1. IMPROVING THE ACCURACY OF
WEIGHT MEASUREMENT
IN PROCESS CONTROL
FOR CONTINUOUS
STEEL CASTING
MGT 5311 GROUP 5
2. Introduction
Commercial Metals Company
Commercial Metals Company (CMC)
- Global leader in steel recycling and manufacturing
- Operations include low-cost metals recycling, manufacturing,
fabrication and trading enterprises with over 200 locations in more
than 20 countries
3. Introduction
CMC Steel Texas
Commercial Metals Company (CMC)
- The mill in Seguin, TX is the first of 5 US mills operated by CMC
and has been in service since 1947.
- Products & Services include raw steel billets, angle/channel, rebar,
and other long bar products
6. DEFINE
Define the problem :
Billets coming from the caster vary greatly from the
target weight established to maximize rolling yield,
creating waste in every billet
Project scoping :
To reduce the variability of billet weight (CTQ) and to
improve the accuracy of measures taken in the casting
process for maximizing yield efficiency
Targeted equipment:
Caster withdraw rollers, cutting torches, and billet
weighing system
Problem Statement
17. IMPROVE
● The problems are specific and technical in nature therefore incremental
corrective actions and improvements by the process owners (shop floor,
QA, Caster Maintenance) should be the main focus
● Improvement Goals:
o Improve the accuracy of measures used in process control
o Make improvements to systems contributing to variation in billet
weight to improve yield in the rolling mill
Overview of process improvement goals
18. IMPROVE
● Process Mapping Improvement - Revised Swimlane
● Poka-Yoke or Mistake Proofing
● Empower Process Owners
Suggestions for Improvements
20. IMPROVE
Poka-Yoke: Mistake Proofing by Automating
New Standards and Procedures on Calibration
● Online billet scale:
o Calibration frequency
o Oscillation filtering
● Billet length verification
Automate Control Adjustments using SPC data in Level 2
● New billet weight targets and control limits must be determined
● Monitor process control charts automatically and reliably
● Make automatic adjustments to the torch cutters in response to out-of-
control trends
21. IMPROVE
Process Owners (Caster floor operators, QA) need to:
● Understand:
The general process and the desired outcomes
Steps of process assigned to them
How their actions affect the operations in other sections of the process
● Appreciate:
The significance of collaboration
● Know:
Their input matters and is respected
They are enabled to make spot on decisions for timely corrective actions
● Acquire:
Six Sigma Green Belt training on methods and certification. Provide incentives
through education reimbursements
Empower the Worker: Knowledge Management & Engagement
22. CONTROL
Ultimately, we need to track, monitor and maintain
performance of key measures by ensuring key variables
remain within the maximum acceptable ranges under the
modified process. Therefore, we want to
ensure that measurements continue to be
reliable, accurate,and verifiable
24. CONTROL
Maintain new standards and procedures
o Proper documentation: SOPs, Dashboard and
scorecards, inspection reports, test data, audit
reports, calibration
o Internal audits
o Periodic status reviews by process owners to
self-check their performance
“CHECK”
25. CONTROL
Maintain Control Limits
o Regular use of statistical process control charts with
data gathered and interpreted automatically
o Reach optimal range of standard deviation, mean,
UCL and LCL
“ACT”
26. CONCLUSION
● Data collection and measurement error prevents reliable use of SPC for
weight measurement/mill yield control
● Cleanup of data highlights weaknesses in procedure, measurement, data
recording, and knowledge management in addition to steel casting defects
● To reduce and control defects, a foundation for continuous PDCA
improvements must be put in place:
Suggestions for immediate improvement: Revise process map to
communicate procedure, automate control systems using reliable SPC
data, integrate knowledge management, and plan for new standards
and procedures
● Future improvements: Use foundation of reliable measurement and
interpretation to improve yield via PDCA cycle
