How can you verify that a process improvement persists after the trial?

Distinguish trial results from sustained performance

After adjusting a machine, energy per cycle, manufacturing time or reject rate may change. A few trial cycles cannot establish that the effect will persist when the shift, batch, mould temperature or auxiliaries change.

Define in advance which indicator should improve, how it is calculated, its baseline value and the criterion for considering a difference relevant. Quantified savings require measurements made under equivalent conditions.

• Indicator and unit: seconds per cycle, kWh per cycle, kWh/kg, reject percentage or another measure.
• Documented baseline condition: product, mould, material, machine and period.
• Adjustment or intervention, with its date and responsible person.
• Follow-up measurement with consistent scope and method.
• External factors that could explain a variation.

Four stages that must remain linked

• Baseline: record representative cycles, production, quality, consumption and actual conditions before intervening.
• Intervention: document exactly what changed and whether another condition changed at the same time.
• Verification: repeat the measurement once operation has stabilised and check that the result meets the engineering and quality criteria.
• Follow-up: observe behaviour over further comparable periods and identify if the result stops being sustained.

KERN IoP can provide signal and operating histories from the instrumented points; the scope of the analysis and the engineering decision are agreed with the personnel responsible for the process.

How to interpret variation

A reduction in average time or energy may coincide with greater dispersion and parts that fail to meet requirements. Review the results and their variability alongside the mean.

If the material, product, cooling flow or included electrical load changes substantially, assess whether the comparison remains valid. Where evidence is insufficient, document the uncertainty and the further work required.

For energy savings, specify the electrical measurement boundary, corresponding production and period. For productivity, confirm quality and line constraints. A change in absolute consumption does not necessarily indicate a change in efficiency.

How to compare injection moulding conditions before and after adjustment

What the next shift needs

An improvement is easier to sustain when the approved recipe, monitoring-variable ranges, inspection criteria, conditions under which the result was achieved and the response to deviations are documented.

The SMARTPRO interface can record operational context, while MONITOR provides access to historical data. Using them for this purpose requires the records and responsibilities defined in the project.

Continuous improvement · KERN IoP | MONITOR

Other relevant questions

• How to record a comparable process signature
• How to separate energy use in production and idle operation
• How to evaluate the result of an injection moulding adjustment

Editorial basis: earlier KERN IoP articles on standardisation and parameter optimisation, reworked with claims tied to specific conditions and verification.