How to estimate the injection molding cycle of plastic products?

zt) Molding Cycle Complete a single injection molding process.

The time required is called the molding cycle, also known as the molding cycle. It actually includes the following parts: Molding cycle: The molding cycle directly affects the labor productivity rate and equipment utilization rate.

Therefore, in the production process, the relevant time in the molding cycle should be shortened as much as possible under the premise of ensuring quality. Injection time and cooling time are the most important in the entire molding cycle, as they have a decisive impact on the quality of the part. The filling time in the injection time is directly inversely proportional to the filling rate, and the filling time in production is generally about 3-5 seconds.

The holding time in the injection time is the pressure time of the plastic in the cavity, which accounts for a large proportion of the entire injection time, generally about 20-120 seconds (extra-thick parts can be as high as 5 10 minutes).Before the melt freezes at the gate, the holding time has an impact on the dimensional accuracy of the product, and if it is later, it has no effect. There is also a minimum value for dwell time, which is known to depend on the material temperature, the mold temperature, and the size of the sprue and gate.

If the size of the sprue and gate and the process conditions are normal, the pressure value with the smallest fluctuation range of the product shrinkage is usually used. The cooling time is mainly determined by the thickness of the product, the tear-filling properties and crystallization properties of the plastic, and the mold temperature. The end of time should be based on the principle of ensuring that the product is not changed when demoulding, the cooling time is generally about 30 120 seconds, and the cooling time is not necessary for too long, which not only reduces the production efficiency, but also causes the difficulty of demoulding to complex parts, and even produces demoulding stress when forcibly demoulding.

The rest of the molding cycle is related to whether the production process is continuous and automated, as well as the degree of dualization.

Before this question, we must know, when can it be ejected? When the actual temperature of the molded part is lower than tg, that is, the glass transition temperature, it is sufficient. If you want to calculate the molding cycle.

First of all, we must understand the molding process: mold clamping, injection, pressure holding, cooling, mold opening, ejection, mold clamping. The most critical calculation is the cooldown time.

Theoretically, this is a problem of thermal equilibrium, the heat emitted by the plastic from the molten state to the glass state is absorbed by the mold (the absorption of mold iron, the absorption of cooling water, the absorption of air, the absorption of radiation...). We can calculate it. This is very difficult to apply in practice.

We know in practice that the thicker the wall, the slower the cooling, so the wall thickness is a key factor. Of course, different materials have different specific thermal capacitances. The difference is also quite large.

Generally speaking, it can be roughly estimated according to the material weight and product thickness, can you tell you the size and thickness of the product?

Different materials have different properties, different fluidity, and different shrinkage.

It depends on the thickness of the product.

Summary. Hello, the cycle time of the injection molding machine to produce products: mold closing time + injection pressure holding time + cooling time (including melt time) + mold opening time + core pulling time + ejection time + pick-up time, estimate each action time, add up to the product cycle time.

Hello, the cycle time of the injection molding machine to produce products: when closing the mold, only the side balance + injection pressure holding time + cooling time (including melt time) + mold opening time + core pulling time + top opening time + pick-up time, estimate each action time, together is the product refers to the cycle time.

Hello, the cycle time of the injection molding machine to produce products: when closing the mold, only the side balance + injection pressure holding time + cooling time (including melt time) + mold opening time + core pulling time + top opening time + pick-up time, estimate each action time, together is the product refers to the cycle time.

If the product structure is not special, the injection time is about 6 seconds, the pressure holding time is 10 seconds, the cooling time is 25 seconds, the mold opening and ejection is 3 seconds, the manipulator picks up the parts in 3 seconds, and if the manual picks up the parts in 6 seconds.

When it is necessary to adjust the working parameters of the vertical injection molding machine due to non-chromatic differences, the injection temperature, back pressure, injection cycle and masterbatch addition amount may not be changed.

At the same time, it is also necessary to observe the influence of process parameter changes on the color, and adjust it in time if the color difference is found. As much as possible, avoid the use of injection molding processes that cause strong shear effects, such as high injection speed and high back pressure, to prevent color difference caused by local overheating or thermal decomposition. Strictly control the temperature of each heating section of the barrel, especially the nozzle and the heating part immediately adjacent to the nozzle.

