A Customer Case on a 1,100 mm Rack, Deformation Risk and a Customized V210CS Solution
In injection molds with threaded parts, hydraulic cylinders are often used to drive unscrewing mechanisms. In these applications, the cylinder does not simply generate linear movement: its movement is transferred through a rack-and-pinion system to produce the rotary movement required to unscrew the threaded component.
This makes the geometry of the rack a critical part of the system.
A Customer case handled by the Vega Team illustrates an important design limitation: the Customer requested a 1,100 mm rack, but Vega determined that this length could lead to significant deformation and therefore could not be supplied as a standard Vega component.
The Vega Team explained that the maximum rack length that could be supplied was 950 mm, and even at this length, deformation problems could occur in some applications.
Rather than simply accepting the longer rack, Vega proposed an alternative:
Vega could supply the hydraulic cylinder and guide, while the Customer could manufacture the 1,100 mm rack locally.
This is a particularly interesting engineering case because it shows that increasing the stroke of an unscrewing cylinder does not automatically mean that every associated rack can simply be made longer.
The mechanical transmission itself can become the limiting factor.
1. The Customer’s Original Requirement
The original request concerned a V210CS hydraulic cylinder for an unscrewing application.
The first quotation request was for a configuration with:
- 50 mm bore;
- 2.5 specification;
- 650 mm stroke;
- specific configuration options;
- one MSU4 magnetic switch.
The Customer subsequently changed the requirement.
The new request was for:
V210CS 50 2.5 1100 A O E M 400 + 2 × MSU4
and specifically asked whether a 1,100 mm rack was possible.
This change transformed the problem from a standard configuration into a much more demanding mechanical application.
2. The V210CS Is Designed for Unscrewing Applications
The V210CS is specifically designed for injection molds requiring an unscrewing movement.
According to Vega’s official product documentation, the V210CS uses a compact V220CC hydraulic cylinder with one or two racks mounted on its sides.
The rack runs parallel to the cylinder and transfers the cylinder’s linear movement to a pinion.
The resulting movement is rotational and can therefore be used to unscrew threaded cores or other rotating mold components.
The basic principle is:
Hydraulic pressure
↓
Linear piston movement
↓
Rack movement
↓
Pinion rotation
↓
Unscrewing movement
This arrangement allows the hydraulic cylinder and the rotary transmission to be integrated into a relatively compact package.
3. Why Rack Length Matters
At first sight, increasing the rack length may seem straightforward.
If the application needs a longer movement, one might simply assume:
longer stroke = longer rack
However, the rack is a mechanical component subjected to forces along its length.
As its length increases, its resistance to deformation becomes increasingly important.
A long slender component can be affected by:
- bending;
- deflection;
- dimensional tolerances;
- alignment;
- manufacturing deviations;
- interaction with the guide;
- tooth engagement with the pinion.
The longer the component becomes, the more difficult it can be to maintain the required geometric accuracy.
This was precisely the concern identified by the Vega Team.
4. Why Vega Did Not Supply the 1,100 mm Rack
The Vega Team explained that a 1,100 mm rack could not be supplied because deformation over that length could be significant.
This was not presented as a simple commercial limitation.
It was an engineering concern.
The rack must remain sufficiently stable and accurately positioned throughout its working length.
If deformation becomes excessive, the relationship between the rack and pinion can be affected.
That can compromise the mechanical transmission of the unscrewing movement.
5. The Maximum Rack Length Was 950 mm
The Vega Team indicated that the maximum rack length that could be supplied was:
950 mm.
Even this length was described as potentially problematic in some applications, with Vega noting that it could already experience deformation issues.
This is a valuable practical lesson.
A manufacturer’s maximum recommended dimension should not automatically be interpreted as a dimension that is ideal under every operating condition.
It may represent the upper limit of what can reasonably be manufactured and controlled.
6. Why the Problem Is Not Simply the Rack Material
A natural question is:
Why not simply make the rack from stronger steel?
Increasing material strength does not necessarily solve a dimensional-stability problem.
Strength and stiffness are different engineering concepts.
A component can have high tensile strength while still undergoing unacceptable deflection under load.
