Unit/load tags are used to identify and track in process and finished units of lumber in a mill. There are a variety of tag styles used ranging from manual to fully automated. The more sophisticated the data capture process, the more capability the mill has to minimize cost.
GOAL:
To more cost effectively utilize raw material for production requirements
and finished goods for sales.
OBJECTIVE:
Lumber is clearly the most costly raw material used in mills. The main
objective is to have the ability to be selective about the raw material
used in production. This will allow the mill to minimize lumber costs
by converting the maximum amount of usable product from the lowest cost
possible lumber in inventory. An additional objective is to prevent lumber
degradation or rejection from unnecessary aging by utilizing first-in
first-out inventory. In order to do this specific data must be available.
By knowing what is in inventory (age, species, grade, dimensions, quantity)
and where it is located, specific material requirements can be assigned
to a job.
THE PROCESS:
Each step in the process is a cost center. A bar
code is scanned at each step to measure accumulated costs and track
location. A typical sequence includes:
If the logs have already been scaled, the tag on each log is scanned into inventory. Inventory is basically organized by row. Row numbers can be assigned by species, by the truckload, or even on a log-by-log basis. As logs are required for production, rows are removed from inventory, or species within rows are removed, or both.
- rough cut processing:
As logs are rough cut, the bar code tag on the logs are lost in waste. In order to track the lumber, large UNIT/LOAD labels/tags with large bar codes are printed on demand and attached to each unit. If pressure sensitive labels are used they can be applied directly to the unit. and bar codes in order to be read/scanned from a distance. Each tag must be stapled or nailed. The tags are printed with large characters describes the load with the following data: species, length, width, thickness, grade, pattern, name of person accountable at this stage, rough or dressed, and volume. The Bar code will associate with a specific order number or inventory number. If an order number, scanning the label will provide order information onsite.Frequently labels are printed in pairs, in order to place a them on adjacent sides of the unit. Alternatively, labels can be printed as a corner wrap label displaying a duplicate portion of the label on two sides of the unit.
Each time a unit is moved from one stage to another, the bar code on the unit is scanned to update location, order status and/or inventory status. As the unit is removed from its existing location, it is removed from inventory. When the unit is placed in the new site, the unit is reentered into inventory, listing the new location. Each stage where the bar code on the unit is scanned is a cost center where labor-handling costs accumulate. If portable scanners are unavailable, an optional stub portion on the tag can be removed and scanned in the office. Each time a unit of lumber changes configuration, a new bar code label/tag is printed and the old label/tag is scanned and disposed to update the inventory change.
If the rough-cut lumber is to be kiln dried, the unit of rough lumber is pulled from inventory and moved to the kiln. The unit bar code is scanned and the inventory is updated. After the unit is pulled dry from the kiln a new label/tag describing the unit as kiln dried is generated an affixed to the unit. The new information is uploaded to the database. If units need to go to the planer or on to the sander, new label/tags are generated at each step, updating the description of the unit.
Using RF scanners, orders can be staged and scanned while the truck is on the way. Scanning creates a ship tally number, in turn generating an invoice and packing slip. From the final scan, the system automatically produces both a bill of lading and an invoice, which can be picked up after the driver has loaded the units and tied them down.
Some programs provide for tracking of units containing an assortment of product lengths, as opposed to a single product length. The system "bundles" inventory into serial numbered units called lots…collections of dimensioned lumber products, in varying lengths and piece counts. The lot product itself defines all possible lengths of a particular species of dimensional lumber.
CONDITIONS:
Tags for lumber inventory tracking are exposed to heavy moisture, cold
and hot temperatures, direct sunlight, heat from the kiln, and turbulence
during highway transportation. These conditions require certain material
and ink considerations.
PRODUCT SIZE:
Any size can be used depending on the information that is needed on the
tag.
MATERIALS:
The key is to have a durable material. The material may be either a pressure
sensitive label or a non- adhesive tag. Options include paper tag, modified
paper, laminated or synthetic substrates depending upon application usage.
The material used will depend on the amount of exposure to moisture, sunlight,
and heat. Pressure sensitive label materials can be directly applied to
the unit, while non-adhesive materials must be stapled, nailed, or taped.
Potential paper products include 100-150# Rite-in-the-Rain tag, 6-10 pt wet resistant tags, and permafibre that has resin imbedded in it. Synthetic products are Tyvek, high-density polyethylene (HDPE), low-density polyethylene (LDPE), and Valeron. These can be written on by permanent marker, printed with impact ribbons, or various thermal transfer ribbons. If pressure sensitive labels are used, adhesives designed for rough wood surfaces, extreme temperatures and moisture ranges must be used.
PRINTING:
These products can be completely preprinted for manual use, partially
preprinted for later imprinting via impact printers, or can be preprinted
with only logos. When preprinted with only logos, the specific unit information
is demand printed on site most frequently with thermal transfer printers.
In all cases the product can be tracked or inventoried by scanning the
bar code on the unit/pallet of product. Heat resistant inks are recommended
for exposure to heat for the kiln. Additional fade resistant ink is recommended
to prevent fading in direct sun light. Frequently, labels/tags are color
coded by season. Another identifying print feature is the use of an "aging
print strip" printed in fade ink. This provides an immediate visual
indicator of loads that have been in inventory an extended period of time.
CONSTRUCTION:
Manual tags or pre bar coded bundle tags are usually manufactured as sheets.
Bundle tags are a semi-automated system. They incorporate a series of
preprinted bar codes and human readable numbers that can be detached and
scanned in the office.
Unit tags that are pre bar coded but printed later in an impact printer are manufactured as continuous pin feed fanfold tags.
Unit tags which are printed on demand at the mill via thermal transfer printers are typically manufactured as rolls.
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