What Production Data Should an SMC Press Record

1. A Cycle Counter Is Not Enough

Traditional hydraulic presses may provide only a limited set of production information:

• current hydraulic pressure;
• current platen position;
• cycle count;
• basic alarm messages.

This may be enough to operate the machine, but it is often insufficient when a process engineer needs to answer questions such as:

• Why did flash increase after several days of stable production?
• Why does the press begin building pressure earlier than before?
• Why is the final mold position changing?
• Why did output decrease even though the molding recipe was unchanged?
• Why did the reject rate increase after changing SMC material lots?

2. Real-Time Display and Historical Data Logging Are Different

A value shown on the HMI is not automatically useful production history.

Real-time monitoring tells the operator what is happening now. Historical data logging allows engineers to review what happened during earlier cycles.

3. The Core SMC Press Data Set: Position, Velocity, Pressure and Time

For most SMC molding applications, four machine signals form the core of useful press data:

4. Record Curves, Not Only Maximum Values

A single maximum value can hide a very different process history.

Consider two cycles that both reach a maximum hydraulic pressure of 160 bar.

If the system stores only:

both cycles appear identical.

More useful process records can include:

• pressure vs time;
• pressure vs platen position;
• position vs time;
• velocity vs position;
• temperature vs time where relevant.

5. What Platen Position Data Should Be Saved?

Final platen position is useful, but additional position points can provide much more diagnostic value.

Depending on machine configuration, useful position data can include:

• top or fully open position;
• fast-to-slow transition position;
• expected material-contact position;
• pressure-control transition position;
• final molding position;
• opening transition position.

Material Contact Position

The point where hydraulic pressure begins to rise can be especially informative.

For example, if a validated mold normally begins developing material resistance around one position and then suddenly begins doing so much earlier, possible checks may include:

• charge stack thickness;
• charge weight;
• incorrect placement;
• foreign material or mold interference;
• material-condition changes.

6. Closing Velocity Should Be Recorded with Pressure

Pressure behavior cannot be interpreted correctly if platen velocity is unknown.

Faster closing changes the rate at which the SMC charge must compress and flow. This can change resistance, pressure rise and material movement.

Useful velocity data may include:

• fast approach velocity;
• deceleration point;
• slow-closing velocity;
• compression velocity;
• actual velocity during pressure build-up;
• opening velocity.

7. Record Both Pressure Setpoint and Actual Pressure

A recipe may specify a pressure target, but the actual machine response can differ.

8. Holding Pressure Stability Is Production Data

The hold stage should not be reduced to one number such as “150 bar for 60 seconds.”

Engineers should also be able to evaluate whether actual pressure remained stable during that period.

9. Mold Temperature Should Be Stored with Press Data

SMC material flow and cure behavior are strongly influenced by temperature, so press data becomes much more useful when mold temperature is recorded at the same time.

Depending on the tool, useful thermal data can include:

• upper mold temperature;
• lower mold temperature;
• individual heating-zone temperatures;
• temperature setpoint;
• actual temperature;
• temperature deviation during production.

If pressure behavior changes while mold temperature also changes, the process engineer has more information than if only the pressure curve is available.

10. Total Cycle Time Should Be Broken into Stages

Total cycle time tells production managers how fast the process is operating, but it does not explain where time is being lost.

A more useful breakdown may include:

11. Record Waiting Time and Micro-Stops

Not every production loss appears as a major machine breakdown.

Small delays can accumulate across hundreds of cycles.

Useful waiting and delay categories can include:

• press ready but waiting for operator;
• material not prepared;
• robot waiting;
• ejector delay;
• mold-temperature recovery;
• alarm reset;
• manual inspection delay;
• part-removal delay.

12. Alarm History Should Record More Than an Alarm Code

An alarm record becomes much more useful when it includes context.

Useful fields can include:

Production and maintenance teams can then ask:

• Which alarm occurs most frequently?
• Which alarm creates the most downtime?
• Does one mold generate more alarms than others?
• Do alarms increase after maintenance or recipe changes?

13. Recipe Data Is Essential for Process Traceability

A production cycle should ideally be linked to the process recipe used to create it.

