished product in the direction of the opening and closing mold from the appearance size of the finished product; /cm2); ③The pressure in the mold varies with the raw material, and the general raw material is 350~400kg/cm2; more than double. So far, the specifications of the clamping unit have been preliminarily determined, and the tonnage of the model has been roughly determined. Then, the following steps must be carried out to confirm which injection unit has a more suitable screw diameter.

5. Shot to fill the injection mold cavity:

Determine the requiredinjection volumeand select the appropriatescrew diameterbased on the weight of the finished product and the number of mold cavities.

To calculate the weight of the finished product, the number of mold cavities (one mold with several cavities) needs to be considered;

For the sake of stability, the injection volume must be more than 1.35 times the weight of the finished product, uas yog, the weight of the finished product must be within 75% of the injection volume.

6. Injection parameters of injection molding machine:

The conditions such asscrew compression ratio” Thiab “txhaj” are judged by the plastic. Some engineering plastics require a higher injection pressure and a suitable screw compression ratio design to have a better molding effect. Yog li ntawd, in order to make the finished product injection better, the injection pressure and compression ratio must also be considered when selecting the screw. . In general, a smaller diameter screw provides higher injection pressure.

7. Txhaj tshuaj of injection molding machine:

Confirmation of “txhaj”. Some finished products require high injection rate and fast injection to form stably, such as ultra-thin products. In this case, it may be necessary to confirm whether the injection rate and injection speed of the machine are sufficient , whether it needs to be equipped with pressure accumulator, closed loop control and other devices. Feem ntau hais lus, under the same conditions, the screw that can provide higher injection pressure usually has a lower injection rate, and on the contrary, the screw that can provide lower injection pressure usually has a higher injection rate.

Yog li ntawd, when selecting the diameter of the screw, the injection volume, injection pressure and injection rate (txhaj) need to be considered and traded off. Tsis tas li ntawd, multi-loop design can also be used to shorten the molding time with synchronous compound actions.

Yog koj muaj lus nug txog txhaj ,thov koj pab dawb FLYSE PAB neeg no,Peb yuav muab kev pab zoo tshaj rau koj!

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