A two platen injection molding machine—also known as a double-platen injection molding machine—features only a stationary platen and a moving platen. Unlike traditional three-platen machines, it eliminates the rear platen, simplifying the structure and reducing the overall footprint.
Two Platen Injection Molding Machine: A Growing Trend in the Industry
Two platen injection molding machine has existed since the early stages of the injection molding industry. The key difference lies in the clamping mechanism. Unlike traditional three-platen machines, which use a toggle system with a moving platen, stationary platen, and tail platen, the two-platen design eliminates the tail platen and toggle system. Instead, it incorporates a fast mold-moving cylinder, a braking device, and a high-pressure clamping cylinder to achieve rapid mold opening and closing with efficient locking force.
In recent years, driven by the automotive industry’s demand for high-tonnage and large-space injection molding equipment, two platen injection molding machine has gained increasing attention. Their space-saving structure, strong clamping capability, and suitability for large-size molds make them a rising trend in the industry. Today, leading manufacturers have developed their own versions of two platen molding machine, which are frequently showcased at major plastics expos.
Mold transfer, holding mechanism
Clamping mechanism
Two Platen Injection Molding Machine:industry standard
Two-Platen Machines: Key Players and Technical Insights
As a subcategory of injection molding machines, two-platen models are primarily led by European and Japanese brands, with manufacturers from Mainland China, Hong Kong, and Taiwan steadily following suit. Representative brands include ENGEL, Demag, MITSUBISHI, Meiki, Haitian, Chen Hsong, and Borche.
The fundamental difference of two platen machine lies in the clamping unit design, while other performance parameters generally remain consistent with conventional three-platen machines of the same tonnage. Most two-platen machines on the market adopt either hydraulic drive systems or hybrid electro-hydraulic configurations. Among them, hydraulic drive is dominant in large-tonnage machines due to its stability and high clamping force.
According to industry data and major plastic machinery exhibitions, two platen machine are gaining popularity for large-part molding, especially in the automotive sector. A notable example is the Borche BU6800T, which currently holds the record as the largest two platen machine in Asia.
To provide a reference point, we compare two platen machine from ENGEL and MITSUBISHI that are similar in tonnage to the Haitian 2800T three-platen machine commonly used in factories.
Note: The following models are standard configurations. As injection molding machines are often modular, actual parameters may vary based on specific application and customization needs.
Comparison of Hydraulic Drive Injection Molding Machines – Two-Platen vs. Three-Platen
| Specification | Unit | ENGEL (Two-Platen) DUO45050/27000 | MITSUBISHI (Two-Platen) 3000MMV | HAITIAN (Three-Platen) MA28000/U |
|---|---|---|---|---|
| Screw Diameter | mm | 200 | 200 | 200 |
| Injection Volume | cm³ | 28,270 | 31,400 | 35,154 |
| Injection Speed | mm/s | 85 | 53 | 66 |
| Injection Rate | cm³/s | 2,680 | 1,675 | 2,095 |
| Injection Pressure | MPa | 163 | 160 | 137 |
| Plasticizing Capacity | kg/h | 511 | 810 | 828 |
| Screw Rotation Speed | r/min | 74 | 59 | 50 |
| Clamping Force | tons (tf) | 2,700 | 3,000 | 2,800 |
| Tie Bar Distance | mm | 2175 × 1750 | 2000 × 1800 | 1900 × 1750 |
| Ejector Force | tons (tf) | 38 | 70 | 43 |
| Ejector Stroke | mm | 400 | 350 | 450 |
| Machine Dimensions (L×W×H) | m | 16.5 × 5.0 × 3.8 | 15.4 × 5.5 × 3.9 | 18.9 × 3.92 × 5.5 |
Comparison of the above table, clamping force of 2800T or so, screw diameter ¢ 200 of the three brands of injection molding machine. The first two columns of two platen machine basically reflects the current situation of the basic parameters of the large-tonnage two platen machine, compared with these two injection molding machine: ENGEL DUO45050/27000 advantage lies in the injection speed, the disadvantage is that the melting amount of glue is small; MITSUBISHI3000MMV advantage of the clamping force is large, the plasticizing capacity is strong, but the screw injection is slow. The difference and preference of equipment performance, combined with the modular matching of injection molding machines provided by each factory, has prompted the development of special-purpose injection molding machines.