For a long rack, parameters such as:
- cross-sectional geometry;
- moment of inertia;
- support conditions;
- length;
- load distribution;
- guidance;
can be just as important as material strength.
The Customer case specifically identifies deformation over the length as the concern.
7. Rack Deflection Can Affect the Pinion
The rack and pinion must maintain the correct geometric relationship.
The rack teeth must engage correctly with the pinion throughout the working stroke.
If the rack deflects, several problems can potentially occur:
- uneven tooth engagement;
- increased friction;
- localized tooth loading;
- backlash variation;
- irregular movement;
- increased wear;
- mechanical noise;
- damage to the rack or pinion.
The exact behavior depends on the mechanical design, but the fundamental principle is simple:
The rack must remain sufficiently stable and accurately guided for the rack-and-pinion transmission to operate correctly.
8. The Importance of the Rack Guide
The V210CS is designed with the rack integrated alongside the hydraulic cylinder, and Vega’s technical documentation highlights the adjustment system that allows precise regulation of the rack-and-pinion engagement and cylinder starting position.
This demonstrates that the rack cannot be considered independently from its guide.
The system consists of:
cylinder + rack + guide + pinion + adjustment
Changing the rack length therefore affects more than just the rack itself.
9. A Longer Rack Requires More Careful Guidance
As the rack becomes longer, maintaining its geometric position over the complete length becomes more demanding.
A 1,100 mm rack is significantly longer than a 650 mm rack.
The Customer’s original request had been for a 650 mm version, but the revised requirement increased this to 1,100 mm.
That is an increase of:
450 mm
or approximately:
69% longer.
This is not a small dimensional change.
It changes the mechanical problem considerably.
10. Why a 69% Increase in Length Matters
The relationship between length and bending behavior is not linear.
For a simple beam-like component under certain loading conditions, deflection can increase very rapidly with length.
In classical beam theory, some common loading conditions produce deflection that is proportional to the cube of the length.
This means that increasing length can have a disproportionately large effect on deformation.
The actual rack behavior depends on its cross-section, support and loading conditions, so the exact deflection cannot be calculated from the Customer case alone.
However, this explains why the Vega Team treated the increase from 950 mm to 1,100 mm as an important engineering limit rather than a minor dimensional change.
11. The Alternative Proposed by the Vega Team
Rather than rejecting the application completely, Vega proposed a practical alternative.
The Vega Team offered to supply:
- the hydraulic cylinder;
- the guide;
while the Customer would manufacture the 1,100 mm rack themselves.
This is an important distinction.
Vega was not saying:
“The application cannot be built.”
The technical recommendation was instead:
The 1,100 mm rack should be manufactured by the Customer according to their own application requirements, while Vega supplies the hydraulic cylinder and guide.
This allows the Customer to manage the long mechanical component according to the specific geometry and structural requirements of the mold.
12. Why Local Rack Manufacturing Can Make Sense
The Customer may have specific capabilities for manufacturing long mechanical components.
For example, the mold builder may be able to:
- manufacture the rack from a suitable material;
- control its cross-section;
- provide additional support;
- integrate it directly into the mold;
- optimize the guide;
- verify alignment during assembly.
This can make a custom rack solution more practical than attempting to extend a standardized rack beyond the manufacturer’s recommended range.
13. The Cylinder and Rack Become Separate Engineering Elements
The proposed solution effectively separates the system into two parts:
Vega-supplied components
Hydraulic cylinder + guide
Customer-supplied component
1,100 mm rack
This approach allows Vega to maintain control over the hydraulic actuator and its integrated guide while allowing the Customer to engineer the unusually long rack around the specific mold.
14. Why the Guide Remains Important
The Vega Team specifically proposed supplying the cylinder with the guide.
This is significant.
The guide is part of the interface between the hydraulic actuator and the rack.
It helps establish the correct relationship between:
- rack;
- cylinder;
- pinion;
- mounting structure.
If the Customer manufactures the rack independently, the guide remains a controlled interface supplied by Vega.
15. The Adjustment System of the V210CS
The official V210CS documentation explains that the cylinder includes an adjustment screw on the rear head that allows precise adjustment of:
- the cylinder starting point;
- the rack position;
- the rack-and-pinion engagement.
