Hobby use and small gifts: a single-head machine with a small frame is enough.
Custom studio: single-head, multi-needle machine. Automatic color change and thread trimming are the features that save real time.
Production: multi-head machine (4, 8, 12, 16 or more heads) sewing several garments at once.
One head sews one garment at a time; each additional head multiplies cost and floor space. If you are starting out, a single-head machine is a practical place to begin, and it remains useful later for sampling and small runs.
A multi-needle head holds several threads at once and changes color automatically - 6, 9, 12 or 15 needles are common configurations. Count the maximum colors in the designs you plan to sew, and choose a machine with enough needles to cover them, plus a little spare.
The embroidery area (frame size) decides the largest design you can sew in one hooping, so think about your biggest placement, not your average one:
Small logos and monograms: around 100 x 100 mm (4 x 4 in) is enough.
Shirt fronts and chest placements: 130 x 180 mm (5 x 7 in) covers most designs.
Garment backs, jacket motifs and larger placements: look for a 300 x 400 mm (12 x 16 in) frame or larger - this is the standard size on commercial single-head and multi-head machines.
A practical rule: buy the largest frame your common designs need. Smaller designs always fit within a larger frame, and it saves the cost of upgrading later.
If your product needs one of these, choose it from the start, because these features are difficult to add later:
Cap machines: frames built to hoop curved cap panels.
3D puff: raised foam embroidery for thick dimensional lettering.
Chenille (towelling) machines: round-head machines that sew with heavy yarn such as 300D rayon or 32S/2 wool for the raised, fluffy lettering on varsity jackets and hats.
Bring your own fabric and a design file, and test on the actual machine: sew at full speed, check stitch consistency and trimming, and listen to the noise level. Ask about training, spare parts and warranty.
Conclusion
Match the machine to your fabric, your colors, your design sizes and your volume, and always test-sew before you commit. In the next article we cover needles, threads and backing choices.