Comparison of the above two-board machine with the factory 2800T injection molding machine, 2800T injection molding machine parameters on the gap is not too obvious. Not considering the structural characteristics of each brand of injection molding machine, only from the length of the comparison of 3000MMV and MA28000/U body, the length of the size of 18.5% reduction.
Two platen injection molding machine Advantages
Two platen molding machine due to the cancellation of the rear template, and the melt glue part and three platen injection molding machine is the same, so in the case of the same tonnage, two platen injection molding machine space size is shorter than the three platen injection molding machine, on the other hand, due to the two platen machine basically adopts the fast cylinder directly acting on the movable template, the mold closing speed is relatively stable, and the mold closing speed. When the mold is closed, the four guide columns are mechanically locked at the end, and the high pressure clamping cylinder at the end of the four guide columns locks the mold differently, which improves the parallelism of the template and reduces quality problems such as cloak, product deformation, and so on.
Space optimization: Due to the elimination of tail plate, the length of the same specification equipment is reduced by more than 20%.
Low resistance: The two platen injection molding machine replaces the green column with two guide rails, which effectively reduces friction, low wear and tear, and easy maintenance.
Fast mold closing speed: The mold closing speed is achieved by the fast mold transfer cylinder, which can optimize the empty cycle time by about 40% with the mold clamping.
Large space for mold opening and closing: mold opening and closing are not limited by the stroke of the curved elbow mechanism, and the length of the guide rail and the stroke of the quick-action cylinder can be enlarged to meet the special space requirements.
Better parallelism: through the guide cylinder differential clamping mode, the four guide columns are subjected to an average force, which can improve the parallelism of the mold bonding surface, and the plane locking force is uniformly distributed.
Longer life: compared with three platen injection molding machines, two platen injection molding machines use fast cylinders to move the mold, the pressure demand is not large, and four hydraulic cylinders are used to pressurize and lock the mold, the force of hydraulic cylinders is even, the force line is short, the load on the hydraulic system is reduced, and the service life of the equipment can be prolonged.
Two platen injection molding machine Disadvantages
As the subsequent development trend of the two platen injection molding machine, in the current use of the following problems
1. Manufacturers to improve the technology: two platen molding machine in the domestic promotion and popularization has just begun, the domestic manufacturers have only launched the two platen molding machine in recent years, the accumulation of technology and precipitation still need a long time to improve.
2. Control of production process parameters: relative to the three platen injection molding machine, two platen molding machine mold part of the parameters may be different from the three platen injection molding machine (depending on the manufacturer), which involves parameter adjustments and the use of experience needs to be accumulated.
3. Daily maintenance of equipment: three platen injection molding machine due to the unique structural design, the design concept of the different decisions of the equipment maintenance and maintenance work is different from three platen injection molding machine, for example, two platen injection molding machine on the level of the higher requirements of the machine, high-pressure clamping cylinders are more difficult to maintain.
Applicability of Two Platen Injection Molding Machine
Advantages of Two Platen Machine in Practical Applications
The suitability of a two platen machine goes beyond core factors like machine precision and electronic control systems. It also excels in the following two key areas:
1. Compact Machine Size
A two platen machine significantly reduces the overall length compared to traditional three platen machines of the same clamping force. This space-saving design is especially attractive to manufacturers with limited floor space. In addition, by eliminating the toggle mechanism, the machine offers a larger mold-opening stroke and more spacious tie-bar clearance. This facilitates mold rotation, shifting, and complex automation functions within the tie-bar area.
2. Advanced Clamping System
The clamping unit of the two platen machine adopts a direct locking structure using tie-bars and high-pressure locking cylinders. This setup ensures smoother and more linear mold clamping motion. The differential locking system allows precise control of clamping force, resulting in uniform stress distribution on the backplate. These advantages are especially beneficial for producing thin-wall parts, minimizing flash, and maintaining high dimensional accuracy.
Thanks to its structural innovations, the two platen machine provides an ideal platform for advanced molding processes such as injection foaming, compression molding, and multi-color or multi-material injection.
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