In hydraulic cylinders used in injection molds, mechanical switches are often installed to detect the position of the cylinder.
The electrical switch itself may be perfectly functional.
Yet the system can still fail to operate correctly if the mechanical interface between the cylinder, the switch and its bracket is not correctly matched.
A real Vega technical case provides a useful example.
After a group of mechanical switches had been installed on hydraulic cylinders, the Customer reported that the control shaft did not fit correctly on four cylinders. A dimensional difference of approximately 5 mm was measured.
The investigation pointed toward an incorrect mechanical configuration, with the possibility that the wrong brackets had been used.
This case highlights an important lesson for mold designers and maintenance teams:
A position switch is only as reliable as the mechanical system that actuates it.
The Problem Appeared After Switch Installation
The Customer reported a problem on four hydraulic cylinders after the switches had been installed.
The control shaft did not appear to fit correctly with the existing mechanical arrangement.
According to the Customer, IKO had measured a difference of approximately 5 mm between the expected and actual position. The Customer therefore asked whether the correct shafts could be supplied.
At first glance, this could look like a simple dimensional problem.
However, a 5 mm discrepancy in a mechanical switch assembly can be significant.
The position of the switch, its control shaft and its bracket are not independent dimensions. They form a mechanical chain in which every component must be correctly matched.
Four Cylinders Were Affected
The problem was not isolated to a single cylinder.
The Customer reported that the same situation occurred on four cylinders.
The Customer also suspected that incorrect brackets had been used and that the installation had not been checked afterward.
This was an important clue.
When the same dimensional problem appears on multiple cylinders, it is reasonable to investigate the common components of the installation rather than assuming that four individual cylinders have independently developed the same defect.
The focus therefore moved toward the configuration of the switch mounting system.
The Importance of Matching the Bracket to the Cylinder
During the technical discussion, the Vega Team identified an apparent mismatch:
the cylinder appeared to be a CM032 fitted with the bracket intended for a CM040.
This is exactly the type of problem that can create an apparently small dimensional discrepancy while preventing correct operation of the complete mechanical assembly.
A bracket is not simply a support component.
Its geometry determines the relative position of:
- the hydraulic cylinder;
- the control shaft;
- the mechanical switch;
- the moving mold component;
- the switching position.
If the bracket belongs to a different cylinder size, the entire geometry can shift.
A few millimeters can therefore be enough to prevent the control shaft from correctly reaching the required position.
Why 5 mm Matters in a Mechanical Switch System
Five millimeters may appear insignificant compared with the dimensions of a complete mold.
For a mechanical switch, however, it can be substantial.
The switch operates through a defined mechanical movement of its contact element. The external component must therefore actuate the switch within the intended mechanical range.
Vega’s technical documentation specifically emphasizes the importance of the operating range of mechanical switches and the correct position of the contact pin. The switch should not simply be considered as a component that works whenever something touches it.
This means that an incorrect bracket can have several consequences.
The control shaft may:
- not reach the switch correctly;
- reach the switch too early;
- fail to provide sufficient movement;
- be positioned outside the intended operating geometry;
- interfere with surrounding components;
- create excessive mechanical loading.
The electrical switch may therefore be completely functional while the overall position-detection system still does not work correctly.
The Mechanical Chain Must Be Considered as a Whole
A useful way to analyse this type of installation is to consider the complete mechanical chain:
Hydraulic cylinder
↓
Mounting bracket
↓
Control shaft
↓
Mechanical switch
↓
Moving mold component
↓
Position signal
Every interface contributes to the final position.
If one component has the wrong geometry, the position of the final switching point can change.
This is why a mechanical switch should not be specified independently from the hydraulic cylinder and its mounting arrangement.
The Cylinder Model Must Be Verified Before Installing the Bracket
The case also illustrates a simple but important rule:
Always verify the exact cylinder model before selecting the corresponding switch bracket or mechanical accessory.
In this situation, the technical correspondence specifically raised the possibility that the cylinder was a CM032 while the bracket was from a CM040 configuration.
The difference between two apparently similar cylinder sizes can be enough to alter the position of the control shaft.
Therefore, before installation, the technician should verify:
- cylinder model;
- cylinder bore;
- cylinder version;
- switch type;
- bracket reference;
- control-shaft geometry;
- mounting position;
- final switch activation position.
This verification is particularly important when several cylinders of different sizes are installed on the same mold.
Why the Installation Check Is Essential
The Customer suggested that the wrong brackets may have been used and that there had been no subsequent check.
This highlights another important point.
Correct component selection is only the first step.
The assembled system should also be checked.
A dimensional verification after installation can identify problems before the mold reaches production.
For a mechanical switch assembly, the final inspection should confirm that:
- the bracket is the correct one;
- the control shaft is correctly positioned;
- the shaft moves freely;
- the switch is activated at the intended cylinder position;
- there is no excessive compression;
- there is no mechanical interference;
- the switch cable and connection are correctly installed.
This type of inspection can prevent a relatively simple mounting error from becoming a mold commissioning problem.
The Control Shaft Is Part of the Position-Detection System
It is easy to focus on the microswitch because it is the component that produces the electrical signal.
However, in a mechanical switching system, the control shaft is equally important.
The shaft physically transfers the movement of the hydraulic cylinder or mold mechanism to the switch.
If its length or position is incorrect, the switch cannot provide the expected signal even if its electrical characteristics are completely correct.
