What is vertical injection molding machine?
Vertical injection molding machine is a mechanical equipment. It is usually composed of injection system, clamping system, hydraulic transmission system, electrical control system, lubrication system, heating and cooling system, safety monitoring system, etc.
Injection system is one of the most important parts of vertical injection machine. There are 3 main type: plunger type, screw type, screw pre plastic plunger injection type. Screw type is the most widely used at present. It is, in a circular plastic injection machine, within a specified time will be a certain number of plastic heating plasticization, pressure and velocity in the screw, through the molten plastic is injected into the mold cavity.
Most of plastic injection molding machines are horizontal, however, there are also some vertical injection molding machines. The difference is that: for the horizontal injection molding machine, the molds should be put onto the machine horizontally, with left half and right half; for the vertical plastic injection moulding machine the molds should be put onto the machine vertically, with top half and bottom half.
Vertical plastic moulding machine is mainly used in insert molding and metal injection molding on the substrate
Insert molding (insert molding) refers to the pre-loaded in the mold insert different materials prepared after the injection of resin, melt bonding material curing and inserts, molded products made of integrated construction method. Substrate injection molding (outsert molding) refers to the local board on the metal injection molding parts embedded in the construction method. HJ Series fixed for the next template, the template on the movable vertical plastic injection machine. Oriented organization with a new, improved the vertical insert molding insert the stability, achieve high-precision molding. Application and insert molding, metal forming and drawing with injection molding on the substrate.
Vertical injection molding machine classification: specific vertical injection molding machine can be divided into the following categories.
1. the vertical injection molding machine series: the vertical injection molding machine model is mainly for cable, all kinds of electronic, computer data lines and plug line of injection molding, precision injection molding products less demanding standard, generally PVC, PE such as plastic material injection led product suitable for the specific application of the general model specification clamping force ranging from 35 T to 15 T, because the manufacturers of specific models Haijiang modulus configuration is different, before purchase certain plants require manufacturers to determine the specific model parameter specifications.
2. Vertical+horizontal injection molding machines, C-type injection molding machine series: the vertical injection molding machine Vertical clamping, horizontal injection plastic because there is no guide posts, due to clamping portion into a letter “C” word and the name. The aircraft structure is complex, with a large amount of injection, because no column-wide work area, mainly engaged in various types suitable for injection molding safety plug, such as the French head, US plug, UK plug, etc.
3. the single-slide type vertical injection molding machine, injection molding machine double skateboard series: the vertical injection molding machine models mainly for engineering plastics, the products have strict requirements for precision, precision or tiny insert injection molding together, but also embedding one piece injection molding optimization program. Because it has a fixed upper mold, the lower mold slide function. The slide having a double double on the lower mold die, alternating two-mode operation, compared suitable for precision metal parts embedded in or take out. General molding products, such as precision electronic connectors, phone connectors, integrated circuits and other components.
4. the disc vertical injection molding machine, rotary series: vertical injection molding machine rotary disc series can be described as insert molding precision parts optimization program, because the machine can be designed on a second lower mold die or lower die function, compared with the advantages of complex embedded and labor-saving suit.
Competitive Advantages: Vertical Molding vs. Horizontal Molding Machines
Vertical molding machines are more flexible in terms of efficient production cycles, cost, and types of products it can handle. Take insert molding as an example. This is when a Pre-formed product is inserted into a mold that needs plastic formed around it
Each cycle requires having the finished product taken out of the mold, and a new one added before the molding process begins.
Attempting to do this on a horizontal machine would be difficult and awkward as you would be fighting gravity, slowing down production and raising the risk of bad parts. Horizontal molding creates even greater risks when it comes to medical injection molding, which requires high tolerance parts.
With a vertical molding machine, the parts can easily be placed in the mold quickly and comfortably without having to worry about the insert becoming misaligned.
An added advantage to vertical molding machines is pairing book molds with a rotary table.
Book Molds and Rotary Tables
Book molds close on the inserts and hold the pieces tightly in place before, during, and after the molding process. Rotary tables can hold between 1-12 molds at a time and rotate giving the mold technician to time to replace the insert without holding up the molding process.
Multiple book molds on a rotary table can offer the fastest cycles and highest possible yields in molding. They also allow different molds for a family of products to be run at one time.
The video at the top of this article shows an example of a vertical injection molding machine with rotary table.
Vertical Molding: Space Saving and Versatile
Another advantage of vertical injection moulding machine vs horizontal is that they take up well over half the space required for a horizontal molding machine. See the two machines pictured side-by-side:
Additionally, the vertical clamp units on vertical molding machines are versatile and allow maximum flexibility with associated mold tooling.
Vertical injections can offer more control when the resin reaches the mold cavity through a short distance. Often times with horizontal machines, the plastic has to travel a longer distance to reach the mold which makes room for resin to cool too quickly and produce bad shots.
How to choose vertical injection molding machine?
