A fixture for medals, coins and buttons should locate each part from stable datums, prevent rotation, maintain safe printhead clearance and allow repeat loading without damaging the finish. Good fixture design is measured by positional repeatability, loading speed, part protection and changeover control—not by how tightly a prototype can hold one object.

What Must the Fixture Control?

Control X-Y position, rotation, height and seating. Raised rims, recesses, domed faces, pins, clasps and thickness variation can change how a part rests. The fixture must also keep the printable face level and accessible to curing while avoiding contact with decorative surfaces.

The medal, coin and button collection frames the application family; each part geometry still needs its own datum review.

Choose Datums That Operators Can Repeat

A circular edge controls center but not rotation. Add a key feature, flat, notch, seam or secondary stop when artwork orientation matters. For a medal with a top loop, the loop may control rotation while the main outer diameter controls center. The fixture should make incorrect loading visibly difficult.

Clearance and Restraint

Design for the tallest allowed part plus measured variation and required safety margin. Restraint should prevent movement during carriage travel without bending pins, marking plating or covering the print zone. Vacuum alone may not control small, uneven or perforated parts; pockets and mechanical datums may be more repeatable.

Multi-Up Layout Without Creating New Risks

Balance part count with loading access, artwork mapping, fixture stiffness and inspection. Number every pocket and keep the same numbering in the artwork file and traveler. Position-specific defects can then be traced to a pocket rather than treated as random printer variation.

A Fixture Acceptance Test

1. Measure representative part variation.
2. Define primary and rotational datums.
3. Build and identify the prototype fixture.
4. Load every pocket repeatedly by different operators.
5. Print a positional target and compare results.
6. Test removal, surface protection and cleaning.
7. Record origin, pocket map, approved part range and service limit.

Published machine information is available on the AJ1206 product page. Final clearance and multi-up capacity require the actual objects and fixture.

Prototype and Changeover Checklist

• Fixture has a unique ID and revision.
• Approved part family and dimensional range are recorded.
• Every pocket is numbered in the same order as the artwork.
• Origin verification target is available.
• Cleaning method does not swell, warp or abrade the fixture.
• Maximum allowed wear or damage is defined.
• Storage protects locating surfaces.

Failure Patterns Reveal Fixture Problems

If every part shifts in the same direction, verify origin and fixture position. If one pocket repeatedly fails, inspect that pocket’s datum and seating. If rotation varies randomly, the fixture may control center without orientation. If image focus changes by part, measure height variation and debris under the parts before changing print settings.

These patterns should be recorded on the pocket map. Correcting the fixture is more reliable than adding artwork offsets for every recurring mechanical error.

Conclusion

A production fixture is a repeatability tool. Stable datums, controlled height, numbered pockets and a documented acceptance test turn small-object alignment from operator judgment into a measurable process.

FAQs

Is a round pocket enough for a coin?

It controls center but not rotation unless artwork is rotationally symmetric.

What fixture material should be used?

Select for stiffness, dimensional stability, cleanability, surface protection and compatibility with the production environment.

When should a fixture be revalidated?

After repair, wear, origin change, new part variation or any repeated position-specific defect.

Sources

1. Medal, Coin and Button Collection
2. AJ1206 Product Page