1. Start mold clamping
1. Start mold clamping pressure: The initial setting value is 25. When the pressure is too small and the speed is too slow, you can try to increase the speed. The pressure is too small and the speed cannot be increased to the required speed. The speed increases by +5 each time. Try and note that when the pressure is set to a large value, the movable template will instantly increase the pressure and change the static state into motion, causing huge friction between the movable template hole and the tie rod. Over time, the wear of the movable template hole and the tie rod will be accelerated, affecting the machine. The decrease in the stability and precision of the movement of the movable template may affect the production of individual molds that require high precision in the mold closing mechanism.
2. Start mold closing speed: It depends on the actual situation, but be careful not to move too fast. The speed should be consistent with the next mold closing movement, rather than an obvious pause between movements. It is best to set the speed to a high speed and reduce the pressure. Set low and pressure controls speed.
2. Low pressure mold clamping
The mold is pushed by low pressure and low speed, starting from the distance that requires safety protection and ending when the mold is completely closed.
1. Low-pressure mold clamping speed: Depending on the actual situation, the speed should be slow. If the speed is too fast, even if low pressure is set, the inertial motion will still have huge impact and destructive force. When there are unexpected hard obstacles such as slide position deviation or ejection pin breakage, the mold closing action will be entered. Under the conditions of effective low pressure and slowness mold closing protection parameters, the impact damage will be greatly reduced.
In fact, you can set the speed to dozens, then leave it alone, and then adjust the pressure to a very low level, such as 5, for testing. Use the pressure to control the speed, and then increase the pressure step by step to the appropriate mold closing protection speed.
2. Low-pressure mold closing pressure: You can first adjust the speed very high and the pressure very low, such as 5 for the mold closing test. Because the pressure is low, even if the speed is set very high, the mold closing speed will not be very high if the pressure support is lost. Fast, control the speed with pressure. On the basis of 5, increase it little by little to the ideal mold closing protection speed, and close the mold with the lowest pressure.
3. Low-pressure mold closing starting position: (i.e., the end position of the previous mold closing). This should be set to a value with a large difference in size according to the size and structure of the mold. It is generally between 5-20 cm before the mold is closed. You can see this position. Let's do it. Many people just start to use low pressure when the mold is closed too close. The distance that should be protected by low pressure in advance is affected by the impact of the larger pressure speed in the previous period. The position of the slider deviates, the ejector pin breaks, and other unexpected hard obstacles occur. , hit quickly and hard, and the low-voltage protection is invalid at this time, and it is too late.
4. End position of low-pressure mold clamping (i.e. starting position of high-pressure mold clamping): This parameter is the position where the mold has just been completely closed, that is, the advance of the movable template has stopped at the end. During debugging, first adjust the low-pressure pressure and speed, and then adjust the position. Set to 0, the door is closed and the manual mold closing test results in a low-pressure mold closing position value;
For example, this value is 2.2. The size of this value is affected by the adjustment of the electronic ruler, the tightness of the mold adjustment, and the mold closing pressure. Furthermore, this value is affected by the machine accuracy and the impact of small debris on the mold surface. Each mold closing may There will be small changes, so you need to set the end position a little larger, for example, add 0.2 to 2.4 (refer to adding 0.1-0.3), and use the lowest position to accurately protect the mold. If you do not use the position value obtained from the low-pressure mold closing test, If the setting is a little larger, just use 2.2. It may often happen that the low-pressure mold closing position is greater than 2.2, and the low-pressure position cannot be ended and cannot be transferred to high-pressure mold locking.
However, more people stop setting the mold with a few centimeters or more before it is completely closed and then start using high pressure. The low-pressure protection is ineffective. It is often seen that some molds are accidentally closed with the ejected finished product. Steel The material cavity is compressed and deformed.
3. High-pressure mold locking
Start using high-pressure pusher to straighten the hinge and tighten the closed mold lock. Many people just set the mold without fully closing it and start using high pressure, and the low pressure protection fails.
1. High-pressure clamping pressure: The initial setting value is 60. When it cannot be met, add 10 pressure each time. If the pressure is too high, there is no need to increase the machine load;
2. High-pressure mold clamping speed: The initial setting value is referenced to 25. When it cannot meet the needs, try to increase the pressure first to check. If it fails, try to speed up the speed, +10 each time. You should not hear excessive noise during high-pressure mold clamping. The speed is doubled, and the friction loss of the mold clamping mechanism is increased by N times.
Everyone should pay attention to the difference between mold closing and mold locking I mentioned above. Mold closing = moving template movement, mold locking = using a high-pressure pusher to straighten and lock the closed mold. In fact, most people use low-pressure mold closing protection settings. The start and end positions of low-pressure mold clamping are not correct;
First, the mold is too close to the low pressure starting position, the position is too small, and the low pressure protection comes too late, which is affected by the higher and faster pressure and speed in the previous section (start, fast, high speed).
The second is that the low-pressure end position ends too early. When the mold is still a few centimeters or more away from closing, the low-pressure protection is terminated and switches to high-pressure mold locking. These two problems generally exist at the same time, which becomes low-pressure closing. If the mold protection position is too short, it will be threatened by the impact of larger pressure and faster mold closing in the front, and will be pinched from both sides by the high pressure clamping pressure in the back, which means that the low pressure mold closing protection is ineffective and useless.