In general, customers in the injection molding industry for many years most have the ability to judge and select the appropriate injection molding machine to produce. However, in some cases, customers may need help.manufacturers specifications in order to decide which of the injection molding machine, and even customers may only samples of the product or idea, and then ask whether the manufacturer of the machine can produce, or what kind of model comparison for. In addition, some products may require special with special devices such as accumulators, closed-loop, injection compression, can produce more efficiently. Thus, how to determine the appropriate injection molding machine to produce, is an extremely important issue. The following information is provided to the reader is referred to.
Usually affect the choice of injection machine molds important factors, products, plastics, molding requirements, therefore, must be collected before making a choice or have the following information: the die size (width, height, thickness), weight, special design; use the type and quantity of plastic (single or multiple plastic materials); injection finished Dimensions (length, width, height, thickness), weight, etc.; molding requirements, such as quality conditions, the production speed.
In obtaining the above information, you can follow these steps to select the appropriate injection molding machine:
1, the election of the type: the decision by the products and plastic models and series.
Very much due to the injection machine type, so the beginning of the right to judge this product by the first of which injection molding machine, or to produce a series which, for example, generally plastic or Bakelite thermoplastic materials such as raw materials or PET, is a single color, color, multi-color, laminated, or blending. In addition, some products require high stability (closed loop), high precision, high rate of fire, or the rapid production of high pressure injection (multi-loop) and other conditions, you must select the appropriate series to produce.
2, let go: the size of the mold to determine the machine’s “distance between tie bars,” “thick model”, “Die minimum size” and “mold plate size,” whether it is appropriate to confirm the mold is let go.
Mold width and height must be less than or at least one side is less than the distance between tie bars; mold width and height of the best in the mold plate size range; mold thickness must be between the mold thickness between the injection molding machine; mold width and height must be consistent with the injection molding machine recommended minimum die size, too small to no good.
3, do have: determined by the mold and finished “opening stroke” and “Ejector Stroke” is enough to make the finished product out.
At least greater than the opening stroke switch mode in the direction of the finished product more than twice the height, and the need to include vertical runner (sprue) in length; ejector stroke will be enough to top the finished product.
4, the lock is maintained: the decision by the products and plastic “clamping force” tonnage.
When the raw material into the mold cavity under high pressure will produce a hold mode when the power, so the injection molding machine clamping unit must provide sufficient “clamping force” so that the mold will not be softened. Clamping force requirement is calculated as follows:
Size obtained by the appearance of finished product in the direction of the projected area of switch mode;
Hold-mode switch-mode power = finished in the direction of the projected area (cm2) × number × mold cavity pressure (kg/cm2);
Mold pressure with different raw materials, raw materials generally take 350 ~ 400kg/cm2;
Machine support mold clamping force must be greater than the power, and to be safe, machine clamping force is usually greater than the hold-mode power to be 1.17 times more.
At this point a preliminary decision has been clamping unit specifications, and generally determine the tonnage models, and then have to proceed the following steps to confirm what a screw injection unit compared to the required diameter.
5, the shot was full: the finished product to determine the weight and number of cavities required for “injection volume” and select the appropriate “screw diameter.”
Calculate the weight of the finished product to be considered number of cavities (a mode a few points);
For stability purposes, the injection volume required is 1.35 times the weight of the finished product, that product the amount of weight required for the injection of 75% or less.
6, shoot it well: to determine by the plastic “screw compression ratio” and “injection pressure” conditions.
Some plastics require a higher injection pressure and the appropriate screw compression ratio design, have good forming effect, so in order to make the product better shot, when the screw should also be considered in the choice of injection pressure and the compression ratio of demand the problem.
In general, the smaller diameter screw provides higher injection pressure.
7, shot quickly: and “injection rate” of the confirmation.
Some products require a high rate of speed of injection to stabilize the injection molding, such as thin as a finish, in this case, the machine may need to confirm the adequacy of injection rate and the rate of fire, whether it be with the accumulator, closed-loop control device. In general, under the same conditions, can provide a higher injection pressure of the screw is usually a lower rate of fire, on the contrary, it may provide a lower injection pressure of the screw is usually a higher rate of fire. Therefore, choosing the screw diameter, the injection volume, injection pressure and injection rate (injection speed), considered to be cross and trade-offs.
In addition, multi-loop design can also be used to shorten the molding compound action synchronization time.
After the above steps, already decided in principle to meet the needs of injection molding machines, but there are some special problems may also be coupled to consider, including:
With the size of the problem:
In some special circumstances, the customer’s mold or mold products may be small but the required large fire, or mold bulky but a small amount of radiation needed, in this case, the manufacturers of the pre-set standard may not meet customer needs, and must be so-called “size distribution” which means “big wall of a small fire” or “small big wall of fire.” The so-called “big wall of a small fire” refers to the original standard clamping screw injection unit with a smaller, on the contrary, the “small big wall of fire” that is, the original standard clamping unit with a large injection screw. Of course, with the clamping and injection may also be a difference of several levels.
