Page 108 - MetalForming October 2015

Tooling by Design
By Peter Ulintz
Lot Traceability
Lot traceability has been
gaining in popularity as
more government and
regulatory bodies mandate
traceability throughout the
supply chain, across all indus-
tries. For North American
manufacturers, regulatory
bodies in Canada and the Unit-
ed States recently have
launched huge initiatives to
address increasing product
recalls. These initiatives aim
to make businesses more
accountable for product trace-
ability throughout the supply
chain. Lot traceability also is a
core component for many
businesses in achieving ISO, TS and FDA compliance.
Lot traceability effectively means that a manufacturer knows which lots of product were used in which finished goods, and who received those finished goods. A key com- ponent in many ERP systems, lot traceability provides com- panies with a way to track problem products from their cus- tomer all the way back to the suppliers who provided materials and processes in between.
An important aspect of lot traceability is to keep track of which supplier’s materials were received to help ensure that, in the event of a recall, raw materials can be traced back to the appropriate supplier (if they were at fault) and to ensure that you know of any other operations applied to that raw material.
For metalforming companies, traceability back to the incoming raw material (sheets, coils, etc.) is a prime concern. Potentially large and costly problems lurk, however, because of the methods used by metalformers to identify material lots. Informal polling I have taken at PMA seminars indicates that many companies still trace products back to the mate-
Peter Ulintz has worked in the metal stamping and tool and die industry since 1978. His background includes tool and die making, tool engineering, process design, engineering management and advanced product development. As an educator and technical presenter, Peter speaks at PMA national seminars, regional roundtables, international confer- ences, and college and university programs. He also provides onsite training and consultations to the met- alforming industry.
Peter Ulintz
Technical Director, PMA pulintz@pma.org
rial heat number provided by the mill. This practice can cause problems, since a heat (or batch) is the equivalent to one ladle of liquid metal. For steel produced by an inte- grated mill, this can be as much as 300 tons of steel.
Let’s assume XYZ Metal- forming produces a high-vol- ume stamped part weighing 0.5 lb. A potential problem with the raw material arises with its customer, and XYZ Metal- forming must identify the potential number of problem parts in the field.
XYZ’s lot-control methods reveal that the suspect parts were produced from steel heat number XX-123. Further investigation reveals that the mill produced 266 tons of steel from that heat, the equivalent of more than one million parts. XYZ management, astonished at the large quantity of suspect products, might find the
company on the brink of financial disaster.
What if XYZ had tracked its raw-material lots by master coil
number rather than heat number? If we assume each mas- ter coil weighed 40,000 lb., we reduce the number of at-risk parts to 80,000—a vast improvement compared to one-mil- lion parts, but the suspect lot size is still considerably large, especially if XYZ is financially responsible not only for the defective parts it supplied but also for the cost of the assem- bly or subassembly in which the parts were used.
The best option: Restrict the material lot size to the exact coil used to produce the suspect parts. Assuming the service center slits each master coil into eight individually identified pup coils to the width that XYZ requires for its progressive die, and that each pup coil weighs approximately 5000 lb., each material now only results in 10,000 parts.
The message here is to work with your material-service center on a methodology that consistently identifies each individual coil and where it was slit from the master coil. For example, you and your service center may agree to identify individual coils by their master coil number, plus an indi- vidual coil designation indicating where each coil came from relative to the slitting line. Moving left to right, slit coils would be identified a, b, c, etc. , and the coil number for the first slit coil coming from the left-hand side of the mas- ter coil would be identified XX-123-a.
106 MetalForming/October 2015
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