Under ineffective low-pressure protection, the following problems may occur when the mold is crushed or damaged: (entraining obstacles and closing the mold at a higher pressure = pressing the mold, entraining hard obstacles and closing the mold at a higher speed = mold collision)
1. Because the structure of the mold is relatively simple, the clamping pressure is not very high, so it will not break.
2. The mold is pressed, which causes the mold precision to decrease, changes the injection molding conditions, and makes it more difficult to debug the process parameters.
3. The mold is pressed, causing the precision of the mold to decrease, causing the burrs of the formed product to increase, increasing the work intensity and workload of the production workers, accelerating the fatigue of the workers, and reducing the output, quality, and efficiency of the product. . Likeability at work is declining, and employee turnover may increase slightly as a result.
4. The mold is pressed, which reduces the precision of the mold and increases the burrs of the formed product. The original personnel can no longer meet the labor needs of the work, and more manpower is needed, making the labor-intensive production of products more labor-intensive, increasing labor expenses, and raising product manufacturing costs.
5. The mold is pressed or bumped, causing the mold to be damaged and unable to produce, which delays production and requires time and expense to repair the mold.
6. The smooth surface of the mold cavity is hit and crushed. No matter how you repair it, it is difficult to avoid leaving a repair mark and leaving a mark on the formed product. For plastic parts that are assembled into finished products and are directly visible, a There is a trace of repair on the smooth surface of the product. This is a flaw in the beauty, and the quality and grade of the product may be affected.
7. The mold was crushed or damaged. Weld and connect broken molds to repair them. The quality and performance of molds are declining at an accelerated pace, and the incidence of mold failure is increasing, which increases the cost of mold operation and maintenance. With the gradual decline of repairs, repairs and precision, the service life of the injection mold will eventually be shortened because it is not well protected during production and will be crushed by accidental impact and pressure during production.
In summary, stamping molds and collision molds, which have a lot of impact on production quality, output, cost, and efficiency, should be done to avoid their occurrence.
picture
Provide sufficient mold clamping force to ensure that the molding mold is reliably locked, the mold is closed and opened at a certain speed within a specified time, and the in-mold parts are ejected. Its structure and performance directly affect the production capacity and products of the injection molding machine. the quality of.
1) Requirements for mold clamping system
Sufficient mold clamping force and system rigidity must be provided to ensure that the molding mold will not be expanded by the pressure of the melt cavity during the injection molding process, so as to meet the requirements of product accuracy.
The template area, template stroke and template spacing should be large enough to adapt to the installation requirements of molds of different shapes and sizes. The mold opening and closing speed should be high and variable speed can be achieved, which can not only achieve smooth ejection of products, but also It enables safe operation of the template and high production efficiency.
There should be accessories such as product ejection, template spacing adjustment and side core pulling. Mold adjustment devices, safety protection devices, etc. should be installed.
2) Hydraulic mold clamping system
The hydraulic mold closing system uses liquid pressure to cooperate with certain auxiliary components to realize the opening, closing and locking of the mold. When the liquid pressure is relieved, the mold closing force also disappears. Common types currently include boosted type, liquid-filled type, liquid-filled boosted type, secondary action stabilized type, etc.
1. Pressurized mold clamping device (not widely used, mainly used in small and medium-sized machines)
2. Liquid-filled mold clamping device
In order to meet the requirements of fast low pressure and slow high pressure locking of the mold closing device of the injection molding machine, in addition to using the method of changing the pressure, it can also be achieved by changing the diameter of the oil cylinder. For example, our company's EH120 machine is composed of a large diameter piston It consists of a mold clamping cylinder and a small diameter plunger type rapid mold transfer cylinder.
3. Liquid-filled pressurized mold clamping device
In order to meet the requirements of large mold clamping force, a liquid-filled and pressurized mold clamping device can be used.
4. Secondary action voltage-stabilized mold clamping device
Although the above-mentioned hydraulic mold clamping device can meet certain requirements in terms of mold moving speed and mold clamping force, it is bulky in structure for large-tonnage injection molding machines. At present, the two-action stabilized mold clamping device is mostly used, which is A small-diameter rapid mold-moving cylinder is used to meet the mold-moving speed.
According to the requirements, mechanical positioning method and large diameter and short stroke clamping cylinder are used to meet the requirements of large mold clamping force. There are hydraulic - gate type and hydraulic - clutch nut type.
3) Hydraulic-mechanical mold closing system
1. Formation of mold clamping system
The hydraulic-mechanical mold closing device uses a connecting rod mechanism or a toggle support plate mechanism. Under the action of oil pressure, the mold closing device generates internal stress to lock the mold.
2. Hydraulic - double toggle mold clamping device
Our company's E-type machine and EA machine use a hydraulic-double toggle mold clamping device. This mold clamping device has a compact structure, large mold clamping force (the force increase factor of the toggle mechanism is more than 20), and high structural stiffness. It has a self-locking effect, the mold closing speed is reasonably distributed, and it saves energy. However, the mechanism is easy to wear, has many components, large template deformation, and complicated mold adjustment.
3. Mold adjustment device
In the mold closing technical parameters of the injection molding machine, the maximum mold thickness and the minimum mold thickness are realized by a device that adjusts the distance between the templates, and it can also adjust the size of the mold closing force.
4. Ejection device
It is set up to eject molded products.
5. The clamping head, second and tail plates are deformed by stress distribution.
6. Corinth pillar, mold adjusting thread nut