Fast machine or high-speed machine concept:
In practice, more and more customers will be required to buy the so-called “high-speed machine” or “fast machine.” In general, the purpose in addition to the demand for the product itself, the other mostly to shorten the molding cycle, increase yield per unit of time, thereby reducing production costs and improve competitiveness. Typically, to achieve the above purpose, there are several approaches:
Injection speed: the electrical motor and pump to increase, or increase the pressure has (plus the best closed-loop control);
Feeding speed: increase the Electric motor and pump, hydraulic motor or feeding piecemeal, so that the screw speed to speed up;
Multi-loop system: double-loop or three-loop design, combined with synchronized movements and shorten the molding time;
Increase the water mold, the mold to enhance the cooling efficiency.
However, “there is no free lunch” performance improvement and transformation of the machine can certainly increase production efficiency, but often also increase the investment cost and operation cost, therefore, pre-investment assessment of the benefits need to be carefully measured to the most appropriate machine type have the highest benefits.
Injection molding machine operation and maintenance procedures
1. when used in machine operation must pay attention to safety, began to check the machine for each operation of safety devices, insurance and security door ejector reliability. Machine running the process, keep in mind which can not reach into the clamping mechanism. In taking products, be sure to open the security door, security personnel in the recognition and no foreign body within the mold before you can close the safe door. In addition, the operation can not be inserted into the hand between the nozzle and the mold gate. In the repair of mold, close the pump motor.
2. Molded products, due to the variety of raw materials, molding products, an area the size and shape of the different needs of the clamping force is different, according to the actual transfer mode when the minimum required clamping force adjustment. This can save power consumption and significantly extend the life of the machine.
3. Hydraulic system pressure regulator according to the requirements of their actions were implemented, not too high, rational use of pressure, help to reduce energy consumption and extend the life of the machine. Similarly, the limit switch position, but also according to the requirements of regulation molding products. Especially during the injection to holding pressure switch point adjustment, must pay attention, or lack of filling products may cause or lead products generate excessive stress and flash, and even cause up mold, leaving the mold is difficult to open.
4. The screw or barrel is no material, the screw should not be high speed (preferably 30 rev / min under). Screw the spiral groove to be filled with material (burning material from the nozzle exit out of time), then screw speed increased to the desired value, so as to avoid idle speed is too high or too long scratch screw or barrel.
5. Cylinder heated from room temperature to the desired temperature, holding for about 10 minutes. To start the screw for feeding to ensure adequate residual melt cold material to avoid damage to the screw.
6. Machine pump safety valve, has been adjusted at the factory, do not easily change.
7. The machine starts running, when the cooling water temperature 5-10 ℃ after (when the water cooler should be subject to water-filled). Gradually open the cooler the valve, and in the course of regulation of water, the oil temperature is kept at 55 ℃ the following; the starting cooler, avoid rapid cooling water inlet valve open, because a lot of cold water flow through the cooler, the will form a layer of cooler tube surface very poor thermal conductivity of the “cold layer”, even after large amounts of water into the cooler would not achieve a good result or cooling effect.
8. Attention to the lubrication of the machine, according to operational requirements strictly enforced, in the case of running short of oil, it will seriously wear parts, especially the clamping of the connecting rod and steel sets, starvation may occur if the bite, and can not work. Replacement of the mold and to “transfer mode” operation, the template must be confirmed four adjustment nuts have been injected full of lubricants containing molybdenum disulfide grease.
9. Plastics such as heated barrel and screw the threaded portion of the connection piece, because at high temperatures, disassembly, threaded parts are coated with heat-resistant grease to (red lead or second-rate of molybdenum) can not be killed so as to avoid disassembly . (Screw head and thread is left hand thread).
10. Model of the mold mounting surface with high precision, do not use the mounting surface and the parallelism bad mold, and poor installation of screw thread, so as not to damage the clamping performance and damage the template.
11. Do not install two flat die a long time (ten minutes or more) to die in a mode-locked state
State to avoid locking rod sets off the oil and steel, the mold may not be open (this is when a power outage more attention should be ten minutes).
12. Keep the surface clean each start.
13. The end of each process:
(1) Close off the feed hopper of the flapper, a “manual” mode of operation, and repeated injections back seat to pre-feeding and injection of plastic, the material remaining inside the barrel as far as possible discharge.
(2) a “manual” mode of operation, so that in a closed mold free state (not fully locked state).
(3) cut off the heating power, turn off the pump motor, total power and cooling to the water.
(4) prepare the machine for cleaning and maintenance.
14. Understand the operation of the switch plate, not to misuse, so as not to damage the parts.
15. Electric heating coil in use, due to heat expansion, may be loose, please pay attention to regular checks in use at any time to tighten.
16. Thermocouple probe with the barrel temperature should ensure good contact with the micropylar end, before driving to check and found that bad, you should always tighten.
17. Should seriously take a good ground, regularly check the insulation of electrical components to avoid electrical shock injuries.
18. Check the low voltage circuit, use a multimeter.
19. To prevent the injection molding machine temperature control instrument zero drift, the Ministry every six months by the manufacturer to inspect electrical calibration.