A stitch to save time

Background: The art of quilting has long played a significant role in America’s culture. Carrying on the tradition, modern-day quilt makers are getting some modern-day help from companies such as Statler Stitcher, a Columbia, Mo.- based manufacturer of computerized quilting systems. Improving on semiautomated processes — machines that require operators to guide framed quilts by hand — the new systems can stitch almost any pattern all by themselves. Quilters simply select a design, or create (program) their own pattern, and the machine does the rest. It determines the pattern and size, size of the block, stitches per inch, pattern repetitions, and pattern offset.

Challenge/solution: When designing the new quilting system, Statler engineers had to optimize speed and precision without sacrificing flexibility and ease of use. They found success by combining PC programmability and servo control.

The system itself consists of a sewing head, table, computer, cables, motion controller, and several servomotors. The motors operate in synchrony under the direction of a threeaxis DMC-1832 PCI-bus motion controller from Galil Motion Control, Rocklin, Calif. The controller, capable of accuracies within 0.004 in. and speeds to 2,500 stitches/min, moves the sewing machine while the quilt remains stationary.

The entire process takes three servomotors: Two control X-Y moves as the sewing arm goes back and forth to stitch the design, and a third motor drives the stitching mechanism. The controller’s linear and circular interpolation mode allows the X-Y paths to be easily programmed and followed for accurate, even stitching, no matter how complicated the design. For long X-Y paths, the DMC-1832 lets new segments be added during motion. Shorter patterns can be simultaneously downloaded as a single file.