Can I use my shirt logo file on a cap?

You can run it, but it will not sew well. A flat file sews in whatever order suited a flat garment, with underlay set for soft fabric. On a cap that produces distortion, gaps at the seam and lettering that drifts. The design has to be re-sequenced centre-out and the underlay rebuilt for a buckram front.

How big can a logo be on a cap front?

Most structured caps give you about 2 to 2.25 inches of usable height and roughly 4.5 to 5 inches of width before you run into the seams and the curve. Unstructured and five-panel caps give slightly more. Measure the flat area on the actual cap, because the usable space is smaller than the panel looks.

Why does small text fill in on caps but not on polos?

Two reasons compound. The buckram front needs heavier underlay, which raises the stitches, and the curve means the edges of the design are not presented squarely to the needle. Keep lettering at or above a quarter of an inch tall on caps, where three sixteenths might survive on a polo.

Cap Digitizing: How Hat Embroidery Files Differ

A logo that sews beautifully on a polo can come out of a cap frame puckered, crooked, or with the last two letters crowding the seam. It is almost never the machine or the thread. A hat is not flat, and it cannot be digitized as though it were.

Three things change on a cap, and all three have to be decided in the file rather than fixed at the machine.

1. The sew order runs centre-out

Caps mount on a curved cap frame and sew from the middle of the front panel outward to each side. The file has to be sequenced the same way: start at the centre, work out, keep the fabric controlled the whole time.

Sew a cap in a flat garment's order and you push fabric ahead of the needle. It shows as distortion in the middle of the design and gaps where two elements should meet. By the time you see it, the file has to be rebuilt, not adjusted.

2. The front panel is structured, so underlay changes

A structured cap has a stiff buckram layer behind the front panel. It behaves nothing like a soft shirt. It needs heavier underlay to lock the design to the panel so stitches do not sink into the buckram or drift across it.

Skimp on underlay and lettering looks loose and uneven, with the tops of letters sitting at slightly different heights. Overdo it and the design stiffens into a plate that the cap fights every time it is worn. The right amount depends on whether the cap is structured, unstructured or a soft five-panel, which is why a digitizer should ask.

3. The curve has to be designed around

The cap front curves away toward the sides and rises toward the crown. The centre is flat and forgiving. The edges are not.

A good cap file keeps the important elements in the middle third and allows for the curve at the sides, so the design does not stretch at the edges or creep up the crown. It also keeps detail clear of the seams, where the curve is harshest and anything fine gets swallowed.

What actually fits on a cap front

This is where most disappointment starts, because the usable area is smaller than the panel looks:

Structured six-panel: roughly 2 to 2.25 inches of usable height, about 4.5 to 5 inches wide. The centre seam breaks the panel, so wide designs crossing it need care.
Unstructured or five-panel: a little more height and an uninterrupted front.
Cap side: 1.5 to 2 inches, and keep it simple.
Cap back: similar to the side, usually a small mark or a date.

Measure the cap you are actually using. Blanks vary, and a design sized from a catalogue photo is a design sized from a guess.

The failures you can predict

Letters filling in. Keep text at or above a quarter inch tall on caps. Three sixteenths can survive on a polo; on buckram under heavy underlay it closes up.
Gaps at the centre seam. Caused by a flat sew order pushing fabric. Fixed by sequencing, not tension.
Design creeping up the crown. The design was placed without allowing for the rise, or it was simply too tall for the panel.
Puckering at the sides. Underlay too light for a structured front, or the design running too close to the curve.

3D puff on caps

If you want the logo raised off the hat, that is 3D puff, and it is a separate technique layered on top of every cap rule above. Foam sits under the stitches and the satin columns have to be wide enough to cover it with the ends sealed, or foam shows through.

Puff on a cap is the hardest common job in embroidery digitizing, because the curve, the buckram and the foam all compound. It is also the one where a properly built file is most obviously different from a converted one.

What to send

Tell your digitizer it is going on caps, and say which caps. Specifically:

The cap model or at least structured versus unstructured
The finished width you want
Whether it is flat or 3D puff
Your machine format

A file digitized for a cap and a shirt file pointed at a cap are different objects, and no amount of machine adjustment turns one into the other. If you want to see the difference, send us the cap logo that keeps coming back and we will digitize it for the frame. The first design is free, so you can judge it on your own machine.

Cap Digitizing: Why Hat Files Are Different and How to Get Them Right