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Service 06 · Root Cause Analysis · Systematic Process Audit

Manufacturing Process
Optimisation

If your plant produces acceptable product but with high batch rejection rates, inconsistent quality, high cost-per-kg, or persistent off-spec results — these are process problems. We conduct a systematic process audit, identify root causes, and deliver a documented plan with revised SOPs, temperature profiles, and quality checkpoints.

18% → 3%
Typical Rejection Rate Improvement
2–3
Production Cycles to Resolution
SOP
Revised Documented Procedure
Remote
Or On-Site Audit
Common Process Problems

Symptoms We Diagnose
and Fix

Inconsistent NLGI Grade — Penetration Varies Batch to Batch
Root causes: Variable saponification temperature hold time, inconsistent milling pass count, fatty acid quality variation between supplier batches, base oil blend ratio drift.
Fix: Temperature hold time standardisation, milling pass count protocol, incoming fatty acid penetration check procedure.
Dropping Point Below Specification — Failing BIS or Customer Limit
Root causes: Insufficient saponification — incomplete reaction due to low hold temperature or short hold time. Under-treatment of complexing acid (for complex soaps). Water not fully removed during dehydration stage.
Fix: Saponification temperature and time audit, complexing acid stoichiometry check, dehydration stage procedure.
High Batch Rejection Rate — Product Consistently Off-Spec
Root causes: Process variability in temperature control (faulty thermocouple or controller), operator dependency (different operators produce different results), raw material substitution without formula adjustment.
Fix: Instrumentation audit, documented step-by-step SOP for every operator, raw material change protocol.
Oil Separation (Bleeding) — Grease Releases Oil in Storage or Under Load
Root causes: Incorrect soap-to-oil ratio, insufficient milling (soap fibres not adequately dispersed in oil), base oil viscosity too low for the soap structure formed.
Fix: Soap content adjustment, milling procedure overhaul, base oil viscosity review against thickener type.
High Cost-per-kg — Yield Lower Than Formula Calculation Predicts
Root causes: Reactor losses (material adhering to walls, inadequate scraping), saponification shrinkage higher than designed, off-spec batch rework consuming additional raw material.
Fix: Yield measurement protocol, reactor wall adherence assessment, batch rejection root cause elimination.
Contamination — Foreign Particles or Colour Variation in Final Product
Root causes: Filter bypass, reactor corrosion producing metal particles, fatty acid colour variation, base oil colour batch variation, container contamination from previous product run.
Fix: Filter integrity audit, reactor inspection protocol, raw material incoming inspection, container cleaning procedure.
The Audit Process

How a Process Audit
Works

1
Production Data Review
Before visiting the plant or conducting any testing, we review all available production records: batch logs, ASTM test results for recent batches, temperature records, raw material certificates of analysis, and rejection records. In most cases, the pattern of failures already suggests the most likely root cause before we see the plant.
2
Process Observation (Remote or On-Site)
We observe a live production batch — either in person or via video. We watch the entire saponification cycle: fatty acid addition, alkali addition, temperature profile execution, hold times, quench, additive addition, and milling. We time each stage and record actual temperatures versus the intended SOP. Deviations are documented.
3
Root Cause Identification
We present a root cause analysis report identifying the specific variables responsible for the inconsistency. Each root cause is ranked by estimated impact on rejection rate. We include supporting evidence from the production data review and process observation. We do not guess — if we cannot confirm a root cause, we say so and design a targeted experiment to determine it.
4
Revised SOP Delivery
We deliver a rewritten Standard Operating Procedure that addresses every identified root cause: specific temperatures with tolerances, hold times with minimum and maximum limits, addition sequences with checkpoints, milling pass count standards, and QC acceptance criteria at each stage. The SOP is written for your specific reactor — not a generic document.
5
Implementation & Verification
We supervise the first two or three production batches under the revised SOP — remotely or on-site — and verify that the rejection rate drops as projected. We make any necessary fine-tuning to the SOP based on actual results. Batch rejection rate is tracked and a final summary report is provided once consistent performance is confirmed.
Case Study

Rejection Rate Cut From
18% to Under 3%

Completed Project · Process Audit & Optimisation
Lithium Soap Grease — Delhi NCR Plant — Inconsistent NLGI Grade Penetration
A Delhi NCR manufacturer producing lithium soap NLGI 2 grease was experiencing an 18% batch rejection rate due to penetration readings falling outside NLGI grade 2 limits (265–295 × 0.1mm) on more than one in six batches. Some batches read NLGI 1 (too soft), some NLGI 3 (too firm). The manufacturer had been adjusting the formula batch-by-batch without a systematic approach — creating further variability.
Process observation of a live batch identified two root causes: (1) the saponification temperature hold time was operator-dependent and ranged from 35 to 55 minutes across different shifts — a 20-minute range that significantly affects soap structure; (2) the milling pass count was being visually estimated rather than counted, resulting in 2 to 5 passes per batch. Both variables independently cause penetration variation; together they created the wide spread.
Before Optimisation
18% batch rejection rate
After New SOP (6 Cycles)
Under 3% rejection rate
Root Causes Identified
Hold time variation + milling inconsistency
Resolution Time
New SOP operational in 2 production cycles
Questions & Answers

Frequently Asked About
Process Optimisation

We are not sure if our problem is the formulation or the process. How do we know which to fix?

The key diagnostic question is: does your product ever pass specification? If yes, the formula is capable of passing — the problem is process variability. If the product never passes even on your best batch, the formula itself may be incorrect.

A second indicator: does the problem occur on specific shifts, with specific operators, or at specific times of year (temperature-related variation)? Process problems have a pattern; formula problems do not.

Can you recover (rework) off-spec batches while we fix the process?
Yes. Reworking off-spec batches — whether too soft (blend with a stiffer batch), too firm (blend with a softer batch or add a small amount of base oil), or low dropping point (in some cases can be re-saponified) — is a standard part of a process audit. We provide specific rework protocols for each failure mode so that rejected material is not wasted.
Do you only work with grease plants, or can you optimise lubricant oil blending too?
Both. Lubricant oil blending process problems are typically simpler than grease process problems — they usually relate to blending order, temperature control during additive addition, or metering accuracy. We can audit and improve a blending process for issues such as viscosity variation batch-to-batch, additive precipitation, or poor mixing homogeneity.
Our reactor controller is faulty and we have been operating manually. Will that affect the audit?
A faulty temperature controller is often itself a root cause — temperature variation at critical saponification stages is a very common reason for inconsistent grease quality. We will assess the controller as part of the audit and recommend repair or replacement if warranted. Manual operation is workable with very clear procedures, but a calibrated and reliable temperature controller significantly reduces operator dependency and process variability.
Related Services

Often Requested
Alongside Process Optimisation

Service 02
Grease Formulation R&D
If the process audit reveals a formulation issue rather than a process issue, we can redesign the formulation and SOP together.
Service 05
Plant Setup & Commissioning
Severe process problems sometimes indicate that equipment upgrades are needed — we advise on what is worth upgrading vs. what can be fixed with better procedures.
Service 04
ASTM Testing & QC
Process optimisation always concludes with a QC protocol — which tests to run, at which stage, and with what acceptance limits to detect problems early.

Batch Rejection Holding
Your Business Back?

Describe the problem — what is failing, how often, and what you have already tried. We respond within one business day with an initial diagnosis and recommended audit scope.

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