Veteran expertise is valuable, but slip release, demoulding decisions, glaze adjustment and kiln exception handling cannot remain in one person's memory and intuition. Stable production requires measurable parameters, defined process windows, consistent operating steps and executable escalation rules.
Parameter standardization does not lock every product to one number. It defines what to measure, how to measure it, the acceptable window, who may adjust it, how far they may go and how the result is verified. New operators can then perform normal production reliably, while experts focus on complex exceptions, process improvement and skills development.
When critical operations depend on personal judgment, quality changes with shifts, people and working conditions. An expert may correct a developing problem before it becomes visible, but the basis for that decision can disappear during leave, transfer or resignation.
The risk often appears as:
· Different release decisions for the same slip condition;
· Different demoulding times and support methods for the same mould;
· Multiple parameter changes after a defect with no retained record;
· New operators memorizing actions without understanding criteria and limits;
· Quality recovery depending on calling the expert back to the line.
Experience is not the problem. The problem is experience that has not become reusable and verifiable process knowledge.
Veteran knowledge normally contains three types of information. A simple operating sequence captures only part of it.
Experience type | Standard to create | Production purpose |
Normal operating knowledge | Sequence, tools, sampling position, measurement method and safety requirements | Enables different people to perform the task in the same way |
Quality judgment | Approved samples, defect images, measurement criteria, release rules and stop conditions | Reduces subjective decisions based on appearance alone |
Exception response | Symptom, possible causes, inspection order, adjustment authority and escalation owner | Prevents new operators from changing several parameters at once |
New operators can work independently only when actions, criteria and exception rules are all clear. Instructions such as check the slip, control drying or adjust as necessary still leave the critical decision to personal intuition.
Sanitary ware production varies with product model, material batch, environment, mould condition and equipment. Copying one value across every product and machine can create new instability.
A complete parameter standard should define:
· Parameter name, unit, measuring device and measurement location;
· Timing, frequency, sample condition and environmental condition;
· Target or acceptable window, warning limit and stop boundary;
· Parameter sequence and restrictions on linked adjustments;
· Inspection order, adjustment authority and verification after deviation;
· Applicable product, equipment, mould and process revision.
Slip viscosity results are comparable only when the test method, temperature and sample condition are consistent. Forming time should also be linked to slip condition, mould ID, actual process curve and green-body result rather than preserved as an isolated number.
Operation | Standardization focus | Result that must be linked |
Slip preparation | Material and slip batches, addition sequence, mixing conditions, density or solids-related indicators, viscosity, thixotropy, temperature and ageing | Filling, casting rate, body density and demoulding behavior |
Forming and demoulding | Mould ID, recipe revision, filling and pressure process, draining, depressurizing, demoulding criteria, support and handling | Body weight, critical thickness, seams, deformation and cracking |
Drying | Loading method, spacing, temperature, humidity and airflow process, stage changes and endpoint criteria | Moisture uniformity, drying shrinkage, cracks and deformation |
Glazing | Glaze batch, condition tests, spray gun and path, application sequence, coverage criteria and cleaning | Glaze uniformity, missed areas, excess glaze and fired surface defects |
Firing | Kiln-loading method, product position, curve revision, critical-stage monitoring and abnormal-batch isolation | Fired dimensions, deformation, color variation, cracks and glaze defects |
Every standard must point to a product result. Equipment settings alone do not prove that the parameters remain suitable. Final inspection without process records cannot trace the cause when a defect appears.
New operators become stable producers when normal tasks can be completed from standards, critical skills are verified in the workplace, and exceptions outside their authority are recognized and escalated promptly.
The Training Within Industry method described by NIST uses a confirmed standard way to train manufacturing newcomers quickly and consistently. For sanitary ware work, instruction should divide a job into major steps, key points and reasons, followed by actual operator practice and confirmation.
A training attendance record is therefore not enough for authorization. The plant should observe whether the operator can sample, measure, record, recognize an exception, stop an incorrect action and request support according to the rule.
Competence level | Authorized scope | Confirmation method |
Observe and learn | Understand safety, process flow and quality objectives without independent operation | Verbal confirmation and workplace identification |
Controlled operation | Perform and record the task under guidance | Direct observation against each work element |
Independent production | Produce independently within approved products and equipment, recognizing and reporting exceptions | Consecutive-shift results and skills assessment |
Adjustment and instruction | Adjust within approved limits, analyze exceptions and train others | Process validation, problem-solving records and periodic reassessment |
Authorization should identify the operation, product or equipment involved. One general trained status cannot cover every task. Process changes, equipment upgrades, long absences or repeated exceptions should trigger competence reassessment.
Begin with an operation that has frequent defects, clear operator-to-operator variation or heavy dependence on one expert. Observe the actual workflow and current settings instead of beginning with an office document.
Next, identify critical product results and process variables, standardize measurement, and support text with approved samples, defect images and process records. Actual operators should test the standard before release.
Then train newcomers through explanation, demonstration, practice and confirmation, with clear limits for normal work and exception escalation. Use consecutive production results to verify whether the standard is effective.
Finally, control revisions and changes. When materials, products, moulds, equipment or processes change, assess whether the document, parameter window and training need to be updated.
A factory should not depend on one veteran expert, but this does not mean rejecting expertise. It means protecting, reproducing and validating it. The most valuable experts should help build standards, develop people and solve problems beyond the standard rather than spend every day fighting the same fires.
When parameters have conditions, operations have steps, quality has criteria, exceptions have boundaries and competence is verified, new operators can produce stable results. Personnel changes no longer force quality to start over, and individual experience becomes sustainable manufacturing capability.