This is particularly important in unscrewing applications.
The rack must not simply move.
It must move in the correct position relative to the pinion.
16. Why Rack-and-Pinion Alignment Is Critical
The rack and pinion form a mechanical transmission.
For the transmission to work properly:
- the tooth profiles must engage correctly;
- the rack must remain aligned;
- the distance between rack and pinion must be controlled;
- the rack must remain adequately supported;
- the pinion must rotate freely.
A small alignment problem can become more significant over a long rack.
This is another reason why the 1,100 mm rack was treated differently from a standard rack.
17. The Sensors Requested by the Customer
The revised Customer request also included:
2 × MSU4 magnetic switches.
The V210CS is designed to accommodate magnetic position sensing.
Vega’s official product documentation explains that the piston contains a magnet and that adjustable electronic sensors can detect the magnetic field and transmit the position signal to the injection molding machine’s PLC.
This allows the hydraulic movement to be monitored by the machine control system.
18. Why Position Detection Matters in an Unscrewing System
An unscrewing system needs to know when the hydraulic movement has reached the required position.
Position detection can be used to confirm:
- starting position;
- end of movement;
- correct cylinder retraction;
- correct cylinder extension;
- completion of the unscrewing sequence.
The two MSU4 sensors requested by the Customer therefore form part of the overall motion-control system.
19. The Revised Configuration
The Customer’s revised request was:
V210CS 50 2.5 1100 A O E M 400 + 2 × MSU4.
The critical issue was not the hydraulic cylinder itself.
It was the requested 1,100 mm rack length.
This distinction is important.
The hydraulic actuator could be supplied, but the rack length created the engineering limitation.
20. The Commercial Alternative
After identifying the rack-length limitation, the Vega Team offered a different configuration.
The Customer could manufacture the rack themselves, while Vega supplied the cylinder and guide.
For this alternative, the quoted price in the original communication was:
€1,370 for one CS 50 2.5 configuration, excluding sensors.
This historical quotation is part of the original 2015 communication and should therefore be considered a historical commercial value, not a current Vega price.
21. What This Case Teaches Mold Designers
The case provides several useful engineering lessons.
1. Stroke is not the only parameter
A longer stroke can create new mechanical problems in the transmission system.
2. Rack length has a practical limit
The rack must remain sufficiently rigid and geometrically stable.
3. The guide is part of the solution
Rack and pinion performance depends on correct guidance and alignment.
4. A custom solution may be preferable
When a standard rack is too long, manufacturing the rack locally can be a viable alternative.
5. The actuator and mechanical transmission can be separated
The hydraulic cylinder can remain a standard Vega component while the unusual mechanical transmission is customized by the mold builder.
22. Why This Is a Good Example of Engineering Customization
The V210CS itself is already a specialized product.
Vega describes it as a hydraulic cylinder specifically intended for unscrewing systems in plastic injection molds.
The standard product includes:
- compact construction;
- one or two racks;
- long strokes;
- rack-and-pinion adjustment;
- magnetic position sensing;
- operation up to 180 bar;
- maximum speed of 0.1 m/s.
But even a specialized product has engineering limits.
The Customer case demonstrates why customization must sometimes stop at the boundary of a component’s mechanical feasibility.
23. The Difference Between “Customizable” and “Unlimited”
Vega’s official documentation states that V210CS cylinders can be customized by submitting a special project to Vega.
However, customization does not mean that every dimension can be increased indefinitely.
A customized cylinder still has to satisfy:
- mechanical requirements;
- manufacturing limitations;
- dimensional stability;
- alignment requirements;
- reliability;
- quality-control requirements.
The 1,100 mm rack request is a good example.
The cylinder could be customized around the application, but the rack itself presented a mechanical limitation.
24. A Practical Design Workflow for Long Unscrewing Systems
For a new mold requiring a long unscrewing movement, the following sequence is useful.
Step 1 — Determine the required rotary movement
Establish how many degrees the threaded component must rotate.
Step 2 — Determine the required linear rack travel
Calculate the rack movement required to achieve that rotation.
