the chiller how to match with the mold and injection molding machine

chiller how to match with the mold and injection molding machine

ਅਗਸਤ 18, 2021

As we all know, chillers are widely used, and one of them is the cooling of plastic molds. Basically, most plastic mold production plants are indispensable for the chiller, so today the flyse will introduce to you in detail. How to choose a suitable chiller in the production of molds. ਇਸਦੇ ਇਲਾਵਾ, since ਇੰਜੈਕਸ਼ਨ ਮੋਲਡਿੰਗ ਮਸ਼ੀਨ are often used together with chillers, it is unavoidable to introduce them here.

ਪਹਿਲਾਂ, how to choose a chiller

air chiller

ਵਾਸਤਵ ਵਿੱਚ, a mold is a heat exchanger. The heat is transferred from the molten plastic to the mold, and then from the mold to the circulating cooling medium-ice water. Only a small amount of heat enters the air and the pressure of the injection molding machine. template. As everyone knows, quite a few of the plastic molding cycles are used for cooling, sometimes accounting for more than 80% ਦੇ plastic molding cycle. ਇਸ ਲਈ, it is absolutely necessary to control the cooling time to a minimum. ਉਦਾਹਰਣ ਲਈ, the molding cycle of a mold is generally 20 ਸਕਿੰਟ. If the water in the cooling tower is replaced by the ice water generated by the chiller, it can be shortened to 16 ਸਕਿੰਟ. Although it is more expensive to select and equip the chiller at the beginning, it can increase the output value by 20%, and can obtain great benefits in the long-term production.

So, how to choose ice water energy? From the above, we can know that it is related to the specific heat capacity of the molding material, the temperature and weight of the melt when the glue is melted, and the temperature when the finished product is demolded.

ਆਮ ਤੌਰ 'ਤੇ, the injection molding mold is cooled, and the ice water pressure is selected from 0.1 to 0.2Mpa to satisfy the request. The microcomputer full-function chiller can satisfy this request. When the pressure request is higher than 0.2Mpa, another plan is required to facilitate the selection of the corresponding pressure. ਦ chiller water pump in order to meet the needs of the system water supply.

The connection table between flow and pipe diameter:

How to match the chiller with plastic molds and injection molding machines?

The formula for calculating the ice water energy required by a mold is: q=w×c×t×s

In the formula: q is the required ice water energy kcal/h;

W is the plastic raw material weight kg/h;

C is the specific heat of plastic raw materials kcal/kg℃;

T is the temperature difference ℃ between the melt temperature and the finished product demoulding;

s is the safety factor (usually 1.35—2.0). When a single machine is matched, a small value is generally selected, and a large value is used when a chiller is matched with multiple molds. ਉਦਾਹਰਣ ਲਈ, when an air-cooled chiller is selected, s is also It should be appropriately larger.

ਉਦਾਹਰਣ ਲਈ: a mold produces pp finished products, and the output value per hour is about 50kg. What is the cooling requirement? What size water chiller should be equipped with? q=50×0.48×200×1.35=6480 (kcal/h); cooling capacity of 6480kcal/h per hour is required, and ls203s chiller can be used.

In the process of selecting chillers in practice, it is difficult to obtain well-compared data. According to our previous years of planning and supporting sales experience, t=200℃, which is an average value of many commonly used products after years of calculation.

If there is a hot glue lane attached to the mold, the energy of the hot glue lane should also be included in the calculation of the cooling capacity. ਆਮ ਤੌਰ 'ਤੇ, the hot glue lane is in kw, and the unit should be converted to kcal/h when calculating, 1kw=860kcal/h. If the water supply to the factory is sufficient, the temperature is low, and the cost is low, there is no need to use a chiller at this moment. This is generally impractical unless the factory can be located near a large lake with a low water temperature. The other is to use urban areas. Deep well water supply meets the needs of temperature and flow, but the cost is often too high. This method can be used for test equipment, but for factories, it is impractical to do so.

Ice water temperature difference

The temperature of the plastic mold cooling fluid (ice water) generally changes greatly due to the processing materials and the shape of the finished product. ਉਦਾਹਰਣ ਲਈ, for polystyrene thin-walled beakers, the mold requires the ice water temperature to be below 0°C; in most other cases, The temperature of the ice water requested by the mold is above 5℃, the microcomputer full-function chiller can provide ice water above 5℃, and the low-temperature intelligent temperature control chiller can satisfy the request below 5℃ and below 0℃.

The temperature difference of the ice water at the entrance and exit of the plastic mold is often set according to the requirements of the finished product. In many cases, the temperature difference of 3-5°C is the most ideal, but sometimes the temperature difference is also required to be 1-2°C. The smaller the temperature difference, it means that the same amount of heat is taken out, the larger the flow of ice water is needed, and vice versa. ਉਦਾਹਰਣ ਲਈ: when the temperature difference is 5°C, the flow rate needs 60l, and when the temperature difference is 2°C, the flow rate needs 150l.

