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Article Excerpt
Oxford Industries, Inc., a leading US apparel manufacturer, implemented a scheduling algorithm that significantly reduced equipment changeovers in its in-house embroidery facility. The company was experiencing difficulties meeting due dates in one of its more profitable, new markets--branded custom-embroidered golfwear. The time Oxford was spending on equipment changeovers was leaving insufficient processing time to meet a surge in demand in this new market. We identified an opportunity for increased production capacity through more efficient scheduling of sequence-dependent changeovers among garments. During the period that we studied, the use of the scheduling algorithm reduced the number of changeovers by an average of 88 percent per order.
Key words: industries: textiles/apparel; production/scheduling: applications, approximations/heuristic, planning, deterministic sequencing, multiple-machine sequencing. History: This paper was refereed.
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Oxford Industries, Inc., headquartered in Atlanta, Georgia, is a diversified, international manufacturer and wholesale marketer of branded and private-label apparel for men, women, and children. Founded in 1942, Oxford has manufacturing and sourcing operations in over 40 countries and provides retailers and consumers with a variety of apparel products. It licenses and owns many internationally recognized brands.
Oxford employs approximately 10,000 people and has annual revenues in excess of $1 billion. Company sales span all major distribution channels: major chains, department stores, specialty stores, direct mail, mass merchants, and off-price stores. Oxford currently maintains five major operating groups: (1) Oxford Womenswear Group, (2) Lanier Clothes, (3) Oxford Slacks, (4) Oxford Shirt Group, and (5) Tommy Bahama Group. The primary focus of this work is in its shirt group, which produces and sells men's and women's branded and private-label dress and sport shirts and golf apparel.
Custom-embroidered garments have increased in popularity in recent years. Much of today's corporate casual apparel, branded insignia fashion apparel, sports apparel, and uniform apparel has multicolor embroidered logos. Oxford's custom-golfwear division provides custom-embroidered, branded golf apparel to golf shops, country clubs, and resorts. The growing custom-golfwear business has made its mark quickly as a very profitable component of the Oxford shirt group. To meet increasing demand for embroidered golf apparel, Oxford developed an in-house embroidery shop but found that it had insufficient capacity to meet its due dates.
The Embroidery Process
The Oxford embroidery shop operates on a make-to-order basis. Golf courses around the country place relatively small orders for a variety of branded golfwear items such as shirts, hats, sweaters, etc. The customer stipulates a specific country club logo to be embroidered on the apparel. The custom-golfwear division purchases men's branded golf-apparel items from external suppliers and subsequently processes them through the in-house embroidery facility to apply club-specific logos.
Country clubs place low-volume, high-variety orders, which may comprise a mixture of apparel items, garment colors, and styles as well as logo colors. The average order size is approximately 14 items but might vary significantly. A given order can consist entirely of garments that are identical in style, garment color, and logo color. Or, each garment in a given order may be different in garment style, garment color, and logo-color combinations. A typical order falls between these two extremes. For example, a 16-item order might include two different garment styles in a mixture of four different color combinations.
While the color and style of garments within an order tend to vary, each garment must be embroidered with the same country club logo or design. For example, if a country club's logo includes a sunburst, each garment must have the same sunburst design or pattern. However, for each unique garment style and color combination, the country club logo could be embroidered using a unique set of thread colors that are chosen specifically to coordinate with the selected garment color. A given logo can incorporate a maximum of 12 different thread colors. We refer to each unique garment style that is manufactured using a specific fabric type/color and embroidered with a unique set of thread colors as a unique garment/color combination.
The sewing process begins when the embroidery shop receives the finished garments for a specific order. Following a garment quality check, thread colors are matched to garment color shades according to customer-specific instructions. An embroidery hoop is positioned on each individual garment at the embroidery site. Embroidery machines are threaded accordingly, and the same logo design is sewn on each garment within a specific order using unique thread-color combinations. The garments are then trimmed, pressed, and packaged for shipping.
This embroidery shop uses three 12-head, 12-needle embroidery machines, one 4-head, 12-needle machine, and one 1-head, 12-needle machine. A 12-head, 12-needle embroidery machine combines 12 sewing machines, or sewing "heads," each with 12 different needles. Up to 12 different thread colors, one thread per needle, can be loaded uniquely onto each sewing head; however, all 12 heads concurrently sew the same design or logo using the same sewing sequence of needles on each head. A 12-head machine can embroider up to 12 garments simultaneously in a given run. A "run" represents one machine cycle. During a run, a 12-head machine can produce from 1 to 12 garments, each with the same logo or pattern, depending on the number of heads utilized; in a given run, a 4-head machine can embroider from 1 to 4 garments simultaneously.
As an example, suppose that Pine Tops Country Club's logo consists of three parts: (1) a sunburst, (2) a tree, and (3) the club's initials, PTCC. These three logo parts are sewn using three different needles, each with potentially unique thread colors on a given head. The specific needle used to sew the sunburst on a given head and run must also sew the sunburst on all remaining heads of the same run. This is also true for the analogous needle assignments made to sew the tree and the club initials across all heads. To further...
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