Servo Proportional Valves for Injection Molding
Not every injection molding press needs the extremely dynamic performance of a high-end servo valve. Many machines have control requirements that are not as tight, so other factors such as robustness and cost are more highly considered. Domin’s P Series servo proportional valves were engineered to address limitations in industrial proportional valves, providing better performance than traditional valves.
Proportional Valves for Control Challenges in Injection Molding
In injection molding, proportional valves often manage injection speed, back-pressure, clamp movement, and secondary axes. These specific control challenges do not often need ultra-high response rates that high-end servo valves, such as the Domin S Series, achieve.
In fact, Domin developed the P series, their proportional valves, to provide stability and precision in applications that aren’t quite as dynamic but still require fine control and fast response rates; this allows strong performance without the price tag of upper limits that won’t be fully used.
Domin Proportional vs Servo Valves for Molding Presses
In injection molding, servo valves have to manage a quick switch from velocity‑controlled fill to precisely held packing pressure and then maintain stable behavior over repetitive, long cycles. Servo proportional valves are designed for exactly this kind of industrial duty, giving presses fast response and fine resolution with a NG06/NG10 footprint with straightforward integration.
For most presses, the Domin P Series is the right choice for stable, day‑to‑day control over extreme bandwidth. The Domin S Series valves (S6, S10, S12) are then reserved for the most dynamic axes such as the main injection unit or critical secondary positions. These points require very fast response, integrated spool feedback, and tight leakage specs directly impact part quality and scrap rates.
On many modern injection molding presses, both series are used side‑by‑side:
Utilizing both series on the same press allows engineers to achieve high performance only where it’s needed, while utilizing cost-effective, efficient control across the rest of the machine.
Our Recommended Valves – P6 Pro
For small to mid-sized injection molding presses, such as ceramic presses or rubber injection molding, the Domin P6 Pro is our primary recommendation. This valve is perfectly suited for applications with NG06 mounting patterns where the control requirements are not as dynamic. The P6 Pro is a durable, cost-effective solution.
On larger presses, or where axes might need higher flow and more coordinated control, it may be beneficial to pair a P6 valve with a higher capacity P Series valve, such as the P10, or even an S Series valve for more dynamic, more precise, faster control. In fact, many presses feature both series on the same press, differentiating between the various control needs.
|
Hysteresis |
<0.2% |
<0.2% |
<0.2% |
|
Leakage |
<0.13 gpm (<0.5 lpm) |
<0.4 gpm (<1 lpm) |
<0.6 gpm (< 2.5 lpm) |
|
Mass |
1.39 lbs (0.63 kg) |
8.8 lbs (4 kg) |
15.4 lbs (<7 kg) |
|
Frequency Response |
>100 Hz (-3 dB, up to ± 25% FS) |
> 65 Hz (-3 dB, up to ± 25% FS) |
> 60 Hz (-3 dB, up to ± 25% FS) |
|
Rated Flow |
2.6 to 10.6 gpm |
10.6 to 42 gpm |
42 to 153 gpm |
|
Response Time |
<10 ms |
<20 ms |
<12 ms |
|
Mounting Pattern |
NG06 |
NG10 |
NG16 |