Ice water flow

The flow of ice water required for a plastic mold is directly related to the heat to be taken away by the mold and the temperature difference between the ice water in and out of the mold. ਉਦਾਹਰਣ ਲਈ: To take the heat of 6480kcal/h away from the mold, if the temperature difference is 3℃, what is the minimum flow rate required? Ice water flow q=6480÷3÷60=36 (l/min).

ਉੱਲੀ ਦੇ ਤਾਪਮਾਨ ਦਾ ਸਹੀ ਨਿਯੰਤਰਣ ਵਾਰਪੇਜ ਨੂੰ ਰੋਕਣ ਲਈ ਹੈ, the theory of ice water quality

The softening of water is also a question that cannot be ignored in the process of using the chiller. The ph value of water also needs to be continuously observed. It is best that the ph value should be equal to 7, and the ph value greater than 7 will cause terrible corrosion. If the method is not adopted, fouling will form in the evaporator and the mold, which will act as heat insulation. When severe, the energy conversion effect will be reduced by 30%. Obviously this requires thinking about the softening of hard water. The most effective way is to equip an electronic hard water softener in the system. Such a softener is planned to be manufactured based on the principle of exchange. Depending on the flow rate, different standard softeners can be equipped, and they can be directly connected to the circulating water pipeline. ਆਮ ਤੌਰ 'ਤੇ, the cost of installing a water treatment softener will not be too high. It can also participate in a certain amount of deduction in the circulating system for a certain period of time. Scale agent.

Five, ice water machine flow and pressure

ਆਮ ਤੌਰ 'ਤੇ, the injection molding mold is cooled, and the ice water pressure can be selected from 0.1 to 0.2mpa, and the request can be satisfied, and the microcomputer full-function chiller can satisfy this request. When the pressure request is higher than 0.2mpa, another plan is required to facilitate the selection of the corresponding pressure From the water pump to meet the needs of the system water supply.

Cooling of hydraulic oil and barrel feeding section

ਆਮ ਤੌਰ 'ਤੇ, the hydraulic oil and barrel feeding section use cooling water tower water to cool, because this is not only the best way, it is cost-effective, but also very economical. Unless there are specific requirements for its temperature, ice water can be used for it. Cool down.

VII. Insulation of ice water pipes

The ice water pipeline must be insulated, because the pipeline insulation can not only prevent the severe loss of cold capacity, but also prevent the condensation formed on the outer wall of the pipe. ਉਦਾਹਰਣ ਲਈ: the temperature of ice water is 10℃, the ambient temperature is 30℃, the heat radiation of a 25-meter-long metal pipe with a surface area of 25m2 can reach 750kcal/h, which is almost 10% of the cooling capacity of a 3hp compressor, 5hp The compressor produces 6% of the cooling capacity.

The connection between the chiller and the plastic mold is generally selected to be connected with a reinforced hose. Since such a hose has the function of heat insulation, but the length exceeds 5m, it is necessary to consider appropriate heat preservation and heat insulation. In the application of the chiller, it is closely related to another equipment, ਜੋ ਕਿ ਹੈ, the injection molding machine. Since it is so relevant, how to choose an injection molding machine, let us introduce you:

How to choose a chiller and an injection molding machine?

The domestic vertical and horizontal injection molding machines are matched when the cooling water condensation temperature of the water-cooled chiller is below 35 degrees (the condensation temperature of the air-cooled chiller is below 43 degrees) when the domestic vertical and horizontal injection molding machines are used at normal ambient temperature.

The first method:

The 1hp water-cooled chiller can be equipped with an 80-ton clamping force injection molding machine with a temperature control of 5-10 degrees;

The 1hp water-cooled chiller can be equipped with a 100-ton clamping force injection molding machine with a temperature control of 10-15 degrees;

The 1hp water-cooled chiller can be equipped with a 120-ton clamping force injection molding machine with a temperature control of 15-20 degrees;

(The matching of the air-cooled chiller is 0.8 times that of the water-cooled chiller, ਜੋ ਕਿ ਹੈ, the 1HP air-cooled chiller can be equipped with a 64-ton injection molding machine with a clamping force. The temperature is controlled at 5-10 degrees.)

The second method:

The 1HP water-cooled chiller can be equipped with an injection molding machine with a single injection volume of 10QZ, and the temperature is controlled at 5-10 degrees.

Injection volume 1QZ=28.5g

The above formula is the result summarized by the thoughts. In addition to using the above formula, the salesperson should consider the actual situation and select the appropriate chiller.