Tajima DST for commercial machines: preparing a file that runs clean on Tajima, Barudan, SWF, Ricoma and Happy

Every commercial embroidery machine reads DST. That is its whole appeal and also its trap: the format was designed in the 1980s for a punched-tape reader and carries stitches, jumps and stops, nothing else. Getting a DST to run clean on a multi-head means supplying the rest yourself. The format itself is described separately; this guide is the preparation.

What the machine reads

A DST record is three bytes: two carry the move (up to ±121 units of 0.1 mm), the third the flags for jump, colour change and end. The 512-byte header before the records has label, stitch count, colour-change count, extents and start point; commercial machines read the extents to check the design fits the frame and the stitch count for the display. Everything else on the machine is set by the operator or the machine's defaults.

Needle order

The one thing that goes wrong on the first sew of any DST. A DST's colour change is a stop code. The machine advances to the next needle in its needle sequence, which the operator sets per design from the machine's panel (Tajima: the "needle bar selection"; Barudan: "colour sequence"; Ricoma and Happy: the colour list on the touch screen). If nobody sets it, the machine uses the last sequence or 1-2-3-4-5 in order.

So a DST needs a colour sheet with the blocks in order and the operator sets the needles from it. Software that writes DST usually writes a companion: the TC lines that some writers put in the header (TC: colour lines, a Wilcom extension), a .col or .inf file (Melco, Barudan), or a PDF. Our converter writes the colour sheet as HTML alongside the file. If the design came without one, the viewer shows the blocks and their stitch counts, which is enough to assign needles from a sample sew.

Native formats carry the needle number in the file: Tajima's TBF has a needle order table, Barudan's U01 stores each block as a needle command. U01 and TBF covers when they are worth using.

Trims

DST has no trim command. Two conventions coexist:

1. Three consecutive jumps with no stitch between them mean "trim here". Tajima established it; most software writes trims this way and most machines read them.
2. Jump length. The machine trims automatically on any jump longer than a threshold, set on the machine (Tajima default about 5 mm; adjustable on all brands).

A DST written from PES, where trims are implied by jumps, comes out with jumps but no triple-jump markers unless the writer adds them. Machines with the length threshold trim anyway; machines set to trim only on the marker leave the jump thread hanging. The pre-flight check counts jumps over 12 mm without a trim marker; cleanup converts those to marked trims. Jumps and trims has the full behaviour.

Trim count also matters for time: each trim on a Tajima costs two to three seconds. A design with 200 trims spends ten minutes trimming. If the count is high, the digitising is at fault (a trim after every element instead of travelling under the next), and the fix is in the design, not the file.

Size and the 12.1 mm record

A single DST record carries at most 12.1 mm. A stitch longer than that is written as two records, or as a jump followed by a stitch, which the machine sews as two needle penetrations. In practice every satin over 12 mm becomes two stitches with a penetration in the middle, which changes the look of a wide satin. Designs with wide satin for commercial machines should be digitised with split satin from the start. The pre-flight check lists stitches over 12.1 mm before conversion so you know where the splits will land.

Extents: the header's +X, -X, +Y, -Y fields say how far the design goes from the start point. Machines compare them to the frame. A DST whose extents are wrong (written by software that miscounted) is refused or, worse, accepted and sewn into the frame. The viewer shows the header's extents next to the measured ones.

Start point and origin

DST starts at the design's centre by convention; the header's AX/AY fields say where the needle ends relative to where it started, which a machine uses to return to origin. A design that ends far from where it started sews fine but leaves the pantograph off-centre for the next run. Cleanup's "centre" option re-bases the design so the start and end are at the centre, which is what operators expect.

Preparing a DST for a run

1. Open the source file in the viewer. Note the colour count and the block order.
2. Run the pre-flight check: short stitches, stitches over 12.1 mm, jumps without trims, density. Fix what the source needs fixed; do not expect the format to hide problems.
3. Convert to DST. Check the result opens and its stitch count is within a few percent of the source (the extra records are split long stitches).
4. Print the colour sheet with the block order.
5. On the machine: set the needle sequence from the sheet, set the trim threshold to your house standard, load the design, sew a sample, check the sample against the sheet.
6. For a multi-head: same file, same needles on every head; check that each head's thread matches the sheet before the run.

Machine-specific notes

Tajima. Reads DST and TBF. The triple-jump trim convention is native. Newer TMBP and TMEZ models read many formats but a DST is still what the operators know.

Barudan. Reads DST, U01 and FDR. Barudan software prefers U01 for needle information; DST runs fine with the sequence set on the panel.

SWF. DST, EBD (SWF's own). Trims on jump length by default.

Ricoma, Happy, Melco. DST universally; Melco prefers EXP with a companion colour file. Trims on jump length; the threshold is in the machine settings.

ZSK. DST and Z01 (ZSK's format). The PES to DST page explains what each conversion keeps and drops.