Useful recipe information can include:

• mold ID;
• product ID;
• recipe ID;
• recipe version;
• pressure target;
• velocity stages;
• position transition points;
• holding time;
• temperature settings;
• decompression settings.

Why Recipe Version Matters

A product may use Recipe V3 for several weeks and then be changed to Recipe V4.

If quality later changes, engineers need to know which recipe version produced each cycle.

14. Link Every Cycle to Mold ID and Product ID

One hydraulic press may operate dozens of different molds over its service life.

Recording only “Press #2” is therefore not enough for meaningful analysis.

This structure allows engineers to compare:

• different molds on the same press;
• different recipes for one mold;
• quality performance before and after process changes;
• machine behavior across multiple products.

15. Material Lot Data Should Be Linked to the Production Cycle

SMC material can vary between production lots because of formulation, maturation, storage and handling conditions.

Material traceability may therefore include:

• material grade;
• supplier;
• batch or lot number;
• production date;
• storage period where relevant.

This information does not necessarily need to originate inside the press PLC. It can be entered by the operator or linked through a factory database or MES.

16. Charge Data Can Be as Important as Press Data

The press can use exactly the same recipe while the SMC charge entering the mold changes.

Useful charge information can include:

• charge weight;
• number of SMC sheets;
• charge pattern ID;
• stack thickness;
• placement orientation;
• automatic weighing result where available.

17. Connect Quality Results to Individual Cycles

Data becomes much more valuable when each production cycle can be associated with the actual part result.

A simple quality classification may include:

Defect codes can then identify specific problems:

Once quality results are linked to machine data, engineers can begin asking much more useful questions:

18. Build a Golden SMC Cycle

Once a mold is producing stable conforming parts, one or several qualified cycles can be saved as a process reference.

A useful golden cycle can include:

Future cycles can then be compared with this known-good reference.

19. Use Tolerance Bands Instead of Expecting Identical Curves

Industrial production always contains normal variation.

The objective is therefore not to make every recorded curve mathematically identical.

A more useful monitoring strategy defines:

Tolerance bands can be applied to:

• pressure;
• position;
• cycle time;
• temperature;
• material-contact position;
• final platen position.

20. Which Data Should Be Recorded as a Curve?

Not every process variable needs high-frequency recording.

This approach helps keep the data system useful without storing every signal at high frequency indefinitely.

21. Do Not Record Data Just Because You Can

Modern PLCs and data systems can collect hundreds or thousands of tags, but more data does not automatically create better production decisions.

Before recording a signal, ask:

22. Raw Curves and Cycle Summaries Do Not Need the Same Retention Period

High-frequency process curves require more storage than one summary row per cycle.

Data-retention strategy may therefore separate:

23. Machine Storage, Factory Database and MES Serve Different Roles

Production information can be organized at several levels.

The required architecture depends on the factory and project.

24. Data Export and Communication Should Be Defined Before Purchase

Production information has limited value if it can only be viewed on one local HMI screen.

Depending on factory requirements, buyers may ask about:

• CSV or spreadsheet export;
• Ethernet communication;
• database connectivity;
• industrial communication protocols where applicable;
• remote production-data access;
• MES or quality-system connection.

25. Practical Example: Diagnosing an Increase in Flash

Consider an SMC mold that has been producing acceptable parts for several days.

Reference Period

Later Production

Instead of immediately reducing pressure, the process team now has evidence suggesting that the press is encountering resistance earlier and finishing at a larger-than-normal position.

First checks may include:

• charge weight;
• charge stack thickness;
• charge placement;
• material condition;
• mold interference.

26. Practical Example: Output Drops but the Press Recipe Did Not Change

A second example shows why stage-time data matters.

The production team expects a total cycle of approximately 120 seconds, but recent average production time has increased to approximately 140 seconds.

The molding sequence itself has not become slower. Most of the lost output comes from increased waiting time.

27. Recommended SMC Press Production Data

28. Minimum vs Advanced SMC Press Data Package

Not every factory requires the same data architecture.

29. What Should Buyers Ask When Ordering an SMC Press?

Production-data requirements should be discussed during machine specification rather than after installation.

30. Production Data Should Lead to Action

Collecting data is not the final objective.

The real value comes from using that information to recognize process drift, investigate root causes and improve production.