First of all, we in the injection molding industry should understand that geometric dimensional fluctuations after plastic parts are formed. In our daily production, there are three points that affect the size fluctuation. Control of material temperature and mold temperature:

Different brands of plastics have different temperature requirements. The poor flow of plastic materials and the use of more than two mixtures will make different situations. Therefore, the plastic material should be controlled within the optimal flow value range.

These are usually easy to do, but the control of mold temperature is more complicated. Different shapes, sizes and wall thickness ratios of parts have certain requirements for the cooling system, and the mold temperature controls the cooling time to a large extent. Therefore, the mold should be kept at a permissible low temperature as much as possible to shorten the injection cycle and improve production efficiency, and when the mold temperature changes, the shrinkage rate will also change, the mold temperature is stable, and the dimensional accuracy is stable to prevent the formation of defects such as deformation, poor gloss, and cooling points, so that the physical properties of the plastic are in the best state.

Of course, there is also a debugging process, especially for multi-cavity molded parts. Therefore, the mold temperature cannot be changed arbitrarily during the production process, and the mold temperature should be set within the temperature range recommended by the material. Regulation and control of pressure and exhaust:

When the mold is debugged, the matching of the appropriate injection pressure and clamping force should be determined. The air in the gap between the mold cavity and the core and the gases generated by the plastic must be exhausted from the exhaust groove. If the venting is not smooth, there will be underfilling, welds, or burn defects.

These three forming defects sometimes appear on the same part. If there is a thick wall around the thin-walled part of the molded part, shrinkage marks will appear when the mold temperature is too low, and burns will occur when the mold temperature is too high. In general, burn marks will occur at the same time.

Exhaust slots are often overlooked and are usually in a smaller state. Therefore, as long as there are no burrs, the depth of the exhaust shoulder should be as deep as possible, and a large ventilation groove should be set at the rear of the shoulder, so that the gas passing through the shoulder can be quickly discharged from the mold. If there is a special need, an exhaust groove should be opened on the ejector rod, and the principle is the same.

Auxiliary adjustment control of the size of injection molded parts: Due to the different shapes and sizes of some plastic parts, deformation and warping will occur under different hood shapes as the temperature and pressure loss change after demoulding. At this point, some auxiliary fixtures can be used to make adjustments.

Remedial measures should be taken in time after the module is out of the mold. After natural cooling and solidification, good correction and adjustment results can be obtained. If the above three steps are strictly managed throughout the injection molding process, the size of the injection molded parts will be well controlled.

【Injection molding cycle estimation】Injection molding is a cyclical process, the molding cycle is mainly composed of storage time, injection holding time, cooling time, mold opening and closing time, ejection and pick-up time, product cooling and screw metering and storage are carried out at the same time, and the larger of the two is taken when calculating the molding cycle (cooling time generally includes storage time).

Storage and injection holding time should be based on the nature of the polymer, the shape of the product and the quality requirements (appearance, size, etc.), it is related to many factors such as injection pressure, injection rate, screw revolution, back pressure and temperature, etc., should ensure the quality of the premise to seek the shortest time, in the estimation of injection molding parts storage time, generally take 65% of the maximum plasticizing capacity (g s) of the injection molding machine.

85% to calculate. The injection process is usually divided into 3 segments (slow-fast-slow), at the time of estimation:

t=w/20~50%v + t

t: total injection time;

W: total amount of injection (weight of a single piece of product x number + nozzle weight);

v: Maximum injection speed of injection molding machine;

t: a base number of times required for the start and stop of the screw;

80t 200t take 1 2s; 200t 500t take 2 3s; 500t 1000t take 3 4s;

The holding time is the time elapsed from the time the cavity is filled to the end of the holding time. The choice of dwell time generally depends on the requirements of the product for appearance shrinkage, as well as size and deformation

Cooling time refers to the time elapsed between the end of holding pressure and the opening of the mold. The length of cooling time is affected by factors such as the shape of the product, the thickness of the wall, the design of the mold cooling water, the mold temperature, and the nature of the melt. On the premise of ensuring good quality of parts, the cooling time should be shortened as much as possible. When the product is certain, the design of the mold cooling water is the key factor affecting the length of cooling time.

The cooldown time is shown in the table below

The time of opening and closing the mold is affected by the size of the machine, the mold structure and other factors, the core-pulling structure (row) on the mold, the rack transmission mechanism of the mold, the three-plate mold (nozzle) mechanism, etc., will affect the time of opening and closing the mold, generally 80t 200t take 4 8s, 200t 500t take 6 10s, 500t 100t take 8 15s.