Step 3 — Select the pinion
The pinion diameter and tooth geometry determine the relationship between linear rack travel and angular rotation.
Step 4 — Select the hydraulic cylinder
Verify bore, stroke, pressure and speed.
Step 5 — Check rack length
Determine whether the required rack is within the manufacturer’s standard range.
Step 6 — Evaluate deformation
For long racks, verify stiffness, support and alignment.
Step 7 — Check the guide
Ensure the rack remains correctly positioned relative to the pinion.
Step 8 — Check sensors
Verify that the required position signals can be obtained.
Step 9 — Validate the complete assembly
The cylinder, rack, guide and pinion must be treated as one mechanical system.
25. The Critical Question: How Long Is Too Long?
There is no universal rack length that is automatically safe for every design.
The acceptable length depends on:
- rack cross-section;
- material;
- support;
- load;
- tooth geometry;
- pinion size;
- guide design;
- installation orientation;
- operating speed;
- acceleration;
- manufacturing tolerances.
The Customer case provides a practical Vega limit:
950 mm maximum supplied rack length, with a warning that even this length could present deformation problems in some circumstances.
The requested 1,100 mm was therefore outside the standard supply range.
26. The Main Engineering Lesson
The most important lesson from this Customer case is:
In a hydraulic unscrewing system, increasing cylinder stroke does not automatically mean that the rack can be extended to the same length without additional mechanical analysis.
The rack is a structural and transmission component.
At sufficient length, deformation can become the dominant limitation.
The correct response is not necessarily to abandon the application.
Instead, the system can be divided into:
standard hydraulic actuator
controlled guide
application-specific rack
This allows the mold builder to design the long mechanical element according to the actual requirements of the mold.
Conclusion
This Customer case shows how an apparently simple request for a longer hydraulic unscrewing cylinder can reveal a deeper mechanical-design issue.
The Customer initially requested a V210CS configuration with a 1,100 mm rack and two MSU4 magnetic switches.
The Vega Team evaluated the request and determined that a rack of this length could experience significant deformation and therefore could not be supplied as a Vega component.
The maximum rack length that Vega could supply was indicated as 950 mm, with the additional observation that deformation could already be problematic at that length in some applications.
Rather than simply rejecting the project, Vega proposed a practical alternative:
Vega supplies the hydraulic cylinder and guide, while the Customer manufactures the 1,100 mm rack.
The V210CS is specifically designed for unscrewing applications and uses one or two racks mounted alongside a compact hydraulic cylinder. Its adjustment system allows the rack-and-pinion engagement and cylinder starting position to be precisely regulated.
The broader engineering lesson is clear:
A hydraulic cylinder is only one part of an unscrewing system. When the required movement becomes very long, the rack, guide, pinion and alignment can become the critical design parameters.
For this reason, long-stroke unscrewing applications should always be evaluated as a complete mechanical transmission system, rather than simply as a hydraulic-cylinder sizing problem.
Useful and Verified URLs
1. V210CS Hydraulic Cylinders for Unscrewing Systems
Official Vega product page dedicated to the V210CS. It describes the cylinder, rack-and-pinion system, adjustment mechanism, available stroke range, magnetic sensors and operating conditions.
V210CS Hydraulic Cylinders for Unscrewing Systems – Vega Cylinders
2. Hydraulic Cylinders for Injection Molds
Official Vega catalog page showing the different hydraulic-cylinder families according to application. The Unscrewing category includes V215CR and V210CS.
Hydraulic Cylinders for Injection Molds – Vega Cylinders
3. Vega Hydraulic Cylinder Shop
Official Vega shop and configurator, useful for reviewing the available hydraulic-cylinder configurations and accessories.
Vega Hydraulic Cylinder Shop & 3D Configurator
4. Vega Hydraulic Cylinder Accessories
Official Vega page covering accessories used to connect hydraulic cylinders to moving mold components and to the hydraulic circuit. It also includes flow-control and connection components.
Hydraulic Cylinder Accessories – Vega Cylinders
5. Vega Cylinders – Official Website
The official Vega website presents the complete hydraulic-cylinder range for plastic injection molds and die-casting applications, including the V210CS unscrewing cylinder.
