Factory Floor · All
Enamel Filling: By Hand and by Machine, One Color at a Time
From our Shenzhen factory floor: how enamel is mixed to Pantone, filled by syringe into each cell of a pin, baked and checked before the next color.
Enamel goes into a pin by hand or by machine, one cell at a time and one color at a time. Each color is baked before the next goes in. A five-color pin passes through this bench five times. This is the slowest stage of making a pin and the one where color accuracy is decided.
Color starts here. The Pantone number on your approved proof is matched by mixing enamel and testing it on a scrap blank, baked, then held against the swatch under the inspection light. Baked enamel is slightly deeper than wet enamel, so we match the baked chip, never the jar. For a reorder we match to the retained sample from the last batch.
Blanks come from the plating line already finished in gold, silver, black nickel or whatever was chosen. For soft enamel, the metal is done; the enamel just has to go in without touching the wall tops. For hard enamel, the blanks arrive unplated and the enamel is overfilled, to be ground flat later.
The syringe puts a bead of enamel into a cell. The operator moves it to the corners and levels it. Small cells take one touch; large cells take several passes to avoid a low spot in the middle. The bead must not climb the wall. If it does, it is wiped and the cell is refilled. This is where a design with very small cells slows down: the tip has to fit and the fill has to be even.
After each color, the tray goes into the oven. Baking sets the enamel hard and bonds it to the cell. Then the tray cools and goes back to the bench for the next color. Colors are usually filled lightest to darkest, so a stray touch of a light color can be covered, not the other way round. Glitter, glow-in-the-dark and transparent enamel are special mixes and are filled as their own pass.
After the last color, every pin is checked: fill level, color against the sample, enamel on the wall tops, bubbles, dust. A low fill or a color that is off goes back for a top-up and re-bake; a pin with enamel on the metal is cleaned or scrapped. The signed sample from proofing sits on the bench through the whole run.
The whole enamel process, soft and hard, is described on the custom enamel pins page. How we check color and fill is on the factory quality page.
Book a live video walk-through of the filling bench: email pin@guangdongcs.com or WhatsApp +86 187 1868 4696 (Bella, Export Sales).
Order Facts
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