The ejection pick-up time is affected by the ejection speed, ejection stroke, and pick-up method (automatic, manual, manipulator), and the automatic drop is generally only used for products with low appearance requirements (internal parts) and small size, and the ejection time is generally taken. When the manipulator takes the product, after the product leaves the mold range, the mold can start to close the mold moving parts, and the item out and pick-up time is generally 3 8s, and the manual is generally 1 3s more than the manipulator to take the product.

Generally, the molding cycle is mainly estimated based on similar products.

The molding cycle is a process, and the process is subject to frequent changes as needed. In the first stage, because the process of product realization has not been, only the approximate cycle time, now in the injection molding, material costs, labor costs, water and electricity costs are dead, customers can control things, only the molding cycle in your hands, therefore, whether a project can get orders or can get good profits, the molding cycle is a crucial factor.

The molding cycle includes: mold opening time - injection time - holding time - cooling time - ejection and ejection time - pick-up time - mold closing time. Among them, the cooling time has the greatest impact on the whole cycle, accounting for more than 50 to 80% of the whole cycle according to different products.

The biggest factors affecting the cooling time are the product structure, size, thickness, and the number of cavities.

The larger and thicker the product, the larger the number of holes, the longer the setting time is required. ** You don't need to be too precise at this stage, just refer to similar products you are already producing to get an approximate estimate of the cooling time. For products the size of ordinary mobile phone cases, the wall thickness is about 1mm, and the cooling time of 4 holes is generally not more than 15 seconds.

The thicker ones need to extend the cooling time appropriately.

In addition, the impact is the structure of the product, it doesn't matter if the ordinary mold is out, when there is gas or oil cylinder out of the mold, it will take a little more time to pull the core according to the mold opening stroke, and the mold is relatively large, and the mold needs to be slower and the speed of the mold is slower, and it will take relatively more time. If the insert is to be overmolded, it will take more time to manually pick and place the insert.

Therefore, it is recommended that you understand the relevant knowledge of injection molding, the entire injection molding process and how much each action occupies in the cycle time. There are also some knowledge of the influence of the structure of the mold on the injection molding process, the influence of plastic materials on the process and so on.

**The cycle time is not difficult to estimate, grasp the principle of high or low, and combine the actual injection cycle of similar products.

If there is a trial production, you can use a stopwatch to test out + wide release time, there is no trial production of new products can be calculated by software, but the weekly answer period of a product also depends on the size of the product, thickness, whether the structure of the product is complex, and the technical ability of molding these affect the cycle of the product, your statement is not very clear, it is difficult to give you an estimate of the more accurate cycle, experienced personnel can estimate the size, thickness and structure of the product, and it is more reasonable!

What is the molding cycle time of injection molded products? How is the timing of each procedure determined? The molding cycle of injection molded products is the sum of the time required to complete the production of injection molded parts.

The operating time of each program in the molding cycle includes the injection time, the cooling time after the melt enters the mold cavity, and other auxiliary time. The injection time includes the injection filling time and the holding time. The auxiliary time includes the time of mold opening, mold closing, coating and release inquiry time, and insert placement time.

The length of the molding cycle of injection molded products has a direct impact on productivity and equipment utilization. Therefore, the selection of the time of each action program in the molding cycle should be as short as possible under the condition of ensuring the quality of injection molded products. (1) Injection time The injection time includes the injection melt filling time and the holding time.

The injection filling time refers to the time taken by the screw to move forward quickly, push the plasticized melt into the mold, and fill the cavity, which is generally 3 5s. Products with high melt viscosity and fast cooling rate should be injected quickly to reduce the melt filling time. Holding time refers to the residence time after the screw is moved forward and injected, that is, the cooling time when the melt enters the mold cavity and the injection pressure is filled.

This period accounts for a large proportion of the total injection time, usually about 20 120 seconds. If the shape of the workpiece is simple and the size is small, the holding time is short; When the size of the large part and the wall thickness is large, the holding time is long. (2) Cooling time Cooling time refers to the cooling and curing time of the product after the melt is filled.

The length of cooling time is related to the thickness of the product, the properties of the raw material and the temperature of the mold. Generally, the product will not cause deformation when the product is demolded, and the shorter the time, the better. The cooling time of the product is generally in the range of 30 120s.