In the case analysed here, the Customer specifically reported that the control shaft did not fit correctly and measured a 5 mm difference.
The corrective action therefore required the correct mechanical components rather than simply replacing the electrical switch.
Do Not Solve a Mechanical Problem by Replacing the Switch
This is an important practical lesson.
If a switch does not activate correctly, the first reaction may be to replace the switch.
But before doing so, it is worth checking the complete mechanical installation.
A useful diagnostic sequence is:
1. Check the cylinder model
↓
2. Check the bracket reference
↓
3. Check the control shaft
↓
4. Measure the actual dimensions
↓
5. Check the switch activation position
↓
6. Verify the complete assembly
↓
7. Only then evaluate whether the switch itself is defective
This approach avoids replacing a perfectly functional component when the real problem is a mechanical mismatch.
A 5 mm Difference Can Indicate the Wrong Component
The 5 mm measurement in this case is particularly useful because it provides a concrete diagnostic clue.
A dimensional difference of this magnitude should immediately lead the technician to ask:
Is the correct accessory installed?
Rather than immediately assuming that the cylinder or microswitch is defective, the investigation should compare the actual installation with the relevant technical drawing.
The Vega Team’s response followed this type of approach by checking the relationship between the cylinder and the bracket and then arranging the correct spare parts. Vega subsequently confirmed that the correct spare parts would be shipped directly to the Customer’s end user.
Mechanical Switches Require Correct Integration
Vega’s current range includes mechanical switches specifically designed for hydraulic-cylinder applications.
The official Vega documentation explains that mechanical switches are used for particular cylinder configurations and that different mounting arrangements are available depending on the cylinder version.
This reinforces a fundamental design principle:
The switch, bracket and cylinder must be considered as one integrated mechanical system.
The correct switch mounted on the wrong bracket can still produce an incorrect result.
Mechanical Switch Position Must Be Checked, Not Assumed
Vega’s technical documentation on mechanical switch operating range shows why the final position of the contact mechanism matters.
The switch has a defined operating field, and the component actuating the switch must bring the contact pin into that field.
Therefore, simply confirming that:
“The shaft touches the switch”
is not enough.
The correct question is:
“Does the shaft actuate the switch at the correct position and within the specified operating range?”
That distinction is essential in injection-mold applications.
What Should Be Checked During Mold Assembly?
For a hydraulic cylinder equipped with a mechanical switch, the following checklist can be useful.
Cylinder identification
Confirm the exact cylinder model and version.
Bracket identification
Confirm that the bracket corresponds to the cylinder model and bore.
Control shaft
Check the shaft length, geometry and position.
Mechanical alignment
Verify that the shaft and switch are correctly aligned.
Switching position
Check that the switch is activated at the required cylinder position.
Mechanical travel
Make sure the switch is neither under-actuated nor unnecessarily over-compressed.
Final dimensional inspection
Measure the assembled system rather than relying only on nominal CAD dimensions.
Functional test
Operate the cylinder and confirm that the switch signal changes reliably at the intended position.
What Can Be Learned from This Customer Case?
This case demonstrates that many apparent “sensor problems” are actually mechanical integration problems.
The Customer had four cylinders with the same issue.
A 5 mm dimensional difference was identified.
The technical investigation then focused on the bracket and cylinder configuration, with the apparent mismatch between CM032 and CM040 becoming a key point of attention.
The solution was therefore not simply to replace the microswitch.
The correct mechanical components had to be identified and supplied.
This is a good example of why technical support should analyse the complete assembly rather than looking at an individual component in isolation.
Conclusion
Mechanical switches are a reliable and practical way of detecting hydraulic-cylinder position in injection molds.
However, their correct operation depends on much more than the electrical switch itself.
The cylinder model, bracket, control shaft, switch position and mold geometry must all be compatible.
In this case, four cylinders showed an incorrect mechanical fit, with a measured difference of approximately 5 mm. The technical investigation identified a possible mismatch between the cylinder and its bracket, specifically a CM032 cylinder associated with a CM040 bracket.
The lesson is simple:
When a hydraulic-cylinder microswitch does not work correctly, check the mechanical interface before replacing the switch.
A wrong bracket, an incorrect control shaft or a small dimensional mismatch can prevent a perfectly good switch from providing the correct position signal.
For mold builders and maintenance teams, the best practice is therefore to verify the complete mechanical assembly against the correct cylinder and switch configuration before commissioning the mold.
Useful Vega Technical Resources
Mechanical Switches for Hydraulic Cylinders
Official Vega page describing mechanical switches and their available configurations for hydraulic cylinders.
Vega Cylinders – Mechanical Switches
End-Stroke Switches for Hydraulic Cylinders
Official overview of Vega magnetic, inductive and mechanical end-stroke switches.
Vega Cylinders – End-Stroke Switches
Mechanical Switch Operating Range
Technical article explaining why the position and operating range of a mechanical switch must be correctly controlled during hydraulic-cylinder installation.
Vega Cylinders – Mechanical Switch Operating Range
Hydraulic Cylinders for Plastic and Die-Casting Molds
Official Vega range of hydraulic cylinders for mold applications.
Vega Cylinders – Hydraulic Cylinders
Hydraulic Cylinder Catalog
Official Vega catalog with cylinder families, configurations and technical information.
Vega Cylinders – Hydraulic Cylinder Catalog
