Injection Mold. What are the test steps for injection molds?

What are the test steps for injection molds?

Optimize mold design and process parameters to avoid unnecessary errors and achieve twice the result with half the effort, while meeting the high quality requirements of mass production. In this way, even if factors such as materials, machine settings, or the environment change, a stable and uninterrupted mass production environment can be ensured. The defects of most molded products are caused by the plasticizing and injection molding stages, but the improper mold design and poor mold structure are the root of all the factors! The influence factors of the test mode: the number of cavities, the design of the cold/hot runner system, the entrance of the injection Type, location and size, as well as the structure of the product itself. Therefore, in order to avoid product defects caused by mold design, we need to analyze the mold design and process parameters when making the mold. It should be emphasized that the purpose and focus of the test mode is to optimize the mold and process to meet the requirements of mass production, not just to test a good product sample.

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The first step: mold empty running test

I. Inspection of the opening and closing mode under the low pressure of the mold

II. Inspection of the mold ejection system (low pressure)

III. Inspection of mold reset

IV. Inspection of the position (slider) action

The second step: cavity injection balance test

I. Continuously press 5 modules in sequence to weigh the weight

II. Record the weight of each piece of each product in each mold

III. Reduce the amount of injection, sequentially fill 20%, 50%, 90% of the sample 3 molds

IV. Weigh and record the weight of each of the above products

V. If the difference between the maximum weight and the minimum weight of the product is less than 2%, it is acceptable. If the weight fluctuation error is within 2%, it indicates that the cavity is balanced, otherwise the glue will be unbalanced.

VI. If it is a single cavity mold, also do the glue balance test (observe the actual glue)

The third step: the test of the holding time (gate freezing) time

I. When the holding time is set to 1 second, each time molding 3 mold products

II. As shown in the table, increase the holding time in turn, reduce the cooling time, and keep the whole cycle time (until the gate is frozen and sealed, the product weight does not increase)

III. Set a number of different dwell time as shown in the figure below. Each time mold 3 products are formed, weigh the product weight of the specified cavity, and record the data in the table. IV. Determine the better dwell time according to the chart.

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Step 4: Determination of better clamping force

I. When the pressure holding switching position/pressure holding pressure is set to the optimum, the clamping force is set to within 90% of the maximum clamping force, and the mold is molded to record the weight of each molded product.

II. The clamping force is reduced by 5Ton in turn, and each time the mold is molded, the weight of each mold product is recorded until the weight of the product suddenly becomes large, and the weight increases by about 5% until the periphery of the product begins to generate flash.

Step 5: Determination of better cooling time

I. When the injection molding process conditions are appropriate (after the product is fully charged), estimate the cooling time (primarily select a longer cooling time to completely cool the product), and use 3 mold products to measure the size.

II. Record the product size in the table and observe the deformation of the rubber parts.

III. The product cooling time is reduced by 1 second, and the 3 mode is used.

IV. Reduce the cooling time until the product begins to deform and the size begins to decrease.

V. The product injected at each cooling time should be measured after the rubber is sufficiently cooled (about 15 minutes).

VI. Basis for determining better cooling times - consider product dimensional stability

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Step 6: Testing of cooling water flow conditions

I. When the injection molding process conditions are appropriate (after the product is fully charged), estimate the cooling time (primarily select a longer cooling time to completely cool the product), and use 3 mold products to measure the size.

II. Record the product dimensions in the table below and observe the deformation of the rubber parts.

III. The product cooling time is reduced by 1 second, and the 3 mode is used.

IV. Reduce the cooling time until the product begins to deform and the size begins to decrease.

V. The product injected at each cooling time should be measured after the rubber is sufficiently cooled (about 15 minutes).

VI. Basis for determining better cooling times - consider product dimensional stability

Step 7: Test of mold cooling uniformityI. Using a mold temperature measuring instrument to measure the temperature of each core and cavity selected 10 points, recorded in the followi

ng table

II. The difference between the actual temperature and the average value of each measurement point should be less than 2 °C. If the difference from the average value exceeds 2 °C, it means that the mold cooling effect is uneven, and the cooling system should be improved.

Step 8: Determine the best injection speed

I. Record hydraulic oil temperature, solution temperature and mold temperature

II. First set the sol termination position, only use the first shot

III. Set the holding pressure and holding time to zero, and determine the injection speed gradually after increasing the injection speed.(injection mold)

IV. Adjust the injection speed to fill the 95% position of the rubber (observe whether there is litter, leave the amount of 5-10mm)

V. Record the highest injection speed achieved when filling the 95% position of the rubber

VI. Record the highest injection speed and peak shot pressure reached by the injection in the "Injection Velocity Analysis Data Sheet"

VII. Gradually reduce the injection speed, increase the injection pressure, observe and record the peak pressure of the injection when it is filled to the 95% position of the rubber.

 

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